Ultra-low temperature wafer implantation process and implantation platform

Abstract

The present invention relates to an ultra-low temperature wafer implantation process and implantation platform. The implantation process uses the ultra-low temperature wafer implantation platform to perform ion implantation on wafers in an ultra-low temperature vacuum environment. The implantation process includes the following steps: wafer loading, vacuuming, transferring the wafers to be processed, cooling the wafers, implanting ions on the wafers, heating the wafers, returning the wafers, unloading the wafers, and marking and storing the wafers. The ultra-low temperature wafer implantation process and implantation platform implement ultra-low temperature ion implantation, forming a complete amorphous layer. This complete amorphous layer allows subsequent ion beams to land on the amorphous layer, thereby distributing subsequent damage to the wafers in the amorphous region. The complete amorphous layer is a high-quality amorphous layer.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor manufacturing and processing, and relates to an ultra-low temperature wafer implantation process and an implantation platform. Background Art

[0002] Semiconductor devices have long been miniaturizing. According to Moore's Law, the number of semiconductor devices per unit area of ​​an integrated circuit chip will double every 18 months. As semiconductor devices become smaller, the majority of their internal structures must also shrink proportionally. Currently, critical dimensions of semiconductor devices have reached the nanometer or deep nanometer scale. Key to improving the performance of complementary metal oxide semiconductors (CMOS) is the ability to fabricate ultra-shallow junctions and abrupt junctions within semiconductor devices, as well as to more completely repair end-of-range defects (EOR) caused by ion implantation during the semiconductor device manufacturing process. Existing theoretical research suggests that addressing these technical challenges generally requires amorphizing the wafer surface.

[0003] Amorphization technology generally involves using neutral atoms such as carbon and germanium to disrupt the original crystal structure of single-crystal silicon on the wafer surface, transforming it into an amorphous state (α-Si). Ion implantation is one of the most widely used techniques for transforming single-crystal silicon into an amorphous state in semiconductor manufacturing in recent years. The principle is to ionize certain electrically neutral atoms or molecules, then direct the desired ion beam at a specific energy and dose at a specific angle into the substrate material (such as a wafer). The incident ions undergo a series of physical or chemical reactions with the substrate, causing changes in the composition, structure, and properties of the substrate surface, thereby transforming the single-crystal silicon into an amorphous state.

[0004] Most of the currently disclosed ion implantation technologies use room temperature ion implantation technology. The ambient temperature during implantation is generally around 20°C. Room temperature ion implantation technology cannot form the required amorphous layer on the wafer surface very well. According to theoretical research, the use of ultra-low temperature ion implantation below -50°C can significantly improve the implantation effect. However, for processes that use ultra-low temperature ion implantation technology, especially ultra-low temperature wafer implantation technology, the ion implantation components used in the original room temperature implantation technology will not be able to be used normally; even if the room temperature ion implantation components are used in shallow low temperature implantation processes above -20°C, the failure rate of the ion implantation components is also very high, and they are often shut down for adjustment and maintenance. This is also one of the important reasons for the shortage of chips and insufficient production capacity in 2021.

[0005] In addition, in room temperature ion implantation technology or shallow low temperature ion implantation technology, as the ion implantation proceeds, the implanted ions will collide with the silicon atoms on the wafer surface, destroying the original crystal structure of the silicon on the wafer surface and causing crystal structure damage. However, since the collision causes the substrate temperature to rise, most of the damage will be repaired as the ion implantation proceeds. This is similar to the rapid annealing phenomenon after ion implantation, but it is a dynamic process, so it can be called dynamic annealing. Because dynamic annealing occurs during room temperature ion implantation or shallow low temperature ion implantation, room temperature ion implantation or shallow low temperature ion implantation cannot form the required amorphous layer on the wafer surface well.

[0006] In order to obtain the desired good amorphous layer or good amorphous state on the wafer surface, a suitable ion implantation technology must be found. Summary of the Invention

[0007] Based on the technical problems existing in the prior art, the present invention provides an ultra-low temperature wafer implantation platform, which utilizes ultra-low temperature ion implantation technology to manufacture ultra-shallow junctions and abrupt junctions, and more completely repairs the end defects of the ion implantation range.

[0008] According to a first aspect of the technical solution of the present invention, a cryogenic wafer implantation process is provided, which is used to perform ion implantation on a wafer in a cryogenic vacuum environment using an cryogenic wafer implantation platform. The cryogenic wafer implantation process includes the following steps:

[0009] Step S1, wafer loading step

[0010] Step S2, vacuuming step;

[0011] Step S3, wafer transfer step to be processed;

[0012] Step S4, wafer cooling step;

[0013] Step S5, wafer ion implantation step;

[0014] Step S6, wafer heating step;

[0015] Step S7, wafer return step;

[0016] Step S8, wafer unloading step;

[0017] Step S9, wafer product marking and storage step.

[0018] Among them, in the wafer loading step of step S1, the wafer transfer box carrying the wafers is placed on the receiving table in the front-end wafer transfer module, and the robot in the front-end wafer transfer module grabs one or more wafers and transfers one or more wafers to the loading platform (11) of the loading module in turn until all the wafers on the receiving table are transferred to the loading platform (11) of the loading module.

[0019] In the vacuuming step of step S2, the gate valve between the front-end wafer transfer module and the loading module is closed, and the chamber of the loading module is vacuumed to reduce the air pressure therein to a high vacuum degree close to that of the vacuum transfer module.

[0020] In the wafer transfer step to be processed in step S3, the gate valve between the loading module and the vacuum transfer module is opened, the front vacuum transfer robot (21) grabs the wafer and transfers it to the alignment platform (22), and the alignment platform (22) calibrates the angular position of the wafer.

[0021] In the wafer cooling step of step S4, the post-vacuum transfer robot 23 grabs the calibrated wafer and transfers it to the vacuum cooling platform (31) to reduce the wafer temperature to the required ultra-low temperature.

[0022] In the wafer ion implantation step of step S5, the post-vacuum transfer robot 23 grabs the cooled wafer and transfers it to the wafer implantation carrier (42), and the wafer is flipped and moved by the wafer scanning robot (41), crossing the ion beam back and forth to complete the ion implantation.

[0023] In the wafer heating step of step S6, the front vacuum transfer robot (21) grabs the wafer processed in step S5 and transfers it to the vacuum heating platform (51), so that the wafer temperature is raised to near room temperature; in the wafer return step of step S7, the front vacuum transfer robot (21) grabs the wafer and transfers it to the loading platform (11).

[0024] In the wafer unloading step of step S8, the gate valve between the loading module and the vacuum transfer module is closed, the air pressure in the loading module chamber is increased to about one atmosphere, the gate valve between the loading module and the front-end wafer transfer module is opened, and the robot in the front-end wafer transfer module transfers the wafer to the wafer transfer box.

