Semiconductor processing apparatus comprising chamber partitioned into reaction and transfer sections

[0001] 1. Field of the Invention

[0002] The present invention generally relates to vacuum load lock semiconductor processing equipment, and more specifically relates to compact single-wafer processing semiconductor processing equipment that can efficiently process wafers continuously or simultaneously.

[0003] 2. Description of the Related Art

[0004] Generally, a semiconductor processing apparatus that uses a vacuum load lock system includes a load lock chamber, a transfer chamber and multiple reaction chambers that are connected to the transfer chamber. For each apparatus, a substrate-handling robot is used to automatically supply substrates to the reaction chambers. In such an arrangement, an atmospheric robot first brings a substrate inside the load lock chamber from a cassette or a front opening unified pod (“FOUP”). The FOUP may comprise a detachable cassette and a box with a front-opening interface. After the substrates are placed in the load lock chamber, the load lock chamber is evacuated, and the substrate is transferred to a reaction chamber by a vacuum robot provided inside a common polygon-shaped transfer chamber. After the substrate is fully processed in the reaction chamber, it is returned to the load lock chamber by the vacuum robot. Lastly, after the load lock chamber is restored to atmospheric pressure, the processed substrate returned to the cassette or the FOUP by the atmospheric robot. This type of apparatus is generally called a “cluster tool.”

[0005] As the number of reaction chambers increases, the area occupied by the processing apparatus (the “footprint”) and the width of the front panel of the apparatus (the “faceprint”) increase, as does the cost of operation. This is because the conventional single-wafer processing apparatus possesses a common polygon-shaped transfer chamber to which each of the reaction chambers is attached, radiating in all directions. Additionally, the number of reaction chambers in a layout is limited by the number of sides of the polygon-shaped transfer chamber. Furthermore, in the conventional single-wafer processing apparatus, each reaction chamber has independent gas and vacuum lines, and each reaction chamber independently performs deposition (film forming). Thus, if the number of reaction chambers is to be increased to improve productivity, the number of gas lines and vacuum pumps must increase as well, thereby increasing the complexity of the processing apparatus.

[0006] To reduce the footprint or the faceprint of the conventional single-wafer processing apparatus, a transfer mechanism has been included inside the load lock chamber. The transfer mechanism is simply a handling unit capable of holding substrates and loading/unloading substrates from the reaction chamber. The load lock chamber is separated from the reaction chamber using a gate valve. This configuration allows the footprint or faceprint of the processing apparatus to be reduced to a certain degree, but the reduction is not satisfactory, no improvement of process efficiency or productivity is made, and the total system is generally not simplified. Furthermore, this configuration makes it difficult to supply wafers to the reaction chambers in a continuous chemical vapor deposition (“CVD”) process, such as in an ashing process. Finally, during deposition a film is apt to form around the gate valve, thereby necessitating installation of an expensive plasma-proof O-ring for CVD processes using plasma.

[0007] Although incorporation of a W-shaped transfer arm into the load lock chamber may solve some of these problems, so doing increases the capacity of the load lock chamber, thereby increasing the time required for evacuating and pressurizing the load lock chamber and thus decreasing processing capacity.

[0008] One object of the present invention is to provide semiconductor processing equipment that realizes low cost, small footprint, small faceprint, stable process and high throughput.

[0009] Another object of the present invention is to reduce the volume of the reaction chambers to reduce gas consumption and to reduce deposition on the reaction chamber walls.

[0010] According to one aspect of the present invention, the semiconductor processing equipment comprises a load lock chamber, a transfer chamber situated next to the load lock chamber, and a reaction chamber situated above the transfer chamber. The semiconductor processing equipment further comprises a thin link wafer transfer arm capable of operating in vacuum, and capable of transferring wafers between the respective chambers.

[0011] According to another aspect of the present invention, the load lock chamber, the transfer chamber and the reaction chamber each have respective exhaust ports. In such a configuration air is evacuated from the transfer chamber and the reaction chamber by switching between the exhaust port of the transfer chamber and the exhaust port of the reaction chamber.

[0012] According to another aspect of the present invention, during deposition and cleaning, the atmosphere of the transfer chamber is effectively separated from the atmosphere of the reaction chamber by an insulation separating plate, and by pressurizing the transfer chamber with an inactive gas. This configuration prevents the reaction gas in the reaction chamber from flowing into the transfer chamber. Furthermore, the presence of separate exhaust ports for the reaction chamber and the transfer chamber facilitates the cleaning of the transfer chamber.

[0013] According to another aspect of the present invention, an insulating material is used to comprise an exhaust duct which also functions as a reaction chamber side wall. This configuration reduces plasma deposition on the interior walls of the reaction chamber.

[0014] According to another aspect of the present invention, the transfer chamber is positioned below the reaction chamber, thereby preventing the formation of a film around the gate valve that separates the load lock chamber from the transfer chamber. This configuration further allows deposition on multiple wafers without the generation of foreign contaminating substances.

