CN110587387A - Device for ultrasonic electrochemical mechanical polishing of sapphire substrate material - Google Patents

Abstract

The invention belongs to the technical field of gemstone polishing, in particular to a device for ultrasonic electrochemical mechanical polishing of sapphire substrate material, comprising a polishing disc and a polishing head, wherein the sapphire substrate material is fixed on the bottom of the polishing head, and the upper surface of the polishing disc is a polishing pad, The polishing disc and the polishing head are respectively driven to rotate by the first linear motor and the second linear motor; an ultrasonic generation control box for generating ultrasonic pulse current is also provided, and the ultrasonic generation control box is connected with the piezoelectric ceramics arranged on the polishing head. Electrically connected, the piezoelectric ceramics generate pulse vibration; and an electrochemical reaction loop is also included. In the present invention, the chemical reaction on the surface of the sapphire substrate material is accelerated under the action of electrochemical corrosion, and the generation of soft substances is accelerated. The invention improves the polishing efficiency and polishing quality of the sapphire substrate material under the combined action of ultrasonic, electrical, chemical and mechanical multi-energy fields.

Description

A device for ultrasonic electrochemical mechanical polishing of sapphire substrate material

technical field

The invention belongs to the technical field of gem polishing, in particular to a device for ultrasonic electrochemical mechanical polishing of sapphire substrate materials.

Background technique

Sapphire is a multifunctional oxide crystal that integrates many excellent optical properties, chemical properties and physical properties. The hardness of single crystal sapphire is second only to that of diamond, and it has good thermal properties, wear resistance, electrical properties and dielectric properties, so it is widely used in optoelectronics, communications, national defense and other fields, among which the more important application is as a GaN-based light emitting Diode (LED) substrate material. LED is the most promising energy-saving lighting technology and industry in the world today. As an important substrate material for LED epitaxial wafers and chip products, sapphire material is in the technological upstream of the international high-end LED chip industry. With the continuous development of science and technology, the above application fields have higher and higher requirements on the processing efficiency, surface quality and processing accuracy of sapphire substrates. However, as a typical hard and brittle material, sapphire crystal has no relatively mature high-efficiency and low-damage processing. method.

Chemical mechanical polishing (CMP) is currently the only polishing technology that can achieve global and local planarization. However, when CMP technology is used to polish sapphire substrates, there are problems of low material removal rate (MRR) and high time cost. Electrochemical mechanical polishing (ECMP) is a promising machining technique to obtain high MRR, low roughness surfaces. In ECMP, the workpiece is oxidized as an anode, and a soft oxide layer is produced on the surface and removed by mechanical force. Scratch-free and subsurface damage-free surfaces can be obtained. In the ECMP process, the anodization rate plays a decisive role in the MRR of ECMP. Ultrasonic vibration machining technology has been proven to be an efficient technology for machining hard and brittle materials. In order to improve the polishing efficiency and processing quality of the sapphire substrate, the present invention simultaneously introduces ECMP and ultrasonic vibration in the traditional CMP processing technology, and utilizes the combined effect of ultrasonic, electrical, chemical, and mechanical multi-energy fields to achieve high-efficiency and ultra-precise sapphire materials. polishing.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the defects of the prior art and provide a device for ultrasonic electrochemical mechanical polishing of sapphire substrate material.

The present invention is realized by the following scheme:

