Method for Connecting Semiconductor Material and Semiconductor Device Used in Connecting Method

1. Field of the Invention

This invention relates to a method for connecting semiconductor material, and more particularly to a connecting method applied when a wireless bonding method, in particular a flip chip bonding method or a tape carrier bonding method are applied for bonding semiconductor tips to a substrate, such as a connection material to be used in the connection method and semiconductor devices manufactured by the above-mentioned connection method.

2. Description of the Prior Art

As the conventional system for forming a bump electrode by using a wire bonding machine, two Japanese publications are relevant; they are Japanese Patent Publication Nos. 61-43438 and 61-219159. In the prior art, after the bump electrode is bonded, the desired position of the wire is cut by an electrical discharge with an electric torch in order to make a specified size of the wire remaining in the ball.

The above-mentioned prior art involves a complicated processing step and has decreased work efficiency.

Other connecting methods are disclosed in Japanese Patent Publication No. 59-208751, wherein the wire is clamped with a clamper after the bonding operation and cut while being pulled up, i.e., a connecting method requiring no special cutting method is disclosed. However, as described in this publication, although a mere clamping and pulling up of the wire with a clamper enables the wire to be cut, it is impossible to keep the size of the wire remaining in the ball always constant, to perform a continuous stable bonding operation and to provide a semiconductor device having high reliability.

At present, as a bump electrode material, PbSn of 5 wt %, PbSn of 40 wt % or the like is used. However, it has been found that a connection of alloy wire made by drawing the alloy manufactured by a normal casting method through a die using a wire bonder operation requires frequent cutting of the wire not at the root part of the ball but at a midway part of the wire. This causes substantial variation in its length and as such the wire is not suitable as a bump electrode.

Cutting of the alloy wire at the wire part is caused by the fact that a tensile strength of the root part of the ball is not sufficiently low as compared with a tensile strength of the wire part.

Due to this reason, the conventional method described in Japanese Patent Publication No. 59-208751 can not always keep the size of wire remaining in the ball constant.

It is an object of the present invention to provide a connection method for semiconductor material and a connection material to be used in the connection method in which a bump electrode can be formed by using a wire bonder. The method is performed in a way such that the cutting position of the wire is always kept constant and a continuously workable and stable bonding operation are performed.

Another object of the present invention is to provide a less expensive semiconductor device having a high reliability which is manufactured by the above-mentioned connecting method.

A connecting method of the present invention as described above is characterized in that any one of Pb, Sn and In is applied as a major element. An end of a fine alloy wire, manufactured by a rapid cooling and condensation method, is heated to form a ball part. The alloy metal is then tensioned while the ball is adhered to the upper surface of a line or the upper surface of a semiconductor material. The ball is then cut at its root part to form a bump electrode on the upper surface of the line or the upper surface of the semiconductor material and the semiconductor material is connected through the bump electrode.

The connection material of the present invention is characterized in that any one of Pb, Sn and In is applied as a major element and an alloy having an additional element added to the major element is made as a fine wire through a rapid cooling and condensation method.

The semiconductor device of the present invention is characterized in that a semiconductor material in a main body of the semiconductor device is electrically connected to a lead wire through a bump electrode supplied from a fine alloy wire manufactured through a rapid cooling and condensation method. According to the present invention, the alloy wire shows a remarkably high tensile strength through structure introducing many defected grids, making fine crystal particles, generating a non-balanced phase, and showing a forced solid solution between elements.

As discussed above, when the end of the alloy wire is heated to form a ball, the non-balanced phase is diminished at a root part of the ball. The forced solid solution formed between the elements is then released, whereby the defected grids are released and the crystal particles are increased in their size to decrease a tensile strength of the root part of the ball. This may cause breakage at that portion being treated.

In view of the foregoing, the ball is cut off from the root part by pulling the wire. The bump electrode is then formed on the upper surface of the semiconductor material or the upper surface of the line from the ball cut from the wire. Thus, according to the present invention, since the ball is supplied from the alloy wire by using a wire bonder and the bump electrode can be formed, a cutting step between the wire and the ball by using an electrical torch is eliminated to simplify the working step. At the same time, a ball cutting position is provided whereby the accuracy of the bump supplying position is improved due to the wire bonder so as to improve reliability of the product. Further, by using an alloy wire made of soldering material having as its major element Pb, Sn and In, this eliminates the need for other connecting materials causing reduced workability and cost of the product.

FIGS. 1 to 5 are sectional views for illustrating a connecting method for a semiconductor material with a flip chip bonding method (preferred embodiment I) and a connecting material to be used in the connecting method.

FIGS. 6 to 10 are sectional views for illustrating a connecting method for semiconductor material through a tape carrier bonding method (preferred embodiment II) and the connecting material to be used in the connecting method.

FIG. 11 is a sectional view for showing a semiconductor device of the preferred embodiment (I).

FIG. 12 is a sectional view for showing a semiconductor device of the preferred embodiment II.

FIGS. 1 to 5 and FIG. 11 illustrate one preferred embodiment of the present invention, wherein a semiconductor device (A) to be used in the preferred embodiment is, as shown in FIG. 11, as a so-called flip chip bonding type. A substrate (1) is formed by an alumina or insulating resin such as glass epoxy resin or the like. The upper surface of the substrate (1) is provided with a wiring (2) comprised of electrical conductive material such as Cu or Cr.Cu or Pt or Pd or Ag or Pd.Ag or Au or Al or Ni or the like. At the same time a central part of the substrate (1) is provided with a chip (3) acting as a semiconductor material which is electrically connected with wiring (2) through bump electrodes (7a).

The semiconductor chip (3) and a part of wiring (2) are sealed by a protective resin such as silicon or the like. FIGS. 1 to 5 are sectional views for showing a connecting method of the present invention for a semiconductor material in the semiconductor device (A).

