Wafer thermal compression bonding machine and wafer cooling method

Abstract

The application discloses a wafer thermal compression bonding machine and a wafer cooling method, wherein the wafer thermal compression bonding machine comprises a base assembly, the upper end of the base assembly is provided with a bonding base, and a lower pressing disc assembly is installed on the inner side of the bonding base; the wafer thermal compression bonding machine comprises a bonding cover assembly, an upper pressing disc assembly is installed in a cover body of the bonding cover assembly, the cover body is hinged to the upper end of the base assembly, the cover body is sealed and covered on the bonding base, and then a sealed cavity is formed between the bonding base and the cover body, and the upper pressing disc assembly and the lower pressing disc assembly are opposite to each other. The wafer cooling time is shortened, and the consumed electric energy in the cooling process is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor manufacturing, and particularly relates to a wafer thermal compression bonding machine and a wafer cooling method. BACKGROUND

[0002] Wafer bonding is a key technology in the field of semiconductor manufacturing and the like, and is used for tightly combining two or more wafers through physical and chemical actions. It is an important link in the process of semiconductor manufacturing. Due to the complexity of the process, various defects such as weld cracking, offset and holes often occur, which greatly affect the performance and reliability of the chip. The main process of wafer bonding is as follows: the wafer is placed on a heated lower disc assembly, the bonding cover is closed, vacuum is extracted, heating is stopped after heating to a specified temperature (the temperature is determined according to the material, and before heating, the heating disc and cold screen of the upper disc assembly and the heating disc and cold screen of the lower disc assembly are separated by a pneumatic cylinder), pressure is applied and maintained for half an hour to complete the bonding, the heating disc and cold screen of the upper disc assembly and the lower disc assembly are attached again by the pneumatic cylinder, the external water cooler supplies cooling water to the cold screen until the wafer is cooled to below 200℃, protective gas is injected into the vacuum cavity (break vacuum), and the bonding cover is opened until the wafer is cooled to room temperature.

[0003] The above bonding process takes several hours to complete, and the cooling process takes the longest time. Therefore, the above bonding process has the following disadvantages:

[0004] 1. In the cooling stage in the vacuum, the heat transfer path of the wafer is: heating disc -> cold screen -> cooling water. Obviously, the heat of the wafer needs to pass through the heating disc and the cold screen, which is indirect heat dissipation, and the heat transfer efficiency is low, which is one of the reasons for the long cooling time of the bonding process.

[0005] 2. The cooling water rises in temperature after passing through the cold screen, and is cooled again by the water cooler before being supplied to the cold screen again to be cooled again, thereby forming a water cooling cycle. A wafer thermal compression bonding machine is usually equipped with multiple water coolers, and the specific number of water coolers is determined according to the bonding temperature. Taking a bonding temperature of 450℃ as an example, the power of each water cooler is 450W, so three water coolers are needed, and the total cooling power of the wafer thermal compression bonding machine is 1350W. After several hours of cooling, more than 10 degrees of electric energy is consumed, which is one of the reasons for the high power consumption of the existing wafer thermal compression bonding machine.

[0006] 3. In the break vacuum stage, normal temperature nitrogen gas is supplied, which can also be other inert gases, but nitrogen gas is low in price and is the conventional choice for break vacuum at present. If low-temperature nitrogen gas is supplied, the temperature of the low-temperature nitrogen gas is too low and is not easy to control accurately, which can easily cause the wafer to deform or break due to sudden temperature drop. Therefore, normal nitrogen gas is still used for break vacuum, and wind cooling is not used in this stage to shorten the cooling time.

[0007] 4、In the room temperature natural cooling stage after the bonding cover is opened, the temperature is reduced from 200 DEG C to room temperature, and the natural cooling time is too long, which is another reason for the long cooling time of the bonding process.