A device for ultrasonic electrochemical mechanical polishing of sapphire substrate material, comprising a polishing disc and a polishing head located above the polishing disc, the sapphire substrate material is fixed on the bottom of the polishing head, the upper surface of the polishing disc is a polishing pad, and the polishing pad is provided on the upper surface of the polishing disc. The optical disc is driven to rotate by the first linear motor at its bottom; the polishing head is driven to rotate by the second linear motor to polish the sapphire substrate material located between the bottom of the polishing head and the polishing pad, and a device for generating ultrasonic pulses is also provided. The current ultrasonic generation control box, the ultrasonic generation control box is electrically connected with the piezoelectric ceramics arranged on the polishing head, and the piezoelectric ceramics generate pulse vibration; it also includes an electrochemical reaction circuit, and the electrochemical reaction circuit includes a As an electrochemical workstation as a power source, the positive electrode of the electrochemical workstation is electrically connected to the sapphire substrate material, and the negative electrode is electrically connected to the cathode plate located on the upper side of the polishing disk. Above the polishing disk, there is a In the cavity, the cathode plate and the sapphire substrate material are all immersed in the polishing solution. The electrochemical workstation, the sapphire substrate material, the polishing solution and the cathode plate form a closed circuit. The polishing solution is pumped by the peristaltic pump to the polishing pad and the polishing pad. between sapphire substrate materials.

The polishing head is connected with the output shaft of the second linear motor through a hollow rotating shaft, a carbon brush is arranged on the outer side of the hollow rotating shaft, a conductive ring is sleeved on the outside of the hollow rotating shaft, and the ultrasonic generation control box is connected with the carbon brush through a wire, The carbon brush is in contact with the conductive ring, and a wire is arranged inside the hollow shaft to connect with the piezoelectric ceramic. The ultrasonic generation control box is electrically connected to the piezoelectric ceramic through the wire, the carbon brush, the conductive ring, and the wire inside the hollow shaft.

The polishing head is a disk-shaped structure, the piezoelectric ceramics include four and are evenly distributed in the four quadrants based on the center point of the rotating shaft of the polishing head, and two opposite piezoelectric ceramics generate longitudinal ultrasonic vibration, and the other two Two opposing piezoelectric ceramics generate horizontal ultrasonic vibration, and four piezoelectric ceramics combine to generate elliptical bending vibration.

The bottom of the polishing disc is a polishing disc base, the polishing disc base extends to one side of the bottom of the polishing disc, a groove is arranged in the extension, and a vertical column extending upward is fixed in the groove. The upper support plate and the lower support plate are arranged in the horizontal direction, the upper support plate is used to support the second linear motor, and the lower support plate is used to support the support frame of the carbon brush, and the support frame is set The vertical brackets are placed on the lower support plate, and three brackets from low to high are arranged in order from near to far away from the hollow shaft. The lower part is set to three, which are respectively connected with three carbon brushes.

The outer ends of the upper support plate and the lower support plate are both sleeved on the outside of the hollow rotating shaft, and a first rolling bearing and a second rolling bearing are respectively provided at the sleeves.

An embracing cylinder is sheathed on the outside of the column, the upper support plate and the lower support plate are fixed on the outer side of the embracing cylinder, and the interior of the embracing cylinder is provided with a cross bar, and the cross bar is matched with the screw rod arranged inside the column and is The screw rod is driven to move up and down, and the embracing cylinder is driven to slide up and down. The upper end of the screw rod is connected with the output shaft of the servo motor and is driven to rotate by it.

The bottom of the embracing cylinder is provided with a distance holder.

There is a groove at the bottom of the polishing head, and an anode metal plate is arranged in the groove. The anode metal plate is closely attached to the sapphire material, and the positive electrode of the electrochemical workstation and the sapphire substrate material pass through the anode metal plate. Make electrical connections.

A vacuum device is integrated above the polishing head, and the sapphire substrate material is fixed on the polishing head by vacuum adsorption.

The beneficial effects of the invention are: under the action of electrochemical corrosion, the chemical reaction on the surface of the sapphire substrate material is accelerated, and the generation of soft substances is accelerated. Under the action of ultrasound, the abrasive grains in the polishing liquid gain additional energy to accelerate and hit the surface of the material. At the same time, the temperature increases under the action of ultrasonic cavitation caused by ultrasonic cavitation, and the chemical reaction between the abrasive particles in the polishing liquid and the sapphire substrate material is accelerated. Under the combined action of ultrasonic, electrical, chemical and mechanical multi-energy fields, the polishing efficiency and polishing quality of the sapphire substrate material are improved.

