Multifunctional pretreatment integrated chamber for preparing semiconductor wafer

Abstract

The invention discloses a multifunctional pretreatment integrated chamber for preparing semiconductor wafers, which comprises a chamber cover, an upper chamber body and a lower chamber body, the upper chamber body and the lower chamber body are communicated and form a closed chamber with the chamber cover, a wafer boat is arranged in the closed chamber, the wafer boat adopts a multi-layer design and is used for placing a plurality of wafers, and the lower chamber body and the upper chamber body are communicated with each other. The wafer boat is placed on the supporting rod, the supporting rod is connected with the transmission mechanism, and the wafer boat can do lifting motion or rotating motion along with the transmission mechanism; an air inlet and an air outlet are formed in the side face of the upper cavity, the air outlet is connected with a vacuum pump, and the lower cavity is provided with a transmission interaction interface. The multifunctional pretreatment integrated chamber for preparing the semiconductor wafer is compact in structure, the number of chambers and the wafer transmission frequency are reduced, the wafer damage risk in the transmission process is reduced, multiple wafers can be treated at the same time, and efficiency is improved.

Description

Technical Field

[0001] The invention relates to a multifunctional preprocessing integrated chamber, in particular to a multifunctional preprocessing integrated chamber for preparing semiconductor wafers. Background Art

[0002] In the semiconductor manufacturing process, thin film deposition is a key step. Thin film deposition needs to be carried out in a high cleanliness and high vacuum environment to prevent contamination and damage to the wafer and ensure the quality and uniformity of the film. In thin film deposition equipment, the loadlock chamber, heating and degassing chamber and cooling chamber are important components of the equipment. Among them, the load lock chamber is used for the transition of the equipment from atmosphere to vacuum, so that the process chamber can always be in a high cleanliness and high vacuum environment to ensure the smooth progress of the process. The heating and degassing chamber is used to heat and remove moisture and volatile impurities on the surface of the wafer to ensure the quality of the coating on the wafer surface; the cooling chamber is used to cool the wafer after coating to ensure that the temperature of the wafer is within a reasonable range when it is transferred to the wafer boat carrying the wafer.

[0003] In the existing technology, the load lock chamber, heating and degassing chamber and cooling chamber are usually separated. When in use, the wafer needs to be transferred to each chamber in turn for operation. For example, after the wafer is placed in the load lock chamber, it is evacuated and the chamber pressure changes from atmospheric state to vacuum state, and then the wafer is transferred to the heating and degassing chamber for heating and degassing; after the degassing is completed, the wafer is transferred to the process chamber by a robot for the next thin film deposition process; after the process is completed, the wafer is transferred to the cooling chamber for cooling; after the cooling is completed, it is transferred to the load lock chamber, and the chamber intake causes the pressure to change from vacuum to atmospheric state, and the wafer is transferred to the Foup (material box). Each load lock chamber, heating and degassing chamber and cooling chamber only supports one wafer.

[0004] The existing technology has the following problems: First, in the existing technology, the load lock chamber, the heating and degassing chamber and the cooling chamber can only process one wafer at a time. When multiple wafers need to be processed, the process needs to be repeated many times, which is inefficient. Figure 1As shown, the wafer heating method of the traditional PVD equipment is heating by a heating plate 8 (heater). The wafer is placed on the heater, and the heater is heated to a predetermined temperature, such as 200-400°C, so that the wafer reaches the preset temperature and maintains it for a certain time. This heating method can only heat one wafer at a time, and the temperature uniformity of a single wafer is generally <±5°C. Due to the complex design of the heater, the thickness and weight are relatively large, the thickness is generally 30-60mm, and the weight is about 40kg. If multiple wafers are heated, multiple heaters need to be stacked, and the size, weight, cost, etc. are all high. Therefore, it is not suitable for heating multiple wafers. Therefore, the current common heating method of PVD equipment is heater heating of a single wafer. Secondly, in the existing technology, the load locking function, heating and degassing function, and cooling function need to be performed in different cavities respectively. Multiple chambers not only increase the footprint of the entire equipment, but also increase the equipment manufacturing and use maintenance costs. Finally, since each functional cavity is separated independently, the wafer needs to be transferred multiple times during the transmission process, and the movement time on the robot is long, which increases the risk of wafer damage during the transmission process. Figure 2 shown. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a multifunctional preprocessing integrated chamber for preparing semiconductor wafers, which not only has a compact structure, reduces the number of chambers and the number of wafer transfers, and reduces the risk of wafer damage during the transfer process, but also can process multiple wafers at the same time, thereby improving efficiency.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is to provide a multifunctional preprocessing integrated chamber for preparing semiconductor wafers, including a chamber cover, an upper chamber and a lower chamber, the upper chamber and the lower chamber are connected and form a closed chamber with the chamber cover, a wafer boat is arranged in the closed chamber, the wafer boat adopts a multi-layer design for placing multiple wafers, the wafer boat is placed on a support rod, the support rod is connected to a transmission mechanism, and the wafer boat can be lifted or rotated with the transmission mechanism; an air inlet and an air outlet are arranged on the side of the upper chamber, the air outlet is connected to a vacuum pump, and the lower chamber is provided with a transmission interaction interface.

