Ultra-thin conducting ring with submillimeter-level thickness, preparation method of conducting ring and clamping driving device without fixed clamping point

Abstract

The invention provides an ultra-thin submillimeter-level thickness conducting ring, a preparation method thereof and a clamping driving device without a fixed clamping point, the clamping driving device is used for clamping the conducting ring without the fixed clamping point and driving the conducting ring to rotate, and in the electroplating and annealing steps in the conducting ring preparation process, the clamping driving device is used for clamping the conducting ring without the fixed clamping point and driving the conducting ring to rotate. The clamping driving device clamps and drives the conducting ring to rotate without a fixed clamping point, the technical problem of uneven electroplating caused by clamping contact points in the conventional electroplating process is solved, the stress relieving effect in the annealing process is more reasonable and uniform, and finally the uniform ultra-thin conducting ring with the submillimeter-level thickness is prepared.

Description

Technical Field

[0001] The present invention relates to the field of electroplating technology, and in particular to a clamping drive device without a fixed clamping point, a method for preparing an ultra-thin sub-millimeter-thickness conductive ring using the clamping drive device, and an ultra-thin sub-millimeter-thickness conductive ring prepared using the preparation method. Background Art

[0002] Electroplating is the process of plating a layer of other metals or alloys on certain metal surfaces using the principle of electrolysis. It uses electrolysis to adhere a layer of metal film to the surface of metal or other materials to prevent metal oxidation, improve wear resistance, corrosion resistance, reflectivity, enhance aesthetics, and improve conductivity.

[0003] During the production process of semiconductor components, their surfaces need to be electroplated. Taking the electroplating of bare wafers as an example, the bare wafer needs to be placed in a specific electroplating fixture, namely the plating head, to participate in the electroplating work; the wafer is fixed in the plating head and fits tightly with the conductive ring. Therefore, during the electroplating process, the wafer can be connected to an external power source through the plating head to form power; the wafer is immersed in the plating solution, and the plating head is powered to achieve electroplating of the wafer.

[0004] With the continuous expansion of demand for semiconductor products, the requirements for the efficiency of electroplating, which is a key process for producing wafers, are becoming increasingly stringent; especially in the field of high-end semiconductor manufacturing, there is an urgent need to find a solution to the low efficiency of wafer electroplating. Through experimental observation, it is found that the biggest factor affecting the low efficiency of wafer electroplating is the poor substrate and poor performance of general conductive rings (performance refers to stress, conductivity, thermal capacitance, etc.), which cannot produce the best effect during electroplating. In addition, conventional hanging plating operations often use a fixture to clamp the wafer and immerse it in the plating solution. Since the contact point between the fixture and the wafer will cause a certain obstruction, the electroplating layer quality of the contact point of the hanging conductive ring will be poor and even there will be leakage plating. Summary of the invention

[0005] In view of the defects in the prior art, the purpose of the present invention is to provide a clamping drive device without a fixed clamping point, a method for preparing an ultra-thin sub-millimeter-thick conductive ring using the clamping drive device, and an ultra-thin sub-millimeter-thick conductive ring prepared using the preparation method. The present invention solves the technical problem of low electroplating efficiency caused by poor substrates of general conductive rings without changing the substrate of the conductive ring; and fundamentally solves the welding phenomenon caused by exposed substrates (that is, in the actual production process, the conductive ring with Cu, Ti and BeCu as the substrate contacts with the exposed wafer (the raw material is Si), and the high temperature generated after the plating head is powered on will cause the edge of the wafer to melt and adhere to the conductive ring); in addition, the present invention also achieves the goal of reducing or eliminating stress by adding a high-temperature annealing process and rotating the conductive ring during the annealing process to make the stress elimination more uniform. At the same time, the present invention provides a clamping drive device without a fixed clamping point to solve the problems of uneven electroplating and missed plating caused by the contact point between the fixture and the conductive ring during electroplating.

[0006] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0007] According to a first aspect of the present invention, there is provided a clamping drive device without a fixed clamping point, comprising a clamp and a drive device; the clamp comprises a plurality of rollers, which are evenly distributed around the outer side of a conductive ring; a slot is provided on the roller, which is used to clamp the conductive ring; the drive device comprises a rotary drive device and a centripetal drive device; the rotary drive device comprises a first driving source and a rotating shaft, the rotating shaft is connected to the roller in a direction perpendicular to the plane of the roller slot, and the first driving source drives the rotating shaft to rotate; the centripetal drive device comprises a lead screw, a transmission nut and a second driving source, the lead screw is located on the upper surface of the conductive ring, and the front end of the lead screw points to the center of the conductive ring along the radius of the conductive ring; the transmission nut is connected to the lead screw, and the transmission nut can move along the lead screw in a direction close to or away from the center of the conductive ring; the second driving source drives the transmission nut to move on the lead screw; the centripetal drive device is connected to the rotary drive device via the transmission nut.