Description of drawings

FIG. 1 is a schematic structural diagram of a device for ultrasonic electrochemical mechanical polishing of sapphire substrate material according to the present invention.

Labels in the figure: 1- ultrasonic generation control box; 2- cross bar; 3- carbon brush; 4- conductive copper slip ring; 5- hollow shaft; 6- piezoelectric ceramic; 8- anode metal plate; 9- polishing head; 10-electrochemical workstation; 11-cathode plate; 12-peristaltic pump; 13-first linear motor; 14-second linear motor; 15-servo motor; 16-screw; 17-distance cage; 18-column ; 19-foot; 20-polishing pad; 21-polishing disc; 22-polishing chassis seat; 23-guard plate; 24-lower support plate; 25-second rolling bearing; 26-first rolling bearing; 27-support frame; 29 30-sapphire substrate material; 31-polishing liquid; 32-upper support plate; 33-vacuum device; 34-third rolling bearing; 35-pressure sensing device.

Detailed ways

The present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

Example: see Figure 1 .

The invention discloses a device for ultrasonic electrochemical mechanical polishing of a sapphire substrate material, comprising a polishing disc 21 and a polishing head 9 located above the polishing disc, the sapphire substrate material 30 is fixed on the bottom of the polishing head 9, and the polishing disc 21 The upper surface is the polishing pad 20, the polishing disc 21 is driven to rotate by the first linear motor 13 at the bottom thereof; the polishing head 9 is driven to rotate by the second linear motor 14, preferably, the first linear motor 13 The steering and rotational speed of the second linear motor 14 are the same, and the sapphire substrate material 30 located between the bottom of the polishing head 9 and the polishing pad 20 is polished, and an ultrasonic generation control box 1 for generating ultrasonic pulse current is also provided, so The ultrasonic generation control box 1 is electrically connected with the piezoelectric ceramic 6 arranged on the polishing head 9, and the piezoelectric ceramic 6 generates pulse vibration; also includes an electrochemical reaction loop, and the electrochemical reaction loop includes an electric power source as a power source. The chemical workstation 10, the positive electrode of the electrochemical workstation 10 is electrically connected to the sapphire substrate material 30, the negative electrode is electrically connected to the cathode plate 11 located on the upper side of the polishing disc 21, and the cathode plate 11 is fixed on the guard plate 23 by an insulating member, Above the polishing plate 21 is a cavity for containing the polishing liquid 31. The cathode plate 11 and the sapphire substrate material 30 are all immersed in the polishing liquid 31. The electrochemical workstation 10, the sapphire substrate material 30, the polishing liquid The liquid 31 and the cathode plate 11 form a closed loop, and the polishing liquid 31 is pumped by the peristaltic pump 12 between the polishing pad 20 and the sapphire substrate material 30 .

Preferably, the polishing head 9 is connected to the output shaft of the second linear motor 14 through a hollow rotating shaft 5, the outer side of the hollow rotating shaft 5 is provided with a carbon brush 7, and the outside of the hollow rotating shaft 5 is sheathed with a conductive ring 4, the ultrasonic The generation control box 1 is connected to the carbon brush 7 through a wire, the carbon brush 7 is in contact with the conductive ring 4, and a wire is arranged inside the hollow shaft 5 to connect with the piezoelectric ceramic 6, and the ultrasonic generation control box 1 sequentially passes through the wire, the carbon brush 7, and the conductive ring. The wires inside the ring 4 and the hollow shaft 5 are electrically connected with the piezoelectric ceramics 6 .

Preferably, the polishing head 9 is a disk-shaped structure, the piezoelectric ceramics 6 include four and are evenly distributed in four quadrants based on the center point of the rotation axis of the polishing head 9, and two opposite piezoelectric ceramics 6 Longitudinal ultrasonic vibration is generated, the other two opposing piezoelectric ceramics 6 generate horizontal ultrasonic vibration, and the four piezoelectric ceramics 6 are combined to generate elliptical bending vibration.