FIG. 1 illustrates an alloy wire (5) acting as a connection material which is inserted into a capillary tube (4) of a wire bonder and an extremity end of the alloy wire is heated by an electrical torch (6) to form a ball (7). The alloy wire (5) is an alloy in which any one of soldering materials such as Pb, Sn and In is applied as a major element and additional elements are mixed with it; further, this is a fine wire made under a rapid cooling and condensation method. That is, as the rapid cooling and condensation method, a wire is directly formed through a so-called liquid spinning method or an alloy material passed through a single rolling method which is cold pressed and pushed to form a wire. The alloy wire (5) is made by drawing the wire so as to make the desired fine wire diameter.

As additional elements for inclusion in the alloy wire (5), one may include at least one element of Be, B, C, Mg, Al, Si, P, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Se, Zr, Nb, Mo, Pd, Ag, Cd, Sb, Te, Ir, Pt, Au, Tl and Bi. These are mixed to each other and the major elements, such as Pb, Sn and In. They may be added to the major element not containing these elements.

Preferred alloy materials include the following:

1) alloy material comprised of Sn of 10 wt %, Cu of 0.9 wt % and a balance of Pb.

2) alloy material comprised of Pb-Ag-Cu with Ag of 3 wt %, Cu of 0.9 wt % and a balance of Pb.

3) alloy material comprised of Pb-Sn-Ag-Cu with Sn of 0.3 to 50 wt %, Ag of 0.5 to 10 wt %, Cu of 0.1 to 0.9 wt % and a balance of Pb.

4) alloy material comprised of Pb-Sn-Ag-Cu with Sn of 0.3 to 5 wt %, Ag of 0.5 to 5 wt %, Cu of 0.1 to 0.9 wt % and a balance of Pb.

5) alloy material comprised of Pb-Sn-Cr-Cu with Sn of 0.5 to 2 wt %, Cr of 3 wt %, Cu of 0.9 wt % and a balance of Pb.

6) alloy material comprised of Pb-Sn-Ag-Ni with Sn of 0.5 to 5 wt %, Ag of 2 to 5 wt %, Ni of 0.1 to 5 wt % and a balance of Pb.

7) alloy material comprised of Pb-Sn-Sb with Sn of 1 to 50 wt %, Sb of 1 to 8 wt %, and a balance of Pb.

8) alloy material comprised of Pb-Sn-Sb-Ag with Sn of 1 to 50 wt %, Sb of 1 to 8 wt %, Ag of 2 to 10 wt % and a balance of Pb.

9) alloy material comprised of Pb-Sn-Sb-Ag with Sn of 1 to 5 wt %, Sb of 1 to 8 wt %, Ag of 2 to 5 wt % and a balance of Pb.

10) alloy material comprised of Pb-Sn-Ag-Cu-Sb with Sn of 1 to 50 wt %, Ag of 2 to 10 wt %, Cu of 0.1 to 0.9 wt %, Sb of 1 to 8 wt % and a balance of Pb.

11) alloy material comprised of Pb-Sn-Ag-Cu-Sb with Sn of 1 to 5 wt %, Ag of 2 to 5 wt %, Cu of 0.1 to 0.9 wt %, Sb of 1 to 8 wt % and a balance of Pb.

12) alloy material comprised of Pb-In-Au with In of 5 to 50 wt %, Au of 0.1 to 5 wt % and a balance of Pb.

13) alloy material comprised of Pb-In-Ag with In of 5 to 50 wt %, Ag of 0.1 to 5 wt % and a balance of Pb.

14) alloy material comprised of Pb-In-Cu with In of 5 to 50 wt %, Cu of 0.1 to 5 wt % and a balance of Pb.

15) alloy material comprised of Sn-Sb-Au-Ag with Sb of 1 to 3 wt %, Au of 1 wt %, Ag of 3 wt % and a balance of Sn.

16) alloy material comprised of Sn-Pb-Au-Ag with Pb of 1 to 3 wt %, Au of 1 wt %, Ag of 3 wt % and a balance of Sn.

17) alloy material comprised of Sn-Sb-Pb with Sb of 1 to 8 wt % , Pb of 35 to 50 wt % and a balance of Sn.

18) alloy material comprised of Sn-Sb-Pb-Ag with Sb of 1 to 8 wt %, Pb of 35 to 50 wt %, Ag of 2 to 10 wt % and a balance of Sn.

19) alloy material comprised of Sn-Sb-Pb-Ag-Cu with Sb of 1 to 8 wt %, Pb of 35 to 50 wt %, Ag of 2 to 10 wt %, Cu of 0.1 to 0.9 wt % and a balance of Sn.

20) alloy material comprised of Sn-Pb-Ag-Cu with Pb of 35 to 50 wt %, Ag of 0.5 to 10 wt %, Cu of 0.1 to 0.9 wt % and a balance of Sn.

21) alloy material comprised of In-Sn-Au-Ag with Sn of 1 to 2 wt %, Au of 1 wt %, Ag of 2 wt % and a balance of In.

22) alloy material of Pb-Sn-Au-Sb-Cu comprised of Sn of 2 to 50 wt %, Au of 0.001 to 0.5 wt %, Sb of 0.01 to 5 wt %, Cu of 0.01 to 1.5 wt % and a balance of Pb.

23) alloy material of Sn-Pb-Au-Sb-Cu comprised of Pb of 40 to 50 wt %, Au of 0.001 to 0.5 wt %, Sb of 0.01 to 5 wt %, Cu of 0.01 to 1.5 wt % and a balance of Sn.

The alloy wire (5) shows a structural state under the above-mentioned rapid cooling process in which grid defects are generated therein, crystal particles are made fine particles, a non-balanced phase is generated and a forced solid solution between the elements to each other is obtained. Further, the alloy wire shows another structural state under the wire drawing work in which grid defects are made as a machine hardening is generated and a solid solution, hardened state, is made by the additional elements.

As shown in FIGS. 2 and 3, capillary tube (4) is pulled up while ball (7) is formed at the end of alloy wire (5) which is attached to wiring (2) by descending capillary tube (4). When ball (7) is cut at its root part from alloy wire (5), the ball (7) is supplied onto the wiring (2) so as to form a bump electrode (7a).

