Laser chip stripping system

Abstract

The invention relates to the technical field of chip stripping, in particular to a laser chip stripping system which comprises a base, and a chip carrying table is arranged on the base and used for placing a chip; the template fixing frame is positioned above the slide holder; the stripping template is positioned on the template fixing frame and is opposite to the slide holder, and a stripping groove corresponding to a stripping area on the chip is formed in the stripping template; and the laser module is located above the stripping template, and a laser focus lens is arranged at a light outlet of the laser module. The chip is placed on the slide holder, the stripping template is installed, and the stripping groove is right opposite to the stripping area on the chip. And the laser module emits laser to penetrate through the stripping groove to be hit on the metal of the chip. In the state, kinetic energy conversion is carried out on laser photons and metal molecules, so that the kinetic energy of the metal molecules irradiated by the laser is rapidly improved, the metal molecules escape from the surface of the material, and the metal stripping effect is achieved. The chip is subjected to metal stripping by adopting laser, the stripping effect is good, the process is simple and convenient, and the use is convenient.

Description

Technical Field

[0001] This application relates to the technical field of chip peeling, and particularly to a laser chip peeling system. Background Art

[0002] In the process of semiconductor laser chip manufacturing, there is a process called liftoff, which is translated into Chinese as peeling; the purpose is to strip the uniformly fabricated metal within a specific area on the chip surface, exposing the bottom material of the chip.

[0003] Limited by the interrelationship between process steps, the area of liftoff is relatively small, and the peeling shape must take into account the subsequent platting process and requires concessions. Too large and too many liftoff areas will affect the subsequent platting process, resulting in unevenness.

[0004] The liftoff process itself involves steps such as yellow light, metal evaporation, peeling, and wet cleaning, which are relatively cumbersome, costly, and prone to rework. Summary of the Invention

[0005] To avoid the above problems, this application provides a laser chip peeling system.

[0006] The laser chip peeling system provided by this application adopts the following technical solutions: A laser chip peeling system includes a base, and on the base is provided a wafer stage for placing the chip; a template fixing frame located above the wafer stage; a peeling template located on the template fixing frame opposite to the wafer stage, and a peeling groove corresponding to the peeling area on the chip is provided on the peeling template; a laser module located above the peeling template, and a laser focusing lens is provided at the light output port of the laser module.

[0007] By adopting the above technical solutions, the chip is placed on the wafer stage, the peeling template is installed, and the peeling groove is opposite to the peeling area on the chip. The laser module emits laser light that passes through the peeling groove and hits the metal on the chip. In this state, the kinetic energy conversion between laser photons and metal molecules causes the kinetic energy of the metal molecules irradiated by the laser to increase rapidly, escaping from the material surface, achieving the effect of metal peeling. Using laser to perform metal peeling on the chip has a good peeling effect, simple process, and convenient use.

[0008] Preferably, the wafer stage includes a y-axis adjustment base horizontally and slidably connected to the base, an x-axis adjustment base horizontally and slidably connected to the y-axis adjustment base, the sliding direction of the x-axis adjustment base being perpendicular to the sliding direction of the y-axis adjustment base, a rotating base rotatably connected to the x-axis adjustment base, and a vacuum chuck provided on the rotating base.

[0009] By adopting the above technical solution, the chip is placed on the vacuum chuck, and the vacuum chuck adsorbs and fixes the chip. The x-axis adjustment base and the y-axis adjustment base can adjust the position of the chip in two directions, and the rotating base can drive the chip to rotate and adjust, so as to adjust the position of the chip to make it directly face the peeling template. The position of the chip is adjusted in three ways, with more adjustment methods and a wider adjustment range.

[0010] Preferably, the template fixing frame includes a fixing rod fixedly connected to the base and a lifting frame vertically and slidably connected to the fixing rod, and a plurality of vacuum adsorption holes are provided on the lifting frame.

[0011] By adopting the above technical solution, the peeling template is placed on the lifting frame, and the lifting frame can drive the peeling template to move up and down to adjust the position of the peeling template. The vacuum adsorption holes on the lifting frame.

[0012] Preferably, a plurality of adsorption channels are provided in the peeling template, a communication hole communicating with the adsorption channel is provided at the edge of the lower surface of the peeling template, the communication hole communicates with one of the vacuum adsorption holes, and a plurality of impurity removal holes communicating with the adsorption channel are provided on the lower surface of the peeling template.