[0008] The clamping drive device provided by the technical solution is used to clamp and drive the conductive ring to rotate, wherein the centripetal drive device is used to drive the rotary drive device to approach or move away from the conductive ring along the radial direction of the conductive ring, and the roller included in the rotary drive device clamps the conductive ring with its slot, and drives the conductive ring to rotate under the drive of the first drive source, thereby realizing clamping electroplating without a fixed clamping point, thereby avoiding the occurrence of plating leakage caused by the contact between the clamp and the conductive ring, making the electroplating of the conductive ring substrate more uniform, smooth and high-quality, which is conducive to realizing electroplating without a fixed clamping point. In the technical solution, the so-called "several" rollers refer to an indefinite amount of 3 or more; the so-called "uniform" distribution does not require that the rollers are evenly distributed on the outer edge of the circumference of the conductive ring. As long as the diameter of the conductive ring is used as the axis and rollers are distributed on both sides, it belongs to the category of "uniform" distribution.

[0009] Preferably, the first driving source and the second driving source are both motors, that is, the first motor and the second motor, and the motor housings are both provided with a cooling water circulation system isolated from the outside.

[0010] In the present technical solution, by adopting the above structure, the cooling water circulation system can protect the motor in a high-temperature closed environment during the annealing process, so that the motor can continuously drive the conductive ring to rotate, which is conducive to a more uniform stress elimination effect.

[0011] Preferably, it also includes an automatic loading and unloading device for a conductive ring, which is used to automatically put the conductive ring into or leave the electroplating position; it includes an umbrella-shaped clamping device and a driving system; the umbrella-shaped clamping device includes a main shaft, a liftable sleeve, a retractable arm and a rubber ball; the liftable sleeve is wrapped outside the main shaft and connected to the retractable arm; the driving system is connected to the liftable sleeve and can drive the liftable sleeve to rise and fall on the main shaft, thereby pulling the retractable arm to open and close; the rubber ball is connected to the end of the retractable arm, and when the retractable arm is opened, the rubber ball presses against the inner edge of the conductive ring, thereby clamping the conductive ring. The driving system may include components such as a cylinder, a pump and an air pipe, which provide power for the lifting and lowering movement of the liftable sleeve on the main shaft.

[0012] In the present technical solution, by adopting the above structure, the conductive ring can be conveniently placed in or out of the electroplating position, wherein the rubber ball can prevent the retractable arm from scratching the conductive ring to be plated when it is extended, thereby affecting the final electroplating effect.

[0013] According to a second aspect of the present invention, a method for preparing an ultra-thin sub-millimeter-thickness conductive ring is provided, using the clamping drive device without a fixed clamping point as described in any one of the above items, comprising the following steps:

[0014] S10, providing a conductive ring body, wherein the conductive ring body is a Cu substrate, a Ti substrate, or a BeCu substrate;

[0015] S20, electroplating the surface of the conductive ring body by using a clamping drive device without a fixed clamping point to uniformly deposit a layer of conductive metal or conductive alloy to form a conductive ring after electroplating;

[0016] The thickness of the conductive metal or conductive alloy is controlled between 100nm and 20um, the conductive metal is any one of Pt, Au, Ag, Pd, Ni, Cu, and W, and the conductive alloy is any alloy of Pt, Au, Ag, Pd, Ni, Cu, and W;

[0017] S30. Clamp the electroplated conductive ring using a clamping drive device without a fixed clamping point to perform a high-temperature annealing process on the electroplated conductive ring. The high-temperature annealing process includes temperature rise, insulation, and drop processes, wherein the temperature rise gradient is between 100 and 200°C / min, the insulation temperature range is between 400 and 800°C, and the temperature drop gradient is between 50 and 120°C / min.

[0018] In the present technical scheme, by adopting the above steps, general conductive ring substrates Cu, Ti and BeCu are selected as the conductive ring body, and a metal or alloy with better conductive performance is plated on the general conductive ring body to improve the conductivity of the conductive ring. The metal or alloy is deposited on the surface of the conductive ring body by precision electroplating, and the thickness (THK) is controlled in the range of 100nm to 20um, so that the coating has a good bonding force with the substrate. The applicant has found that the thickness is controlled within this range to obtain a more uniform metal coating and very few pores. Finally, the present technical scheme performs a high-temperature annealing process on the electroplated conductive ring obtained in the above steps to improve the surface hardness (HV, Vickers hardness unit) of the electroplated conductive ring, and finally achieves a hardness of 100kg / mm ​​for the electroplated conductive ring. 2 ~500kg / mm 2 The surface hardness of the conductive ring is higher than that of the general conductive ring. In addition, the present technical solution also changes the traditional way of clamping the conductive ring by using a clamping drive device without a fixed clamping point for electroplating, so that there is no fixed clamping contact point between the clamp and the conductive ring, thereby ensuring the uniformity and consistency of electroplating and avoiding the phenomenon of missed plating. In addition, the present technical solution achieves the goal of reducing or eliminating stress by controlling the temperature rise, insulation, and decline process of high-temperature annealing. And in the annealing process, since there is no contact point between the clamp and the conductive ring, it is conducive to more reasonable and uniform stress elimination.