[0008] Therefore, the existing wafer thermal compression bonding has the technical problem of long cooling time, resulting in low wafer bonding efficiency. SUMMARY

[0009] In view of the deficiencies of the prior art, the wafer cooling time is shortened, and the electric energy consumed in the cooling process is reduced. The present application provides a wafer thermal compression bonding machine, which comprises a base assembly, the upper end of the base assembly is provided with a bonding base, and a lower pressing disc assembly is installed on the inner side of the bonding base; a bonding cover assembly is further included, an upper pressing disc assembly is installed in the cover body of the bonding cover assembly, the cover body is hinged to the upper end of the base assembly, and the cover body is sealed and covered on the bonding base, thereby forming a sealed cavity between the bonding base and the cover body, and the upper pressing disc assembly and the lower pressing disc assembly are opposite to each other; a cooling system is further included, the cooling system comprises a low-temperature gas source and a normal-temperature gas source; the low-temperature gas of the low-temperature gas source and the normal-temperature gas of the normal-temperature gas source are both passed through a first temperature control pipeline and then enter the upper pressing disc assembly, the mixed gas passing through the upper pressing disc assembly is passed through a second temperature control pipeline and then enters the lower pressing disc assembly and the sealed cavity respectively, and the mixed gas passing through the lower pressing disc assembly and the sealed cavity is recycled.

[0010] In the preferred scheme of the wafer thermal compression bonding machine in the present application, a recovery cover for recovering the mixed gas is included; the recovery cover is installed on the upper end of the base assembly through a mechanical arm, and the lower end opening of the recovery cover is matched with the bonding base. The function of the recovery cover is to recover the mixed gas passing through the wafer after the bonding cover assembly is opened, and the recovery cover replaces the vacuum cavity to avoid the overflow of the cooling gas.

[0011] In the preferred scheme of the wafer thermal compression bonding machine in the present application, the upper pressing disc assembly comprises an upper fixed disc, an upper cold screen, an upper heating disc and an upper pressing disc connected in sequence from top to bottom, wherein the upper cold screen is communicated between the first temperature control pipeline and the second temperature control pipeline at both ends; the lower pressing disc assembly comprises a lower pressing disc, a lower heating disc, a lower cold screen and a lower fixed disc connected in sequence from top to bottom, wherein the lower cold screen is communicated between the second temperature control pipeline and the recovery pipeline at both ends; the bonding base is provided with an air inlet pipe, the cover body is provided with an air outlet pipe, and the recovery cover is provided with an air inlet hole matched with the air inlet pipe. The air inlet pipe is added to the structure of the existing lower pressing disc assembly, the air outlet pipe is added to the cover body, and the temperature suitable cooling gas is introduced in the breaking vacuum stage to reduce the temperature in the vacuum cavity. The air inlet pipe and the air outlet pipe can form a circulating cooling channel of the cooling gas, and the wafer is continuously cooled, so that the time required for wafer cooling is greatly shortened.

[0012] The preferred scheme of the wafer thermal compression bonding machine in the application is: the first temperature control pipeline comprises a first regulating valve, a second regulating valve, a first stop valve and a first deformable mixing container; the low-temperature gas source is communicated with the first deformable mixing container through the first regulating valve, the normal-temperature gas source is communicated with the first deformable mixing container through the second regulating valve, and the first deformable mixing container is communicated with the upper cold screen through the first stop valve, and the first deformable mixing container is provided with a temperature probe electrically connected with the first stop valve. The second temperature control pipeline comprises a third regulating valve, a fourth regulating valve, a second stop valve and a second deformable mixing container; the low-temperature gas source is communicated with the second deformable mixing container through the third regulating valve, the upper cold screen is communicated with the second deformable mixing container through the fourth regulating valve, and the second deformable mixing container is communicated with the lower cold screen and the gas inlet pipe through the second stop valve, and the second deformable mixing container is provided with a temperature probe electrically connected with the second stop valve. In addition, the low-temperature gas source and the first regulating valve are connected with a one-way valve and a third stop valve in sequence, and the normal-temperature gas source and the second regulating valve are connected with a one-way valve and a fourth stop valve in sequence. The structures of the first temperature control pipeline and the second temperature control pipeline are similar, and both are to mix the low-temperature gas with other gases and temporarily store them in the deformable mixing container. As the gases increase, the volume of the deformable mixing container increases correspondingly, thereby solving the problems of the temperature control pipeline that cannot circulate and the internal pressure continuously increases. The deformable mixing containers are both provided with high-precision temperature probes, and the deformable mixing container can be used for cooling only when the temperature of the deformable mixing container reaches the set temperature, thereby improving the temperature control precision of the cooling gas and effectively solving the technical problem that the existing wafer bonding machine cannot control the quality of the wafer due to uneven cooling.

