CN117381659A - Semiconductor material grinding processing clamp with controllable and adjustable pressure measurement and processing method - Google Patents

Abstract

The invention discloses a pressure-measurable and controllable-adjustment semiconductor material grinding processing clamp which comprises an outer clamp support, a clamp sleeve, an adsorption head and an inner clamp shaft, wherein the outer clamp support is fixedly connected with the clamp sleeve, the adsorption head is fixedly connected with the lower end of the inner clamp shaft, the adsorption head is arranged in the outer clamp support, the inner clamp shaft is arranged in the clamp sleeve, a pressure rough adjusting button is in threaded fit with the clamp sleeve, an upper substrate is connected to the pressure rough adjusting button, the upper substrate is longitudinally connected with a motor through a tension pressure sensor, the motor drives the inner clamp shaft to longitudinally move relative to the clamp sleeve, and the upper substrate, the tension pressure sensor, the motor, a screw nut kinematic pair and the inner clamp shaft are jointly longitudinally moved when the pressure rough adjusting button rotates, and the tension pressure sensor is used for measuring longitudinal tension pressure. According to the invention, the pressure range is regulated through the pressure rough regulating button, the motor is finely regulated in real time to reach the set pressure, and high-precision measurement and control of the pressure in the grinding process are realized.

Description

Semiconductor material grinding processing clamp with controllable and adjustable pressure measurement and processing method

Technical Field

The invention relates to a semiconductor material processing clamp, in particular to a semiconductor material grinding processing clamp with controllable and adjustable pressure.

Background

In the processing of semiconductor wafers or materials, it is necessary to perform an abrasive polishing process on the wafer or material. During the grinding process, the clamp holds the wafer or material for precision machining on a grinder. The clamp needs to exert a certain pressure on the wafer or material while processing to ensure that the wafer or material is processed correctly.

In polishing semiconductor materials, particularly antimonide represented by GaSb, inSb, inAs and the like and polishing of group III-V materials, it is necessary to control back pressure on wafers or materials well, and to prevent chipping, scribing, and the like of materials due to excessive pressure. When some small wafers and devices are back ground, the required pressure is 100-800 g, and the pressure control is required to be more precise and accurate.

The current precision grinding clamp is pressurized in a mechanical mode, such as directly adding a load block with a certain weight, adjusting the downward pressure by a mechanical knob and the elasticity of a spring, or adopting a cylinder to set the pressure, etc., the pressurizing modes are rough, and the applicable pressure is larger. Due to inaccuracy of the spring, cylinder control, errors exceeding 10% in a small pressure range below 1000g and reproducibility are poor. These are detrimental to accurate control of pressure and are not compatible with high standard semiconductor material processing.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, the present invention aims to provide a semiconductor material polishing jig with controllable and adjustable pressure measurement, which aims to improve the pressure accuracy in the pressure range of 1kg or less, and also to improve the repeatability consistency of the polishing removal amount and the surface consistency after material processing. Another object of the present invention is to provide a processing method using the semiconductor material polishing processing jig of the present invention.

The technical scheme of the invention is as follows: the utility model provides a pressure measurement controllable semiconductor material grinds adds clamping apparatus, includes anchor clamps outer support, anchor clamps sleeve, absorption head and anchor clamps interior axle, the anchor clamps outer support with anchor clamps sleeve fixed connection, the absorption head with the lower extreme fixed connection of anchor clamps interior axle, the absorption head set up in the anchor clamps outer support, the anchor clamps interior axle sets up in the anchor clamps sleeve, screw-thread fit has the pressure rough adjustment button on the anchor clamps sleeve, be connected with the upper base plate on the pressure rough adjustment button, the below of upper base plate is connected with the motor through pulling pressure sensor longitudinal connection, the motor drive the anchor clamps interior axle relatively anchor clamps sleeve longitudinal movement, the pressure rough adjustment button drives when rotating the upper base plate pulling pressure sensor the motor lead screw nut kinematic pair and the common longitudinal movement of anchor clamps interior axle, pulling pressure sensor is used for measuring longitudinal tension pressure.