[0015] According to another aspect of the present invention, the transfer chamber is positioned below the reaction chamber, thereby making it possible to install a temporary storing mechanism for wafers adapted to increase the overall throughput of the semiconductor processing equipment. Additional details on the wafer buffer mechanism are provided in U.S. patent application Ser. No. 10/187,670, filed 1 Jul. 2002.

[0016] According to another aspect of the present invention, the reaction chamber is evacuated from a position below the surface of a semiconductor wafer being transferred into the reaction chamber, thereby reducing the adhesion of particles that may be generated when a semiconductor wafer is transferred into the transfer chamber or during deposition. Furthermore, this configuration provides a smaller reaction chamber, thereby increasing the efficiency of the semiconductor processing equipment.

[0023] FIGS. 1 through 4 schematically illustrate one embodiment of semiconductor processing equipment that uses a vacuum load lock system. The embodiment comprises a load lock chamber 10 adapted to queue semiconductor wafers 40 before processing, a transfer chamber 20 and a reaction chamber 30 for growing a film on semiconductor wafers 40. The transfer chamber 20 is positioned adjacent to the load lock chamber 10, and the reaction chamber 30 is positioned above the transfer chamber 20. A transfer robot 22 is positioned outside the load lock chamber 10, and comprises a thin link wafer transfer arm 24 capable of transferring semiconductor wafers 40 from the transfer robot 22 to the load lock chamber 10, the transfer chamber 20, and the reaction chamber 30.

[0024] In such embodiments, the load lock chamber 10 further comprises a load lock exhaust port 12, the transfer chamber 20 further comprises a transfer exhaust port 26, and the reaction chamber 30 further comprises a reaction exhaust port 32. These exhaust ports allow the transfer chamber 20 and the reaction chamber 30 to be evacuated.

[0025] During a semiconductor wafer deposition process, and during cleaning of the semiconductor processing equipment, the atmosphere of the transfer chamber 20 is effectively isolated from the atmosphere of the reaction chamber 30. This isolation is accomplished through by using an insulation separating plate 34, and by bringing an inactive gas into the transfer chamber 20. These steps prevent the reaction gas present in the reaction chamber 30 from flowing into the transfer chamber 20.

[0026] Additionally, an insulating material may be used to comprise the reaction exhaust port 32, and the side walls of the reaction chamber 30. This configuration reduces plasma deposition on the reaction chamber side walls, thereby increasing the efficiency of the semiconductor processing equipment and reducing the cleaning costs associated with operation of the equipment.

[0027] Furthermore, placing the transfer chamber 20 below the reaction chamber 30 provides multiple advantages. For example this configuration reduces the formation of film around the gate valve 14 that separates the transfer chamber 20 from the load lock chamber 10, thereby allowing deposition on multiple semiconductor wafers 40 without generating contaminating substances. Additionally, this configuration permits installation of a wafer buffer mechanism 42, that can be used in the transfer of semiconductor wafers 40 between the load lock chamber and the transfer chamber 20. Additional details of the wafer buffer mechanism 42 are available in U.S. patent application Ser. No. 10/187,670, filed 1 Jul. 2002.

[0028] By evacuating the reaction chamber 30 from below the surface of a semiconductor wafer 40 that is being transferred from the transfer chamber, the adhesion of particles generated during wafer transfer or during deposition is reduced or prevented. Furthermore, this exhausting configuration allows the reaction chamber to be made smaller. By switching the active exhaust port from the transfer chamber 20 to the reaction chamber 30, and by feeding a purge gas into the transfer chamber 20, the flow of reaction gas into the transfer chamber 20 is prevented. During cleaning, this same gas flow configuration may be used, although cleaning may be performed using the transfer exhaust port, thereby enabling the cleaning of the interior of the transfer chamber 20.

[0029] FIG. 2 schematically illustrates one embodiment of the mechanism that prevents the reaction gas in the reaction chamber 30 from flowing into the transfer chamber 20. In such embodiments, an inactive gas is introduced into the transfer chamber 20 during deposition, thereby effectively isolating the transfer chamber 20 from the reaction chamber 30.

[0030] As illustrated in FIG. 3, when a semiconductor wafer 40 is transferred to the reaction chamber 30, or is being queued in the transfer chamber 20, the atmosphere of the reaction chamber 30 is evacuated from the transfer exhaust port 26, which is located below the surface of the semiconductor wafer 40. This configuration prevents particles generated during wafer transfer or during deposition from adhering to the surface of the semiconductor wafer 40.

[0031] FIG. 4 schematically illustrates the configuration of the gas and vacuum lines according to one embodiment of the present invention.

[0032] The semiconductor processing equipment according to the embodiments described above features reduced operating cost, footprint, and faceprint. Additionally, by reducing the capacity of the reaction chamber 30, and by comprising the reaction chamber walls of an insulating material, deposition on the walls of the reaction chamber 30 is minimized, thereby allowing this equipment to be operated with increased efficiency, throughput, and stability.