[0013] By adopting the above technical solution, the vacuum adsorption hole communicates with the adsorption channel, and negative pressure suction is generated in the vacuum adsorption hole, so that suction is generated in the adsorption channel. After the metal molecules escape from the chip, they are sucked into the impurity removal holes and finally discharged from the vacuum adsorption hole through the adsorption channel. The impurity removal holes absorb and remove the escaped metal molecules to prevent the metal molecules from remaining in the device.

[0014] Preferably, a positioning block bulging downward is provided at the edge of the peeling template, and a positioning groove corresponding to the positioning block is provided on the lifting frame.

[0015] By adopting the above technical solution, the peeling template is defined by the positioning block and the positioning groove to ensure the installation accuracy of the peeling template.

[0016] Preferably, the vacuum chuck is connected with an adsorption hose, an impurity removal chamber is provided on the lifting frame, the impurity removal chamber communicates with the vacuum adsorption hole, an adsorption net is provided in the impurity removal chamber, the end of the impurity removal chamber far away from the vacuum adsorption hole is connected with an external negative pressure device through a vacuum tube, the adsorption hose communicates with the vacuum adsorption hole, and a one-way valve is provided at the connection between the vacuum adsorption hole and the adsorption hose.

[0017] By adopting the above technical solution, the negative pressure device applies negative pressure suction through a vacuum tube, enabling the lifting frame to adsorb and fix the peeling template, the vacuum suction table to adsorb and fix the chip, and removing the escaped metal molecules, which is convenient to use. The one-way valve protects the vacuum suction table to prevent metal molecules from entering the vacuum suction table and affecting the chip. After the metal molecules enter the impurity removal cavity, they are absorbed by the adsorption net, and the adsorption net collects the metal molecules for subsequent processing.

[0018] Preferably, a vertically arranged lifting rod is connected to the base, and a laser fixing frame is provided at the upper end of the lifting rod, and the laser module is fixed to the laser fixing frame.

[0019] By adopting the above technical solution, the height of the laser module can be adjusted through the lifting rod, which is convenient to use.

[0020] Preferably, the laser fixing frame is horizontally rotatably connected to the lifting rod, and a microscope is provided at one end of the laser fixing frame away from the laser module.

[0021] By adopting the above technical solution, the operator can observe the positional relationship between the peeling template and the chip through the microscope, and adjust the position of the chip in cooperation with the x-axis adjustment base, y-axis adjustment base and rotating base, so that the peeling area on the chip is aligned with the peeling groove, improving the peeling accuracy of the chip. Then rotate the laser fixing frame to turn the laser module above the peeling template for laser peeling.

[0022] Preferably, the laser module selects a semiconductor laser of 405nm or 450nm.

[0023] By adopting the above technical solution, the light of this wavelength band is more easily absorbed, thus ensuring the peeling effect.

[0024] In summary, the present application includes the following beneficial technical effects: Using laser to peel the metal on the chip, the kinetic energy conversion between the laser photons and the metal molecules enables the kinetic energy of the metal molecules irradiated by the laser to increase rapidly, escape from the material surface, achieving the effect of metal liftoff. The process is simple, the cost is low and the qualification rate is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the overall structural schematic diagram of the embodiment; Figure 2 is the connection schematic diagram of the peeling template and the lifting frame in the embodiment; Figure 3 is Figure 2 the enlarged schematic diagram of part A in Figure 4 is the internal structural schematic diagram of the impurity removal cavity in the embodiment.

[0026] Description of reference numerals: 1. Base; 2. Wafer stage; 21. Y-axis adjustment base; 22. X-axis adjustment base; 23. Rotating base; 24. Vacuum chuck table; 241. Adsorption through-hole; 242. Suction groove; 25. Adsorption hose; 3. Template fixing frame; 31. Fixing rod; 32. Lifting frame; 321. Vacuum adsorption hole; 3211. Bevel; 322. Positioning groove; 323. Deburring chamber; 324. Adsorption mesh; 325. Vacuum tube; 326. Step; 327. Lifting knob; 4. Stripping template; 41. Stripping groove; 42. Adsorption channel; 43. Communication hole; 44. Deburring hole; 45. Positioning block; 451. Connection hole; 452. Connecting rod; 453. Connecting gear; 454. Connecting spring; 46. Connecting pipe; 461. Connecting rack; 5. Laser module; 6. Lifting rod; 61. Laser fixing frame; 62. Microscope; 63. X-axis telescopic rod; 64. Y-axis telescopic rod. Detailed implementation manners

[0027] The present application will be further described in detail below with reference to all the attached drawings.