Further, a distance measuring device is arranged on the top surface of the outer clamp bracket and used for measuring the longitudinal moving distance of the adsorption head.

Further, the device comprises a controller, wherein the controller is respectively and electrically connected with the pull pressure sensor, the motor and the distance measuring device. The operation of the motor is controlled by the controller according to the signals of the tension pressure sensor and the distance measuring device, and the motor is controlled by the tension change and the moving distance of the adsorption head respectively, so that the repeatability is better.

Further, in order to improve the accuracy of the longitudinal movement of the inner shaft of the clamp, the inner shaft of the clamp is prevented from rotating during coarse adjustment, the upper base plate is fixedly connected with a supporting cylinder, the supporting cylinder is connected with the pressure coarse adjustment button through a bearing, the upper base plate is in rotary connection with the pressure coarse adjustment button through the supporting cylinder, and the clamp sleeve is in longitudinal sliding fit with the inner shaft of the clamp.

Further, the motor is arranged in the supporting cylinder, and the upper end of the inner shaft of the clamp stretches into the supporting cylinder.

Further, the motor is connected with the upper end of the inner shaft of the clamp through a screw-nut kinematic pair.

Further, a rotary joint for leading in vacuum is arranged on the upper substrate, and a vacuum leading-out joint is arranged on the upper substrate.

Further, the adsorption head is provided with a vacuum cavity, a vacuum interface is arranged on the vacuum cavity, and the vacuum interface extends out of the outer bracket of the clamp.

Further, the distance measuring device is a wireless dial indicator.

The other technical scheme of the invention is as follows: the semiconductor material grinding processing method capable of being controlled and adjusted by pressure measurement comprises the steps of adsorbing a wafer on the lower end face of an adsorption head, placing the semiconductor material grinding processing clamp on a grinding and polishing disc, firstly adjusting a pressure rough adjusting button to enable deviation between the pressure Fw borne by the wafer and required processing pressure to be less than 100g, and then controlling a motor to act so that Fw reaches the required processing pressure by a controller, wherein Fw=W-F2, W is the integral weight formed by sequentially connecting the motor, a clamp sleeve, the adsorption head and the wafer, F2 is the pulling force measured by a pulling pressure sensor, and controlling the motor to act according to the pulling force change measured by the pulling pressure sensor and the longitudinal moving distance of the adsorption head measured by a distance measuring device in the grinding and polishing process so as to enable Fw to be stable at the required processing pressure.

Compared with the prior art, the invention has the advantages that:

the device adopts the supporting plate with the first adjusting mechanism, adopts the detection roller to cooperate with the piezoelectric vibration sensor to detect defects, can adjust the position of the supporting plate according to the size and shape of a specific guide rail, and simultaneously can change the position of the detection roller without recalibrating the sensor due to the change of the size of the guide rail, so that the detection device is more easily suitable for detecting the defects of the elevator rails with various sizes. The whole device can be arranged at the bottom of the elevator car without adjusting the structure of the original elevator, has small influence on the original elevator, and widens the application scene of the device.

Drawings

Fig. 1 is a schematic perspective view of an embodiment of a pressure-measurable controllably adjustable semiconductor material polishing jig.

Fig. 2 is a schematic diagram showing a cut-away structure of a semiconductor material polishing jig with pressure measurement controllable adjustment according to an embodiment.

Fig. 3 is a schematic view of external electrical connection structure of a semiconductor material polishing jig with pressure measurement controllable adjustment according to an embodiment.

Fig. 4 is a schematic diagram of a pipeline connection structure of a pressure-measurable, controllably adjustable semiconductor material polishing clamp according to an embodiment.

FIG. 5 is a diagram of a wafer non-pressure hover state diagram.

FIG. 6 is a graph of the pressure applied to a wafer.

Detailed Description

The invention is further illustrated, but is not limited, by the following examples.