[0007] Furthermore, the upper cavity and the lower cavity adopt a split structure, and a metal sealing ring or an O-ring is used to seal the upper cavity and the lower cavity; a metal sealing ring or an O-ring is used to seal the cavity cover and the upper cavity.

[0008] Furthermore, the material of the metal sealing ring is oxygen-free copper or silver-plated oxygen-free copper, and the material of the O-ring is fluororubber.

[0009] Furthermore, the wafer boat includes an upper support plate and a lower support plate, the upper support plate and the lower support plate are connected via side support bars, a wafer support block is arranged on the side support bar, and a step is formed on the wafer support block.

[0010] Furthermore, the wafer support blocks are arranged in layers, the layer spacing is designed to be 5-50 mm, the total number of layers is 1-50 layers, and one wafer is placed on each layer.

[0011] Furthermore, the height of the step is 0.1-2 mm, and the gap between the step and the wafer is 0.5-5 mm.

[0012] Furthermore, the number of the side support bars is 3.

[0013] Furthermore, when the air inlet is heated, high-temperature gas of 100-500°C is introduced, the air flow rate is 40-200SLM, the insulation time is 10s-60s, the vacuum pumping speed is 1800L / s-3200L / s, until the atmospheric pressure is pumped to 5E-4pa, and the temperature of multiple wafers is 325-334°C.

[0014] Furthermore, a heating device is provided at the bottom of the upper cavity, and the heating device is a lamp tube, a heating wire, a microwave heater or an induction heater.

[0015] Furthermore, the transmission mechanism is installed on the lower cavity through a sealing flange, and the transmission interaction interface is provided with a transmission valve for sealing.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1) Higher efficiency: The present invention can process multiple wafers at the same time, thereby improving efficiency. 2) Lower cost: The present invention integrates the load lock chamber, heating and degassing chamber and cooling chamber into one chamber, reducing the number of chambers under the same function, thereby reducing the footprint of the entire machine, reducing manufacturing costs, and making maintenance and disassembly easier, thereby reducing maintenance costs. 3) Reduced risk of wafer damage during the transmission process: The present invention integrates the load lock, heating and degassing functions and cooling functions into one chamber, thereby reducing the number of wafer transmissions. Since the movement time of the wafer on the robot is reduced, the risks of eccentricity, breakage, contamination, etc. caused by the high-speed movement of the robot can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of a heating plate for an existing single wafer; Figure 2 It is a scheduling diagram of the existing PVD equipment; Figure 3 This is a schematic diagram of the structure of a multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to the present invention; Figure 4It is a schematic diagram of the cross-sectional structure when the wafer of the present invention is located in the upper cavity; Figure 5 It is a schematic diagram of the cross-sectional structure when the wafer of the present invention is located in the lower cavity; Figure 6 It is a schematic diagram of the structure of a wafer boat in the multifunctional integrated chamber for pre-processing wafers of the present invention; Figure 7 An enlarged view of the wafer support block of the present invention carrying the wafer; Figure 8 The vacuum chamber pressure-time variation diagram of the present invention; Fig. 9 It is a scheduling diagram of the PVD equipment of the present invention.

[0018] The markings in the figure are: 1. Cavity cover; 2. Upper cavity; 3. Lower cavity; 4. Wafer; 5. Wafer boat; 6. Support rod; 7. Transmission interaction interface; 8. Heating plate; 11. Air inlet; 12. Air outlet; 13. Lamp tube; 14. Transmission mechanism; 51. Upper support plate; 52. Lower support plate; 53. Side support bar; 54. Wafer support block; 55. Step. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] Figure 3 This is a schematic diagram of the structure of a multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to the present invention; Figure 4 It is a schematic diagram of the cross-sectional structure when the wafer of the present invention is located in the upper cavity; Figure 5 It is a schematic diagram of the cross-sectional structure when the wafer of the present invention is located in the lower cavity.