[0025] In the wafer product marking and warehousing step S9, the wafers transferred and unloaded in step S8 are marked and sorted and put into the warehouse according to certain warehousing rules.

[0026] According to the second aspect of the technical solution of the present invention, an ultra-low temperature wafer injection platform using the above-mentioned ultra-low temperature wafer injection process is provided, and the ultra-low temperature wafer injection platform at least includes a front-end wafer transfer module, a loading module, a vacuum transfer module, a vacuum cooling module, a vacuum injection module and a vacuum heating module. The front-end wafer transfer module, the loading module, the vacuum transfer module, the vacuum cooling module, the vacuum injection module and the vacuum heating module cooperate with each other and form an organic whole, which realizes ultra-low temperature wafer ion injection; the front-end wafer transfer module, the loading module, the vacuum transfer module, the vacuum cooling module, the vacuum injection module and the vacuum heating module are each separately provided with a chamber of corresponding structure; during the wafer ion injection process, the vacuum transfer module, the vacuum cooling module and the vacuum injection module form an ultra-low temperature working environment, and realize the processing and transfer of wafers in an ultra-low temperature environment.

[0027] Compared with the prior art, the ultra-low temperature wafer implantation process and implantation platform of the present invention have the following beneficial technical effects:

[0028] 1. The ultra-low temperature wafer implantation process and implantation platform of the present invention adopt ultra-low temperature wafer implantation, which effectively suppresses dynamic annealing during the ion implantation process, so that atoms in the interstitial position can no longer return to the lattice replacement position, thereby increasing the number of amorphous packages and gradually expanding the range of amorphous packages. Finally, the boundaries of all amorphous packages are connected together to form a complete amorphous layer.

[0029] 2. The ultra-low temperature wafer implantation process and implantation platform realize ultra-low temperature ion implantation, forming a complete amorphous layer. The complete amorphous layer allows subsequent ion beams to fall on the amorphous layer, thereby distributing the damage caused to the subsequent wafer in the amorphous area. The complete amorphous layer is a high-quality amorphous layer; compared with existing technologies, its amorphous layer is thicker.

[0030] 3. Using the ultra-low temperature wafer implantation process and implantation platform of the present invention, the amorphous silicon generated under low temperature conditions can not only suppress the channeling effect during subsequent ion implantation, but also facilitate the formation of ultra-shallow junctions and abrupt junctions, and can also limit the damage caused by subsequent ion implantation to the amorphous layer, thereby making it easy to repair.

[0031] 4. Using the ultra-low temperature wafer implantation process and implantation platform of the present invention, low temperature ion implantation of carbon, germanium, fluorine and other elements can effectively suppress the transient enhanced diffusion effect (TED) of boron doping atoms.

[0032] 5. Experimental results show that the lower the temperature during ion implantation, the greater the degree of suppression of dynamic annealing. The ultra-low temperature wafer implantation process and implantation platform of the present invention achieve the following: when the temperature during ion implantation can be gradually reduced from room temperature to -100°C, it can be clearly found in the processed wafer that the thickness of the amorphous silicon layer gradually increases, the roughness of the amorphous-crystalline interface is significantly reduced, and the floc-like islands remaining in the amorphous layer gradually disappear as the temperature decreases. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the overall structure of the ultra-low temperature wafer implantation platform according to the present invention.

[0034] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of the electrostatic chuck.

[0035] Figure 3 for Figure 1 Schematic diagram of the top view of the electrostatic chuck.

[0036] Figure 4 for Figure 1 Schematic diagram of the structure of the wafer mechanical auxiliary fixture part.

[0037] Figure 5 for Figure 4 A partial enlarged view of .

[0038] Figure 6 for Figure 4 Schematic diagram of the top view of the wafer mechanical auxiliary fixture part.

[0039] Figure 7 for Figure 1 A first structural diagram of the medium vacuum cooling platform and the electrostatic chuck part thereon.

[0040] Figure 8 for Figure 1 A second structural diagram of the medium vacuum heating platform and the electrostatic chuck part thereon.

[0041] Figure 9 FIG. 4 is a schematic cross-sectional structural diagram of an electrostatic chuck in yet another embodiment.

[0042] Figure 10 FIG. 4 is a schematic cross-sectional structural diagram of an electrostatic chuck in yet another embodiment.

[0043] Figure 11 FIG. 4 is a schematic cross-sectional structural diagram of an electrostatic chuck in another embodiment.

[0044] Explanation of reference numerals in the accompanying drawings: A: loading module; 11: loading platform; B: vacuum transfer module; 21: front vacuum transfer robot; 22: alignment platform; 23: rear vacuum transfer robot; C: vacuum cooling module; 31: vacuum cooling platform; D: vacuum implantation module; 41: wafer scanning robot; 42: wafer implantation carrier; 43: ion beam inlet; 44: beam collection Faraday; E: vacuum heating module; 51: vacuum heating platform; F: front-end wafer transfer module;

[0045] S: wafer; 311: electrostatic chuck body; 312: first printed electrode flexible layer; 313: electrode arrangement; 314: adhesive filling layer; 315: second printed electrode flexible layer; 316: gap; 317: cooling pipe structure; 318: filament; 319: thermal conductive filling layer;

[0046] J: electrostatic suction cup; 4201: clamp; 4202: slide bar; 4203: sleeve; 4204: first return spring; 4205: traction rope; 4206: pulley; 4207: lifting rod; 4208: lifting slider; 4209: screw rod; 4210: installation flexible layer; 4211: second return spring; 4212: guide rail; 4213: driving component. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] The present invention provides an ultra-low temperature wafer implantation process, which is used to perform ion implantation on a wafer in an ultra-low temperature vacuum environment using an ultra-low temperature wafer implantation platform. The ultra-low temperature wafer implantation process includes the following steps:

[0049] Step S1, wafer loading step

[0050] Step S2, vacuuming step;

[0051] Step S3, wafer transfer step to be processed;

[0052] Step S4, wafer cooling step;

[0053] Step S5, wafer ion implantation step;

[0054] Step S6, wafer heating step;

[0055] Step S7, wafer return step;

[0056] Step S8, wafer unloading step;

[0057] Step S9, wafer product marking and storage step.

[0058] Figure 1 The present invention provides an ultra-low temperature wafer implantation process for use in an ultra-low temperature wafer implantation platform. The ultra-low temperature wafer implantation platform includes at least a front-end wafer transfer module F, a loading module A, a vacuum transfer module B, a vacuum cooling module C, a vacuum implantation module D, and a vacuum heating module E. The front-end wafer transfer module F, the loading module A, the vacuum transfer module B, the vacuum cooling module C, the vacuum implantation module D, and the vacuum heating module E cooperate with each other and form an organic whole, which realizes ultra-low temperature wafer ion implantation; the front-end wafer transfer module F, the loading module A, the vacuum transfer module B, the vacuum cooling module C, the vacuum implantation module D, and the vacuum heating module E are each individually provided with a chamber of corresponding structure. During the wafer ion implantation process, the vacuum transfer module B, the vacuum cooling module C, and the vacuum implantation module D form an ultra-low temperature working environment, and realize the processing and transport of the wafer in an ultra-low temperature environment. The ultra-low temperature is below minus 50 degrees Celsius, preferably a low temperature of minus 160 degrees Celsius to minus 100 degrees Celsius.

