Wax feeding device and method for reducing clamping damage to edge of ultrathin germanium wafer

Abstract

The invention relates to the field of semiconductor material processing, in particular to a wax discharging device for reducing clamping damage to the edge of an ultrathin germanium wafer, the wax discharging device comprises a wafer unloading mechanism, a ceramic disc rotating mechanism, an unloading wafer collecting channel and a wafer collecting mechanism, and a method for using the device comprises the steps of mounting, wafer unloading, collecting and adjusting. According to the device, through the integrated solution of wafer unloading, collection and damage prevention, manual wafer unloading is replaced by mechanical automation, and the wafer unloading efficiency is effectively improved; compared with conventional manual wafer unloading, the method effectively avoids direct physical damage such as fragments, scratches and microcracks caused by improper manual operation, the edges of the obtained germanium wafers are free of cracks and broken edges, the consistency and uniformity between the wafers are good, and the large-scale production requirement is met.

Description

Technical Field

[0001] This invention relates to the field of semiconductor material processing, and in particular to a waxing apparatus and method for reducing edge clamping damage to ultrathin germanium wafers. Background Technology

[0002] Germanium wafers play an irreplaceable and crucial role in the field of space solar cells. The high lattice matching between germanium wafers and gallium arsenide materials provides a high-quality growth foundation for the cell structure. Furthermore, germanium-based power supplies possess ultra-high conversion efficiency, excellent radiation resistance, and stable temperature characteristics. However, traditional germanium wafers have high density and thickness, leading to increased weight. Since emission costs are extremely sensitive to weight, the fabrication of ultra-thin, high-performance germanium wafers is particularly important. Polishing is an indispensable key process for eliminating processing defects, improving surface quality, meeting epitaxial growth requirements, and ultimately realizing the manufacturing of high-performance devices.

[0003] Germanium itself is soft, brittle, and easily damaged. Its rigidity decreases further after thinning, making it susceptible to breakage due to mechanical stress during polishing. Conventional CMP polishing processes use adsorption pads, but the vacuum suction or mechanical clamping force generated by these pads creates uneven stress distribution on the thin wafer surface, easily leading to lattice damage, microcracks, or even overall warping and breakage. For ultrathin germanium wafers requiring nanoscale surface integrity, this additional mechanical stress introduced by the fixing method is fatal, directly damaging its subsurface structure and failing to meet the requirements of high-end applications. Wax polishing allows ultrathin germanium wafers to be firmly adhered to a ceramic disk using paraffin wax, preventing slippage during polishing and avoiding the localized stress and clamping damage problems caused by adsorption pads. However, wax polishing also has limitations. Currently, the wax polishing process relies on manual wax removal and wafer unloading. Therefore, the surface integrity of the ultrathin germanium wafer during unloading depends entirely on the operator's skill and experience, ultimately leading to unstable yield rates. This severely restricts production efficiency and large-scale manufacturing, failing to meet the high consistency and high reliability requirements of modern precision optoelectronics industries. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention presents a waxing device and method for reducing edge clamping damage to ultra-thin germanium wafers.

[0005] An invention discloses a wax removal device that reduces edge clamping damage to ultra-thin germanium wafers, suitable for waxing and polishing processes and mounted on a support. The wax removal device includes a wafer unloading mechanism, a ceramic disc rotation mechanism, a wafer unloading and collection channel, and a wafer receiving mechanism, wherein:

[0006] The unloading mechanism includes a suspension support plate, a first pneumatic push rod, a guide rail, and a robotic arm. The suspension support plate is fixedly connected to a bracket, and the guide rail is installed obliquely on the suspension support plate. The robotic arm consists of a slider support arm, a rotating arm, a second pneumatic push rod, and an arc-shaped wedge. The slider cooperates with the guide rail, and the lower side of the slider is fixedly connected to one end of the support arm. The other end of the support arm is hinged to one end of the rotating arm. The two ends of the second pneumatic push rod are respectively hinged to the slider and the rotating arm. An arc-shaped wedge is provided at the other end of the rotating arm.

[0007] The ceramic disc rotation mechanism includes a slotted disc, a drive wheel, a first motor, and a limiting wheel. The slotted disc is inclinedly connected to the bottom of the robotic arm. The drive wheel and the limiting wheel are both fixed on the slotted disc, and a space is reserved between the drive wheel and the limiting wheel to accommodate the ceramic disc. The drive wheel is driven by the first motor.