[0019] Preferably, in step S10, the conductive ring body is made of titanium alloy, and in step S20, Pt is electroplated and deposited on the surface of the conductive ring body.

[0020] Preferably, in step S10, the conductive ring body is made of BeCu, and in step S20, rose gold is deposited on the surface of the conductive ring body by electroplating.

[0021] Preferably, in step S20, the electroplating without fixed clamping points comprises the following steps:

[0022] In the first step, the main axis of the umbrella-shaped clamping device and the position centers of several evenly distributed rollers are concentrically calibrated, and then the automatic loading and unloading device of the conductive ring is started and controlled to be lowered to the level of the rubber ball and flush with the conductive ring body, and then the telescopic arm is opened to clamp the conductive ring body and move the conductive ring body to the electroplating position;

[0023] The second step is to start the second driving source to drive the roller to move toward the center of the conductive ring body until the conductive ring body is inserted into the roller slot and becomes tangent to the outer diameter of the roller; at the same time, the automatic loading and unloading device retracts the retractable arm to separate from the conductive ring body;

[0024] The third step is to start the first driving source to drive the roller to rotate around the rotation axis, thereby driving the conductive ring body to rotate around the center of the circle, thereby achieving electroplating without a fixed clamping point.

[0025] Preferably, in step S30, the heat preservation process includes heat preservation stages at different temperatures to avoid new stress caused by too rapid changes in the temperature field.

[0026] Preferably, in step S30, the annealing process further includes the following steps:

[0027] In the first step, the second driving source is started to drive the roller to move toward the center of the electroplated conductive ring until the electroplated conductive ring is clamped into the roller clamping groove and is tangent to the outer diameter of the roller.

[0028] In the second step, the first driving source is started to drive the roller to rotate around the rotation axis, thereby driving the conductive ring to rotate around the center of the circle as the axis.

[0029] In the technical solution, by adopting the above steps, the conductive ring after electroplating can have no fixed contact points for clamping the conductive ring during the annealing process, so that the stress elimination effect is more reasonable and uniform.

[0030] According to a third aspect of the present invention, there is provided an ultra-thin sub-millimeter-thickness conductive ring, which is prepared by any of the above-mentioned ultra-thin sub-millimeter-thickness conductive ring preparation processes.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. Solve the current situation that the general conductive ring has poor conductivity: the conductive ring of the present invention is provided with a metal plating layer with good conductivity, which reduces the conductive impedance of the conductive ring and enhances the stability of the current transmitted by the conductive ring; at the same time, it can also reduce the maintenance of the conductive ring and save the cost of maintenance and replacement.

[0033] 2. Solve the current situation of uneven, rough, too thin or too thick coating thickness of general conductive rings: The present invention controls the coating thickness of the conductive ring within a suitable range. The uniform coating thickness can ensure the consistency and uniformity of the current distribution density when the conductive ring is working, and ensure the total quality of the coating on the wafer surface. At the same time, the thicker coating can well protect the conductive ring body and reduce the frequency of replacing the conductive ring.

[0034] 3. During the electroplating process, the non-uniformity of current density will lead to inconsistent stress in the electroplating layer, which will increase the risk of lattice dislocation. Under the extrusion of the rotating electroplating head, crack expansion or tearing may occur at individual stress peaks. In view of the requirements of precision electroplating and ensuring the reduction of the contact resistance of the conductive ring, the present invention adds a high-temperature annealing process to control the temperature rise, insulation and drop process of the high-temperature annealing to achieve the goal of reducing or eliminating stress. At the same time, during the annealing process, a clamping drive device without a fixed clamping point is used to drive the conductive ring to rotate, so as to achieve a more uniform effect of eliminating stress.

[0035] 4. Solve the problems of poor quality of electroplating layer and missed plating at the contact points of the conductive rings in conventional hanging plating: The present invention provides a clamping drive device without fixed clamping points to achieve precision electroplating. The device changes the traditional way of clamping the conductive ring, so that there is no fixed clamping contact point between the clamp and the conductive ring, thereby ensuring the uniformity and consistency of electroplating and avoiding missed plating. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0037] Figure 1 This is a schematic structural diagram of the clamping drive device without a fixed clamping point described in Example 1;

[0038] Figure 2 Schematic diagram of the preferred uniform distribution of rollers in Example 1;

[0039] Figure 3 is a schematic diagram of the structure of the clamp in Example 1;

[0040] Figure 4 This is a schematic structural diagram of the conductive ring automatic loading and unloading device in Example 1;

[0041] Figure 5A diagram showing the process of loading a conductive ring by the conductive ring automatic loading and unloading device in Example 1;

[0042] Figure 6 This is a flow chart of the steps for preparing an ultra-thin sub-millimeter-thickness conductive ring in Example 2.