[0059] Among them, the front-end wafer transfer module F is used to move and transfer wafers to be processed or wafers after ion implantation; the loading module A is used to convert between a vacuum environment and a normal temperature atmospheric environment and load wafers to be processed or unload wafers after ion implantation; the vacuum transfer module B is used to transfer wafers to be processed to the vacuum cooling module C under a vacuum environment, or to transfer processed wafers from the vacuum injection module D to the vacuum heating module E; the vacuum cooling module C is used to cool the wafers to be processed to ensure that the wafers to be processed are in a low temperature state; the vacuum injection module D is used to perform ion implantation on the wafers; the vacuum heating module E is used to heat the processed or ion-implanted wafers, and the processed or ion-implanted wafers are processed or ion-implanted wafers transferred from the vacuum injection module D via the vacuum transfer module B. During operation, the chambers of the connected vacuum transfer module B, vacuum cooling module C, vacuum injection module D and vacuum heating module E are always pumped by at least one vacuum pumping device (such as a vacuum pump) to keep the above vacuum chambers at the required high vacuum level; and at least one vacuum measuring device (such as a vacuum gauge) connected to the above vacuum chambers monitors the air pressure.

[0060] The front-end wafer transfer module F includes at least one robotic arm for moving wafers and a loading platform for accommodating and carrying wafers to be processed. Optionally, the loading platform is used to accommodate and carry wafer cassettes to be processed. The front-end wafer transfer module F is connected to one side of the loading module A, with a controllable gate valve installed at the connection point. The chamber of the loading module A can accommodate at least one wafer and is equipped with a loading platform 11 for placing wafers. The gate valve is preferably a gate valve driven by a cylinder operation, wherein the gate valve is formed by clamping a connecting mechanism that displaceably connects the driving base and the rod part and a cam mechanism that tilts and rotates the rod part between a driving base operated by the cylinder and a rod part fixed on a valve shaft integral with the valve plate. At the same time, a stop part mechanism is provided to stop the rod part at the opposite position or the fully open position of the valve plate. After the stop part mechanism stops the rod part at the opposite position or the fully open position, the cam mechanism tilts and rotates the rod part to tilt the valve plate, thereby tilting the valve plate and pushing the valve seal toward the valve seat or wall surface around the opening.

[0061] The loading module A also includes a vacuum device connected to its chamber, preferably a vacuum pump, which can evacuate the loading module A to a high vacuum and inflate the high vacuum to normal pressure. The vacuum degree of the high vacuum is preferably on the order of 10 — 6 torr or 10 —7 torr.

[0062] Loading module A is used to switch between vacuum environment and normal temperature atmosphere and load wafers to be processed or unload wafers after ion implantation. The specific operation process is as follows:

[0063] Loading module A loads the wafers to be processed in a room-temperature atmosphere. After loading, it enters a high vacuum state and then transfers the wafers to downstream equipment under high vacuum. Loading module A receives the wafers after ion implantation under high vacuum. Afterward, loading module A returns to a room-temperature atmosphere and transfers them to the front-end wafer transfer module F under room-temperature atmosphere.

[0064] The other side of loading module A is connected to vacuum transfer module B. A controllable closed gate valve, preferably a gate valve, is installed at the junction of the two. When both the gate valve and gate valve on loading module A are closed, the chamber becomes sealed. Vacuum transfer module B is a vacuum chamber that includes at least one robot for transferring wafers. In one embodiment, vacuum transfer module B is equipped with a front vacuum transfer robot 21 and a rear vacuum transfer robot 23. Both the front vacuum transfer robot 21 and the rear vacuum transfer robot 23 have a wafer-holding portion at their ends, such as a metal plate, clamp, or suction cup. Preferably, the front vacuum transfer robot 21 is located near the loading platform 11. Vacuum transfer module B also includes an alignment platform 22 for determining and calibrating the wafer notch position to ensure that the wafer is implanted at the correct angle and position. The alignment platform 22 may utilize mechanical or optical alignment methods, for example. Preferably, the alignment platform 22 is located between the front vacuum transfer robot 21 and the rear vacuum transfer robot 23.

[0065] The other side of the vacuum transfer module B is connected and communicated with the vacuum cooling module C, which cools the wafer to a temperature lower than the temperature set by the injection process conditions before injection, which is below -50 degrees Celsius. The vacuum cooling module C includes a cooling device, which is preferably a vacuum cooling platform 31. The vacuum cooling platform 31 is connected to a cooling system. A wafer holding portion is provided on the vacuum cooling platform 31, and the wafer holding portion is preferably a low-temperature resistant electrostatic suction cup. The cooling system reduces the temperature of the wafer holding portion on the vacuum cooling platform 31 to a temperature significantly lower than room temperature, for example, below -60 degrees Celsius. Preferably, the position of the rear vacuum transfer robot 23 is close to the position of the vacuum cooling platform 31. Furthermore, nitrogen is filled between the wafer holding portion and the wafer to be cooled, so that the wafer cools down faster, and the wafer can be cooled to a specified temperature in a very short time.

[0066] The other side of the vacuum transfer module B is connected and communicated with the vacuum injection module D. The vacuum injection module D includes a vacuum process chamber, in which the semiconductor wafer is ion-implanted under ultra-low temperature process conditions. A wafer scanning robot 41 is provided in the vacuum process chamber, and a wafer injection carrier 42 is provided at the end of the scanning robot 41. The wafer injection carrier 42 is preferably an electrostatic suction cup, etc. The wafer injection carrier 42 is used to carry and hold the wafer. The wafer scanning robot 41 is used to move and flip the wafer injection carrier 42. An ion source generation and ion beam shaping module (not shown in the figure) is fixedly provided on the outside of one side wall of the vacuum injection module D. An ion beam inlet 43 is provided at the connection between the ion source generation and ion beam shaping module and the vacuum injection module D, and a beam collection Faraday 44 is provided on a side wall of the vacuum process chamber of the vacuum injection module D opposite to the ion beam inlet 43. Preferably, the wafer scanning robot 41 is located between the ion beam inlet 43 and the beam collection Faraday 44.