The bump electrode (7a) can be continuously formed on an entire wiring (2) on the upper surface of the substrate (1) with such a method as described herein.

The cutting step of alloy wire (5) is performed in such a way so that the above-mentioned non-balanced phase is diminished at the root part of ball (7). When ball (7) is heated and formed, a forced solid solution between the elements is released, grid defects are released, and the crystal particles show roughly enlarged structural state, so that the tensile strength at that portion is decreased. A mere pulling-up of the alloy wire (5) through the capillary tube (4) causes the ball (7) to be stressed and broken at its root part.

As shown in FIG. 4, bump electrodes (7a) are supplied and adhered to the upper surfaces of wires (2) and adhered to electrodes (3a) arranged at the surface of the semiconductor chip (3). The wires (2) and the electrodes (3a) are electrically connected to each other and at the same time the semiconductor chip (3) is fixed to it.

As shown in FIG. 5, in order to make a mechanically rigid coupling having a low electrical resistance between the wires (2) and the bump electrodes (7a) or between the bump electrodes (7a) and the electrodes (3a) at the surface of the semiconductor tip, ground metallic layers (3b, 3c) are formed by standard vapor depositing process, sputtering process, a plating process or the like. For example, if the electrode (3a) material of the semiconductor tip is Al, a single layer or piled layer surface having Cr or Ti or Cu or Ni or Pd or Ag or Pt or Au or the like is formed on the ground metallic layer (3b). In a preferred embodiment, ball (7) is adhered onto the wires (2) in order to form the bump electrodes (7a) on the wires (2). It is also possible to adhere ball (7) onto electrode (3a) in order to form the bump electrode (7a) on the electrode (3a) of the semiconductor chip (3).

FIGS. 6 to 10 and FIG. 12 illustrate another preferred embodiment of the present invention, wherein a semiconductor device (B) to be used in the preferred embodiment is a so-called tape carrier bonding type as shown in FIG. 12. A bump electrode (7a) is formed on the electrode (3a) of chip (3) acting as the semiconductor material, a film lead (10) is connected to the bump electrode, and wire (8) on the substrate (9) and film lead (10) are connected to each other.

FIGS. 6 to 10 are sectional views for showing a connecting method for a semiconductor material according to the present invention in the semiconductor device (B).

FIG. 6 shows the same step as found in the previous preferred embodiment, wherein an alloy wire (5) acting as a connection material to be inserted into capillary tube (4) of the wire bonder is shown, and the end of the alloy wire is heated by an electrical torch (6) to form the ball (7). The alloy wire (5) is made of the same connection material as that of the previous preferred embodiment and for the sake of clarity in description, its description is eliminated.

As shown in FIGS. 7 and 8, the capillary tube (4) is descended and then the capillary tube (4) is pulled up while the ball (7) formed at the end of the alloy wire (5) is attached to the film lead (10). The ball (7) is then cut at its root part from the alloy wire (5), wherein the ball (7) is supplied onto the film lead (10) so as to form the bump electrode (7a).

In such a method as above, the bump electrode (7a) is continuously formed in an entire film lead (10) and the cutting of the alloy wire (5) is performed in the same manner as that of the previous preferred embodiment in which a mere pulling-up of the alloy wire (5) with the capillary tube (4) causes the ball (7) to be cut at its root part.

As shown in FIG. 9, the bump electrode (7a) supplied and adhered onto the upper surface of the film lead (10) is adhered to the electrode (3a) and arranged on the surface of the semiconductor chip (3), thereby the film lead (10) and the electrode (3a) are electrically connected to each other and at the same time the semiconductor chip (3) is fixed.

As shown in FIG. 10, in order to make an electrically low resistant and mechanically rigid connection between the film lead (10) and the bump electrode (7a) or the bump electrode (7a) and the electrode (3a) at the surface of the semiconductor chip, the ground metallic layers (3b, 3c) which may easily form the alloy with these materials are formed with a vapor depositing method, sputtering method, a plating method or the like. In the preferred embodiment, in order to form the bump electrode (7a) on the film lead (10), the ball (7) is adhered onto the film lead (10) and in turn it is also possible to adhere the ball (7) onto the electrode (3a) in order to form the bump electrode (7a) on the electrode (3a) of the semiconductor chip (3).

Preferred features of the present invention will now be described together with a comparison product made by the conventional manufacturing method.

A cooling speed of the alloy wire according to the present invention at its rapid cooling and condensation time is 10.sup.3 .degree. to 10.sup.5 .degree. C./sec and both the worked product of the present invention and the wire of the comparison product had a wire diameter of 60 um.sup..phi., respectively.

The workability in the above-mentioned characteristics of the test piece was compared by the following two steps, namely whether an elongation work can be performed or not without heat treatment up to 60 um.sup..phi.. That is, an evaluation with a circle mark shows a workability and another evaluation with an x-mark shows a certain problem in workability such as a frequent cutting of the wire or the like.