Referring to fig. 1 to 4, a pressure-measuring, controllably adjustable semiconductor material polishing jig 100 according to the present embodiment includes a rotary joint 1, an upper substrate 2, a pull pressure sensor 3, a motor 4, a support cylinder 5, a screw sleeve 6, a bearing 7, a rough pressure button 8, a jig inner shaft 9, a jig sleeve 10, a vacuum interface 11, a vacuum chamber 12, an adsorption head 13, a driving ring 15, a jig outer bracket 16, and a wireless dial indicator 17.

The lower end of the rotary joint 1 is fixedly connected with the upper substrate 2, and a vacuum leading-out joint 2a is arranged at the side of the upper substrate 2. Vacuum is led in from the top of the rotary joint 1 and led out from a vacuum leading-out joint 2a of the upper substrate 2, and wiring terminals 1a are respectively arranged on the side surfaces of the rotary joint 1 so as to realize the electrical connection of the pulling pressure sensor 3 and the motor 4 in the semiconductor material grinding processing clamp and an external controller 18.

The upper substrate 2 is fixed on top of the support cylinder 5. The supporting cylinder 5 is hollow, a tension and pressure sensor 3 is fixedly arranged at the bottom of the upper substrate 2, a motor 4 is connected below the tension and pressure sensor 3, and the longitudinal tension and pressure is measured by the tension and pressure sensor 3.

The outer edge of the bottom of the supporting cylinder 5 is fixed with the outer plate of the bearing 7, the axis of the bearing 7 is longitudinally arranged, and the inner plate of the bearing 7 is fixedly connected with the top of the pressure rough adjusting button 8, so that the supporting cylinder 5 can be prevented from rotating under the action of the bearing 7 when the pressure rough adjusting button 8 is rotated.

The pressure rough adjusting button 8 is internally provided with a precise thread, the clamp sleeve 10 is matched with the pressure rough adjusting button 8, the upper end of the clamp sleeve 10 is also provided with a precise thread, the pressure rough adjusting button 8 is in threaded connection with the clamp sleeve 10, and when the pressure rough adjusting button 8 rotates, the pressure rough adjusting button 8 and the clamp sleeve 10 can generate axial displacement (longitudinal displacement).

The clamp sleeve 10 is fixedly connected with the clamp outer bracket 16, a driving ring 15 is fixedly arranged on the bottom surface of the clamp outer bracket 16, and a concave cavity in the clamp outer bracket 16 is used for accommodating the adsorption head 13 so as to adsorb the wafer 14.

The rotating shaft of the motor 4 is downwards arranged, the rotating shaft of the motor 4 is connected with a screw rod, a screw rod sleeve 6 is matched with the screw rod to form a screw rod nut kinematic pair, and the screw rod sleeve 6 is driven to longitudinally displace by the rotation of the motor 4.

The lower sleeve of the screw rod sleeve 6 is fixed at the top end of the clamp inner shaft 9, the clamp inner shaft 9 is vertically arranged and is positioned on the clamp sleeve 10, the clamp inner shaft 9 and the clamp sleeve 10 are longitudinally matched in a sliding mode, and the clamp sleeve 10 is used for guiding displacement of the clamp inner shaft 9. The inner shaft 9 of the clamp is fixedly connected with the adsorption head 13, so that the adsorption head 13 can be driven to perform accurate longitudinal displacement by the screw rod sleeve 6 and the inner shaft 9 of the clamp under the driving of the motor 4, so as to adjust the pressure on the adsorption head 13 for adsorbing the wafer.

The inside of absorption head 13 sets up the vacuum chamber, and the bottom surface of absorption head 13 sets up and communicates slot and through-hole with vacuum chamber 12, and the top of absorption head 13 still sets up by vacuum interface 11, and vacuum interface 11 and vacuum chamber switch-on, the top of vacuum interface 11 is worn out from the roof of anchor clamps outer support 16, is connected to the vacuum of upper base plate 2 through the hose and derives joint 2a. Through this passage, the vacuum chamber is evacuated, and suction is formed on the wafer 14 by the grooves and the through holes in the bottom of the suction head 13.