Preferably, the bottom of the polishing disc 21 is a polishing disc base 22, the polishing disc base 22 extends to one side of the bottom of the polishing disc 21, a groove is formed in the extending portion, and a groove extending upward is fixed in the groove The upright column 18 is provided above the upright column 18 with an upper support plate 32 and a lower support plate 24 connected to it in a horizontal direction. The upper support plate 32 is used to support the second linear motor 14, and the lower support plate 24 is used for For the support frame 27 supporting the carbon brushes, the support frame 27 is a vertical support frame arranged on the lower support plate 24, and three support frames from low to high are arranged in order from near to far from the hollow shaft 5 , the carbon brushes 7 are sequentially installed on the three support frames 27, and the conductive rings 4 are arranged in three from top to bottom, and are respectively connected with the three carbon brushes.

Preferably, the outer ends of the upper support plate 32 and the lower support plate 24 are sleeved on the outside of the hollow rotating shaft 5 , and the sleeves are provided with a first rolling bearing 25 and a second rolling bearing 26 respectively. First pass through the lower support plate 24 through the second rolling bearing 26, the outer ring of the second rolling bearing 26 is fixed on the lower support plate 24 through the bearing seat, and the inner ring matches the hollow rotating shaft 5 and rotates together with it; The second linear motor 14 is connected to the upper support plate 32 . The outer ring of the first rolling bearing 25 is fixed on the lower support plate 24 through the bearing seat, and the inner ring is matched with the hollow rotating shaft 5 and rotates together with it.

Preferably, an embracing cylinder 29 is sleeved on the outside of the upright column 18 , the upper support plate 32 and the lower supporting plate 24 are fixed on the outer side of the embracing cylinder 29 , and the interior of the embracing cylinder 29 is provided with a cross bar 2 , and the cross bar 2 The screw rod 16 is matched with the screw rod 16 arranged inside the column and is driven to move up and down by the screw rod 16, which drives the encircling cylinder 29 to slide up and down. The upper end of the screw rod 16 is connected to the output shaft of the servo motor 15 and is driven to rotate by it. The lead screw 16 is connected to the servo motor 15 through a third rolling bearing 34 . The outer ring of the third rolling bearing 34 is fixed on the upper end of the column 18 through the bearing seat, and the inner ring is matched with the shaft on the upper part of the screw 16, so that the upper support plate 32, the lower support plate 24 and the polishing head 9 can be realized by the rotation of the servo motor 15. move up and down. A distance holder 17 is installed under the surrounding cylinder of the upright column 18, which can effectively prevent the impact on the equipment caused by the loss of control of the polishing head 9. That is, when the encircling cylinder descends to the distance holder 17, it is blocked and cannot continue to descend. The installation height from the holder 17 can be calculated according to the positions of the right polishing head and the sapphire substrate material 30 .

The uprights 18 are bolted into the grooves of the polished chassis base 22 through the uprights 19 .

Preferably, a groove is provided at the bottom of the polishing head 9, and an anode metal plate 8 is arranged in the groove, and the anode metal plate 8 is closely attached to the sapphire material 30. The positive electrode of the electrochemical workstation 10 Electrical connection to the sapphire substrate material 30 is achieved through the anode metal plate 8 .

Preferably, a vacuum device 33 is integrated above the polishing head 9, and the sapphire substrate material 30 is fixed on the polishing head 9 by vacuum adsorption

The device for ultrasonic electrochemical mechanical polishing of sapphire substrate material of the present invention is used to polish the sapphire substrate material, and the steps are as follows:

S1. the sapphire substrate material 30 is fixed on the polishing head 9 by the integrated vacuum device 33;

S2. Turn on the servo motor 15 to adjust the upper support plate 32 and the lower support plate 24 to move vertically downward along the column 18, until the sapphire substrate material 30 on the polishing head 9 is in contact with the polishing pad 20 on the polishing disc 21, close Servo motor 15;

