Patent Application
20100055330
1. Field of the Invention
The present invention relates to the field of wafer processing system. More particularly, the present invention relates to an epitaxy processing system and its processing method which comprises a transportation device which can move the susceptor out from high temperature reacting chamber to a cooling device which afterward can rapidly cool down the wafers and the susceptor to increase the production capacity.
2. Description of the Prior Art
In the fabrication of integrated circuit and compound semiconductor, processing system is generally employed to process semiconductor wafers. Those processing system include a reacting chamber to effectuate depositions, epitaxy, etching, and so on.
The conventional processing system includes a glove box with a loadlock and a reacting chamber arranged inside the glove box. When a fabrication process is going to proceed, the operator must first put the wafer boat into the glove box via the loadlock, followed by pick and place the wafers onto the susceptor which locates in the reacting chamber by manual operation, then close the reacting chamber lid and the epitaxy process is starting to proceed. After process ends, the susceptor with wafers will not move out of the reacting chamber immediately until the nitrogen gas cycle purge inside the reacting chamber and reacting chamber temperature lower down to 150° C. However, this step occupies lots of machine time to process next one cycle and consumes lots of nitrogen gas.
The present invention generally provides a wafer processing system and its processing method including a reacting chamber, a transportation device which provides the susceptor transportation and a cooling device which provides a quickly temperature-lowering down function and a volume minimized stacked cassette as a loadlock function.
A volume minimized stacked cassette containing a plurality of susceptors, wherein each susceptor has at least a wafer placed thereon. A transportation device is utilized for transmitting those susceptors between the reacting chamber, the cooling device, and the stacked cassette. At process initial, the transportation device transmits the susceptor in stacked cassette through a chamber gate valve to reacting chamber which maintain at high temperature environment. After process ends, the transportation device transmits the susceptor from high temperature reacting chamber to cooling device for quickly cooling down. Wherein the transportation device follows up transmits another susceptor in stacked cassette to the reacting chamber for next one run processing. After that, the cooled down susceptor on the cooling device is transmitting to the stacked cassette.
In one embodiment of the present invention, an epitaxy processing system including: a stacked cassette for containing a plurality of susceptors, wherein each of the susceptors has at least a wafer placed thereon; a transportation device for transporting the susceptors; a reacting chamber having a chamber gate valve, wherein the susceptor is transported by the transportation device from the stacked cassette through the chamber gate valve and the wafer is processed while the chamber gate valve is closed; and a cooling device for cooling the processed wafer transported by the transportation device from the reacting chamber under a high temperature, and the processed wafer is cooled down to a lower temperature. After transporting the processed wafer into the cooling device, the transportation device transports another susceptor from the staked cassette into the reacting chamber for next one run processing.
In another embodiment of the present invention, an epitaxy processing system is provided. The epitaxy processing system includes a stacked cassette for containing a plurality of susceptors, wherein each of those susceptor has at least a wafer placed thereon. A transportation device is utilized for transmitting those susceptors. A plurality of reacting chambers are arranged around the transportation device, each of the reacting chambers having a chamber gate valve, wherein the susceptors are respectively transported by the transportation device from the stacked cassette to those reacting chambers; and for each of those reacting chambers, the susceptor is transported while the chamber gate valve is open, and the wafer is processed while the chamber gate valve is closed. And, a cooling device is utilized for sequentially cooling the processed wafers transported by the transportation device respectively from those reacting chambers under a high temperature, and the processed wafers are respectively cooled down to a lower temperature, wherein those cooled processed wafers are removed out the cooling device by the transportation device to load in the stacked cassette. Once one susceptor is removed out from one reacting chamber, another susceptor is transported from the stacked cassette to the empty reacting chamber by the transportation device.
In another embodiment of the present invention, an epitaxy processing method is provided. The epitaxy processing method including: providing a plurality of susceptors disposed in a stacked cassette, wherein each of the susceptors has at least a wafer placed thereon; transporting the susceptor by a transportation device from the stacked cassette into a reacting chamber having a chamber gate valve, the susceptor is transported while the chamber gate valve is open and the wafer is processed while the chamber gate valve is closed; transporting the processed wafer by the transportation device from the reacting chamber under a high temperature into a cooling device; cooling the processed wafer to a lower temperature by the cooling device; and after transporting the processed wafer into the cooling device, transporting another susceptor from the staked cassette into the reacting chamber by the transportation device for next run processing.