The top plate of the outer clamp bracket 16 is fixedly provided with a wireless dial indicator 17 serving as a distance measuring device, and a thimble of the wireless dial indicator 17 is arranged in a concave cavity of the outer clamp bracket 16 and is in contact with the upper surface of the adsorption surface 13 for measuring the moving distance of the adsorption surface 13.

As shown in fig. 3, a vacuum pump 19 is connected to a vacuum filter 20 and then connected to a rotary joint 1 through a vacuum line to supply vacuum to a semiconductor material grinding jig 100, and a solenoid valve 21 is provided on the vacuum line, and the solenoid valve 21 is electrically connected to an external controller 18. The external controller 18 is also electrically connected with a motor controller 22, a sensing controller 23 and a signal receiver 24, wherein the motor controller 22 is used for being connected with the motor 4 and controlling the motor to work, the sensing controller 23 is used for pulling a pressure signal through the pull pressure sensor 3, and the signal receiver 24 is connected with the wireless dial indicator 17 and receives a measured distance signal.

Referring to fig. 5 and 6, the method for performing pressure-measuring, controllably and adjustably polishing a semiconductor material using the semiconductor material polishing jig 100 is as follows:

the wafer 14 is sucked to the lower end face of the suction head 13 and the semiconductor material polishing jig 100 is placed on the polishing plate 200. When the wafer 14 is not in contact with the surface of the polishing plate 200, the processed surface of the wafer 14 is not subjected to pressure. The screw sleeve 6, the inner shaft 9 of the clamp, the suction head 13 and the wafer 14 which are sequentially connected are taken as a whole, the weight of the whole is W1, and the whole is subjected to upward pulling force F1 of the motor 4 at the moment, and W1=F1. When the weight of the motor 4 is W2 and the motor 4 and the foregoing are taken as a large whole, the total weight thereof is w=w1+w2. At this time, the whole is subjected to its own downward gravity W, pulling the upward pulling force F2 of the pressure sensor 3. W=f2. Wherein F2 can be measured by a pull pressure sensor 3, and W1 and W2 can be weighed. F1 in the figure is the tension received by the motor 4.

When the wafer 14 contacts the surface of the polishing platen 200, a pressure is generated, which can also be understood as the force of the surface of the platen against the wafer 14, fw. At this time, the tension pressure sensor 3 applies a large overall upward tension force F2. W=f2+fw. The wafer is thus subjected to a pressure fw=w-F2.

When the processing pressure of the wafer 14 is set, the rough pressure adjusting button 8 is adjusted to ensure that the deviation between the pressure Fw of the wafer 14 and the required processing pressure is not more than 100g, and then the external controller 18 controls the motor 4 to operate to adjust the height of the adsorption head 13, so that Fw reaches the required processing pressure, wherein Fw=W-F2.

During the polishing process, the external controller 18 controls the motor 4 to act according to the tension change measured by the tension pressure sensor 3 and the longitudinal moving distance of the adsorption head 13 measured by the wireless dial indicator 17, so that Fw is stabilized at the required processing pressure. Specifically, the surface material of the wafer 14 is removed, so that the gap between the surface of the wafer 14 and the surface of the polishing plate 200 is increased, resulting in a decrease in the acting force Fw applied to the wafer 14, and in order to keep Fw stable, the motor 4 needs to act to move the suction surface 13 and the wafer 14 downward as a whole to compensate for the height of the removal of the surface material of the wafer 14. This process is repeated throughout the polishing process until the desired thickness of the wafer 14 is reached and stopped. The external controller 18 calculates the travel length of the motor 4 in real time during the grinding process, and further calculates the thickness of the material removed from the surface of the wafer 14. At the same time, the wireless dial gauge 17 also monitors and records the removal thickness of the surface material of the wafer 14 in real time. The two detection modes are performed simultaneously, and the accuracy and repeatability of the thickness removal of the material on the surface of the wafer 14 can be improved through the comparison and correction of the system.