S3. Adjust the polishing pressure by adjusting the servo motor 15, and the specific value is measured by the pressure sensing device 35;

S 4. Start the peristaltic pump 12 to transport the polishing liquid 31 to the polishing pad 20;

S5. Start the electrochemical workstation 10, the positive electrode is connected to the anode metal plate 8 through the wire, the carbon brush 7 and the conductive copper slip ring 28, and the negative electrode is connected to the cathode metal plate 11 through the wire, and a complete loop is formed through the polishing liquid 31 to realize the sapphire Anodic electrochemical corrosion of substrate material 30:

S6. Start the ultrasonic power supply control box 1. The ultrasonic power supply is connected to the positive and negative terminals of the piezoelectric ceramic 6 through the wire, the carbon brush 3 and the conductive copper slip ring 4. The piezoelectric ceramic 6 converts the electrical signal into a mechanical vibration signal, and the ultrasonic The vibration is transmitted through the polishing head 9 to the sapphire substrate material 30 mounted thereon;

S7. Turn on the first linear motor 13 and the second linear motor 14 to realize the synchronous rotation of the polishing head 9, the polishing disc 21 and the polishing pad 20, so as to realize the ultrasonic electrochemical mechanical polishing of the sapphire substrate material 30;

S8. Turn off all switches in turn after finishing processing.

The main process parameters are as follows:

Electrochemical workstation voltage: AC220V±5%, 50Hz±1%;

Ultrasonic power supply voltage: AC220V±5%, 50Hz±1%;

Working frequency: 20-40KHz;

Ultrasonic maximum output power: 3Kw;

Polishing disc speed 0-1000r/min;

Polishing pad speed 0-1000r/min;

Polishing head speed 0-1000r/min;

Although the technical solutions of the present invention have been described and enumerated in more detail, it should be understood that, for those skilled in the art, modifications to the above-mentioned embodiments or equivalent alternative solutions are Obviously, these modifications or improvements made without departing from the spirit of the present invention belong to the scope of protection of the present invention.

Claims (9)