Other advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of the present invention.
The foregoing aspects and many of the accompanying advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
FIG 3A is a schematic diagram showing one embodiment of an epitaxy processing system and its processing method in accordance with one embodiment of the present invention;
The present invention generally provides an epitaxy processing system and its processing method including a reacting chamber, a transportation device which provides the susceptor transportation and a cooling device which provides a quickly temperature-lowering function and a volume minimized stacked cassette as a loadlock function. The detailed explanation of the present invention is described as following. The described embodiments are presented for purposes of illustrations and description, and they are not intended to limit the scope of the present invention.
Firstly, refer to FIG 1A, FIG 1A shows a schematic diagram illustrating an epitaxy processing system and its processing method in accordance, with one embodiment of the present invention. As shown in the figure, the epitaxy processing system 100 of one embodiment of the present invention includes a stacked cassette 110, which is volume minimized, for containing a plurality of susceptors 120, wherein each susceptor 120 has at least a wafer W placed thereon. A transportation device 130 is utilized for transporting those susceptors 120, and one susceptor 120 is transported at a time. Those susceptors 120 are transported by the transportation device 130 from the stacked cassette 110 into a reacting chamber 140 and the wafer W is processed in the reacting chamber 140, wherein the reacting chamber 140 has a chamber gate valve 142 and the chamber gate valve 142 is open when the transportation device 130 carries the susceptor 120 into or out from the reacting chamber 140. And, a cooling device 150 is utilized for cooling the processed wafer W which is still in a high temperature, such as over 500° C. and transported by the transportation device 130 from the reacting chamber 140 after reacting, and then another susceptor 120 which has a un-processed wafer placed thereon is transmitted from the stacked cassette 110 to the reacting chamber 140 which remains substantially at the high temperature by the transportation device 130. The transportation device 130 can take out the susceptor 120 with the wafer W which are still in a high temperature from the reacting chamber 140 into the cooling device 150 immediately, and then the transportation device 130 can pick another susceptor with a wafer from the stacked cassette 110 into the reacting chamber 140 to react while the reacting chamber 140 is still in the high temperature so that the processing time can be reduced to improve the throughput. It is understood that the temperature may be slightly lower down when the gate valve 142 of the reacting chamber 140 is open. However, the effects of the invention may hot be affected.
Continuing the above description, in one embodiment, the transportation device 130, the cooling device 150 and the reacting chamber 140 are arranged in a closed space, which is called a glove box, and the glove box is cycle purged with an inert gas, such as the nitrogen gas, to lower down the concentration of oxygen in the glove box to a PPM level. The stacked cassette 110 is a closed space in the system and has two cassette gate valves; one of the cassette gate valves, such as cassette gate valve 112, is faced to an external atmospheric environment; and another, cassette gate valve 114 for example, is faced to the epitaxy processing system 100, and the stacked cassette 110 is cycle purged with the nitrogen gas also. In another embodiment, the stacked cassette 110 can have a two-directional susceptor picking structure and can be fixed or rotated. An operator can pick those wafers which are placed on the wafer boat onto the susceptor 120 in the working area in atmospheric environment, and then load these susceptors 120 into the stacked cassette 110 from cassette gate valve 112. Hereafter, stacked cassette 110 is purged with the nitrogen gas and those wafers W are transported into the reacting chamber 140 by the transportation device 130. In one embodiment, the transportation device 130 can has a robot or a linear slide guide to transfer the susceptor 120 and wafer W placed thereon, especially one susceptor 120 each time.