[0067] The other side of the vacuum transfer module B is connected to and communicated with the vacuum heating module E. The vacuum heating module E includes a temperature controller with an internal locking function and a heating device connected thereto, so that the wafer is heated to about room temperature after injection. A wafer holding portion is fixedly provided on the heating device. The wafer holding portion is preferably an electrostatic suction cup. The wafer is held on the wafer holding portion, and the wafer holding portion heats up each wafer individually. The heating device and the wafer holding portion to which it is connected may adopt contact heat conduction or radiation heat transfer or other methods. In a specific embodiment, the heating device is a vacuum heating platform 51, and the temperature controller adjusts its temperature so that the temperature of the wafer holding portion to which it is connected is maintained at 40 degrees Celsius to 80 degrees Celsius.

[0068] Compared to the prior art method of heating multiple wafers stacked together, the vacuum heating module E of the present invention uses a contact heating method to increase the adsorption force between the wafer holder and the wafer, making the wafer holder and the wafer closer together, ensuring and controlling the temperature rise of each wafer. This overcomes the problems of the prior art method of heating stacked wafers through ventilation, resulting in uneven heating and long periods of low-temperature storage, which may cause impurities to deposit on the wafer surface and cause defects.

[0069] As can be seen from the attached figure, Figure 1 The robots in the illustrated embodiment include a front vacuum transfer robot 21, a rear vacuum transfer robot 23, and a wafer scanning robot 41. In other embodiments, the number and location of the robots can be adjusted as needed, with any robot capable of performing transfer functions. All robots can provide one or more degrees of freedom, such as translation, elevation, and rotation of wafers.

[0070] A particularly ingenious design lies in the fact that the ultra-low-temperature wafer implantation platform includes a vacuum heating module E, which is used to individually heat the wafers after ultra-low-temperature implantation to near room temperature. This is because the wafer temperature is lowered to, for example, below -110°C under high vacuum before ion implantation; then, the wafers are individually heated to near room temperature under high vacuum. This prevents volatile substances and vapors from condensing on the wafers during the process.

[0071] An ultra-low temperature wafer implantation process using the ultra-low temperature wafer implantation platform is as follows, comprising the following steps:

[0072] Step S1, wafer loading step

[0073] Step S2, vacuuming step;

[0074] Step S3, wafer transfer step to be processed;

[0075] Step S4, wafer cooling step; (cooling platform)

[0076] Step S5, wafer ion implantation step;

[0077] Step S6, wafer heating step;

[0078] Step S7, wafer return step;

[0079] Step S8, wafer unloading step;

[0080] Step S9, wafer product marking and storage step.

[0081] An ultra-low temperature wafer implantation process of the present invention specifically comprises the following steps:

[0082] Step S1, wafer loading step: placing a wafer cassette carrying wafers on the receiving platform in the front-end wafer transfer module F, and the robot in the front-end wafer transfer module F grabs one or more wafers and sequentially transfers one or more wafers to the loading platform 11 of the loading module A until all the wafers on the receiving platform are transferred to the loading platform 11 of the loading module A;

[0083] Step S2, vacuuming step: closing the gate valve between the front-end wafer transfer module F and the loading module A, and vacuuming the chamber of the loading module A to reduce the air pressure therein to a high vacuum degree close to that of the vacuum transfer module B;

[0084] Step S3, wafer transfer step to be processed; the gate valve between the loading module A and the vacuum transfer module B is opened, the front vacuum transfer robot 21 grabs the wafer and transfers it to the alignment platform 22, and the alignment platform 22 calibrates the angular position of the wafer;

[0085] Step S4, wafer cooling step; the vacuum transfer robot 23 grabs the calibrated wafer and transfers it to the vacuum cooling platform 31 to reduce the wafer temperature to the required ultra-low temperature;

[0086] Step S5, wafer ion implantation step; the vacuum transfer robot 23 grabs the cooled wafer and transfers it to the wafer implantation carrier 42, and the wafer scanning robot 41 flips and moves the wafer back and forth across the ion beam to complete the ion implantation;

[0087] Step S6, wafer heating step; the front vacuum transfer robot 21 grabs the wafer processed in step S5 and transfers it to the vacuum heating platform 51, so that the wafer temperature is raised to near room temperature;

[0088] Step S7, wafer return step; the front vacuum transfer robot 21 grabs the wafer and transfers it to the loading platform 11;

[0089] Step S8, wafer unloading step: the gate valve between the loading module A and the vacuum transfer module B is closed, the air pressure in the chamber of the loading module A is increased to about 1 atmosphere, the gate valve between the loading module A and the front-end wafer transfer module F is opened, and the robot in the front-end wafer transfer module F transfers the wafer to the wafer transfer box;

[0090] Step S9 is a wafer product marking and warehousing step; the wafers transferred and unloaded in step S8 are marked and sorted and put into the warehouse according to certain warehousing rules.

[0091] Furthermore, the specific process is as follows:

[0092] In step S1, the initial state is that the gate valve and gate valve of the chamber of loading module A are both closed. Wafers to be implanted are placed in corresponding positions in the front-end wafer transfer module F, preferably 25 wafers stacked together, in a wafer transfer box. When the pressure in the chamber of loading module A is at normal pressure (1 standard atmosphere or approximately 1 standard atmosphere), the gate valve between the front-end wafer transfer module F and loading module A is opened, and the robot in the front-end wafer transfer module F moves one or more wafers to the loading platform 11 in loading module A.

[0093] Close the gate valve between the front-end wafer transfer module F and the loading module A to seal the chamber of the loading module A. Then, evacuate the chamber of the loading module A to reduce the pressure to a high vacuum level (preferably 10) close to that of the remaining chambers (the remaining chambers are the chambers containing the vacuum transfer module B, the vacuum cooling module C, the vacuum injection module D, and the vacuum heating module E). —6 torr or 10 —7 torr).

[0094] The gate valve between loading module A and vacuum transfer module B is opened, and the pre-vacuum transfer robot 21 is activated to grab the wafer on the loading platform 11. The wafer is then moved to the alignment platform 22, which aligns the position and orientation of the wafer's notch. If the position does not meet the requirements, the robot (preferably the pre-vacuum transfer robot 21) is activated to adjust the wafer's position.

[0095] The post-vacuum transfer robot 23 then grabs the calibrated wafer from the alignment platform 22 and moves it to a wafer holding portion (e.g., an electrostatic chuck, preferably an ultra-low-temperature electrostatic chuck) on the vacuum cooling platform 31. The cooling system lowers and maintains the temperature of the vacuum cooling platform 31 near a first cooling temperature Qc1, maintaining the temperature of the wafer holding portion (e.g., an electrostatic chuck, preferably an ultra-low-temperature electrostatic chuck) thereon near a second cooling temperature Qc2, and then lowering the temperature of the electrostatic chuck to a third cooling temperature Qc3. In some embodiments, the temperature of the wafer holding portion on the vacuum cooling platform 31, i.e., Qc2, is monitored by a device such as a temperature sensor. In another specific embodiment, Qc2 is less than or equal to -70 degrees Celsius, preferably between -110 degrees Celsius and -160 degrees Celsius, and more preferably -130 degrees Celsius. The wafer is placed on the wafer holding portion on the vacuum cooling platform 31 for a first time T1, allowing the wafer temperature to quickly drop to the desired ultra-low temperature.