[0028] Embodiment

[0029] An embodiment of the present application discloses a laser chip stripping system. Referring to Figure 1 , it includes a base 1. A wafer stage 2 is provided on the base 1. A template fixing frame 3 is provided above the wafer stage 2. A stripping template 4 is installed on the template fixing frame 3. A stripping groove 41 corresponding to the stripping area on the chip is formed on the stripping template 4. A laser module 5 is provided above the template fixing frame 3. The chip is placed on the wafer stage 2 directly below the stripping template 4. The laser module 5 emits laser light that passes through the stripping groove 41 to strip the metal on the chip.

[0030] Referring to Figure 1 , the wafer stage 2 includes an X-axis adjustment base 22, a Y-axis adjustment base 21, and a rotating base 23 that are sequentially arranged on the base 1 from bottom to top in the vertical direction. An X-axis lead screw is rotatably connected to the base 1, and an X-axis knob is fixed to the end of the X-axis lead screw. An X-axis adapter block fixedly connected to the X-axis adjustment base 22 is provided on the X-axis lead screw. A Y-axis lead screw perpendicular to the Y-axis lead screw is rotatably connected to the upper surface of the X-axis adjustment base 22, and a Y-axis knob is fixed to the end of the Y-axis lead screw. A Y-axis adapter block fixedly connected to the Y-axis adjustment base 21 is provided on the Y-axis lead screw.

[0031] Referring to Figure 1 , an operator can adjust the position of the chip in the X-axis and Y-axis directions by rotating the X-axis knob and the Y-axis knob, so as to ensure the position accuracy of the chip and the stripping template 4.

[0032] Referring to Figure 1, a rotating seat 23 is rotatably connected to the upper surface of the y-axis adjusting seat 21, and a rotating shaft passing through the y-axis adjusting seat 21 is coaxially fixed at the center of the rotating seat 23. A rotating rod is horizontally rotatably connected in the y-axis adjusting seat 21, and the rotating rod and the rotating shaft are connected by a bevel gear pair. The end of the rotating rod extends out of the y-axis adjusting seat 21 and is fixed with a rotating knob. The operator rotates the rotating knob, and the rotating rod drives the rotating seat 23 to rotate, thereby adjusting the angle of the chip so that the chip can be directly opposite to the peeling template 4, facilitating the laser peeling of the metal layer.

[0033] Refer to Figure 1 , a vacuum suction table 24 is fixed on the upper surface of the rotating seat 23, and the chip is installed in the vacuum suction table 24. An adsorption through hole 241 is formed in the vacuum suction table 24, and a plurality of suction grooves 242 communicating with the adsorption through hole 241 are formed on the upper surface of the vacuum suction table 24. The adsorption through hole 241 is connected to an external negative pressure device through an adsorption hose 25. When the chip is placed on the vacuum suction table 24, negative pressure suction is generated in the adsorption through hole 241 to adsorb the chip on the vacuum suction table 24.

[0034] Refer to Figure 1 and Figure 2 , the template fixing frame 3 includes fixing rods 31 fixedly installed on the base 1. There are four fixing rods 31 and they are respectively located at the four corners of the base 1. The wafer stage 2 is located within the area surrounded by the four fixing rods 31. A lifting frame 32 is vertically slidably connected above the fixing rods 31. At one corner of the lifting frame 32, an adjusting screw rod is vertically rotatably connected. The lower end of the adjusting screw rod is rotatably connected to one of the fixing rods 31. The adjusting screw rod is threadedly connected to the lifting frame 32, and the upper end of the adjusting screw rod is fixed with a lifting knob 327. Driven telescopic rods are provided at the other three corners of the lifting frame 32. One end of each driven telescopic rod is connected to the lifting frame 32, and the other end is connected to the fixing rod 31. The three driven telescopic rods are connected to the four fixing rods 31 one by one.