[0013] The wafer thermal compression bonding machine in the application has the following beneficial effects:

[0014] 1. The cooling gas actively absorbs the heat of the wafer, the upper pressing disc assembly and the lower pressing disc assembly, and the heat dissipation efficiency is greatly improved compared with the existing indirect heat dissipation structure, and the heat dissipation time is obviously reduced.

[0015] 2. The low-temperature gas can be liquid nitrogen, and the normal-temperature gas can be normal-temperature nitrogen. The price of industrial liquid nitrogen is several hundred yuan per ton, and one ton of liquid nitrogen can be vaporized to obtain about 600 cubic meters of nitrogen, that is, 600000 liters. According to the calculation, the price of nitrogen after the vaporization of each liter of liquid nitrogen is less than 1 yuan, and the price of normal-temperature industrial nitrogen is several cents per liter. The cooling system itself consumes very low power, only the electromagnetic valves and the controller consume power, and the total power is several tens of watts. Compared with the water cooling unit of more than 1000 watts, the power consumption is greatly reduced, and the use cost of liquid nitrogen and normal-temperature nitrogen is low. Therefore, the use of the cooling system instead of the existing water cooling unit can greatly reduce the cooling cost.

[0016] The application further provides a wafer cooling method based on the wafer thermal compression bonding machine, which comprises the following steps: after wafer bonding, the steps are as follows:

[0017] Firstly, the driving mechanism on the upper end of the bonding cover assembly drives the upper platen assembly to rise, the upper platen assembly separates from the wafer, and the upper cold screen of the upper platen assembly is attached to the upper heating disc. The first temperature control pipeline mixes the low-temperature gas and the normal-temperature gas to temperature T1, the first stop valve is opened, and the temperature of the upper platen assembly is reduced; the mixed gas passing through the upper cold screen returns to the second regulating valve through the first return pipeline, and the consumption of the normal-temperature gas source is reduced, and thus the cycle is repeated until the temperature of the upper platen assembly is reduced to the set temperature.

[0018] Then, the driving mechanism inside the base assembly drives the lower cold screen of the lower platen assembly to be attached to the lower heating disc. The second temperature control pipeline mixes the low-temperature gas and the mixed gas passing through the upper platen assembly to temperature T2, the second stop valve is opened, the vacuum is broken, and the temperature of the lower platen assembly and the wafer is reduced; part of the mixed gas passing through the lower cold screen and the sealing cavity returns to the second regulating valve through the first branch pipeline, another part of the mixed gas returns to the fourth regulating valve through the second branch pipeline, and the remaining part of the mixed gas is recycled through the exhaust pipe, the fifth stop valve is closed, the consumption of the normal-temperature gas source is reduced, and thus the cycle is repeated until the temperature of the wafer is reduced to the set temperature.

[0019] Finally, the second stop valve is closed, the bonding cover assembly is opened, the mechanical arm seals the cover of the recovery cover on the bonding base, and the air inlet hole of the recovery cover is communicated with the air inlet pipe; the second stop valve is opened, the recovery cover is communicated with the recovery pipeline, the mixed gas continues to cool the wafer to room temperature, the cooling is completed, the cooling system is reset, and the mechanical arm drives the recovery cover to reset. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments described in the present application, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

[0021] Figure 1 It is a structure schematic diagram of the wafer thermal compression bonding machine in the present application;

[0022] Figure 2 It is a structure schematic diagram of the wafer thermal compression bonding machine in the present application; Figure 1 It is a structure schematic diagram of the wafer thermal compression bonding machine in the present application; Figure 1 ;

[0023] Figure 3 It is a structure schematic diagram of the wafer thermal compression bonding machine in the present application; Figure 1 It is a structure schematic diagram of the wafer thermal compression bonding machine in the present application; Figure 2 ;

[0024] Figure 4 It is a structure schematic diagram of the wafer thermal compression bonding machine in the present application; Figure 1Schematic diagram of the key bonding cover assembly after opening Figure 3 ;

[0025] Figure 5 Piping diagram for wafer cooling method in the present application.

[0026] Reference signs: 1, base assembly; 2, bonding base; 3, bonding cover assembly; 4, cover body; 5, upper platen assembly; 6, lower platen assembly; 7, recovery cover; 8, mechanical arm; 9, air inlet pipe; 10, air outlet pipe; 11, driving mechanism. DETAILED DESCRIPTION

[0027] In view of the deficiencies in the prior art, the present inventors have long studied and practiced to come up with the technical solution of the present application. The technical solution, its implementation process and principles will be further explained in the following with reference to the drawings in the embodiments of the present application and specific implementation cases.