[0043] Description of reference numerals:

[0044] 1- Clamping drive device without fixed clamping point 2- Conductive ring 3- Clamp

[0045] 4-driving device 5-roller 6-slot

[0046] 7-Rotation drive device 8-Centriptial drive device 9-Screw rod

[0047] 10- transmission nut 11- second motor 12- first motor

[0048] 13-rotating shaft 14-sleeve 15-conductive ring automatic loading and unloading device

[0049] 16- umbrella-shaped clamping device 17- driving system 18- spindle

[0050] 19-liftable sleeve 20-retractable arm 21-rubber ball

[0051] 22- Cylinder 23- Pump 24- Air pipe DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0053] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0054] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in the subsequent figures. In addition, all directional indications in this application (such as up, down, left, right, front, back, bottom...) are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the figures). If the specific posture changes, the directional indication will also change accordingly. Furthermore, the descriptions involving "first", "second", etc. in the application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated.

[0055] Example 1

[0056] like Figure 1-Figure 4 As shown, this embodiment provides a clamping drive device 1 without a fixed clamping point, which can clamp the conductive ring 2 close to and without a fixed contact point. Under the action of friction, the device drives the conductive ring 2 to rotate in the electroplating solution and perform electroplating by its own rotation. Since there is no fixed contact point between the conductive ring 2 and the clamp 3 during the electroplating process, the electroplating can be made more uniform and smooth, thereby avoiding the possibility of missed plating in conventional hanging plating.

[0057] The clamping drive device 1 without a fixed clamping point comprises a clamp 3 and a drive device 4. The clamp 3 is used to clamp the conductive ring 2, and comprises a plurality of rollers 5 evenly distributed around the outer side of the conductive ring, wherein the plurality of rollers 5 is three or more in number, and the plurality of rollers 5 is as follows: Figure 2 As shown, they are evenly distributed around the conductive ring 2. Each roller 5 is provided with a slot 6, the plane of the slot 6 is parallel to the plane of the conductive ring 2, and the slot 6 is used to clamp the conductive ring 2. When the clamping drive device 1 without a fixed clamping point is working, the roller 5 is driven to approach the conductive ring 2 until the conductive ring 2 is clamped into the slot 6 of the roller and is tangent to the roller 5. Since the roller 5 is tangent to the conductive ring 2, there is no fixed contact point between the conductive ring 2 and the clamp 3. Under the action of friction, the conductive ring 2 will rotate with the rotation of the roller 5.

[0058] Furthermore, the driving device 4 includes a rotation driving device 7 and a centripetal driving device 8 .

[0059] Among them, the rotation drive device 7 is used to control the rotation of the roller 5, which includes a first motor 12 and a rotating shaft 13. The roller 5 is nested on the rotating shaft 13 through a sleeve 14 with the rotating shaft 13 as the axis, and the rotating shaft 13 is perpendicular to the plane direction of the roller slot 6. At the same time, the rotating shaft 13 is connected to the first motor 12. When the first motor 12 drives the rotating shaft 13 to rotate, the roller 5 connected to the rotating shaft 13 also rotates around the rotating shaft 13. At this time, since the conductive ring 2 is clamped by the roller 5, the conductive ring 2 is driven by a number of evenly distributed rollers 5 to rotate with the center of the circle as the axis under the action of friction. The centripetal drive device 8 is connected to the rotation drive device 7 through a transmission nut 10.

[0060] Furthermore, the centripetal drive device 8 is used to drive a number of evenly distributed rollers 5 to automatically locate the center of a circle like a lathe chuck and approach and clamp the conductive ring 2. The centripetal drive device 8 is arranged in the direction of the rotating shaft 13 and is connected to the rotating shaft 13. It can drive the rollers 5 and the rotating shaft 13 to approach or move away from the center of the conductive ring 2 to achieve the purpose of the rollers 5 clamping or disengaging from the conductive ring 2. It includes a screw 9, a transmission nut 10 and a second motor 11. The screw 9 is parallel to the upper surface of the conductive ring 2, and its front end points to the center of the conductive ring 2 along the radius of the conductive ring 2; the transmission nut 10 is nested on the screw 9, and the transmission nut 10 can move along the screw 9 in the direction of approaching or moving away from the center of the conductive ring 2. The second motor 11 is connected to the transmission nut 10 and is used to provide a driving force for the movement of the transmission nut 10 on the screw 9. Since the transmission nut 10 is connected to the rotation drive device 7, under the drive of the second motor 11, the transmission nut 10 can drive the rotation drive device 7 and the roller 5 connected thereto to approach the conductive ring 2 along the screw 9 until the roller 5 is tangent to the outer circumferential surface of the conductive ring 2, thereby achieving the effect of the roller 5 clamping the conductive ring 2.