[0035] Refer to Figure 1 and Figure 2 , a concave positioning groove 322 is formed on the lifting frame 32, and a positioning block 45 that bulges downward and is adapted to the positioning groove 322 is formed on the edge of the peeling template 4. When the peeling template 4 is installed on the lifting frame 32, the positioning block 45 is embedded in the positioning groove 322 to limit the position of the peeling template 4 and improve the installation accuracy.

[0036] Refer to Figure 1 and Figure 2 , a plurality of vacuum adsorption holes 321 are formed on the lifting frame 32. When the peeling template 4 is installed on the lifting frame 32, the vacuum adsorption holes 321 adsorb and fix the peeling template 4.

[0037] Refer to Figure 1 and Figure 2, an adsorption channel 42 is provided in the stripping template 4, and a plurality of impurity removal holes 44 communicating with the adsorption channel 42 are provided on the lower surface of the stripping template 4. When the laser hits the metal layer of the chip, the metal molecules escape from the chip and are sucked into the impurity removal holes 44 and discharged through the adsorption channel 42, preventing the metal molecules from remaining in the device.

[0038] Refer to Figures 1 to 3 , a vacuum adsorption hole 321 is provided in the positioning groove 322, and a communication hole 43 opposite to the vacuum adsorption hole 321 is provided on the positioning block 45. When the positioning block 45 penetrates into the positioning groove 322, the communication hole 43 is aligned with the vacuum adsorption hole 321. The communication hole 43 is communicated with the adsorption channel 42. After the stripping template 4 is installed on the lifting frame 32, while generating a negative pressure suction force in the lifting frame 32 to adsorb and fix the stripping template 4, a negative pressure suction force is also generated in the adsorption channel 42 through the communication hole 43, so as to absorb and remove the metal molecules.

[0039] Refer to Figures 1 to 3 , the vacuum adsorption hole 321 in the positioning groove 322 is provided at the bottom of the positioning groove 322, and the diameter of the vacuum adsorption hole 321 is smaller than the diameter of the bottom of the positioning groove 322, and a step 326 is formed between the bottom of the positioning groove 322 and the vacuum adsorption hole 321. The communication hole 43 is provided on the lower surface of the positioning block 45, and a connecting pipe 46 for inserting into the vacuum adsorption hole 321 is vertically slidably connected in the communication hole 43. The outer wall of the connecting pipe 46 is made of soft rubber material. The outer diameter of the connecting pipe 46 is not less than the diameter of the vacuum adsorption hole 321, and the diameters of the vacuum adsorption hole 321 and the communication hole 43 are the same.

[0040] Refer to Figures 1 to 3 , the outer wall of the connecting pipe 46 is pressed and embedded in the communication hole 43, so that an interference fit is formed between the outer wall of the connecting pipe 46 and the outer wall of the communication hole 43, improving the sealing performance. When the communication hole 43 is aligned with the vacuum adsorption hole 321. The lower end of the connecting pipe 46 extends into the vacuum adsorption hole 321 to seal and connect the vacuum adsorption hole 321 and the communication hole 43, improving the connection stability.

[0041] Refer to Figures 1 to 3 , an inclined groove 3211 is provided at the upper end of the vacuum adsorption hole 321, and the diameter of the inclined groove 3211 is larger than the outer diameter of the connecting pipe 46. When the connecting pipe 46 extends downward and inserts into the vacuum adsorption hole 321, the lower end of the connecting pipe 46 hits the inclined groove 3211, and the inclined groove 3211 guides and compresses the connecting pipe 46 and introduces it into the vacuum adsorption hole 321, so as to ensure the insertion effect of the connecting pipe 46.

[0042] Refer to Figures 1 to 3, a connecting hole 451 facing the step 326 is formed at the bottom of the positioning block 45. A connecting rod 452 is slidably connected in the connecting hole 451. The upper end of the connecting rod 452 is connected to the connecting rod 452 through a connecting spring 454. When the connecting spring 454 is in a natural state, the lower end of the connecting rod 452 extends out of the connecting hole 451. A connecting gear 453 is rotatably connected in the connecting hole 451. A connecting tooth groove meshing with the connecting gear 453 is provided at the upper end of the connecting rod 452. A connecting rack 461 meshing with the connecting gear 453 is fixed on the outer wall of the connecting pipe 46. The connecting rack 461 and the connecting rod 452 are located on both sides of the connecting gear 453.