[0096] It should be noted that, from a microscopic perspective, the contact surface between the wafer and the wafer holding portion of the vacuum cooling platform 31 is not a completely flat surface contact, but rather a multi-spot contact, with most of the area being a vacuum gap. The efficiency of vacuum heat conduction is low, and the time required for cooling is long. Therefore, in a preferred embodiment, after the wafer is placed on the vacuum cooling platform 31, nitrogen gas at a pressure of approximately 0.2-2.0% of atmospheres is filled into the small gap between the two. In this case, since the mean free path of nitrogen molecules is greater than the width of the gap, it can effectively act as a medium for heat conduction between the wafer and the platform, shortening the required cooling time. For example, in another embodiment, the wafer cooling time (first time T1) is 20 to 40 seconds, and more preferably 30 seconds ± 2 seconds.

[0097] Next, the post-vacuum transfer robot 23 grabs the ultra-low temperature wafer from the vacuum cooling platform 31 and moves the ultra-low temperature wafer to the wafer implantation carrier 42 in the vacuum implantation module D, where it is held by the wafer implantation carrier 42. The ion source generation and ion beam shaping module continuously generates the required ion beam. When the wafer is not implanted, the ion beam is moved along the Figure 1The ion beam enters the ion beam entrance 43 in the direction of the arrow shown, passes through the vacuum process chamber without obstruction, and is finally received by the beam collection Faraday 44 to detect whether the ion beam size meets the requirements. If the ion beam meets the requirements, the wafer scanning robot 41 will be activated to flip the wafer implantation carrier 42 and the wafer on it to the side of the ion beam without contacting the ion beam. Figure 1 As shown, the wafer scanning robot 41 flips the wafer to be roughly perpendicular to the drawing paper, and makes the wafer face the ion beam inlet 43, forming a certain angle with the direction of ion beam travel. For example, when the ion beam is incident on the wafer vertically, the angle is 90 degrees; when the ion beam is incident on the wafer obliquely, it is adjusted to the corresponding angle. Thereafter, the wafer is driven back and forth by the wafer scanning robot 41, so that the wafer repeatedly crosses the cross section in the longitudinal direction (perpendicular to the wafer). Figure 1 The ion beam is irradiated repeatedly on the wafer surface to realize ion implantation.

[0098] After that, the wafer scanning robot 41 is activated and then moves the wafer to a side close to the vacuum transfer module B, for example. The front vacuum transfer robot 21 is activated, grabs the wafer on the wafer injection carrier 42, and then moves the wafer to the wafer holding portion on the vacuum heating platform 51. The heating duration is the second time T2, so that the wafer is quickly heated from a low temperature to near room temperature. The temperature controller increases the temperature of the vacuum heating platform 51 and maintains it near the first heating temperature Qh1, so that the temperature of the wafer holding portion thereon is maintained at the second heating temperature Qh2, and then the temperature of the wafer is increased to the third heating temperature Qh3. In some embodiments, the temperature of the wafer holding portion on the vacuum heating platform 51, i.e., Qh2, is monitored by a device such as a temperature sensor. In a further specific embodiment, the second heating temperature Qh2 is preferably 40 to 80 degrees Celsius, and more preferably about 70 degrees Celsius.

[0099] In one embodiment, the wafer holding portion on the vacuum heating platform 51 and the wafer are also filled with nitrogen to achieve rapid heating of the wafer. It should be noted that the provision of two nitrogen pipelines will increase the complexity of the structure and may cause confusion in gas transmission control. To solve this problem, in another specific embodiment, the nitrogen flow method is not adopted, and the wafer holding portion on the vacuum heating platform 51 (such as an electrostatic chuck, preferably an ultra-low temperature electrostatic chuck) still adopts the existing multi-spot contact form. By increasing the adsorption force of the electrostatic chuck, the electrostatic chuck and the wafer are more closely attached and the contact area is larger, thereby accelerating heat conduction and reducing the time required for heating. At the same time, since the second heating temperature Qh2 is higher than room temperature, the temperature gradient of the heating process is large, so the temperature of the wafer changes faster during the heating process than during the cooling process, so that a shorter heating time can be achieved without using nitrogen filling as a medium to assist heat transfer. The heating time (i.e., the second time T2) is 30 to 70 seconds, and more preferably 60 seconds.

[0100] After the heating is completed, the front vacuum transfer robot 21 moves to grab the wafer on the vacuum heating platform 51 and moves it to the loading platform 11 .

[0101] This process is repeated until all wafers have been processed, returned, and stacked on the loading platform 11. Finally, the gate valve between the loading module A and the vacuum transfer module B is closed, raising the pressure in the loading module A to atmospheric pressure. The gate valve between the front-end wafer transfer module F and the loading module A is then opened, and the wafers are transferred to the wafer transfer pod (FOUP) via the robot in the front-end wafer transfer module F.

[0102] In a preferred embodiment, at least an ultra-low temperature electrostatic chuck is used on the vacuum cooling platform 31. The ultra-low temperature electrostatic chuck can withstand temperatures as low as -150 degrees Celsius. The structure of the ultra-low temperature electrostatic chuck is as follows: Figure 2 、 Figure 3 As shown, it is a structure of at least four layers, including an electrostatic suction cup body 311. In one embodiment, it is disc-shaped or plate-shaped, and there is no restriction on the shape and thickness of the bottom surface; the material is generally metal, such as aluminum, titanium, etc. A first printed electrode flexible layer 312 is bonded and fixed to the electrostatic suction cup body 311 by a glue layer (the material is, for example, liquid glue, not shown in the figure). At least two groups of electrode arrangements 313 are provided on the side of the first printed electrode flexible layer 312 away from the electrostatic suction cup body 311. Specifically, the electrode arrangement 313 can be connected by, for example, bonding. Preferably, a circuit printed board manufacturing method is used to place metal (such as copper) in a set geometric pattern (such as Figure 3As shown, the electrode arrangement is a plurality of parallel, non-intersecting wavy lines) fixed to the first printed electrode flexible layer 312. It is understood that in actual production, the process is, for example, to first print the electrode arrangement 313 onto the first printed electrode flexible layer 312, and then adhere the entire assembly to the electrostatic chuck body 311 via adhesive. An adhesive filler layer 314 (made of a low-temperature-resistant, flexible, adhesive, and nearly electrically insulating material, such as a low-temperature-resistant resin) is also fixedly disposed on the surface of the first printed electrode flexible layer 312 bearing the electrode arrangement 313. A second printed electrode flexible layer 315 is also bonded to the adhesive filler layer 314. The adhesive filler layer 314 fills the gaps between the electrode arrangements 313 and serves to bond the second printed electrode flexible layer 315 to the first printed electrode flexible layer 312 and the electrode arrangement 313. In one specific embodiment, the second printed electrode flexible layer 315 has the same shape and size as the first printed electrode flexible layer 312, and their edges overlap.