[0061] Furthermore, the housings of the first motor 12 and the second motor 11 are provided with cooling water circulation systems isolated from the outside world, so as to protect the motors in a high-temperature closed environment during the annealing process.

[0062] Furthermore, if Figure 3-4As shown, it also includes an automatic loading and unloading device 15 for a conductive ring, which is used to automatically move the conductive ring 2 to the electroplating position or remove the conductive ring 2 from the electroplating position. It includes an umbrella-shaped clamping device 16 and a driving system 17. The umbrella-shaped clamping device 16 includes a main shaft 18, a lifting sleeve 19, a retractable arm 20 and a rubber ball 21. The lifting sleeve 19 is wrapped outside the main shaft 18, and is connected to the retractable arm 20. The lifting sleeve 19 can be lifted and lowered on the main shaft 18, thereby pulling the retractable arm 20 to open and close. The rubber ball 21 is connected to the end of the retractable arm 20. When the retractable arm 20 is opened, the rubber ball 21 presses against the inner edge of the conductive ring 2, thereby clamping the conductive ring 2. The driving system 17 is composed of a cylinder 22, a pump 23 and an air pipe 24. The working principles of the cylinder 22, the pump 23 and the air pipe 24 are already in the prior art, and the applicant will not repeat them here.

[0063] The conductive ring automatic loading and unloading device 15 is used to load and unload the conductive ring. When it is connected to the automatic control equipment, the automated operation of loading and unloading the conductive ring can be realized. The process of loading the conductive ring mainly includes the following steps: ① First, the position center of the main shaft 18 and the three rollers 5 is concentrically calibrated (using the automatic control equipment for debugging to set the initial position of the conductive ring automatic loading and unloading device 15), then the conductive ring automatic loading and unloading device 15 is started and controlled to descend to the level of the rubber ball 21 and flush with the plane of the conductive ring 2, and then the retractable arm 20 is opened to clamp the conductive ring 2 and move the conductive ring 2 to the electroplating position. ② Start and control the roller centripetal drive device 8 to make the roller 5 move toward the center of the conductive ring 2 until the roller 5 is tangent to the outer diameter of the conductive ring 5. At the same time, the conductive ring automatic loading and unloading device 15 continues to work to make the retractable arm 20 retract and detach from the conductive ring 2. ③ After completing step ②, the main shaft 18 is lowered to a suitable distance, and the retractable arm 20 is folded and then raised to leave the processing range of the conductive ring 2. At this point, the automatic loading of the conductive ring 2 is completed. The steps for unloading the conductive ring 2 refer to the steps for loading the conductive ring 2 and the reverse operation can be performed to remove the conductive ring 2 smoothly.

[0064] Example 2

[0065] This embodiment provides a method for preparing an ultra-thin sub-millimeter-thickness conductive ring, which uses the clamping drive device without fixed clamping points in Example 1. For ease of description, this embodiment continues to use the reference numerals in Example 1. This embodiment uses the clamping drive device without fixed clamping points to make all parts of the conductive ring (especially the outer edge of the conductive ring) fully and evenly contact the electroplating solution during the electroplating process, so that the electroplating is carried out uniformly.

[0066] Specifically, the method for preparing an ultra-thin sub-millimeter-thickness conductive ring provided in this embodiment comprises the following steps:

[0067] S10, providing an ultra-thin conductive ring body with a thickness of sub-millimeter level, wherein the conductive ring body is a Cu substrate, a Ti substrate, or a BeCu substrate;

[0068] S20. Use the clamping drive device without a fixed clamping point described in Example 1 to perform precision electroplating on the electroplated surface of the conductive ring body, thereby plating a metal or alloy with better conductive properties, thereby improving the conductivity of the conductive ring. The plating metal is selected from any one of Pt, Au, Ag, Pd, Ni, Cu, and W, and the plating alloy is selected from any multiple alloys of Pt, Au, Ag, Pd, Ni, Cu, and W.

[0069] By precisely electroplating the electroplated surface of the conductive ring body, the electroplated layer thickness (THK) is controlled within the range of 100nm to 20um, thereby making the coating have a good bonding force with the substrate, and the applicant has found that the thickness control within this range can obtain a relatively uniform metal coating and very few pores. At the same time, the applicant has found that electroplating the conductive ring body without a fixed contact point can avoid the poor quality of the electroplated layer or even the phenomenon of missing plating caused by the contact point of the conductive ring body in the conventional hanging plating method, thereby achieving more uniform and high-quality electroplating.