[0028] Example One

[0029] As shown in Figure 1 and Figure 4 , Example One provides a wafer thermal compression bonding machine, which includes a base assembly 1, the upper end of the base assembly 1 is provided with a bonding base 2 and a lower platen assembly 6 is installed on the inner side of the bonding base 2; it includes a bonding cover assembly 3, an upper platen assembly 5 is installed in the cover body 4 of the bonding cover assembly 3, the cover body 4 is hinged to the upper end of the base assembly 1, and is sealed and covered on the bonding base 2 through the cover body 4, thereby forming a sealed cavity between the bonding base 2 and the cover body 4 and the upper platen assembly 5 and the lower platen assembly 6 are opposite. The specific structure of the upper platen assembly 5 and the lower platen assembly 6 adopts the existing structure, specifically, the upper platen assembly 5 includes an upper fixed disc, an upper cold screen, an upper heating disc and an upper pressure disc connected in sequence from top to bottom, and the lower platen assembly 6 includes a lower pressure disc, a lower heating disc, a lower cold screen and a lower fixed disc connected in sequence from top to bottom.

[0030] The present embodiment also includes a cooling system, which includes a low-temperature gas source and a normal-temperature gas source, the low-temperature gas source adopts a liquid nitrogen storage cylinder, and the normal-temperature gas source adopts a normal-temperature nitrogen cylinder. The low-temperature gas of the low-temperature gas source and the normal-temperature gas of the normal-temperature gas source are both passed through a first temperature control pipeline to the upper platen assembly 5, the mixed gas passing through the upper platen assembly 5 is passed through a second temperature control pipeline to the lower platen assembly 6 and the sealed cavity respectively, and the mixed gas passing through the lower platen assembly 6 and the sealed cavity is recovered.

[0031] As shown in Figure 2 and Figure 3As shown, in terms of structure, the embodiment further comprises a recovery cover 7 for recovering the mixed gas; the recovery cover 7 is installed at the upper end of the base assembly 1 through a mechanical arm 8, and the lower end opening of the recovery cover 7 is adapted to the bonding base 2. The bonding base 2 is provided with an air inlet pipe 9, the cover body 4 is provided with an air outlet pipe 10, and the recovery cover 7 is provided with an air inlet hole adapted to the air inlet pipe 9. When the recovery cover 7 is sealed and closed on the bonding base 2, the air inlet hole of the recovery cover 7 is just connected in communication with the air inlet pipe 9. The function of the recovery cover 7 is to recover the mixed gas passing through the wafer after the bonding cover assembly 3 is opened. The recovery cover 7 replaces the vacuum cavity to avoid the overflow of the nitrogen gas for cooling, causing the local area to be oxygen-deficient and accidents to occur.

[0032] The specific structure of the first temperature control pipeline is as follows:

[0033] The first temperature control pipeline comprises a first regulating valve, a second regulating valve, a first stop valve and a first deformable mixing container. The low-temperature gas source is communicated with the first deformable mixing container through the first regulating valve, the normal-temperature gas source is communicated with the first deformable mixing container through the second regulating valve, and the first deformable mixing container is communicated with the upper cold screen through the first stop valve, and the first deformable mixing container is provided with a temperature probe electrically connected with the first stop valve.

[0034] The specific structure of the second temperature control pipeline is as follows:

[0035] The second temperature control pipeline comprises a third regulating valve, a fourth regulating valve, a second stop valve and a second deformable mixing container. The low-temperature gas source is communicated with the second deformable mixing container through the third regulating valve, the upper cold screen is communicated with the second deformable mixing container through the fourth regulating valve, and the second deformable mixing container is respectively communicated with the lower cold screen and the air inlet pipe 9 through the second stop valve, and the second deformable mixing container is provided with a temperature probe electrically connected with the second stop valve. In addition, the low-temperature gas source and the first regulating valve are connected with a one-way valve and a third stop valve in sequence, and the normal-temperature gas source and the second regulating valve are connected with a one-way valve and a fourth stop valve in sequence.