[0103] It can be imagined that the role of the adhesive filling layer 314 is to fill the gap of the electrode arrangement 313 and fix the second printed electrode flexible layer 315, the first printed electrode flexible layer 312 and the electrode arrangement 313. Therefore, if the above method is used for production, the actual structure may be as follows: Figure 9 As shown, the adhesive filling layer 314 will exceed the upper surface of the electrode arrangement 313 and then be connected as a whole, covering the electrode arrangement 313, so that the contact area between the adhesive filling layer 314 and the second printed electrode flexible layer 315 is larger and the bonding is stronger. Similarly, another feasible embodiment is as follows Figure 10 As shown, it is equivalent to Figure 2 The stacked structure of the first printed electrode flexible layer 312, the electrode arrangement 313, the adhesive filling layer 314, and the second printed electrode flexible layer 315 is inverted. Figure 11 As shown, the adhesive filling layer 314 covers the upper and lower surfaces of the electrode arrangement 313 .

[0104] Both the first printed electrode flexible layer 312 and the second printed electrode flexible layer 315 are polyimide films, typically with a thickness of 15 to 100 microns. Table 1 lists the physical properties of a polyimide film. Polyimide film serves as a dielectric film in an electrostatic chuck. Polyimide film is non-conductive. Positive or negative charges applied to one side of the polyimide film induce charges of opposite polarity on the other side. Due to its flexible, tough, and ductile properties, and the thinness of the metal electrode arrangement 313, it can absorb stress caused by thermal expansion and contraction of different materials. This prevents the polyimide film and electrode arrangement 313 from separating or cracking even at -150°C. Furthermore, the polyimide film has an operating temperature range of, for example, -200 to 350°C, meeting the ultra-low temperature requirements of the electrostatic chuck (e.g., room temperature during manufacturing and installation, and -150°C during operation).

[0105] Table 1 Physical properties of a polyimide film

[0106] performance index Maximum tensile strength, kpsi (23°C) 25.0 3% yield point, kpsi (23℃) 9.5 5% elongation pressure, kpsi (23℃) 15.0 Density, g / cc or g / ml 1.4170 Linear elongation coefficient, ppm / C 47 Specific heat, J / g·K 1.26 Glass transition temperature (TG), ℃ 420 Dielectric strength, V / mil 3500

[0107] When using, such as Figure 2 As shown, on a microscopic scale, a gap 316 exists between the wafer S and the electrostatic chuck. An external power source applies a set voltage to the electrode array 313, charging the electrode array 313. Based on the principle of electrostatic induction, the wafer S placed on the electrostatic chuck generates induced charges and an electric field, causing the wafer S to be attracted to the electrostatic chuck due to the attractive force between the positive and negative charges. Furthermore, the magnitude of this attractive force can be controlled by adjusting the applied voltage.

[0108] In a specific embodiment, Figure 7 As shown, the vacuum cooling platform 31 is fixed or integrally formed below the electrostatic chuck. The vacuum cooling platform 31 has a cooling pipe structure 317. A cooling medium, such as a coolant, is continuously introduced and flows through the pipes of the cooling pipe structure 317. The cooling medium absorbs heat at the vacuum cooling platform 31, thereby maintaining the vacuum cooling platform 31 and the electrostatic chuck thereon at the desired ultra-low temperature. It should be noted that on a microscopic scale, the lower surface of the electrostatic chuck and the upper surface of the vacuum cooling platform 31 are not completely flat. Therefore, there is multi-spot contact between the two, with most of the area being gaps. In addition, there are no gas molecules as a medium in the vacuum environment, resulting in a slow heat conduction rate. Therefore, preferably, a thermally conductive filling layer 319 is further provided between the vacuum cooling platform 31 and the electrostatic chuck. The specific material is indium, preferably pure aluminum after annealing. The thermally conductive filling layer 319 is relatively soft and has a high thermal conductivity coefficient, and can fill the vacuum gap between the electrostatic chuck and the vacuum cooling platform 31, thereby improving the heat conduction rate.

[0109] In this way, a three-layer structure of stacked "vacuum cooling platform 31-ultra-low temperature electrostatic chuck-wafer" is formed during the cooling process, and heat is transferred in sequence and the temperature rises in sequence. For example, the vacuum cooling platform 31 is -160 degrees Celsius, the ultra-low temperature electrostatic chuck is -130 degrees Celsius, and the temperature of the wafer is -100 degrees Celsius after staying for a period of time.

[0110] In another specific embodiment, Figure 8 As shown, the vacuum heating platform 51 includes a filament 318. For example, the vacuum heating platform 51 is generally in the shape of a flat, hollow box, which houses the filament 318. The middle section of the filament 318 may be shaped like a spiral mosquito coil, a wavy line, or a spiral column. Both ends of the filament 318 are connected to a power source, which can control the power supply to the filament 318 and cause it to heat. Preferably, the filament 318 is a graphite filament. If the temperature of the filament 318 and the vacuum heating platform 51 is high, direct contact with the electrostatic chuck is not recommended. A gap must be maintained between the vacuum heating platform 51 and the electrostatic chuck. During operation, this gap is a vacuum, allowing heat to be transferred by radiation. Specifically, for example, a fixed support device can be provided on the side or bottom of the electrostatic chuck to securely position the electrostatic chuck above the vacuum heating platform 51 without contacting it. Alternatively, a gasket made of an insulating material can be fixedly provided between the electrostatic chuck and the vacuum heating platform 51 to support the electrostatic chuck, and so on. Any specific structure that can achieve this technical effect is acceptable. Preferably, the temperature controller maintains the temperature of the filament 318 at a temperature within the range of 300 degrees Celsius to 700 degrees Celsius, and the temperature of the wafer holding portion (preferably the electrostatic chuck) does not exceed 80 degrees Celsius.

[0111] In another preferred embodiment, at least the wafer injection carrier 42 is provided with an electrostatic chuck having a wafer mechanical auxiliary fixture, the structure of which is shown in FIG. Figures 4 to 6 The wafer mechanical auxiliary fixture is arranged on the back of the electrostatic chuck J. The wafer mechanical auxiliary fixture includes a mounting flexible layer 4210, which is fixedly arranged on the lower surface of the electrostatic chuck J (the side opposite to the contact surface of the wafer S). Specifically, the mounting flexible layer 4210 and the electrostatic chuck J can be fixed by, for example, bonding or other methods; preferably, as Figure 4 As shown, a bolt connection method is adopted, one or more blind holes with internal threads are opened on the back of the electrostatic suction cup J, and corresponding through holes are opened on the mounting flexible layer 4210. The bolts pass through the through holes and are screwed into the threaded holes to fix them; in this way, the bolts are removable and easy to adjust, repair, and replace.