It should also be noted that during the polishing process, the material on the surface of the wafer 14 is removed, resulting in a reduction in the overall weight W1, and that Fw also changes after the material is removed. Taking a 2 inch InSb example, the weight varies by about 5g when the entire grinding process removes 400 microns thickness. The 2 inch sheet was subjected to a pressure of 800g (40 g/cm 2), and the polishing removal rate was about 10 μm/min and the polishing removal rate was about 400 μm/min, with a change in W1 per minute due to material removal of 0.13g. For smaller sized chips, such as 20mm by 20mm chips, the change in W1 due to the total thickness 300 microns is only about 0.7 gram, while the impact is very small for the downforce 160g (40 g/cm 2) and the material removal. Therefore, in the grinding process using the jig, the influence of the removal of the material on the W1 and the removal amount is negligible.

In example 1, the total weight w1=2560 g was designed, the weight w2=300 g of the motor 4 was calculated as f2=2060 g by using a 2 inch InSb test piece and the preset pressure fw=800 g.

Before grinding, the whole fixture is placed on a pressure test calibration device, a pressure rough adjusting button 8 is adjusted to enable the reading of the pulling pressure sensor 3 to be 1960g, and then the pressure rough adjusting button 8 is locked. Then, the motor 4 is controlled to operate, so that the whole W1 moves upward by a small distance to read 2060g from the pull pressure sensor 3.

Ensuring that the polishing disc 200 is flat and the surface is uniformly distributed with the abrasive A, and integrally placing the clamp with the adjusted pressure on the polishing disc 200. And (3) operating the grinding process A to grind, and clearing the wireless dial indicator. The external controller 18 records the starting position X1 of the motor 4 and detects the reading of the pulling pressure sensor 3 in real time, and when the reading is smaller than 2060g, the motor 4 is controlled to adjust the upward movement of the whole 1 so as to always keep the pressure at 2060g; when the pressure is larger than 2060g, the motor 4 is controlled to adjust the downward movement of the whole 1, so that the pressure is always 2060g. The pressure changes are recorded in real time and a pressure profile is formed. Until the value of the wireless dial indicator 17 reaches the removal thickness 300um, recording the end position X2 of the motor 4 at the moment, and simultaneously comparing the difference value of X2-X1 with the value reached by the wireless dial indicator 17. And recording the total time, and calculating the material removal rate to be 9.6um/min; the values of X2-X1 and the wireless dial indicator 4 are compared, the difference value ranges from +/-2um, the thickness error is +/-0.67%, the TTV thickness variation of the surface of the 2-inch test piece is 1 micrometer, and the wafer edge has no edge breakage and no obvious scratch on the surface. The real-time pressure variation range is 6g, and the error of the pressure of the experimental sheet is +/-0.4%.

In example 2, the total weight w1=2560 g was designed, the weight w2=300 g of the motor 4 was calculated as f2=2700g by using a 20mm×20mm InSb test piece, the preset pressure fw=160 g, and the force to be measured by the pull pressure sensor 3 was calculated.

Before grinding, the whole fixture is placed on a pressure test calibration device, a pressure rough adjusting button 8 is adjusted to enable the reading of the pulling pressure sensor 3 to be about 2600g, and then the pressure rough adjusting button 8 is locked. Then, the motor 4 is controlled to operate, so that the whole W1 moves upward by a small distance to read 2700g from the pull pressure sensor 3.

Ensuring that the polishing disc 200 is flat and the surface is uniformly distributed with the abrasive B, and integrally placing the clamp with adjusted pressure on the polishing disc 200. And meanwhile, the wireless dial indicator 17 is cleared, and the starting position X3 of the motor 4 is recorded. And when the pressure is larger than 2700g, the motor 4 is controlled to adjust the downward movement of the whole 1, so that the pressure is always 2700g. The pressure changes are recorded in real time and a pressure profile is formed. Until the value of the wireless dial indicator 17 reaches the removal thickness of 300um, recording the end position X4 of the motor 4, recording the total time, calculating the material removal rate to be 8.9um/min, comparing the value of the X4-X3 and the value of the wireless dial indicator 17, wherein the difference value range is +/-3um, the thickness error is +/-1%, the TTV of the measurement surface is 1 micrometer, and the wafer edge has no edge breakage and no obvious scratch on the surface. The real-time pressure variation range is 8g, and the error of the chip pressure is +/-2.5%.