[0036] The first deformable mixing container and the second deformable mixing container in the embodiment are both annular pipelines, which comprise an inflatable pipeline and a fixed pipeline, and the fixed pipeline is provided with a circulating fan. The inflatable pipeline can change the volume to meet the temperature control in the nitrogen mixing stage, and serves as a temporary storage space, and the circulating fan can quickly mix the low-temperature nitrogen and the normal-temperature nitrogen, so that the temperature of the mixed nitrogen quickly tends to a stable value, and the mixing effect is obviously improved.

[0037] Further, the embodiment also reduces the consumption of the normal temperature gas source through the reflux pipeline. Specifically, a first reflux pipeline is connected between the upper cold screen and the fourth regulating valve through the first reflux pipeline to the normal temperature gas source and the fourth regulating valve, and the first reflux pipeline is provided with a one-way valve and a fifth stop valve. A first branch pipeline of a second reflux pipeline is connected between the lower cold screen and the recovery pipeline to the normal temperature gas source and the fourth regulating valve, and a second branch pipeline of the second reflux pipeline is connected between the upper cold screen and the fourth regulating valve; the first branch pipeline is provided with a one-way valve and a sixth stop valve, and the second branch pipeline is provided with a one-way valve and a seventh stop valve.

[0038] All the stop valves and all the regulating valves in the embodiment are electromagnetic valves, and the cooling system is provided with a controller. The controller automatically controls the on-off of each electromagnetic valve according to a set program, and automatically completes the wafer cooling process.

[0039] Embodiment two;

[0040] Embodiment two provides a wafer cooling method, and embodiment two is based on the wafer thermal compression bonding machine of embodiment one. The method is as follows:

[0041] First, the driving mechanism 11 at the upper end of the bonding cover assembly 3 drives the upper platen assembly 5 to rise, the upper platen assembly 5 is separated from the wafer, and the upper cold screen of the upper platen assembly 5 is attached to the upper heating disc. The first temperature control pipeline mixes the low-temperature gas and the normal temperature gas to temperature T1, the first stop valve is opened, and the temperature of the upper platen assembly 5 is reduced; the mixed gas passing through the upper cold screen returns to the second regulating valve through the first reflux pipeline, thereby reducing the consumption of the normal temperature gas source, and the cycle continues until the temperature of the upper platen assembly 5 is reduced to the set temperature.

[0042] Then, the driving mechanism 11 inside the base assembly 1 drives the lower cold screen of the lower platen assembly 6 to attach to the lower heating disc. The second temperature control pipeline mixes the low-temperature gas and the mixed gas passing through the upper platen assembly 5 to temperature T2, the second stop valve is opened, the vacuum is broken, and the temperature of the lower platen assembly 6 and the wafer is reduced; part of the mixed gas passing through the lower cold screen and the sealed cavity returns to the second regulating valve through the first branch pipeline, another part of the mixed gas returns to the fourth regulating valve through the second branch pipeline, and the remaining part of the mixed gas is recovered through the exhaust pipe 10, the fifth stop valve is closed, the consumption of the normal temperature gas source is reduced, and the cycle continues until the temperature of the wafer is reduced to the set temperature.

[0043] Finally, the second stop valve is closed, the bonding cover assembly 3 is opened, the mechanical arm 8 seals the recovery cover 7 on the bonding base 2, the air inlet hole of the recovery cover 7 is connected with the air inlet pipe 9, the second stop valve is opened, the recovery cover 7 is connected with the recovery pipeline, the mixed gas continues to cool the wafer to room temperature, the cooling ends, the cooling system is reset, and the mechanical arm 8 drives the recovery cover 7 to reset.

