Semiconductor device package

[0001] 1. Field of the Invention

[0002] This invention relates to semiconductor device packages, and more specifically to semiconductor device packages which are shielded to protect against electromagnetic interference (EMI).

[0003] 2. Description of the Related Art

[0004] Semiconductor device packages typically have electrical circuitry implemented on a circuit substrate, such as a printed circuit board or a ceramic substrate. The performance of the circuitry may be adversely affected by electromagnetic interference (EMI). Electromagnetic interference (EMI) is the generation of undesired electrical signals, or noise, in electronic system circuitry due to the unintentional coupling of impinging electromagnetic field energy.

[0005] The coupling of signal energy from an active signal net onto another signal net is referred to as crosstalk. Crosstalk is within-system EMI, as opposed to EMI from a distant source. Crosstalk is proportional to the length of the net parallelism and the characteristic impedance level, and inversely proportional to the spacing between signal nets.

[0006] Electronic systems are becoming smaller, and the density of electrical components in these systems is increasing. As a result, the dimensions of the average circuit element is decreasing, favoring the radiation of higher and higher frequency signals.

[0007] At the same time, the operating frequency of these electrical systems is increasing, further favoring the incidence of high frequency EMI. EMI can come from electrical systems distant from a sensitive receiving circuit, or the source of the noise can come from a circuit within the same system (crosstalk or near source radiated emission coupling). The additive effect of all these sources of noise is to degrade the performance, or to induce errors in sensitive systems.

[0008] It is therefore an object of the present invention to provide semiconductor device packages which are shielded to protect against electromagnetic interference (EMI).

[0009] To achieve the above listed and other objects, a semiconductor device package having features of the present invention generally includes a semiconductor device mounted to a substrate, a wall erected around the semiconductor device with a height taller than the height of the semiconductor device, at least one metal member provided in the wall or against the wall; and a lid secured to the metal member. Note that the metal member and the lid enclose substantially the semiconductor device for providing electromagnetic interference shielding. Preferably, the wall is integrally formed with the substrate.

[0010] In accordance with the present invention, there is provided another semiconductor device package includes a semiconductor device mounted to a substrate having at least one metal member provided therein and a metal cover secured to the metal member thereby enclosing substantially the semiconductor device for providing electromagnetic interference shielding.

[0011] In accordance with the present invention, there is provided another semiconductor device package includes a semiconductor device mounted to a substrate and a metal cover secured to the substrate for providing electromagnetic interference shielding. Specifically, the metal cover has a base portion and a side wall extending from the base portion, and the size of the side wall is slightly larger than the size of a top portion of the substrate to enable the top portion of the substrate to be received within the metal cover. The side wall of the metal cover abuts the bottom portion of the substrate when the top portion of the substrate is received within the metal cover.

[0012] In accordance with the present invention, the lid may be a metal plate or a film with a conductive coating thereon. The metal member may be a metal ring or four metal bars arranged around the semiconductor device. Preferably, the metal member is connected to ground potential. The substrate may be an organic substrate or a ceramic substrate.

[0023] FIG. 1 illustrates a semiconductor device package 100 according to one embodiment of the present invention. The package 100 includes a semiconductor device 110 attached to a substrate 120 by means of a conductive adhesive (not shown) such as a silver-filled epoxy or a non-conductive adhesive (not shown). As shown, the semiconductor device 110 is connected to the substrate 120 by a plurality of bonding wires 112 which act as electrical input/output (I/O) connections to conductive traces or pads (not shown) of the substrate 120. Alternatively, the semiconductor device 110 may be connected to the substrate 120 by a plurality of solder balls. The solder balls may be formed on an active surface of the semiconductor device 110 using one of any known bumping procedures.

[0024] Referring to FIG. 1, the package 100 is provided with a wall 130 erected from the periphery of the substrate 120 with a height taller than the height of the semiconductor device 110. Note that a metal member 140 is provided in the wall 130, and a lid such as a metal plate 150 sized and dimensioned to engage the wall 130, preferably without extending thereover. Alternatively, the lid may be a film with a conductive coating thereon. The metal plate 150 is suitably bonded to the wall 130 to hermetically close the semiconductor device 110 therein. In this way, the semiconductor device 110 is EMI shielded by the metal member 140 and the metal plate 150. The metal plate 150 may be secured to the metal member 140 by a soldering interface (e.g., Au—Sn solder), a conductive adhesive interface, or resistance welding. Both the metal member 140 and the metal plate 150 may be constructed from silver or copper to effectively reduce the amount of radiation which can penetrate therethrough thereby reducing the total dose radiation received at the semiconductor device 110 to a level less than the total dose tolerance of the semiconductor device 110. Preferably, the upper surface of the metal plate 150 has a solder layer 152 (or a black-oxidation layer) formed thereon for mark ability.