Claims (10)

1. The utility model provides a pressure measurement controllable semiconductor material grinds adds clamping apparatus, its characterized in that, includes anchor clamps outer support, anchor clamps sleeve, absorption head and anchor clamps in the axle, the anchor clamps outer support with anchor clamps sleeve fixed connection, the absorption head with the lower extreme fixed connection of anchor clamps in the axle, the absorption head set up in the anchor clamps outer support, the setting of anchor clamps in the axle is in the anchor clamps sleeve, screw-thread fit has the pressure coarse tuning button on the anchor clamps sleeve, be connected with the upper substrate on the pressure coarse tuning button, the below of upper substrate is connected with the motor through pulling pressure sensor longitudinal connection, the motor drive during the rotation of pressure coarse tuning button the upper substrate pull pressure sensor motor lead screw nut kinematic pair and the common longitudinal movement of anchor clamps in the axle, pull pressure sensor is used for measuring longitudinal tension pressure.

2. The pressure-measurable controllably adjustable semiconductor material grinding jig of claim 1, wherein the top surface of the jig outer bracket is provided with a distance measuring device for measuring the longitudinal movement distance of the suction head.

3. The pressure-measurable controllably adjustable semiconductor material grinding jig of claim 2, comprising a controller electrically connected to the pull pressure sensor, the motor, and the distance measuring device, respectively.

4. The pressure-measurable and controllably adjustable semiconductor material grinding jig according to claim 1, wherein the upper base plate is fixedly connected with a support cylinder, the support cylinder is connected with the pressure rough adjustment button through a bearing, the upper base plate is rotatably connected with the pressure rough adjustment button through the support cylinder, and the jig sleeve is longitudinally slidably engaged with the jig inner shaft.

5. The pressure-measurable controllably adjustable semiconductor material grinding jig of claim 4, wherein the motor is disposed within the support cylinder, and wherein an upper end of the inner shaft of the jig extends into the support cylinder.

6. The pressure-measurable controllably adjustable semiconductor material grinding jig of claim 1, wherein the motor is connected to the upper end of the jig inner shaft by a lead screw nut kinematic pair.

7. The pressure-measurable and controllably adjustable semiconductor material grinding jig of claim 1, wherein the upper base plate is provided with a rotary joint for introducing vacuum, and the upper base plate is provided with a vacuum outlet joint.

8. The pressure-measurable controllably adjustable semiconductor material grinding jig of claim 1, wherein the suction head is provided with a vacuum chamber having a vacuum port extending from the jig outer support.

9. The pressure-measurable, controllably adjustable semiconductor material grinding jig of claim 2, wherein the distance measuring device is a wireless dial gauge.

10. The semiconductor material grinding processing method capable of being controlled and adjusted by pressure measurement is characterized by comprising the steps of adsorbing a wafer on the lower end face of an adsorption head and placing the semiconductor material grinding processing clamp on a grinding and polishing disc, firstly adjusting a rough pressure button to enable deviation between the pressure Fw borne by the wafer and required processing pressure to be not more than 100g, and then controlling a motor to act to enable Fw to reach the required processing pressure by a controller, wherein Fw=W-F2, W is the integral weight formed by sequentially connecting the motor, a clamp sleeve, the adsorption head and the wafer, F2 is the tension measured by a tension pressure sensor, and controlling the motor to act to enable Fw to be stabilized at the required processing pressure according to the tension change measured by the tension pressure sensor and the longitudinal moving distance of the adsorption head measured by a distance measuring device in the grinding and polishing process.