Continuously, in one embodiment, the reacting chamber 140 has a gas distribution apparatus that provides separate and uniform distribution of at least two gases and a fluid cooling pathway provided within the reacting chamber. In the gas distribution apparatus, a thin-plated susceptor made of high thermal conductivity, low thermal mass and high density material is provided to quick temperature ramp-up/down for processing equipment and automation handling. Referring to FIG. 1B, in another embodiment, the reacting chamber 140 also can be set outside the closed space. Therefore, the transportation device 130, the cooling device 150 and the chamber gate valve 142 are arranged in the closed space. Besides, the closed space, such as the glove box, and the stacked cassette are cycle purged with nitrogen gas. It is very convenient to the operator when the reacting chamber 140 needs to be maintained, the operator can just open the lid of the reacting chamber to check out.
For easily transmitting those susceptors 120 and pick and place by the transportation device 130, the schematic diagram of the susceptor of the present invention is shown in -type profile, and the susceptor 120 includes a plate 122 to have at least a wafer W placed thereon; an ring-like flange 124, which is an peripherally extension of the plate 122, for detachably contact with the transportation device 130; and an encircled supporting wall 126 underneath the plate 122, the inner side 127 of the supporting wall 126 is beveled outwardly, the beveled edge is inclined so that there is an obtuse angle between the plate 122 and the inner side 127 of the supporting wall 126, in order to mount on a rotor 152 of the cooling device 150. In one embodiment, the transportation device 130 is utilized to hold the ring-like flange 124 of the susceptor 120 in a regular way or clip the outer lateral of the plate 122 of the susceptor 120 to move outward in changing the width of the transportation device 130. Continuously, in one embodiment, the cooling device 150 can utilize an upper gas sparging cooling method, a lower fluid pipe conduction cooling method or a superconductor medium contact cooling method to lower down the temperature of those susceptors and wafers. In one embodiment, the cooling device 150 is designed to control the cooling rate and the susceptors and wafers which are still in the high temperature can be cooled down gradually and immediately. Besides, because of the design of the cooling device 150, the nitrogen gas usage during the cooling can be reduced.
In another embodiment, a plurality of reacting chambers 240 can be applied in the epitaxy processing system 200, wherein the structure of the stacked cassette 210, the susceptor 220, the transportation device 230 and the cooling device 250 are approximately the same as last embodiment so that it is no unnecessary detailed here. The arrangement of the reacting chambers 240 and the cooling device 250 are described in the following. Please refer to
In another embodiment, an epitaxy processing method is provided herein including the following step. First, providing a plurality of susceptors disposed in a stacked cassette, wherein each of those susceptors has at least a wafer placed thereon. Next, transporting the susceptor by a transportation device from the stacked cassette into a reacting chamber having a chamber gate valve, the susceptor is transported while the chamber gate valve is open and the wafer is processed while the chamber gate valve is closed. And then, transporting the processed wafer by the transportation device from the reacting chamber under a high temperature into a cooling device. Next, cooling the processed wafer to a lower temperature by the cooling device. Finally, after transporting the processed wafer into the cooling device, transporting another susceptor from the staked cassette into the reacting chamber by the transportation device for next run processing.
Continuing the above description, in one embodiment, the cooling method includes an upper gas sparging purging cooling method, an underneath fluid pipe conduction cooling method or a superconductor medium contact cooling method. Besides, in another embodiment, the high temperature is over 500° C., and the lower temperature is below 150° C. The epitaxy processing method can be utilized to sequentially cool down those susceptors respectively from each reacting chamber which remains substantially at the high temperature after reacting so that the production output of the system can be improved.
Continuously, in the above-mentioned embodiments, those reacting chambers can co-use at least one cooling device to cool down the susceptors and the wafers placed thereon under high temperature to provide a maximum temperature-lowering function and increase the production capacity. Besides, the function and recipe of those reacting chambers can be different. Moreover, when the number of the reacting chambers is increased to a specific amount, another cooling device can be added to the system.
To sum up the foregoing descriptions, the present invention generally provides an epitaxy processing system and processing method including a reacting chamber, a transportation device which provides the susceptor transportation and a cooling device which provides a quickly temperature-lowering function and a volume minimized stacked cassette as a loadlock function.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustrations and description. They are not intended to be exclusive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the an to best utilize the invention and various embodiments with various modifications as are suited to particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.