[0044] The wafer cooling method of the embodiment is divided into three cooling stages. After the wafer bonding step is completed, the first stage is that the first regulating valve and the second regulating valve in the first temperature control pipeline release low-temperature liquid nitrogen and normal-temperature nitrogen gas according to the proportion set by the controller, and the first deformable mixing container is quickly mixed. The first deformable mixing container is increased, and the temperature is captured in real time by the temperature probe during the mixing process. When the temperature reaches T1, the first regulating valve and the second regulating valve are both closed, the first stop valve is opened, and the nitrogen gas with accurate temperature is introduced into the upper cold shield by the internal pressure of the first deformable mixing container. The temperature of the nitrogen gas rises, and the nitrogen gas after temperature rise is stored in the temporary gas storage cylinder between the upper cold shield and the fifth stop valve. This part of the nitrogen gas will be used in the next temperature adjustment step. When the temperature of the upper pressure disc assembly 5 decreases to the set temperature, or the gas pressure of the first deformable mixing container decreases to the extent that it cannot continue to fill the temporary gas storage cylinder, the first stop valve is closed, the first regulating valve and the second regulating valve are opened, and the above temperature adjustment step is repeated, but the nitrogen gas in the temporary gas storage cylinder participates in the temperature adjustment. The temperature of this part of the nitrogen gas is higher than that of the normal-temperature nitrogen gas. For example, T1 is 10°C, and the temperature of the nitrogen gas in the temporary gas storage cylinder is 50-70°C. The higher-temperature nitrogen gas mixed with liquid nitrogen can reduce the consumption of normal-temperature nitrogen gas, and then the upper pressure disc assembly 5 is cooled until it decreases to the set temperature.

[0045] The second stage is to release low-temperature liquid nitrogen and nitrogen gas passing through the upper cold shield by the third regulating valve and the fourth regulating valve in the second temperature control pipeline according to the proportion set by the controller. Since the wafer is protected, the temperature of the wafer is controlled at T2=20°C to avoid large temperature difference from causing defects in the wafer. T1 and T2 can be selected according to actual conditions, and the embodiment does not limit them. The temperature regulation mode of the second temperature control pipeline is the same as that of the first temperature control pipeline, but the difference is that the backflow nitrogen gas is divided into three parts. One part of the nitrogen gas participates in the temperature regulation of the first temperature control pipeline, another part of the nitrogen gas is used for the temperature regulation of the second temperature control pipeline, and the remaining part of the nitrogen gas is recovered through the exhaust pipe 10 of the cover 4. The second step simultaneously meets the two requirements of breaking vacuum and direct cooling.

[0046] The third stage is that the wafer is at normal temperature and normal pressure, the recovery cover 7 is sealed on the wafer and the lower pressure disc assembly 6 by the mechanical arm 8, and the wafer is still cooled by using 20°C nitrogen gas. In this process, the recovery cover 7 is in communication with the recovery pipeline, and the remaining nitrogen gas is recovered through the recovery cover 7.

[0047] The above three cooling stages all use temperature-accurate nitrogen gas to directly contact and cool, which can greatly reduce the time required for cooling compared with the existing water cooling and natural cooling methods, thereby improving the wafer bonding efficiency.

[0048] It should be understood that the above embodiments are only to illustrate the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and it cannot be considered that the specific implementation of the present application is limited to these descriptions. For ordinary skilled in the art to which the present application belongs, without departing from the concept of the present application, some simple deductions or substitutions can be made, and any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A wafer hot press bonding machine, comprising a base assembly, wherein a bonding base is provided at the upper end of the base assembly and a lower pressure plate assembly is installed inside the bonding base; The assembly includes a bonding cover assembly, an upper pressure plate assembly installed inside the cover body of the bonding cover assembly, and a cover body hinged to the upper end of the base assembly. The cover body seals and covers the bonding base, thereby forming a sealed cavity between the bonding base and the cover body, with the upper pressure plate assembly and the lower pressure plate assembly facing each other. Its features are: It also includes a cooling system, which includes a low-temperature gas source and a normal-temperature gas source; the low-temperature gas from the low-temperature gas source and the normal-temperature gas from the normal-temperature gas source both pass through the first temperature control pipeline and then to the upper pressure plate assembly. The mixed gas passing through the upper pressure plate assembly passes through the second temperature control pipeline and then to the lower pressure plate assembly and the sealing cavity respectively. The mixed gas passing through the lower pressure plate assembly and the sealing cavity is recovered. The upper pressure plate assembly includes an upper fixed plate, an upper cooling plate, an upper heating plate, and an upper pressure plate connected sequentially from top to bottom, wherein the two ends of the upper cooling plate are connected between the first temperature control pipeline and the second temperature control pipeline; the lower pressure plate assembly includes a lower pressure plate, a lower heating plate, a lower cooling plate, and a lower fixed plate connected sequentially from top to bottom, wherein the two ends of the lower cooling plate are connected between the second temperature control pipeline and the recovery pipeline; the bonding base is provided with an air inlet pipe, the cover is provided with an exhaust pipe, and the recovery hood is provided with an air inlet hole adapted to the air inlet pipe; The first temperature control pipeline includes a first regulating valve, a second regulating valve, a first shut-off valve, and a first deformable mixing container; the low-temperature gas source is connected to the first deformable mixing container through the first regulating valve, the normal temperature gas source is connected to the first deformable mixing container through the second regulating valve, and the first deformable mixing container is connected to the upper cooling screen through the first shut-off valve, and a temperature probe electrically connected to the first shut-off valve is provided inside the first deformable mixing container. The second temperature control pipeline includes a third regulating valve, a fourth regulating valve, a second shut-off valve, and a second deformable mixing container; the low-temperature gas source is connected to the second deformable mixing container through the third regulating valve, the upper cooling screen is connected to the second deformable mixing container through the fourth regulating valve, and the second deformable mixing container is connected to the lower cooling screen and the air inlet pipe through the second shut-off valve, and a temperature probe electrically connected to the second shut-off valve is provided inside the second deformable mixing container.