[0008] The wafer collection channel includes a sliding plate and guide blocks. The sliding plate is inclinedly connected to the bottom of the slot disk. Two guide blocks are provided on the sliding plate, and a channel for accommodating germanium wafers is reserved between the two guide blocks.

[0009] The receiving mechanism includes a lifting assembly, a clamping assembly, and a flower basket. The lifting assembly consists of a base, a guide rail, a slider, a second motor, and a lead screw. The base has a vertical guide rail, and a slider that mates with the guide rail is mounted on the guide rail. The second motor is mounted on the base, and a lead screw is mounted outside the output shaft of the second motor. A thread matching the lead screw is provided on one side of the slider. The clamping assembly includes a support and a clamp. The support is L-shaped, and the rear side of the vertical portion of the support is connected to the slider, allowing the support to move vertically along the guide rail. A clamp is mounted on the front side of the vertical portion of the support, and the clamp is used to clamp the flower basket.

[0010] Ideally, the arc-shaped wedge is connected to the rotating arm via fasteners. During use, the arc-shaped wedge with different curvatures at the top can be replaced to accommodate different germanium wafer sizes.

[0011] Ideally, the drive wheel and the limit wheel should be grooved wheels; the slotted plate has several through holes, and fasteners are used to fix the drive wheel and the limit wheel to the slotted plate. In actual use, different through holes can be selected for fixing according to the size of the ceramic plate to adjust the distance between the drive wheel and the limit wheel.

[0012] Ideally, a ramp is provided on the side corresponding to the guide block, and a guide post is provided on the upper surface of the guide block to provide a certain fault tolerance during sheet removal; several through holes are provided on the sliding plate, and fasteners are used to fix the guide block on the sliding plate in conjunction with the through holes.

[0013] Ideally, the clamp includes a locking seat, a pressure rod, and a handle. The locking seat has a through hole, and the pressure rod is placed inside the through hole. The pressure rod moves vertically along the through hole. A soft pad is placed at the bottom of the pressure rod. The top of the pressure rod is hinged to one end of a V-shaped transmission rod, and the other end of the V-shaped transmission rod is hinged to the handle. The handle is also hinged to the locking seat. When the handle is rotated, it drives the pressure rod to press down or lift up to lock or unlock the basket.

[0014] Ideally, the support is also equipped with a heating mechanism for melting the wax, which facilitates the sliding of the germanium wafer from the ceramic plate.

[0015] The waxing method based on the above-mentioned waxing device includes the following steps:

[0016] S1, Installation: Install the ceramic disc with the waxed germanium wafer between the drive wheel and the limit wheel of the ceramic disc rotation mechanism, so that any germanium wafer is located below the unloading mechanism; at the same time, install the basket on the support of the receiving mechanism and clamp it with the clamp, and adjust the position of the basket by the lifting component so that the bottom of the basket is level with the bottom of the unloading collection channel.

[0017] S2, Unloading: Adjust the robotic arm of the unloading mechanism so that the robotic arm contacts the germanium wafer on the ceramic disk under the action of the first pneumatic push rod and the second pneumatic push rod, pushing the germanium wafer to slide down;

[0018] S3, Collection: Under the influence of gravity, the germanium wafers slide into the basket along the wafer collection channel;

[0019] S4, Adjustment: The ceramic disc starts to rotate under the power of the drive wheel, so that the other germanium wafer on the ceramic disc is located below the unloading mechanism; at the same time, the position of the basket is adjusted downward by the lifting component so that the bottom of the remaining space of the basket that has been loaded with germanium wafers is level with the bottom of the unloading collection channel. Repeat the above steps until the ceramic disc is empty and then replace the ceramic disc, or replace the basket when it is full.

[0020] After the germanium wafers are removed along with the basket, they are placed in a spin dryer to dry, and then the germanium wafers are removed for edge inspection.

[0021] The beneficial effects of this invention are as follows: This device, through an integrated solution of "wafer unloading – collection – damage prevention", effectively improves wafer unloading efficiency by replacing manual wafer unloading with mechanical methods; compared with conventional manual wafer unloading, this method effectively avoids direct physical damage such as fragments, scratches and microcracks caused by improper human operation, and the obtained germanium wafers have no cracks or broken edges, and have good consistency and uniformity between wafers, meeting the needs of large-scale production. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0023] Figure 2This is a partially enlarged view of the unloading mechanism of the present invention.