[0112] A plurality of clips 4201 are provided at the edge of the flexible layer 4210, the number of which is more than two, preferably, the number is odd, and further preferably, as shown in FIG. Figure 6As shown, there are three evenly distributed ones. Each clamp 4201 is connected to the mounting flexible layer 4210 through a clamp limiting sliding mechanism and is located below the electrostatic suction cup J, and the top of the clamp 4201 is located higher than the upper surface of the wafer S (the other side of the wafer S opposite to the contact surface) after the electrostatic suction cup J adsorbs the wafer S, thereby ensuring that the clamp 4201 can clamp to the edge of the wafer S. The center of the inscribed circle at the location of several clamps 4201 is the same as that of the electrostatic suction cup J and the diameter is larger than that of the electrostatic suction cup J. The clamp 4201 slides through the clamp limiting sliding mechanism, so that the diameter of the inscribed circle at the location of several clamps 4201 increases or decreases, thereby achieving clamping and release of the wafer S.

[0113] In a specific embodiment, Figure 5 As shown, the clamp limiting sliding mechanism includes a slide bar 4202 and a sleeve 4203 of matching shapes. The outer diameter of the slide bar 4202 is equal to or slightly smaller than the inner diameter of the sleeve 4203. The slide bar 4202 coaxially passes through the sleeve 4203 and can slide smoothly along its axial direction under the restriction of the sleeve 4203. One side of the sleeve 4203 is fixedly connected to the mounting flexible layer 4210, and the other side does not exceed the lower surface of the electrostatic suction cup J. The slide bar 4202 has a section with a diameter smaller than the rest of the section. A first reset spring 4204 is provided outside this end and inside the sleeve 4203. One end of the first reset spring 4204 is fixedly connected to the slide bar 4202, and the other end is fixedly connected to the sleeve 4203. For example Figure 5 In the illustrated embodiment, the side of the slide bar 4202 near the center of the flexible mounting layer 4210 is a section with a smaller diameter. A clamp 4201 is fixedly connected to the slide bar 4202, for example, by screws. A traction rope 4205 is fixedly attached to the other end of the slide bar 4202. Thus, when the traction rope 4205 is pulled inward, the first return spring 4204 is compressed, and the clamp 4201 clamps the wafer S. When the tension is removed, the first return spring 4204 returns to its original position, and the clamp 4201 also returns to its original position, releasing the wafer S. A through hole is provided at the center of the flexible mounting layer 2410. A lifting mechanism is fixedly disposed below the through hole. The portion of the lifting mechanism that performs the lifting motion is fixedly connected to the end of the traction rope 4205, thereby controlling the pulling and release of the traction rope 4205. Preferably, a pulley 2406 is also provided on the installation flexible layer 4210. The pulley 4206 is located near the intersection of the sliding rod 4202 and the movement direction of the lifting mechanism. The traction rope 4205 is placed on the pulley 4206 and is always in contact with the pulley 4206 during the movement of each component, thereby reducing friction and making the clamp 4201 move more smoothly.

[0114] In one embodiment, see Figure 4 、 Figure 5The lifting mechanism includes a lifting sleeve and a lifting rod 4207 that performs lifting motion. The lifting sleeve extends downward (away from the electrostatic chuck J) along the edge of the through hole where the flexible layer 4210 is installed. The lifting rod 4207 is arranged in the lifting sleeve and is fixedly connected to the traction rope 4205. For example, Figure 4 As shown, the upper end of the lifting rod 4207 is provided with a number and position corresponding to the number of small holes in the clamp 4201, through which the traction rope 4205 is inserted and secured by bonding, knotting, snapping, etc. Preferably, a second return spring 4211 is provided, which is sleeved outside the lifting rod 4207 and inside the lifting sleeve. One end of the second return spring 4211 is fixedly connected to the lifting sleeve or the installation flexible layer 4210, and the other end is fixedly connected to the lifting rod 4207. During the clamping operation, the lifting rod 4207 moves downward under the action of an external force, and the second return spring 4211 is stretched. During the release operation, the external force is removed, and the lifting rod 4207 is pulled back to its initial position by the second return spring 4211.

[0115] Further, such as Figure 4 As shown, the lifting mechanism also includes a lifting slider 4208, a screw rod 4209, and a motor 4213. The lower section of the lifting sleeve is a guide rail 4212, the inner surface of which matches the outer surface of the lifting slider 4208 in shape and size, so that the lifting slider 4208 can only move smoothly under the restraining action of the guide rail 4212. In one embodiment, the motor 4213 is a linear motor, which is fixedly connected to the screw rod 4209, which is fixedly connected to the lifting slider 4208 via threads. The motor 4213 directly controls the lifting or lowering of the lifting slider 4208. In another embodiment, the motor 4213 is a rotor motor, which is fixedly connected to the screw rod 4209, and the screw rod 4209 is threadedly connected to the lifting slider 4208; the cross-sectional shape of the lifting slider 4208 is a shape other than a circle, such as a polygon or other irregular shape, and the cross-sectional shape of the guide rail 4212 corresponds to it, so that the lifting slider 4208 cannot rotate in the guide rail 4212; the motor 4213 controls the screw rod 4209 to rotate clockwise / counterclockwise along its axis, and due to the cooperation of the thread, the lifting slider 4208 will make corresponding lifting and lowering movements in the guide rail 4212.

[0116] It can be imagined that the purpose of the above-mentioned lifting mechanism is to control the movement of the end of the traction rope 4205. The above is only described with reference to the illustrated embodiment, and other specific structures that can achieve similar functions are also possible.

[0117] Preferably, the clip 4201 is made of thermosetting polyimide (Vespel) material to avoid metal contamination, which is used in vacuum equipment such as integrated circuit etching and chemical vapor deposition (CVD); the material of the sleeve 4203, lifting sleeve, etc. is, for example, quartz.

[0118] The wafer mechanical auxiliary clamp of the present invention can be directly installed on the electrostatic chuck of an existing ion implanter without causing contamination of the implanted metal. The electrostatic chuck with the wafer mechanical auxiliary clamp provides auxiliary fixation during the wafer clamping and release processes. When residual charge prevents the wafer from being lifted smoothly and gas must be introduced into the gap between the wafer and the electrostatic chuck, the wafer is secured by the clamp and prevents it from shifting or falling. All clamping mechanisms are located on the back of the electrostatic chuck, shielded from the ion beam; all moving parts are confined within a quartz sleeve, ensuring that particles do not migrate onto the wafer.