[0025] The substrate 120 may be an organic substrate formed from a core layer made of fiberglass reinforced BT (bismaleimide-triazine) resin or FR-4 fiberglass reinforced epoxy resin. Alternatively, the substrate 120 may be a multi-layer ceramic substrate. Preferably, the substrate 120 and the wall 130 are integrally formed by a LTCC (Low Temperature Cofired Ceramic) manufacturing process.

[0026] Alternatively, as shown in FIG. 2, the metal member 140 may extend from the wall 130 into the substrate 120 for providing better EMI shielding.

[0027] FIG. 3 illustrates a semiconductor device package 200 according to another embodiment of the present invention. The package 200 includes a semiconductor device 110 attached to and electrically coupled to a substrate 122. As shown, the metal member 140 is provided in the substrate 122, and the package 120 is provided with a metal cover 210 secured to the metal member 140 thereby enclosing substantially the semiconductor device 110 for providing electromagnetic interference shielding.

[0028] Preferably, the upper surface of the metal cover 210 has a solder layer 212 (or a black-oxidation layer) formed thereon for mark ability. The metal cover 210 may be secured to the metal member 140 by a soldering interface (e.g., Au—Sn solder), a conductive adhesive interface, or resistance welding. Both the metal member 140 and the metal cover 210 may be constructed from silver or copper to effectively reduce the amount of radiation which can penetrate therethrough thereby reducing the total dose radiation received at the semiconductor device 110 to a level less than the total dose tolerance of the semiconductor device 110.

[0029] Alternatively, as shown in FIG. 4, the metal member 140 may extend from an upper surface 122a to a lower surface 122b of the substrate 122 for providing better EMI shielding.

[0030] FIG. 5 illustrates a semiconductor device package 400 according to another embodiment of the present invention. The package 400 is substantially identical to the package 100 shown in FIG. 1 except that the metal member 140 is not provided in the wall 130 but provided against the inner surface of the wall 130. Alternatively, as shown in FIG. 6, the metal member 140 may extend from the wall 130 into the substrate 120 for providing better EMI shielding.

[0031] Preferably, the metal member 140 shown in FIGS. 1-6 is connected to ground potential. Specifically, the metal member 140 may be connected to one independent grounding portion (not shown) provided in the substrate 120 or the substrate 122 by a dedicated vertical terminal such as via 120a (see FIG. 1, FIG. 3 and FIG. 5). The grounding portion may be distributed in the substrate 120 or the substrate 122 in any available location, and is electrically joined to an electrical ground of an external printed circuit (PC) main board (not shown) for supplying ground potential. In the embodiments shown in FIG. 2, FIG. 4 and FIG. 6, the metal member 140 may be directly connected to one independent grounding portion (not shown) provided in the substrate 120 or the substrate 122.

[0032] Note that the metal member 140 shown in FIGS. 1-6 may be a metal ring 140a shown in FIG. 7 or metal bars 140b arranged around the semiconductor device 110 as shown in FIG. 8.

[0033] FIG. 9 illustrates a semiconductor device package 300 according to another embodiment of the present invention. The package 300 includes a semiconductor device 110 mounted to a substrate 310 and a metal cover 320 secured to the substrate 310 for providing electromagnetic interference shielding. Specifically, the substrate 310 includes a top portion 312 and a bottom portion 314, wherein the size of the bottom portion 314 is larger than the size of the top portion 312. The metal cover 320 has a base portion 320a and a side wall 320b extending from the base portion 320a, and the size of the side wall 320b is slightly larger than the size of the upper portion 310a of the substrate 310 to enable the upper portion 310a to be received within the metal cover 320. The side wall 320b of the metal cover 320 abuts the bottom portion 314 of the substrate 310 when the top portion 312 of the substrate 310 is received within the metal cover 320. Preferably, the metal cover 320 may be connected to one independent grounding portion (not shown) provided in the substrate 310 by a dedicated vertical terminal provided in the bottom portion 314 of the substrate 310 or a dedicated conductive trace extending on the bottom portion 314 of the substrate 310 (not shown in FIG. 7). The metal cover 320 may be secured to the dedicated vertical terminal or the dedicated conductive trace by a soldering interface (e.g., Au—Sn solder) 314a. The soldering interface 314a may be replaced by a conductive adhesive interface. The grounding portion may be distributed in the substrate 310 in any available location, and is electrically joined to an electrical ground of an external printed circuit (PC) main board (not shown) for supplying ground potential.

[0034] Although the invention has been explained in relation to its preferred embodiments, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.