[0021] See also Figure 3 , Figure 4 and Figure 5 The multifunctional pretreatment integrated chamber for preparing semiconductor wafers provided by the present invention is mainly composed of a chamber cover 1, an upper cavity 2, a lower cavity 3, a wafer 4, a wafer boat 5, a support rod 6, a transmission interaction interface 7, an air inlet 11, an air outlet 12, a lamp tube 13, a transmission mechanism 14, etc.

[0022] Chamber structure: Figure 4 and Figure 5As shown, the upper chamber 2 and the lower chamber 3 are connected, and together with the chamber cover 1, they form a closed chamber for evacuating, heating and cooling the wafer. The parts are made of stainless steel or aluminum alloy, and the chamber cover 1, the upper chamber 2 and the lower chamber 3 are sealed with metal sealing rings or O-rings. The metal sealing ring can be made of materials such as oxygen-free copper or silver-plated oxygen-free copper, and the O-ring can be made of materials such as fluororubber. The lower chamber 3 is used for overall load-bearing support, and is installed on the side with the whole machine to ensure installation accuracy, and an interface is reserved for wafer transfer interaction with the EFEM (Equipment Front - End Module) and the TM module (Transfer Chamber). The EFEM is used to transfer wafers from the outside to the inside of the equipment, and the transfer chamber is used to maintain a stable vacuum environment and dock with multiple different chambers. There are two reserved interfaces, one on each side, a 50*336mm rectangular interface, which is sealed with a transfer valve. When the transfer valve is opened, EFEM and LL or TM and LL interact. When the transfer valve is closed, the cavity is closed to perform heating, cooling and vacuuming functions. The transmission mechanism 14 is divided into lifting and lowering motion and rotational motion, driving the crystal boat 5 and the support rod 6 to lift and rotate. The rotation transmission mechanism uses a servo motor, a reducer and a synchronous belt structure for transmission. During installation and debugging, the rotation angle position information is determined, and the parameters are pre-stored in the PLC to communicate with the motor so that the motor runs to the specified position every time. To ensure the precise docking of each layer of the crystal boat, the principle is consistent with the above. The lifting transmission mechanism uses a servo motor, a synchronous belt and a ball screw structure for transmission. During installation and debugging, the position information of the reserved interface of each layer of wafers to be lifted is determined, and the parameters are pre-stored in the PLC to communicate with the motor so that the motor runs to the specified position every time.

[0023] The cavity of the existing PVD equipment can generally only support the storage of a single wafer, and the cavity volume is relatively small, about 15-30L, so an ordinary vacuum pump can meet the process requirements, and the vacuuming time of a single wafer is about 15-25s. The cavity designed by the present invention can store 0-50 wafers, and the layer spacing is adjustable from 5-50mm, so the cavity volume is relatively large; preferably, the cross-section of the wafer boat 5 is slightly larger than the wafer 4, the volume of the upper cavity 2 is slightly larger than the volume of the wafer boat 5, and the volume of the lower cavity 3 is slightly larger than the upper cavity 2. The size of the entire cavity is between 120L-200L, so it is necessary to ensure that the vacuuming is completed quickly to meet the efficiency improvement of the whole WPH.

[0024] Ordinary vacuum pumps can no longer meet the requirements. Since vacuum pumps with high pumping speeds are generally larger in size, after the pumping speed is calculated through simulation, the vacuum pump needs to be customized according to the cavity size to meet the vacuuming needs of multiple wafers. After simulation calculations of vacuum pumps with different pumping speeds, when the pumping speed is 1800L / s-3200L / s, it can meet the vacuuming efficiency requirements of large volumes. Figure 8To simulate the vacuuming of a cavity storing 20 wafers, a vacuum pump with a pumping speed of 3200L / s is used. It takes 1.8min, or 108s, to evacuate from atmospheric pressure to 5E-4pa. On average, for a single wafer, the vacuuming time is 108s / 20=5.4s. It can be seen that compared with traditional PVD equipment, the innovative design not only meets the vacuuming needs of multiple wafers, but also significantly improves efficiency.

[0025] Wafer boat structure: The wafer boat 5 is placed on the support rod 6 and can be lifted or rotated along with the transmission mechanism 14. Multiple wafers 4 can be placed in the wafer boat 5. The number can be adjusted according to different processes. At least one wafer is placed, and it is recommended to place no more than 50 wafers. The wafer boat is made of quartz, silicon carbide, silicon or stainless steel.