[0070] Among them, the electroplating without fixed clamping points in step S20 specifically includes the following steps:

[0071] The first step is to calibrate the center of the main axis of the conductive ring automatic loading and unloading device and several evenly distributed rollers concentrically, then start and control the conductive ring automatic loading and unloading device to make it drop to the level of the rubber ball and flush with the plane of the conductive ring body, then the retractable arm can be opened to clamp the conductive ring body and move the conductive ring body to the electroplating position.

[0072] In the second step, the second motor is started to drive the roller to move toward the center of the conductive ring body until the conductive ring body is inserted into the roller slot and is tangent to the outer diameter of the roller. At the same time, the automatic loading and unloading device retracts the retractable arm to separate from the conductive ring body.

[0073] The third step is to start the first motor to drive the roller to rotate around the rotation axis, thereby driving the conductive ring body to rotate around the center of the circle, thereby realizing electroplating without a fixed clamping point.

[0074] Furthermore, the applicant has found that in the process of electroplating the electroplated surface of the conductive ring body, the non-uniformity of the current density will lead to inconsistent stress in the electroplated layer, which will increase the risk of lattice dislocation. Under the extrusion of the rotating electroplating head, crack expansion or tearing may occur at individual stress peaks, resulting in damage to the conductive ring. Therefore, the present invention adds the following steps under the requirements of high-quality precision electroplating without fixed contact points and ensuring the reduction of the contact resistance of the conductive ring:

[0075] S30, the conductive ring after electroplating is subjected to a high temperature annealing process, the high temperature annealing process includes a temperature rise, heat preservation, and temperature drop process, wherein the temperature rise gradient is between 100 and 200°C / min, the heat preservation temperature range is between 400 and 800°C, and the temperature drop gradient is between 50 and 120°C / min, thereby achieving the goal of reducing or eliminating stress by controlling the temperature rise, heat preservation, and temperature drop process of high temperature annealing. In addition, there is also a set of metal clamping drive devices without fixed clamping points during the high temperature annealing process, wherein the hardness of the metal material should be selected to be a soft metal that can maintain friction contact single rocker electroplating. The conductive ring after electroplating is clamped and rotated by the device without fixed clamping points during the annealing process, so that the stress elimination effect is more reasonably and evenly distributed.

[0076] Furthermore, since the annealing process is often in a high-temperature closed environment, general motors cannot withstand high temperatures, and the magnetism of the electrodes will change at high temperatures. To address this problem, the present invention provides a closed cooling water circulation system isolated from the outside world in the housings of the first motor and the second motor to protect the motors in a high-temperature environment.

[0077] Example 3

[0078] This embodiment provides an ultra-thin sub-millimeter-thickness conductive ring. The conductive ring is made using the preparation method in Example 2. In order to solve the problem of low electroplating efficiency caused by poor substrates of general conductive rings and electric welding caused by exposed substrates, this embodiment provides two preferred solutions for the combination of conductive ring substrates and plated metal materials.

[0079] Option 1: TC4 substrate + Pt coating

[0080] (1) Material

[0081] A titanium alloy (TC4) is used as a conductive ring substrate, and a Pt coating is coated on the surface of the conductive ring substrate, wherein the thickness of the conductive ring substrate is 0.2 to 0.5 mm, and the thickness of the coating is 2 to 10 μm; and the resistivity of TC4 is ρ=160×10-8Ω·m, and the resistivity of Pt is ρ=9.8×10-8Ω·m;

[0082] (2) Thermal conductivity

[0083] The applicant has verified that under a low current solution (current <1A), the conductive ring has positive effects such as good thermal conductivity and electrical conductivity, and has basically no negative impact on the electroplating process.

[0084] However, under high current scheme (current>1A), since the thermal conductivity of TC4 is 5.44W / m·K, its thermal conductivity is 1 / 5 of iron and 1 / 10 of aluminum; the thermal conductivity of Pt is 70W / m·K. The seed layer of the wafer is generally made of Cu, and the maximum thermal conductivity is 401W / m·K. Therefore, during the long-term electroplating process with high current, a large amount of heat will accumulate at the contact point between the conductive ring and the seed layer, resulting in poor heat conduction performance, causing TC4 to melt or blacken, and then damaging the wafer seed layer, affecting the entire electroplating process.

[0085] Therefore, the solution of using TC4 as the conductive ring substrate and Pt as the coating is suitable for electroplating the wafer under low current conditions (current <1A).