The ball forming capability evaluates the ball forming circumstance with the following two steps in which each of the test pieces is passed through a capillary tube of ceramics. The ball is formed under an arc discharge between the electrode arranged near the end of the test piece and the test piece under injection of gas added with hydrogen gas of 5 vol % to argon gas. That is, the evaluation with a circle mark shows a formation of ball having a superior degree of sphere and a smooth surface and an evaluation with an x-mark shows a ball having a poor degree of sphere, a high degree of disturbance and a poor surface shape. Results are set forth in the following Table. - Worked Product of the Present Invention Comparison Product Ball Ball Ball Ball Kind of Test Forming Tensile Elong- Hard- Cutting at Forming Tensile Elong- Hard- Cutting at Piece Work- Charac- Strength ation ness the Root Work- Charac- Strength ation ness the Root (wt. %) ability teristic (kg/mm.sup.2) (%) (Hv) of Ball ability teristic (kg/mm.sup.2) (%) (Hv) of Ball PbSn.sup.10 Cu.sup.0.9 .largecircle. .largecircle. 3.4 28 10 Available X .largecircle. 2.4 40 10 Not Available PbAg.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 10.9 1.5 9 Available .largecircle. .largecircle. 3.0 38 9 not Available PbSn.sup.0.3 Ag.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 9.8 1.7 9 Available .largecircle. .largecircle. 3.1 37 9 Not Available PbSn.sup.0.5 Ag.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 9.0 2.0 9 Available .largecircle. .largecircle. 3.1 37 9 Not Available PbSn.sup.0.7 Ag.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 8.5 2.2 9 Available .largecircle. .largecircle. 3.2 36 9 Not Available PbSn.sup.1 Ag.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 7.3 2.5 9 Available .largecircle. .largecircle. 3.3 35 9 Not Available PbSn.sup.2 Ag.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 5.6 3.0 9 Available .largecircle. .largecircle. 3.7 32 9 Not Available PbSn.sup.5 Ag.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 4.9 7.5 10 Available .largecircle. .largecircle. 4.0 30 10 Not Available PbSn.sup.0.5 Ag.sup.0.5 Cu.sup.0.9 .largecircle. .largecircle. 5.0 1.5 9 Available X .largecircle. 2.5 39 9 Not Available PbSn.sup.0.5 Ag.sup.1 Cu.sup.0.9 .largecircle. .largecircle. 6.3 1.0 9 Available X .largecircle. 2.8 38 9 Not Available PbSn.sup.0.5 Ag.sup.2 Cu.sup.0.9 .largecircle. .largecircle. 7.5 1.3 9 Available .largecircle. .largecircle. 3.1 35 9 Not Available PbSn.sup.0.5 Ag.sup.4 Cu.sup.0.9 .largecircle. .largecircle. 8.5 1.8 9 Available .largecircle. .largecircle. 3.2 36 9 Not Available PbSn.sup.0.5 Ag.sup.5 Cu.sup.0.9 .largecircle. .largecircle. 8.0 3.5 10 Available .largecircle. .largecircle. 3.3 36 10 Not Available PbSn.sup.1 Ag.sup.0.5 Cu.sup.0.9 .largecircle. .largecircle. 4.0 1.8 9 Avaiable X .largecircle. 2.3 40 9 Not Available PbSn.sup.1 Ag.sup.1 Cu.sup.0.9 .largecircle. .largecircle. 5.1 1.3 9 Available X .largecircle. 2.7 39 9 Not Available PbSn.sup.1 Ag.sup.2 Cu.sup.0.9 .largecircle. .largecircle. 7.0 1.6 9 Available .largecircle. .largecircle. 3.1 35 9 Not Available PbSn.sup.1 Ag.sup.4 Cu.sup.0.9 .largecircle. .largecircle. 7.5 2.1 9 Available .largecircle. .largecircle. 3.2 36 9 Not Available PbSn.sup.1 Ag.sup.5 Cu.sup.0.9 .largecircle. .largecircle. 7.3 3.9 10 Available .largecircle. .largecircle. 3.3 36 10 Not Available PbSn.sup.0.5 Ag.sup.3 Cu.sup.0.1 .largecircle. .largecircle. 12.5 1.5 9 Available .largecircle. .largecircle. 3.1 35 9 Not Available PbSn.sup.0.5 Ag.sup.3 Cu.sup.0.2 .largecircle. .largecircle. 9.5 0.8 9 Available .largecircle. .largecircle. 3.1 35 9 Not Available PbSn.sup.0.5 Ag.sup.3 Cu.sup.0.4 .largecircle. .largecircle. 8.5 1.5 9 Available .largecircle. .largecircle. 3.1 34 9 Not Available PbSn.sup.1 Ag.sup.3 Cu.sup.0.1 .largecircle. .largecircle. 11.5 1.7 9 Available .largecircle. .largecircle. 3.2 35 9 Not Available PbSn.sup.1 Ag.sup.3 Cu.sup.0.2 .largecircle. .largecircle. 9.0 1.0 9 Available .largecircle. .largecircle. 3.2 35 9 Not Available PbSn.sup.1 Ag.sup.3 Cu.sup.0.4 .largecircle. .largecircle. 8.0 1.8 9 Available .largecircle. .largecircle. 3.2 34 9 Not Available PbSn.sup.0.5 Cr.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 9.9 1.6 9 Available .largecircle. .largecircle. 3.0 37 9 Not Available PbSn.sup.0.7 Cr.