2. The wafer hot-press bonding machine according to claim 1, characterized in that: It includes a recovery hood for recovering mixed gases; the recovery hood is mounted on the upper end of a base assembly via a robotic arm, and the lower opening of the recovery hood is adapted to the bonding base.

3. The wafer hot-press bonding machine according to claim 1, characterized in that: The low-temperature gas source is connected to the first regulating valve by a check valve and a third shut-off valve in sequence, and the normal-temperature gas source is connected to the second regulating valve by a check valve and a fourth shut-off valve in sequence.

4. A wafer hot-press bonding machine according to claim 3, characterized in that: The upper cooling screen and the fourth regulating valve are connected through a first return pipeline to the ambient temperature gas source and the fourth regulating valve, and the first return pipeline is equipped with a check valve and a fifth shut-off valve; the lower cooling screen and the recovery pipeline are connected through a first branch of the second return pipeline to the ambient temperature gas source and the fourth regulating valve, and through a second branch of the second return pipeline to the upper cooling screen and the fourth regulating valve; the first branch pipeline is equipped with a check valve and a sixth shut-off valve, and the second branch pipeline is equipped with a check valve and a seventh shut-off valve.

5. A wafer hot-press bonding machine according to claim 4, characterized in that: Both the first deformable mixing container and the second deformable mixing container are annular pipes. The annular pipe includes an expandable pipe and a fixed pipe, and the fixed pipe is equipped with a circulating fan.

6. A wafer cooling method, characterized in that: Applied to the wafer hot-press bonding machine of claim 5, after wafer bonding, the steps are as follows: S1. The drive mechanism at the top of the bonding cover assembly drives the upper pressure plate assembly to rise, the upper pressure plate assembly separates from the wafer, and the upper cold screen of the upper pressure plate assembly is attached to the upper heating plate. S2. The first temperature control pipeline mixes the low-temperature gas and the normal-temperature gas to temperature T1. The first shut-off valve opens to reduce the temperature of the upper pressure plate assembly. The mixed gas that has passed through the upper cooling screen flows back to the second regulating valve through the first return pipeline to reduce the consumption of the normal-temperature gas source. This cycle continues until the temperature of the upper pressure plate assembly drops to the set temperature. S3. The drive mechanism inside the base assembly drives the lower cooling screen of the lower pressure plate assembly to fit against the lower heating plate; S4. The second temperature control pipeline mixes the low-temperature gas with the mixed gas passing through the upper pressure plate assembly to a temperature of T2. The second shut-off valve opens, breaking the vacuum and reducing the temperature of the lower pressure plate assembly and the wafer. Part of the mixed gas passing through the lower cooling screen and the sealing cavity flows back to the second regulating valve through the first branch pipeline, and another part of the mixed gas flows back to the fourth regulating valve through the second branch pipeline. The remaining mixed gas is recovered through the exhaust pipe. The fifth shut-off valve is closed to reduce the consumption of room temperature gas source. This cycle continues until the wafer temperature drops to the set temperature. S5. Close the second shut-off valve, open the bonding cover assembly, and the robotic arm seals the recovery cover onto the bonding base. The air inlet of the recovery cover is connected to the air inlet pipe. Open the second shut-off valve, and the recovery cover is connected to the recovery pipeline. The mixed gas continues to cool the wafer to room temperature. When the cooling ends, the cooling system is reset, and the robotic arm drives the recovery cover to reset.

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