[0119] Existing technologies only produce relatively thin amorphous layers, which cannot provide sufficient resistance to subsequent ion implantation, resulting in severe channeling. Effective control of junction depth and the sudden change in doping concentration within the junction depth cannot be guaranteed. Furthermore, the damage caused by ion implantation cannot be fully recovered after the subsequent rapid thermal annealing process, and residual defects lead to increased device leakage. However, the ultra-low temperature wafer implantation platform of the present invention forms a thicker and more complete amorphous layer in actual production. A thicker and more complete amorphous layer reduces ion beam tail crosstalk, and the resulting damage is more distributed in the amorphous region, with less damage introduced into the crystalline region outside the amorphous-crystalline interface.

[0120] It should be noted that, in the ultra-low temperature wafer injection platform in the preferred embodiment of the present invention, during operation, the only parts that are at ultra-low temperature are the vacuum cooling platform 31, the ultra-low temperature electrostatic chuck on the vacuum cooling platform 31, and the wafer. In this way, the entire equipment is basically kept at room temperature and operates stably. During the injection process, only the wafer may be at ultra-low temperature (if the wafer injection carrier 42 in contact with the wafer has the wafer mechanical auxiliary clamp of the present invention, the wafer injection carrier 42 will not reach ultra-low temperature; of course, the wafer injection carrier 42 may also adopt the ultra-low temperature electrostatic chuck of the present invention).

[0121] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. An ultra-low temperature wafer implantation process, characterized in that: It is used to perform ion implantation on a wafer in an ultra-low temperature vacuum environment using an ultra-low temperature wafer implantation platform, and includes the following steps: Step S1, wafer loading step; Step S2, vacuuming step; Step S3, wafer transfer step to be processed; Step S4, wafer cooling step; Step S5, wafer ion implantation step; Step S6, wafer heating step; Step S7, wafer return step; Step S8, wafer unloading step; Step S9, wafer product marking and storage step; In the wafer loading step of step S1, a wafer transfer box carrying wafers is placed on a receiving platform in a front-end wafer transfer module, and a robot in the front-end wafer transfer module grabs one or more wafers and sequentially transfers one or more wafers to a loading platform (11) of a loading module until all wafers on the receiving platform are transferred to the loading platform (11) of the loading module; In the vacuuming step of step S2, the gate valve between the front-end wafer transfer module and the loading module is closed, and the chamber of the loading module is vacuumed to reduce the air pressure therein to a high vacuum level close to that of the vacuum transfer module; In the wafer transfer step to be processed in step S3, the gate valve between the loading module and the vacuum transfer module is opened, the front vacuum transfer robot (21) grabs the wafer and transfers it to the alignment platform (22), and the alignment platform (22) calibrates the angular position of the wafer; In the wafer cooling step of step S4, the post-vacuum transfer robot (23) grabs the calibrated wafer and transfers it to the vacuum cooling platform (31) to reduce the wafer temperature to the required ultra-low temperature; The vacuum cooling platform (31) adopts an ultra-low temperature electrostatic chuck, wherein the ultra-low temperature is -150 degrees Celsius, and the ultra-low temperature electrostatic chuck can withstand ultra-low temperature. The ultra-low temperature electrostatic chuck has at least four layers, including an electrostatic chuck body (311), and a first printed electrode flexible layer (312) is fixed thereon by adhesive layer. At least two groups of electrode arrangements (313) are arranged on the side of the first printed electrode flexible layer (312) away from the electrostatic chuck body (311), and an adhesive filling is also fixed on the side of the first printed electrode flexible layer (312) with the electrode arrangement (313). A layer (314) is provided, a second printed electrode flexible layer (315) is also fixed on the adhesive filling layer (314) by bonding, and a gap (316) exists between the wafer and the electrostatic chuck body (311); a cooling pipe structure (317) is provided in the vacuum cooling platform (31), a cooling medium is continuously introduced and flows through the pipe of the cooling pipe structure (317), and the cooling medium absorbs heat at the vacuum cooling platform (31), thereby maintaining the vacuum cooling platform (31) and the electrostatic chuck thereon at a desired ultra-low temperature, and a heat-conducting filling layer (319) is also provided between the vacuum cooling platform (31) and the electrostatic chuck; In the wafer ion implantation step of step S5, the post-vacuum transfer robot (23) grabs the cooled wafer and transfers it to the wafer implantation carrier (42), and the wafer is flipped and moved by the wafer scanning robot (41), so that the wafer traverses the ion beam back and forth to complete the ion implantation; Wherein, the rear vacuum transfer robot (23) grabs the ultra-low temperature wafer from the vacuum cooling platform (31), and moves the ultra-low temperature wafer to the wafer injection carrier (42) in the vacuum injection module, and is held by the wafer injection carrier (42). The wafer injection carrier (42) adopts an electrostatic suction cup with a wafer mechanical auxiliary clamp, and the wafer mechanical auxiliary clamp is arranged behind the electrostatic suction cup. The wafer mechanical auxiliary clamp includes an installation flexible layer (4210), and the installation flexible layer (4210) is fixedly arranged on the lower surface of the electrostatic suction cup opposite to the wafer contact surface.

2. The ultra-low temperature wafer implantation process according to claim 1, characterized in that: In the wafer heating step of step S6, the front vacuum transfer robot (21) grabs the wafer processed in step S5 and transfers it to the vacuum heating platform (51), so that the wafer temperature is raised to near room temperature; In the wafer return step of step S7, the front vacuum transfer robot (21) grabs the wafer and transfers it to the loading platform (11).

3. The ultra-low temperature wafer implantation process according to claim 2, characterized in that: In the wafer unloading step of step S8, the gate valve between the loading module and the vacuum transfer module is closed, the air pressure in the loading module chamber is increased to about one atmosphere, the gate valve between the loading module and the front-end wafer transfer module is opened, and the robot in the front-end wafer transfer module transfers the wafer to the wafer transfer box.

4. The ultra-low temperature wafer implantation process according to claim 3, characterized in that: In the wafer product marking and warehousing step S9, the wafers transferred and unloaded in step S8 are marked and sorted and put into the warehouse according to certain warehousing rules.

5. An ultra-low temperature wafer implantation platform using any one of the ultra-low temperature wafer implantation processes of claims 1-4, characterized in that: The ultra-low temperature wafer injection platform includes at least a front-end wafer transfer module, a loading module, a vacuum transfer module, a vacuum cooling module, a vacuum injection module and a vacuum heating module. The front-end wafer transfer module, the loading module, the vacuum transfer module, the vacuum cooling module, the vacuum injection module and the vacuum heating module cooperate with each other and form an organic whole, which realizes ultra-low temperature wafer ion injection; the front-end wafer transfer module, the loading module, the vacuum transfer module, the vacuum cooling module, the vacuum injection module and the vacuum heating module are each separately provided with a chamber of corresponding structure; during the wafer ion injection process, the vacuum transfer module, the vacuum cooling module and the vacuum injection module form an ultra-low temperature working environment, and realize the processing and transfer of wafers in an ultra-low temperature environment.

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