[0086] Option 2: BeCu substrate + rose gold plating

[0087] (1) Material

[0088] BeCu is used as a conductive ring substrate, and a layer of rose gold is electroplated on the surface of the conductive ring substrate; wherein the thickness of the conductive ring substrate is 0.1-0.3 mm, and the thickness of the rose gold is 100 nm-10 μm; and the resistivity of BeCu is ρ=1.75×10-8Ω·m, and the resistivity of Au is ρ=2.4×10-8Ω·m.

[0089] (2) Thermal conductivity

[0090] The thermal conductivity of Au is 318W / m·K, and the seed layer of the wafer is generally made of Cu, with a maximum thermal conductivity of 401W / m·K. In this case, the thermal conductivity between the conductive ring and the wafer is not much different, and the thermal conductivity is good, which effectively solves the seed layer damage phenomenon mentioned above.

[0091] Furthermore, in the above two preferred solutions:

[0092] (3) Electroplating uniformity

[0093] If there are fixed contact points between the conductive ring and the clamping mechanism in the conductive ring electroplating process, these contact points will lead to the inability to guarantee the electroplating quality, the inability to meet the requirements of the electroplating uniformity, and even areas of missed plating. For this reason, the applicant provides a clamping drive device without fixed clamping points. The device is used to carry out the electroplating processes of the above two preferred schemes. During the electroplating process, the ultra-thin sub-millimeter thickness conductive ring achieves contact without fixed points, avoiding the possibility of missed plating in conventional hanging plating and improving the uniformity of electroplating.

[0094] (4) Stress

[0095] The conductive ring contacts the wafer and needs to have a certain elasticity to ensure the uniformity of the contact points. This elasticity is actually to compensate for the unevenness of the surface thickness and roughness through a certain elastic deformation caused by the extrusion of the conductive ring to reduce the contact resistance. However, this elastic deformation will cause uneven stress distribution and even lattice defects that produce peak stress concentration, so the applicant further added a subsequent high-temperature annealing process.

[0096] As for TC4, it has good elasticity; the elastic modulus E=113GPa, the elastic modulus is relatively low, about 1 / 2 of that of steel, so titanium alloy is easily deformed during processing.

[0097] As for BeCu, it combines excellent mechanical properties, physical properties and chemical properties. After heat treatment (solid solution treatment and aging treatment), it has high strength limit, elastic limit, yield limit and fatigue resistance limit comparable to special steels. At the same time, it has high electrical conductivity, thermal conductivity, high hardness, corrosion resistance, wear resistance, good casting performance, non-magnetic and impact-free spark characteristics.

[0098] Ultra-thin submicron level (100nm-300nm) precision electroplating (controlling current density and edge electric field effect, time, temperature, additives) of the above two metals is not enough to completely overcome the environment of uneven electroplating current distribution density, so ultra-thin submicron electroplating needs to overcome the problem of uneven stress distribution.

[0099] To this end, the applicant proposed to use a high-temperature annealing process after the electroplating deposition of the conductive ring to achieve lattice repair of the uneven stress distribution, so as to further reduce the contact resistance of the conductive ring, and in the high-temperature annealing process, control the temperature rise, insulation, and drop process of the high-temperature annealing to achieve the goal of reducing or eliminating stress. The high-temperature annealing insulation temperature range is 400-800℃, the temperature rise gradient is 100-200℃ / min, and the temperature drop gradient is in the range of 50-120℃ / min.

[0100] The temperature control process of high temperature annealing needs to be adjusted according to parameters such as the characteristics and thickness of the electroplated metal material, the current density setting of the electroplating process, etc. The temperature control process includes temperature rise, insulation (if necessary, there can be several insulation stages with different temperatures), and temperature drop control.

[0101] Furthermore, the applicant provides a clamping drive device without a fixed clamping point, which is used to carry out the high-temperature annealing process of the above two preferred schemes. During the high-temperature annealing process, the ultra-thin sub-millimeter thickness conductive ring and the clamping device achieve contact and rotation without a fixed point, making the stress elimination effect more reasonable and uniform.

[0102] The above describes the specific embodiments of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention.

Claims

1. A clamping drive device without a fixed clamping point, used for clamping and driving a conductive ring to rotate, characterized in that: Including a clamp and a drive device; The clamp comprises a plurality of rollers which are evenly distributed around the outer side of the conductive ring; the rollers are provided with clamping grooves which are used to clamp the conductive ring; The driving device comprises a rotary driving device and a centripetal driving device; The rotary drive device comprises a first drive source and a rotary shaft, the rotary shaft is connected to the roller in a direction perpendicular to the plane of the roller slot, and the first drive source drives the rotary shaft to rotate; The centripetal drive device includes a lead screw, a transmission nut and a second drive source. The lead screw is located on the upper surface of the conductive ring, and the front end of the lead screw points to the center of the conductive ring along the radius of the conductive ring. The transmission nut is connected to the lead screw, and the transmission nut can move along the lead screw in a direction close to or away from the center of the conductive ring. The second driving source drives the transmission nut to move on the screw rod; the centripetal driving device is connected to the rotary driving device through the transmission nut.