[0026] Heating function: The upper cavity 2 can heat the wafer in a variety of ways by installing different components, including but not limited to gas heating, lamp heating, heating wire heating, microwave heating, induction heating, etc. If gas heating is used, other heating is not required, but it is necessary to switch between hot and cold gases; if other heating is used, the gas can be used only for cooling, and there is no need to switch between hot and cold gases. Multiple wafers 4 are placed in the wafer boat 5. Under the action of the transmission mechanism 14, the wafer 4, the wafer boat 5, and the support rod 6 move upward together, so that multiple wafers enter the upper cavity 2. For example, an air inlet 11 and an air outlet 12 are set on the side of the upper cavity 2, and high-temperature gas is introduced into the air inlet 11 and circulated from the air outlet 12 through a vacuum pump to perform gas heating; or, for example, a lamp tube 13 is installed on the inner side of the upper cavity 2, and lamp tube heating can be performed. Since the upper cavity 2 needs to be installed with the lamp tube 13 or the air inlet 11 and the air outlet 12 high-temperature air inlet and outlet pipes, etc., in order to facilitate installation and maintenance, the upper cavity 2 and the lower cavity 3 are made into separate structures and fastened with screws to facilitate the disassembly, assembly and replacement of the upper cavity 2.

[0027] The main difficulty of the multifunctional chamber of the present invention for placing multiple wafers in the wafer boat structure is how to ensure the temperature uniformity of the multiple wafers. If it cannot be ensured, the quality and uniformity of the coating will be affected. To this end, the heating device of the present invention ensures the temperature uniformity of heating multiple wafers from the following three aspects.

[0028] i) The high-temperature gas heating structure is adopted. The high-temperature gas of 100-500℃ is introduced through the air inlet to fill the entire cavity. The cavity is closed, so that multiple wafers are kept in the entire high-temperature gas atmosphere for a certain period of time to reach the preset temperature of the wafer. This heating method can achieve the heating of multiple wafers. At the same time, since the upper and lower surfaces of each wafer are in contact with the gas, the temperature uniformity of multiple wafers is better.

[0029] ii) The design uses a multi-layer wafer boat to structurally ensure the storage of multi-layer wafers. At the same time, the layer spacing of 5-50mm can be adjusted as needed, preferably 10mm.

[0030] iii) Through simulation analysis of different air flow rates and holding times, it is found that when the air flow rate is 40-200SLM and the holding time is within 10s-60s, better temperature uniformity can be achieved. Preferably, the temperature of a single wafer is 328°C with a uniformity of <±1°C; the temperature of multiple wafers is 325-334°C with a uniformity of <±5°C, which meets the process requirements.

[0031] Similarly, other heating methods, such as lamp heating, heating wire heating, microwave heating, induction heating, etc., can also achieve this effect through reasonable design. The simulated temperature uniformity using high-temperature gas generally meets the design requirements, and the relatively low temperature is at the bottom of the upper cavity 2. Preferably, high-temperature gas heating and other heating methods can be used in combination, and the above-mentioned other heating devices are also arranged at the bottom of the upper cavity 2 to improve temperature uniformity and reduce the control difficulty of a single method.

[0032] Cooling function: The high-temperature air from the air inlet 11 on the upper cavity 2 is replaced with normal-temperature or low-temperature gas, and the air is pumped out through the air outlet 12 by a vacuum pump for circulation, thereby cooling the multiple wafers 4 in the wafer boat 5 .

[0033] Load locking function: Multiple wafers 4 are placed in the wafer boat 5, and the wafers 4, the wafer boat 5, and the support rods 6 are lowered into the lower cavity 3 along with the transmission mechanism 14. Figure 5 As shown; the upper chamber 2 or the lower chamber 3 is provided with an air inlet and outlet on the chamber wall, and the chamber pressure can reach atmospheric pressure by continuous air intake, at which time the wafer can be transferred and interacted with the EFEM; the air outlet 12 is connected to a vacuum pump, and the chamber pressure can be pumped to a high vacuum state, at which time the wafer can be transferred and interacted with the TM chamber. Therefore, the integrated chamber of the present invention has a load locking function for multiple wafers.

[0034] As a preferred implementation, please continue to refer to Figure 6 The wafer boat 5 is composed of an upper support plate 51, a lower support plate 52, three vertical side support bars 53, and support blocks 54 for supporting the contact between wafers. A wafer 4 is supported by three support blocks 54, and the support blocks 54 are fixed to the side support bars 53 by screws. By replacing the side support bars 53 of different heights and matching different numbers of support blocks 54, the storage requirements of different numbers of wafers 4 can be met, such as 1-50 wafers can be placed.