[0024] Figure 3 This is a partially enlarged view of the ceramic disc rotation mechanism of the present invention.

[0025] Figure 4 This is a partially enlarged view of the unloading and collection channel of the present invention.

[0026] Figure 5 This is a partially enlarged view of the receiving mechanism of the present invention.

[0027] Figure 6 This is a partially enlarged view of the clamp of the present invention.

[0028] Figure 7 The images shown are microscope images of the edge of a germanium wafer at 20x magnification for the examples and comparative examples, where a is the example and b is the comparative example.

[0029] The components include: a plate unloading mechanism 1, a suspension support plate 1-1, a first pneumatic push rod 1-2, a guide rail 1-3, a robotic arm 1-4, and an arc-shaped wedge 1-5; a ceramic disc rotating mechanism 2, a slotted disc 2-1, a drive wheel 2-2, a first motor 2-3, and a limit wheel 2-4; a plate unloading and collection channel 3, a sliding plate 3-1, and a guide block 3-2; and a plate collecting mechanism 4, a lifting assembly 4-1, a clamping assembly 4-2, and a basket 4-3. Detailed Implementation

[0030] Example: A wax removal device for reducing edge clamping damage of ultra-thin germanium wafers is disclosed in this invention. It is suitable for waxing and polishing processes and is mounted on a support. The wax removal device includes a wafer unloading mechanism, a ceramic disc rotation mechanism, a wafer unloading and collection channel, and a wafer receiving mechanism, wherein:

[0031] The unloading mechanism includes a suspension support plate, a first pneumatic push rod, a guide rail, and a robotic arm. The suspension support plate is fixedly connected to a bracket, and the guide rail is installed obliquely on the suspension support plate. The robotic arm consists of a slider support arm, a rotating arm, a second pneumatic push rod, and an arc-shaped wedge. The slider cooperates with the guide rail, and the lower side of the slider is fixedly connected to one end of the support arm. The other end of the support arm is hinged to one end of the rotating arm. The two ends of the second pneumatic push rod are respectively hinged to the slider and the rotating arm. An arc-shaped wedge is provided at the other end of the rotating arm.

[0032] The ceramic disc rotation mechanism includes a slotted disc, a drive wheel, a first motor, and a limiting wheel. The slotted disc is inclinedly connected to the bottom of the robotic arm. The drive wheel and the limiting wheel are both fixed on the slotted disc, and a space is reserved between the drive wheel and the limiting wheel to accommodate the ceramic disc. The drive wheel is driven by the first motor.

[0033] The wafer collection channel includes a sliding plate and guide blocks. The sliding plate is inclinedly connected to the bottom of the slot disk. Two guide blocks are provided on the sliding plate, and a channel for accommodating germanium wafers is reserved between the two guide blocks.

[0034] The receiving mechanism includes a lifting assembly, a clamping assembly, and a flower basket. The lifting assembly consists of a base, a guide rail, a slider, a second motor, and a lead screw. The base has a vertical guide rail, and a slider that mates with the guide rail is mounted on the guide rail. The second motor is mounted on the base, and a lead screw is mounted outside the output shaft of the second motor. A thread matching the lead screw is provided on one side of the slider. The clamping assembly includes a support seat and a clamp. The support seat is L-shaped, and the rear side of the vertical portion of the support seat is connected to the slider, allowing the support seat to move vertically along the guide rail. The clamp is located on the front side of the vertical portion of the support seat. The clamp includes a locking seat, a pressure rod, and a handle. The locking seat has a through hole, and the pressure rod is located inside the through hole, moving vertically along the through hole. A soft pad is provided at the bottom of the pressure rod, and the top of the pressure rod is hinged to one end of a V-shaped transmission rod. The other end of the V-shaped transmission rod is hinged to the handle, which is also hinged to the locking seat. When the handle is rotated, it causes the pressure rod to press down or lift up, thereby locking or unlocking the flower basket.

[0035] The support is also equipped with a heating mechanism for melting the wax, which facilitates the sliding of the germanium wafer from the ceramic plate.

[0036] Specifically, the angle of the card slot and the sliding plate is set to 40°.