2. The clamping drive device without fixed clamping points according to claim 1, characterized in that: The first driving source and the second driving source are both motors, and the motor housings are both provided with a cooling water circulation system isolated from the outside.

3. The clamping drive device without fixed clamping points according to claim 1, characterized in that: The roller is made of plastic or metal.

4. The clamping drive device without fixed clamping points according to claim 1, characterized in that: It also includes an automatic loading and unloading device for conductive rings, which is used to automatically place the conductive rings in or out of the electroplating position; it includes an umbrella-shaped clamping device and a driving system; the umbrella-shaped clamping device includes a main shaft, a liftable sleeve, a retractable arm and a rubber ball; the liftable sleeve is wrapped around the main shaft and connected to the retractable arm; the driving system is connected to the liftable sleeve and can drive the liftable sleeve to rise and fall on the main shaft, thereby driving the retractable arm to open and close; the rubber ball is connected to the end of the retractable arm, and when the retractable arm is opened, the rubber ball presses against the inner edge of the conductive ring, thereby clamping the conductive ring.

5. A method for preparing an ultra-thin sub-millimeter-thickness conductive ring, characterized in that: The clamping drive device without fixed clamping points according to any one of claims 1 to 4 comprises the following steps: S10, providing a conductive ring body, wherein the conductive ring body is a Cu substrate, a Ti substrate, or a BeCu substrate; S20, electroplating the surface of the conductive ring body by using a clamping drive device without a fixed clamping point to uniformly deposit a layer of conductive metal or conductive alloy to form a conductive ring after electroplating; The thickness of the conductive metal or conductive alloy is controlled between 100nm and 20um, the conductive metal is any one of Pt, Au, Ag, Pd, Ni, Cu, and W, and the conductive alloy is any alloy of Pt, Au, Ag, Pd, Ni, Cu, and W; S30. Clamp the electroplated conductive ring using a clamping drive device without a fixed clamping point to perform a high-temperature annealing process on the electroplated conductive ring. The high-temperature annealing process includes temperature rise, insulation, and drop processes, wherein the temperature rise gradient is between 100 and 200°C / min, the insulation temperature range is between 400 and 800°C, and the temperature drop gradient is between 50 and 120°C / min.

6. The method for preparing an ultra-thin sub-millimeter-thickness conductive ring according to claim 5, characterized in that: In step S10, the conductive ring body is made of titanium alloy, and in step S20, Pt is electroplated and deposited on the surface of the conductive ring body.

7. The method for preparing an ultra-thin sub-millimeter-thickness conductive ring according to claim 5, characterized in that: In step S10, the conductive ring body is made of BeCu material, and in step S20, rose gold is electroplated and deposited on the surface of the conductive ring body.

8. The method for preparing an ultra-thin sub-millimeter-thickness conductive ring according to claim 5, characterized in that: In step S20, the electroplating without fixed clamping points includes the following steps: In the first step, the main axis of the umbrella-shaped clamping device and the position centers of several evenly distributed rollers are concentrically calibrated, and then the automatic loading and unloading device of the conductive ring is started and controlled to be lowered to the level of the rubber ball and flush with the conductive ring body, and then the telescopic arm is opened to clamp the conductive ring body and move the conductive ring body to the electroplating position; The second step is to start the second driving source to drive the roller to move toward the center of the conductive ring body until the conductive ring body is inserted into the roller slot and becomes tangent to the outer diameter of the roller; at the same time, the automatic loading and unloading device retracts the retractable arm to separate from the conductive ring body; The third step is to start the first driving source to drive the roller to rotate around the rotation axis, thereby driving the conductive ring body to rotate around the center of the circle, thereby achieving electroplating without a fixed clamping point.

9. The method for preparing an ultra-thin sub-millimeter-thickness conductive ring according to claim 5, characterized in that: In step S30, the heat preservation process includes heat preservation stages at different temperatures.

10. The method for preparing an ultra-thin sub-millimeter-thickness conductive ring according to claim 5, characterized in that: In step S30, the clamping drive device without a fixed clamping point clamps the electroplated conductive ring. The following steps are involved: In the first step, the second driving source is started to drive the roller to move toward the center of the electroplated conductive ring until the electroplated conductive ring is clamped into the roller clamping groove and is tangent to the outer diameter of the roller. In the second step, the first driving source is started to drive the roller to rotate around the rotation axis, thereby driving the conductive ring to rotate around the center of the circle as the axis.

11. An ultra-thin sub-millimeter thickness conductive ring, characterized in that: The method is prepared by any one of claims 5 to 10.

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