1. A device for ultrasonic electrochemical mechanical polishing of a sapphire substrate material, comprising a polishing disk (21) and a polishing head (9) positioned above the polishing disk, and the sapphire substrate material (30) is fixed on the bottom of the polishing head (9) , the upper surface of the polishing disc (21) is a polishing pad (20), the polishing disc (21) is driven to rotate by a first linear motor (13) at the bottom of the polishing disc (21); the polishing head (9) is rotated by a second linear motor (14) Drive the rotation to polish the sapphire substrate material (30) between the bottom of the polishing head (9) and the polishing pad (20), and is characterized in that: an ultrasonic generation control box ( 1), the ultrasonic generation control box (1) is electrically connected to a piezoelectric ceramic (6) disposed on the polishing head (9), and the piezoelectric ceramic (6) generates pulse vibration; further comprising an electrochemical reaction loop, The electrochemical reaction loop includes an electrochemical workstation (10) as a power source, the positive electrode of the electrochemical workstation (10) is electrically connected to the sapphire substrate material (30), and the negative electrode is connected to the side located above the polishing disc (21). The cathode plate (11) is electrically connected, a cavity for holding the polishing liquid (31) is arranged above the polishing disc (21), the cathode plate (11) and the sapphire substrate material (30) are soaked in In the polishing liquid (31), the electrochemical workstation (10), the sapphire substrate material (30), the polishing liquid (31), and the cathode plate (11) form a closed loop, and the polishing liquid (31) is driven by a peristaltic pump (12) Pumped between the polishing pad (20) and the sapphire substrate material (30). 2 . The device for ultrasonic electrochemical mechanical polishing of sapphire substrate material according to claim 1 , wherein the polishing head ( 9 ) passes through the hollow rotating shaft ( 5 ) and the output shaft of the second linear motor ( 14 ). 3 . connection, the outer side of the hollow shaft (5) is provided with a carbon brush (7), the outer side of the hollow shaft (5) is covered with a conductive ring (4), and the ultrasonic generation control box (1) is connected to the carbon brush (7) through a wire ) connection, the carbon brush (7) is in contact with the conductive ring (4), a wire is arranged inside the hollow shaft (5) to connect with the piezoelectric ceramic (6), and the ultrasonic generation control box (1) passes through the wire and the carbon brush (7) in turn. ), the conductive ring (4), and the wires inside the hollow shaft (5) are electrically connected to the piezoelectric ceramics (6). 3 . The device for ultrasonic electrochemical mechanical polishing of sapphire substrate material according to claim 2 , wherein the polishing head ( 9 ) is a disc-shaped structure, and the piezoelectric ceramic ( 6 ) comprises four And the polishing head (9) is evenly distributed in the four quadrants based on the center point of the rotating shaft of the polishing head (9), and the two opposing piezoelectric ceramics (6) generate longitudinal ultrasonic vibration, and the other two opposing piezoelectric ceramics (6) generate horizontal ultrasonic vibrations. Ultrasonic vibration, four piezoelectric ceramics (6) composite to generate elliptical bending vibration. 4. A device for ultrasonic electrochemical mechanical polishing of sapphire substrate material according to claim 2, characterized in that: the bottom of the polishing disk (21) is a polishing disk base (22), and the polishing disk base ( 22) Extending to one side of the bottom of the polishing disc (21), a groove is provided in the extension part, and a vertical column (18) extending upward is fixed in the groove, and the upper part of the vertical column (18) is connected with it an upper support plate (32) and a lower support plate (24) in a horizontal direction, the upper support plate (32) is used to support the second linear motor (14), and the lower support plate (24) is used to support the carbon brush The support frame (27) is a vertical support frame arranged on the lower support plate (24), and according to the distance from the hollow shaft (5) from near to far, three from low to low are arranged in order. To the high bracket, the carbon brushes (7) are installed on the three support brackets (27) in sequence, and the conductive rings (4) are arranged in three from top to bottom, and are respectively connected with the three carbon brushes. 5. A device for ultrasonic electrochemical mechanical polishing of sapphire substrate material according to claim 4, characterized in that: the outer ends of the upper support plate (32) and the lower support plate (24) are sleeved in a hollow rotating A first rolling bearing (25) and a second rolling bearing (26) are respectively provided on the outside of the shaft (5) and at the sleeve. 6 . The device for ultrasonic electrochemical mechanical polishing of sapphire substrate material according to claim 4 , characterized in that: an embracing cylinder ( 29 ) is sleeved on the outside of the upright column ( 18 ), and the upper support plate ( 32 ), the lower support plate (24) is fixed on the outer side of the embracing cylinder (29), the interior of the embracing cylinder (29) is provided with a cross bar (2), the cross bar (2) and the screw rod (16) arranged inside the column ) is matched and is driven up and down by the screw (16), which drives the embracing cylinder (29) to slide up and down, and the upper end of the screw (16) is connected to the output shaft of the servo motor (15) and is driven to rotate by it. 7 . The device for ultrasonic electrochemical mechanical polishing of sapphire substrate material according to claim 6 , wherein a distance holder ( 17 ) is provided at the bottom of the embracing cylinder ( 29 ). 8 . 8 . The device for ultrasonic electrochemical mechanical polishing of sapphire substrate material according to claim 1 , wherein a groove is provided at the bottom of the polishing head ( 9 ), and an anode metal is provided in the groove. 9 . plate (8), the anode metal plate (8) is closely attached to the sapphire material (30), and the anode of the electrochemical workstation (10) and the sapphire substrate material (30) are electrically connected through the anode metal plate (8). connect. 9. A device for ultrasonic electrochemical mechanical polishing of sapphire substrate material according to claim 1, characterized in that: a vacuum device (33) is integrated above the polishing head (9), and the sapphire substrate material (30) is integrated above the polishing head (9). ) is fixed on the polishing head (9) by vacuum adsorption.