[0037] This embodiment also provides a method for removing an ultrathin germanium substrate using the above-described wax removal device, comprising the following steps:

[0038] A wax removal method for reducing edge clamping damage to ultrathin germanium wafers includes the following steps:

[0039] S1, Installation: Install 10 ultra-thin germanium wafer ceramic discs to be melted between the drive wheel and the limit wheel of the ceramic disc rotation mechanism. The germanium wafers are 4 inches in size and 140±15μm thick, so that any germanium wafer is located below the unloading mechanism. At the same time, install the basket on the support seat of the receiving mechanism and clamp it with the clamp. Adjust the position of the basket by the lifting component so that the bottom of the basket is level with the bottom of the unloading and collecting channel.

[0040] S2, wafer unloading: Raise the ambient temperature to 80°C, adjust the robotic arm of the wafer unloading mechanism, and make the robotic arm contact the germanium wafer on the ceramic disk under the action of the first pneumatic push rod and the second pneumatic push rod, pushing the germanium wafer to slide down;

[0041] S3, Collection: Under the influence of gravity, the germanium wafers slide into the basket along the wafer collection channel;

[0042] S4, Adjustment: The ceramic disc begins to rotate under the power of the drive wheel, positioning the other germanium wafer below the unloading mechanism. Simultaneously, the position of the basket is adjusted downwards via the lifting assembly, ensuring the bottom of the remaining space in the basket already loaded with germanium wafers is level with the bottom of the unloading collection channel. This process is repeated until the ceramic disc is empty, at which point the ceramic disc is replaced; or until the basket is full, the basket is replaced. The germanium wafer, along with the basket, is removed and placed in a spin dryer for drying. The wafer is then removed and its edges are inspected. Microscopic examination reveals no cracks, notches, or scratches at the edges; intact edges are considered the standard for substrate integrity. The results are shown in the table below.

[0043] Film number Substrate edge state Film number Substrate edge state 1 Complete and without gaps 6 Complete and without gaps 2 Complete and without gaps 7 Complete and without gaps 3 Complete and without gaps 8 Complete and without gaps 4 Complete and without gaps 9 Complete and without gaps 5 Complete and without gaps 10 Complete and without gaps

[0044] Upon inspection, all 10 substrates unloaded from a single tray showed intact edges without breakage or cracks, and the entire unloading process took 5 minutes. Edge inspection under a microscope is shown below. Figure 7 As shown.

[0045] Comparative Example: Traditional manual wax removal method was used. The same germanium wafers to be waxed as in Example 1 were placed on a ceramic tray in an electric oven and heated to a set temperature for a period of time until the surface temperature of the ceramic tray reached the wax removal temperature range. Then, the ceramic tray was manually rotated sequentially to complete the wafer removal process. The wafer removal process included baking the ceramic tray, manual removal with tweezers, cleaning with wax remover, and individual wafer drying. The edge detection results are shown in the table below.

[0046] Film number Substrate edge state Film number Substrate edge state 1 Complete and without gaps 6 Complete and without gaps 2 Complete and without gaps 7 Complete and without gaps 3 fragments 8 Edge scratches 4 edge crack 9 Complete and without gaps 5 Complete and without gaps 10 edge crack

[0047] Testing revealed that during manual removal of 10 germanium wafers, 1 wafer was found to be fragmented, 2 wafers had edge cracks, and 1 wafer had an edge scratch. The entire removal process took 10 minutes. Microscopic edge inspection results are as follows. Figure 7 As shown.