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 9.7 1.8 9 Available .largecircle. .largecircle. 3.1 37 9 Not Available PbSn.sup.1 Cr.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 9.1 2.0 9 Available .largecircle. .largecircle. 3.2 36 9 Not Available PbSn.sup.2 Cr.sup.3 Cu.sup.0.9 .largecircle. .largecircle. 8.7 2.5 9 Available .largecircle. .largecircle. 3.6 32 9 Not Available PbSn.sup.0.5 Ag.sup.3 Ni.sup.0.1 .largecircle. .largecircle. 13.0 1.5 9 Available .largecircle. .largecircle. 3.1 35 9 Not Available PbSn.sup.0.5 Ag.sup.3 Ni.sup.0.5 .largecircle. .largecircle. 7.0 1.6 9 Available .largecircle. .largecircle. 3.3 34 9 Not Available PbSn.sup.0.5 Ag.sup.3 Ni.sup.1 .largecircle. .largecircle. 6.5 1.7 9 Available .largecircle. .largecircle. 3.5 33 9 Not Available PbSn.sup.0.5 Ag.sup.3 Ni.sup.2 .largecircle. .largecircle. 6.4 1.7 10 Available .largecircle. .largecircle. 4.3 33 10 Not Available PbSn.sup.0.5 Ag.sup.3 Ni.sup.5 .largecircle. .largecircle. 6.3 2.0 11 Available .largecircle. .largecircle. 5.0 32 11 Not Available PbSn.sup.1 Ag.sup.3 Ni.sup.0.1 .largecircle. .largecircle. 12.5 1.6 9 Available .largecircle. .largecircle. 3.2 35 9 Not Available PbSn.sup.1 Ag.sup.3 Ni.sup.0.5 .largecircle. .largecircle. 6.5 1.7 9 Available .largecircle. .largecircle. 3.4 34 9 Not Available PbSn.sup.1 Ag.sup.3 Ni.sup.1 .largecircle. .largecircle. 5.9 1.8 9 Available .largecircle. .largecircle. 3.6 33 9 Not Available PbSn.sup.1 Ag.sup.3 Ni.sup.2 .largecircle. .largecircle. 5.9 2.0 10 Available .largecircle. .largecircle. 4.5 33 10 Not Available PbSn.sup.1 Ag.sup.3 Ni.sup.5 .largecircle. .largecircle. 5.8 2.3 11 Available .largecircle. .largecircle. 4.9 32 11 Not Available PbSn.sup.5 Ag.sup.2 Ni.sup.0.1 .largecircle. .largecircle. 6.7 4.0 10 Available .largecircle. .largecircle. 4.2 34 10 Not Available PbSn.sup.5 Ag.sup.5 Ni.sup.5 .largecircle. .largecircle. 5.5 7.3 11 Available .largecircle. .largecircle. 5.0 30 10 Not Available PbSn.sup.1 Sb.sup.1 .largecircle. .largecircle. 9.1 1.5 10 Available .largecircle. .largecircle. 3.0 22 10 Not Available PbSn.sup.1 Sb.sup.3 .largecircle. .largecircle. 9.5 1.5 10 Available .largecircle. .largecircle. 3.5 20 10 Not Available PbSn.sup.1 Sb.sup.5 .largecircle. .largecircle. 9.8 1.6 10 Available .largecircle. .largecircle. 3.7 19 10 Not Available PbSn.sup.3 Sb.sup.3 .largecircle. .largecircle. 8.3 2.2 10 Available .largecircle. .largecircle. 3.8 18 10 Not Available PbSn.sup.3 Sb.sup.5 .largecircle. .largecircle. 8.6 1.9 11 Available .largecircle. .largecircle. 4.0 17 11 Not Available PbSn.sup.5 Sb.sup.1 .largecircle. .largecircle. 7.6 2.9 11 Available .largecircle. .largecircle. 3.5 15 11 Not Available PbSn.sup.5 Sb.sup.3 .largecircle. .largecircle. 7.8 2.9 11 Available .largecircle. .largecircle. 4.1 14 11 Not Available PbSn.sup.5 Sb.sup.5 .largecircle. .largecircle. 8.2 2.7 11 Available .largecircle. .largecircle. 4.2 13 11 Not Available PbSn.sup.10 Sb.sup.3 .largecircle. .largecircle. 6.4 3.6 12 Available .largecircle. .largecircle. 4.7 16 12 Not Available PbSn.sup.10 Sb.sup.5 .largecircle. .largecircle. 6.8 3.7 12 Available .largecircle. .largecircle. 4.8 15 12 Not Available PbSn.sup.30 Sb.sup.5 .largecircle. .largecircle. 6.3 4.9 14 Available .largecircle. .largecircle. 4.9 20 14 Not Available PbSn.sup.30 Sb.sup.8 .largecircle. .largecircle. 6.5 4.8 14 Available .largecircle. .largecircle. 5.0 19 14 Not Available PbSn.sup.50 Sb.sup.5 .largecircle. .largecircle. 6.1 5.6 15 Available .largecircle. .largecircle. 5.3 30 15 Not Available PbSn.sup.50 Sb.sup.8 .largecircle. .largecircle. 6.6 5.8 15 Available .largecircle. .largecircle. 5.4 28 15 Not Available PbSn.sup.1 Sb.sup.1 Ag.sup.2 .largecircle. .largecircle. 9.4 1.6 10 Available .largecircle. .largecircle. 3.2 21 10 Not Available PbSn.sup.1 Sb.sup.5 Ag.sup.3 .largecircle. .largecircle. 10.0 1.5 10 Available .largecircle. .largecircle. 3.8 21 10 Not Available PbSn.sup.1 Sb.sup.8 Ag.sup.10 .largecircle. .largecircle. 10.5 1.5 11 Available .largecircle. .largecircle. 4.2 18 11 Not Available PbSn.sup.3 Sb.sup.5 Ag.sup.3 .largecircle. .largecircle. 9.0 1.8 10 Available .largecircle. .largecircle. 4.0 20 10 Not Available PbSn.sup.5 Sb.sup.5 Ag.sup.3 .largecircle. .largecircle. 8.1 2.5 11 Available .largecircle. .largecircle. 4.2 20 11 Not Available PbSn.sup.10 Sb.sup.5 Ag.sup.3 .largecircle. .largecircle. 