[0035] When multiple wafers 4 are placed in the wafer boat 5 of the present invention, the interlayer spacing of the wafer boat is between 5-50 mm, preferably 10 mm. Specifically, the interlayer spacing of the wafers can be adjusted by replacing the spacing between the fixing holes of two adjacent layers of the support blocks of the support bar. Figure 7It is an enlarged view of the wafer support block carrying the wafer. The wafer support block 55 is designed with a step 55 to form a stepped surface. The height of the step 55 is 0.1-2mm, and the gap between the step 55 and the wafer 4 is 0.5-5mm. After the wafer 4 is placed on the stepped surface of the wafer boat by the robot, during the movement and rotation process, due to the presence of the stepped surface, the wafer 4 will not slip out and generate the risk of fragmentation.

[0036] The multifunctional pretreatment integrated chamber for preparing semiconductor wafers provided by the present invention has the following advantages: 1) Integrate heating and degassing functions, cooling functions, and load lock functions into one chamber The present invention integrates three functions into one cavity, reducing the number of cavities, thereby reducing the footprint of the entire device and reducing costs. Fig. 9 As shown in the figure, under the condition of meeting the same function, the number of wafer transfers is reduced, the scheduling scheme is significantly simplified, and the efficiency is improved. In addition, since the number of wafer transfers is reduced, the movement time of the wafer on the robot is reduced, thus reducing the risk of wafer damage and contamination.

[0037] 2) Multiple wafers are vacuumed, heated, degassed and cooled simultaneously The present invention designs a multi-layer wafer boat in a cavity, so that multiple wafers can be vacuumed, heated, degassed and cooled simultaneously, thereby improving efficiency.

[0038] 3) Easy maintenance The present invention designs the upper and lower chambers into separate structures, so that the upper heating and cooling chamber is easy to disassemble and maintain, and the lower transmission chamber ensures the transmission interaction and the installation accuracy of the whole machine, so as to achieve the purpose of convenient maintenance and disassembly and reduce maintenance time.

[0039] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A multifunctional pre-processing integrated chamber for preparing semiconductor wafers, characterized in that: The invention comprises a chamber cover (1), an upper chamber (2) and a lower chamber (3), wherein the upper chamber (2) and the lower chamber (3) are connected and form a closed chamber with the chamber cover (1), wherein a wafer boat (5) is arranged in the closed chamber, wherein the wafer boat (5) adopts a multi-layer design and is used to place a plurality of wafers (4), wherein the wafer boat (5) is placed on a support rod (6), wherein the support rod (6) is connected to a transmission mechanism (14), and wherein the wafer boat (5) can perform lifting or rotating motion along with the transmission mechanism (14); an air inlet (11) and an air outlet (12) are arranged on the side of the upper chamber (2), wherein the air outlet (12) is connected to a vacuum pump, and wherein the lower chamber (3) is provided with a transmission interaction interface (7).

2. The multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to claim 1, characterized in that: The upper cavity (2) and the lower cavity (3) adopt a split structure, and a metal sealing ring or an O-ring is used to seal between the upper cavity (2) and the lower cavity (3); and a metal sealing ring or an O-ring is used to seal between the cavity cover (1) and the upper cavity (2).

3. The multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to claim 2, characterized in that: The material of the metal sealing ring is oxygen-free copper or silver-plated oxygen-free copper, and the material of the O-ring is fluororubber.

4. The multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to claim 1, characterized in that: The wafer boat (5) comprises an upper support plate (51) and a lower support plate (52); the upper support plate (51) and the lower support plate (52) are connected via a side support bar (53); a wafer support block (54) is provided on the side support bar (53); and a step (55) is formed on the wafer support block (54).

5. The multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to claim 4, characterized in that: The wafer support blocks (54) are arranged in layers, the layer spacing is designed to be 5-50 mm, the total number of layers is 1-50, and one wafer is placed on each layer.

6. The multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to claim 4, characterized in that: The height of the step (55) is 0.1-2 mm, and the gap between the step (55) and the wafer (4) is 0.5-5 mm.

7. The multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to claim 4, characterized in that: The number of the side support bars (53) is 3.

8. The multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to claim 1, characterized in that: When the air inlet (11) is heated, a high-temperature gas of 100-500°C is introduced, the air flow rate is 40-200SLM, the insulation time is 10s-60s, the vacuum pumping speed is 1800L / s-3200L / s, until the atmospheric pressure is pumped to 5E-4pa, and the temperature of the multiple wafers is 325-334°C.

9. The multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to claim 8, characterized in that: A heating device is provided at the bottom of the upper cavity (2), and the heating device is a lamp tube, a heating wire, a microwave heater or an induction heater.

10. The multifunctional pre-processing integrated chamber for preparing semiconductor wafers according to claim 1, characterized in that: The transmission mechanism (14) is mounted on the lower cavity (3) via a sealing flange, and the transmission interaction interface (7) is provided with a transmission valve for sealing.

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