Claims

1. A wax removal device for reducing edge damage during ultra-thin germanium wafer clamping, suitable for waxing and polishing processes and mounted on a support, characterized in that... The wax unloading device includes a wafer unloading mechanism, a ceramic disc rotation mechanism, a wafer unloading and collection channel, and a wafer collection mechanism, wherein: The unloading mechanism includes a suspension support plate, a first pneumatic push rod, a guide rail, and a robotic arm. The suspension support plate is fixedly connected to a bracket, and the guide rail is installed obliquely on the suspension support plate. The robotic arm consists of a slider support arm, a rotating arm, a second pneumatic push rod, and an arc-shaped wedge. The slider cooperates with the guide rail, and the lower side of the slider is fixedly connected to one end of the support arm. The other end of the support arm is hinged to one end of the rotating arm. The two ends of the second pneumatic push rod are respectively hinged to the slider and the rotating arm. An arc-shaped wedge is provided at the other end of the rotating arm. The ceramic disc rotation mechanism includes a slotted disc, a drive wheel, a first motor, and a limiting wheel. The slotted disc is inclinedly connected to the bottom of the robotic arm. The drive wheel and the limiting wheel are both fixed on the slotted disc, and a space is reserved between the drive wheel and the limiting wheel to accommodate the ceramic disc. The drive wheel is driven by the first motor. The wafer collection channel includes a sliding plate and guide blocks. The sliding plate is inclinedly connected to the bottom of the slot disk. Two guide blocks are provided on the sliding plate, and a channel for accommodating germanium wafers is reserved between the two guide blocks. The receiving mechanism includes a lifting assembly, a clamping assembly, and a flower basket. The lifting assembly consists of a base, a guide rail, a slider, a second motor, and a lead screw. The base has a vertical guide rail, and a slider that mates with the guide rail is mounted on the guide rail. The second motor is mounted on the base, and a lead screw is mounted outside the output shaft of the second motor. A thread matching the lead screw is provided on one side of the slider. The clamping assembly includes a support and a clamp. The support is L-shaped, and the rear side of the vertical portion of the support is connected to the slider, allowing the support to move vertically along the guide rail. A clamp is mounted on the front side of the vertical portion of the support, and the clamp is used to clamp the flower basket.

2. The wax removal device for reducing edge clamping damage of ultra-thin germanium wafers as described in claim 1, characterized in that... The arc-shaped wedge is connected to the rotating arm by fasteners.

3. The wax removal device for reducing edge clamping damage of ultra-thin germanium wafers as described in claim 1, characterized in that... The drive wheel and the limit wheel are grooved wheels; the slot plate is provided with several through holes, and fasteners are used to fix the drive wheel and the limit wheel on the slot plate in conjunction with the through holes.

4. The wax removal device for reducing edge clamping damage of ultra-thin germanium wafers as described in claim 1, characterized in that... A ramp is provided on the corresponding side of the guide block, and a guide post is provided on the upper surface of the guide block; several through holes are provided on the sliding plate, and fasteners are used to fix the guide block on the sliding plate in conjunction with the through holes.

5. The wax removal device for reducing edge clamping damage of ultra-thin germanium wafers as described in claim 1, characterized in that... The clamp includes a locking seat, a pressure rod, and a handle. The locking seat has a through hole, and the pressure rod is placed inside the through hole. The pressure rod moves vertically along the through hole. A soft pad is placed at the bottom of the pressure rod. The top of the pressure rod is hinged to one end of a V-shaped transmission rod, and the other end of the V-shaped transmission rod is hinged to the handle. The handle is also hinged to the locking seat. When the handle is rotated, it drives the pressure rod to press down or lift up to lock or unlock the flower basket.

6. The wax removal device for reducing edge clamping damage of ultra-thin germanium wafers as described in claim 1, characterized in that... The support frame is also equipped with a heating mechanism.

7. A wax removal method for reducing edge clamping damage of ultrathin germanium wafers, based on the wax removal apparatus for reducing edge clamping damage of ultrathin germanium wafers according to claim 1, characterized in that... This method is implemented through the following steps: S1, Installation: Install the ceramic disc with the waxed germanium wafer between the drive wheel and the limit wheel of the ceramic disc rotation mechanism, so that any germanium wafer is located below the unloading mechanism; at the same time, install the basket on the support of the receiving mechanism and clamp it with the clamp, and adjust the position of the basket by the lifting component so that the bottom of the basket is level with the bottom of the unloading collection channel. S2, Unloading: Adjust the robotic arm of the unloading mechanism so that the robotic arm contacts the germanium wafer on the ceramic disk under the action of the first pneumatic push rod and the second pneumatic push rod, pushing the germanium wafer to slide down; S3, Collection: Under the influence of gravity, the germanium wafers slide into the basket along the wafer collection channel; S4, Adjustment: The ceramic disc starts to rotate under the power of the drive wheel, so that the other germanium wafer on the ceramic disc is located below the unloading mechanism; at the same time, the position of the basket is adjusted downward by the lifting component so that the bottom of the remaining space of the basket that has been loaded with germanium wafers is level with the bottom of the unloading collection channel. Repeat the above steps until the ceramic disc is empty and then replace the ceramic disc, or replace the basket when it is full.

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