6.8 3.5 12 Available .largecircle. .largecircle. 4.7 18 12 Not Available PbSn.sup.30 Sb.sup.5 Ag.sup.3 .largecircle. .largecircle. 6.7 4.9 14 Available .largecircle. .largecircle. 5.0 20 14 Not Available PbSn.sup.50 Sb.sup.5 Ag.sup.3 .largecircle. .largecircle. 6.7 6.0 15 Available .largecircle. .largecircle. 5.4 30 15 Not Available PbSn.sup.1 Ag.sup.2 Cu.sup.0.9 Sb.sup.1 .largecircle. .largecircle. 7.3 2.8 10 Available .largecircle. .largecircle. 3.3 23 10 Not Available PbSn.sup.1 Ag.sup.3 Cu.sup.0.1 Sb.sup.1 .largecircle. .largecircle. 7.6 2.7 10 Available .largecircle. .largecircle. 3.5 21 10 Not Available PbSn.sup.1 Ag.sup.3 Cu.sup.0.1 Sb.sup.3 .largecircle. .largecircle. 8.5 2.5 10 Available .largecircle. .largecircle. 3.6 20 10 Not Available PbSn.sup.1 Ag.sup.3 Cu.sup.0.1 Sb.sup.5 .largecircle. .largecircle. 8.8 2.7 11 Available .largecircle. .largecircle. 3.8 20 11 Not Available PbSn.sup.1 Ag.sup.3 Cu.sup.0.1 Sb.sup.8 .largecircle. .largecircle. 9.1 2.8 12 Available .largecircle. .largecircle. 3.9 19 12 Not Available PbSn.sup.1 Ag.sup.10 Cu.sup.0.9 Sb.sup.8 .largecircle. .largecircle. 9.5 2.5 13 Available .largecircle. .largecircle. 4.2 19 13 Not Available PbSn.sup.3 Ag.sup.3 Cu.sup.0.1 Sb.sup.1 .largecircle. .largecircle. 6.6 2.1 10 Available .largecircle. .largecircle. 3.8 22 10 Not Available PbSn.sup.3 Ag.sup.3 Cu.sup.0.1 Sb.sup.3 .largecircle. .largecircle. 8.1 2.3 11 Available .largecircle. .largecircle. 3.9 22 11 Not Available PbSn.sup.3 Ag.sup.3 Cu.sup.0.1 Sb.sup.5 .largecircle. .largecircle. 8.3 3.2 11 Available .largecircle. .largecircle. 4.0 20 11 Not Available PbSn.sup.3 Ag.sup.3 Cu.sup.0.1 Sb.sup.8 .largecircle. .largecircle. 8.6 3.4 12 Available .largecircle. .largecircle. 4.2 19 12 Not Available PbSn.sup.5 Ag.sup.3 Cu.sup.0.1 Sb.sup.1 .largecircle. .largecircle. 7.1 3.0 11 Available .largecircle. .largecircle. 3.9 22 11 Not Available PbSn.sup.5 Ag.sup.3 Cu.sup.0.1 Sb.sup.3 .largecircle. .largecircle. 7.7 3.9 11 Available .largecircle. .largecircle. 4.1 21 11 Not Available PbSn.sup.5 Ag.sup.3 Cu.sup.0.1 Sb.sup.5 .largecircle. .largecircle. 8.0 4.0 12 Available .largecircle. .largecircle. 4.2 20 12 Not Available PbSn.sup.5 Ag.sup.3 Cu.sup.0.1 Sb.sup.8 .largecircle. .largecircle. 8.4 4.2 12 Available .largecircle. .largecircle. 4.4 19 12 Not Available PbSn.sup.10 Ag.sup.3 Cu.sup.0.1 Sb.sup.5 .largecircle. .largecircle. 6.5 4.9 12 Available .largecircle. .largecircle. 4.7 19 12 Not Available PbSn.sup.30 Ag.sup.2 Cu.sup.0.9 Sb.sup.1 .largecircle. .largecircle. 6.0 6.0 14 Available .largecircle. .largecircle. 4.8 20 14 Not Available PbSn.sup.30 Ag.sup.3 Cu.sup.0.1 Sb.sup.5 .largecircle. .largecircle. 6.4 5.5 14 Available .largecircle. .largecircle. 5.0 21 14 Not Available PbSn.sup.30 Ag.sup.10 Cu.sup.0.9 Sb.sup.8 .largecircle. .largecircle. 7.0 5.3 15 Available .largecircle. .largecircle. 5.4 21 15 Not Available PbIn.sup.5 Au.sup.0.1 .largecircle. .largecircle. 6.1 2.0 10 Available X .largecircle. 2.7 51 10 Not Available PbIn.sup.5 Au.sup.1 .largecircle. .largecircle. 6.5 1.6 10 Available .largecircle. .largecircle. 3.0 50 10 Not Available PbIn.sup.5 Au.sup.2 .largecircle. .largecircle. 6.9 1.5 10 Available .largecircle. .largecircle. 3.3 48 10 Not Available PbIn.sup.5 Au.sup.5 .largecircle. .largecircle. 7.4 1.6 10 Available .largecircle. .largecircle. 3.5 48 10 Not Available PbIn.sup.10 Au.sup.0.1 .largecircle. .largecircle. 6.5 2.0 10 Available .largecircle. .largecircle. 3.2 47 10 Not Available PbIn.sup.10 Au.sup.1 .largecircle. .largecircle. 7.0 1.8 10 Available .largecircle. .largecircle. 3.4 46 10 Not Available PbIn.sup.10 Au.sup.2 .largecircle. .largecircle. 7.3 1.7 11 Available .largecircle. .largecircle. 3.5 45 11 Not Available PbIn.sup.10 Au.sup.5 .largecircle. .largecircle. 7.6 1.5 11 Available .largecircle. .largecircle. 3.7 45 11 Not Available PbIn.sup.12 Au.sup.4 .largecircle. .largecircle. 7.8 1.4 11 Available .largecircle. .largecircle. 3.9 41 11 Not Available PbIn.sup.30 Au.sup.5 .largecircle. .largecircle. 8.0 1.5 13 Available .largecircle. .largecircle. 4.9 40 13 Not Available PbIn.sup.50 Au.sup.5 .largecircle. .largecircle. 8.5 3.0 15 Available .largecircle. .largecircle. 4.7 43 15 Not Available PbIn.sup.5 Ag.sup.0.1 .largecircle. .largecircle. 5.8 2.0 10 Available X .largecircle. 2.8 50 10 Not Available PbIn.sup.5 Ag.sup.1 .largecircle. .largecircle. 6.3 1.7 10 Available .largecircle. .largecircle. 3.1 49 10 Not Available PbIn.sup.5 Ag.sup.2 .largecircle. .largecircle. 6.5 1.6 10 Available .largecircle. .largecircle. 3.2 48 10 Not Available PbIn.sup.5 Ag.sup.5 .largecircle. .largecircle. 6.9 1.5 10 Available .largecircle. .largecircle. 3.3 47 10 Not Available PbIn.sup.10 Ag.sup.0.1 .largecircle. .largecircle. 6.1 1.9 10 Available .largecircle. .largecircle. 3.3 45 10 Not Available PbIn.sup.10 Ag.sup.1 .largecircle. .largecircle. 6.6 2.0 11 Available .largecircle. .largecircle. 3.4 43 11 Not Available PbIn.sup.10 Ag.sup.2 .largecircle. .largecircle. 6.9 2.0 11 Available .largecircle. .largecircle. 3.6 42 11 Not Available PbIn.sup.10 Ag.sup.5 .largecircle. .largecircle. 7.2 1.9 11 Available .largecircle. .largecircle. 3.9 41 11 Not Available PbIn.sup.30 Ag.sup.5 .largecircle. .largecircle. 7.5 2.1 13 Available .largecircle. .largecircle. 4.5 40 13 Not Available PbIn.sup.50 Ag.sup.5 .largecircle. .largecircle. 8.0 3.0 15 Available .largecircle. .largecircle. 4.1 41 15 Not Available PbIn.sup.5 Cu.sup.0.1 .largecircle. .largecircle. 5.5 2.0 10 Available X .largecircle. 2.7 50 10 Not Available PbIn.sup.5 Cu.sup.1 .largecircle. .largecircle. 6.0 1.9 10 Available .largecircle. .largecircle. 3.0 47 10 Not Available PbIn.sup.5 Cu.sup.2 .largecircle. .largecircle. 6.4 1.5 10 Available .largecircle. .largecircle. 3.3 47 10 Not Available PbIn.sup.5 Cu.sup.5 .largecircle. .largecircle. 7.0 1.6 10 Available .largecircle. .largecircle. 3.5 45 10 Not Available PbIn.sup.10 Cu.sup.0.1 .largecircle. .largecircle. 5.9 1.9 10 Available .largecircle. .largecircle. 3.4 47 10 Not Available PbIn.sup.10 Cu.sup.1 .largecircle. .largecircle. 6.4 1.8 11 Available .largecircle. .largecircle. 3.6 46 11 Not Available PbIn.sup.10 Cu.sup.2 .largecircle. .largecircle. 6.8 1.8 11 Available .largecircle. .largecircle. 3.9 44 11 Not Available PbIn.sup.10 Cu.sup.5 .largecircle. .largecircle. 7.5 1.7 11 Available .largecircle. .largecircle. 4.3 43 11 Not Available PbIn.sup.30 Cu.sup.5 .largecircle. .largecircle. 8.3 2.0 13 Available .largecircle. .largecircle. 5.1 40 13 Not Available PbIn.sup.50 Cu.sup.5 .largecircle. .largecircle. 8.9 2.2 15 Available .largecircle. .largecircle. 4.9 41 15 Not Available SnSb.sup.1 Au.sup.1 Ag.sup.3 .largecircle. .largecircle. 9.5 1.0 10 Available X .largecircle. 2.8 40 10 Not Available SnSb.sup.2 Au.sup.1 Ag.sup.3 .largecircle. .largecircle. 8.1 2.5 11 Available .largecircle. .largecircle. 3.1 35 11 Not Available SnSb.sup.3 Au.sup.1 Ag.sup.3 .largecircle. .largecircle. 7.0 5.0 11 Available .largecircle. .largecircle. 4.0 30 11 Not Available SnPb.sup.1 Au.sup.1 Ag.sup.3 .largecircle. .largecircle. 9.0 1.0 10 Available .largecircle. .largecircle. 3.0 39 10 Not Available SnPb.sup.2 Au.sup.1 Ag.sup.3 .largecircle. .largecircle. 7.8 2.0 10 Available .largecircle. .largecircle. 3.3 34 10 Not Available SnPb.sup.3 Au.sup.1 Ag.sup.3 .largecircle. .largecircle. 6.9 5.1 11 Available .largecircle. .largecircle. 4.2 29 11 Not Available SnSb.sup.1 Pb.sup.35 .largecircle. .largecircle. 10.1 1.1 12 Available .largecircle. .largecircle. 5.4 20 12 Not Available SnSb.sup.8 Pb.sup.35 .largecircle. .largecircle. 8.1 2.6 16 Available .largecircle. .largecircle. 6.6 10 16 Not Available SnSb.sup.1 Pb.sup.40 .largecircle. .largecircle. 10.0 1.0 12 Available .largecircle. .largecircle. 5.5 20 12 Not Available SnSb.sup.5 Pb.sup.40 .largecircle. .largecircle. 9.1 1.5 14 Available .largecircle. .largecircle. 6.3 12 14 Not Available SnSb.sup.8 Pb.sup.40 .largecircle. .largecircle. 8.2 2.5 16 Available .largecircle. .largecircle. 6.7 10 16 Not Available SnSb.sup.1 Pb.sup.35 Ag.sup.2 .largecircle. .largecircle. 10.0 1.3 12 Available .largecircle. .largecircle. 5.2 25 12 Not Available SnSb.sup.1 Pb.sup.40 Ag.sup.5 .largecircle. .largecircle. 11.3 1.0 13 Available .largecircle. .largecircle. 5.6 20 13 Not Available SnSb.sup.5 Pb.sup.40 Ag.sup.5 .largecircle. .largecircle. 9.5 1.6 15 Available .largecircle. .largecircle. 6.4 15 15 Not Available SnSb.sup.8 Pb.sup.35 Ag.sup.10 .largecircle. .largecircle. 8.9 2.0 17 Available .largecircle. .largecircle. 7.0 13 17 Not Available SnSb.sup.8 Pb.sup.40 Ag.sup.5 .largecircle. .largecircle. 8.7 2.0 17 Available .largecircle. .largecircle. 6.8 13 17 Not Available SnSb.sup.1 Pb.sup.35 Ag.sup.2 Cu.sup.0.9 .largecircle. .largecircle. 11.0 1.0 12 Available .largecircle. .largecircle. 5.5 20 12 Not Available SnSb.sup.8 Pb.sup.35 Ag.sup.10 Cu.sup.0.9 .largecircle. .largecircle. 8.0 3.6 18 Available .largecircle. .largecircle. 6.9 13 18 Not Available SnSb.sup.1 Pb.sup.40 Ag.sup.2 Cu.sup.0.1 .largecircle. .largecircle. 11.5 1.0 12 Available .largecircle. .largecircle. 5.4 20 12 Not Available SnSb.sup.1 Pb.sup.40 Ag.sup.5 Cu.sup.0.1 .largecircle. .largecircle. 11.0 1.0 13 Available .largecircle. .largecircle. 5.6 19 13 Not Available SnSb.sup.1 Pb.sup.40 Ag.sup.10 Cu.sup.0.1 .largecircle. .largecircle. 10.2 3.5 15 Available .largecircle. .largecircle. 5.8 18 15 Not Available SnSb.sup.5 Pb.sup.40 Ag.sup.2 Cu.sup.0.1 .largecircle. .largecircle. 9.8 1.5 14 Available .largecircle. .largecircle. 6.2 17 14 Not Available SnSb.sup.5 Pb.sup.40 Ag.sup.5 Cu.sup.0.1 .largecircle. .largecircle. 9.3 2.0 15 Available .largecircle. .largecircle. 6.5 15 15 Not Available SnSb.sup.5 Pb.sup.40 Ag.sup.10 Cu.sup.0.1 .largecircle. .largecircle. 8.7 4.0 16 Available .largecircle. .largecircle. 6.7 13 16 Not Available SnSb.sup.8 Pb.sup.40 Ag.sup.2 Cu.sup.0.1 .largecircle. .largecircle. 9.2 2.1 15 Available .largecircle. .largecircle. 6.5 16 15 Not Available SnSb.sup.8 Pb.sup.40 Ag.sup.5 Cu.sup.0.1 .largecircle. .largecircle. 8.5 3.0 17 Available .largecircle. .largecircle. 6.7 15 17 Not Available SnSb.sup.8 Pb.sup.40 Ag.sup.10 Cu.sup.0.1 .largecircle. .largecircle. 8.2 4.5 18 Available .largecircle. .largecircle. 6.9 13 18 Not Available SnPb.sup.35 Ag.sup.2 Cu.sup.0.1 .largecircle. .largecircle. 7.3 3.0 10 Available .largecircle. .largecircle. 4.5 36 10 Not Available SnPb.sup.35 Ag.sup.5 Cu.sup.0.1 .largecircle. .largecircle. 7.5 4.0 11 Available .largecircle. .largecircle. 4.6 36 11 Not Available SnPb.sup.35 Ag.sup.10 Cu.sup.0.1 .largecircle. .largecircle. 7.8 5.0 12 Available .largecircle. .largecircle. 4.8 35 12 Not Available InSn.sup.1 Au.sup.1 Ag.sup.2 .largecircle. .largecircle. 4.3 15 2 Available X .largecircle. 1.3 50 2 Not Available InSn.sup.2 Au.sup.1 Ag.sup.2 .largecircle. .largecircle. 3.0 11 3 Available X .largecircle. 1.8 46 3 Not Available InPb.sup.1 Au.sup.1 Ag.sup.2 .largecircle. .largecircle. 4.3 17 2 Available X .largecircle. 1.2 51 2 Not Available InPb.sup.2 Au.sup.1 Ag.sup.2 .largecircle. .largecircle. 2.7 13 3 Available X .largecircle. 1.4 47 3 Not Available InPb.sup.1 Cu.sup.1 Ag.sup.2 .largecircle. .largecircle. 4.4 15 2 Available X .largecircle. 1.3 49 2 Not Available InPb.sup.2 Cu.sup.1 Ag.sup.2 .largecircle. .largecircle. 3.1 13 3 Available X .largecircle. 1.6 47 3 Not Available PbSn.sup.2 Au.sup.0.001 Sb.sup.0.01 Cu.sup.0.01 .largecircle. .largecircle. 4.5 2.0 9 Available X .largecirc le. 2.0 32 9 Not Available PbSn.sup.2 Au.sup.0.01 Sb.sup.0.5 Cu.sup.0.1 .largecircle. .largecircle. 4.7 2.0 9 Available X .largecircl e. 2.0 31 9 Not Available PbSn.sup.2 Au.sup.0.02 Sb.sup.0.5 Cu.sup.0.1 .largecircle. .largecircle. 4.7 1.8 9 Available X .largecircl e. 2.0 30 9 Not Available PbSn.sup.2 Au.sup.0.5 Sb.sup.5 Cu.sup.1.5 .largecircle. .largecircle. 9.0 1.5 12 Available .largecircle. .largecircle. 3.7 20 12 Not Available PbSn.sup.5 Au.sup.0.001 Sb.sup.0.01 Cu.sup.0.01 .largecircle. .largecircle. 4.4 3.0 9 Available X .largecirc le. 2.4 15 9 Not Available PbSn.sup.5 Au.sup.0.01 Sb.sup.0.05 Cu.sup.0.1 .largecircle. .largecircle. 4.5 3.0 9 Available X .largecircl e. 2.4 15 9 Not Available PbSn.sup.5 Au.sup.0.02 Sb.sup.0.5 Cu.sup.0.1 .largecircle. .largecircle. 4.5 2.9 9 Available X .largecircl e. 2.5 15 9 Not Available PbSn.sup.5 Au.sup.0.5 Sb.sup.5 Cu.sup.1.5 .largecircle. .largecircle. 8.0 2.4 12 Available .largecircle. .largecircle. 4.3 13 12 Not Available SnPb.sup.40 Au.sup.0.001 Sb.sup.0.01 Cu.sup.0.01 .largecircle. .largecircle. 7.2 2.2 12 Available .largecircl e. .largecircle. 4.4 13 12 Not Available SnPb.sup.40 Au.sup.0.01 Sb.sup.0.5 Cu.sup.0.1 .largecircle. .largecircle. 7.3 2.2 12 Available .largecircle . .largecircle. 4.5 13 12 Not Available SnPb.sup.40 Au.sup.0.02 Sb.sup.0.5 Cu.sup.0.1 .largecircle. .largecircle. 7.3 2.2 12 Available .largecircle . .largecircle. 4.5 13 12 Not Available SnPb.sup.40 Au.sup.0.5 Sb.sup.5 Cu.sup.1.5 .largecircle. .largecircle. 9.0 2.0 14 Available .largecircle. .largecircle. 6.4 12 14 Not Available