[0043] Refer to Figures 1 to 3 , when the positioning block 45 is inserted downward into the positioning groove 322, the connecting rod 452 extends out of the connecting hole 451 under the action of the connecting spring 454 and protrudes from the lower surface of the positioning block 45. The connecting rod 452 first contacts the step 326. As the positioning block 45 descends, the connecting rod 452 is gradually pressed into the connecting hole 451. The connecting rod 452 slides upward in the connecting hole 451, driving the connecting gear 453 to rotate. The connecting gear 453 drives the connecting pipe 46 to slide downward through the connecting rack 461, so as to gradually extend out of the communication hole 43 until it is inserted into the vacuum adsorption hole 321.

[0044] Refer to Figures 1 to 4 , a foreign matter removal cavity 323 is formed in the lifting frame 32. The foreign matter removal cavity 323 is communicated with the vacuum adsorption hole 321. An adsorption net 324 for sucking metal molecules is provided in the foreign matter removal cavity 323. The end of the foreign matter removal cavity 323 far from the vacuum adsorption hole 321 is connected to an external negative pressure device through a vacuum pipe 325. The adsorption hose 25 is communicated with the vacuum adsorption hole 321, and a one-way valve is provided at the connection between the vacuum adsorption hole 321 and the adsorption hose 25.

[0045] Refer to Figures 1 to 4 , the negative pressure device applies negative pressure suction through the vacuum pipe 325, so that the lifting frame 32 adsorbs and fixes the stripping template 4, the vacuum suction table 24 adsorbs and fixes the chip, and the escaping metal molecules are sucked and removed, which is convenient to use. The one-way valve protects the vacuum suction table 24 to prevent metal molecules from entering the vacuum suction table 24 and affecting the chip. After the metal molecules enter the foreign matter removal cavity 323, they are absorbed by the adsorption net 324, and the adsorption net 324 collects the metal molecules for subsequent processing.

[0046] Refer to Figure 1, a lifting rod 6 is vertically connected to the base 1. The upper end of the lifting rod 6 is rotatably connected to a laser fixing bracket 61. The laser module 5 is installed at one end of the laser fixing bracket 61, and a microscope 62 is provided at the other end of the laser fixing bracket 61. A laser focusing lens is provided at the light outlet of the laser module 5. An x-axis telescopic rod 63 is installed on the laser fixing bracket 61, and a y-axis telescopic rod 64 is installed on the x-axis telescopic rod 63. The laser module 5 is installed on the y-axis telescopic rod 64. The laser module 5 can move in the x-axis and y-axis directions to peel the chip.

[0047] Referring to Figure 1 , the laser module 5 selects a semiconductor laser of 405 nm or 450 nm. The operator can observe the positional relationship between the peeling template 4 and the chip through the microscope 62, and adjust the position of the chip in cooperation with the x-axis adjustment base 22, the y-axis adjustment base 21 and the rotation base 23, so that the peeling area on the chip is directly opposite to the peeling groove 41, improving the peeling accuracy of the chip. Then rotate the laser fixing bracket 61 to turn the laser module 5 above the peeling template 4 for laser peeling.

[0048] The implementation principle of a laser chip peeling system according to an embodiment of the present application is as follows: The operator places the chip on the vacuum suction table 24 and installs the peeling template 4 on the lifting frame 32. Observe the positional relationship between the peeling template 4 and the chip through the microscope 62, and adjust the positions of the chip and the peeling template 4 through the lifting knob 327, the x-axis knob, the y-axis knob and the rotation knob, so that the chip is directly opposite to the peeling template. Subsequently, rotate the laser fixing bracket 61 so that the laser module 5 is directly opposite to the peeling template 4. The x-axis telescopic rod 63 and the y-axis telescopic rod 64 are activated to drive the laser module 5 to move, thereby adjusting the position of the laser module 5. The laser emitted by the laser module 5 passes through the peeling groove 41 to peel the metal layer on the chip. The metal molecules are absorbed by the impurity removal holes 44 and finally fall into the impurity removal cavity 323.

[0049] The above are all preferred embodiments of the present application. The protection scope of the present application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A laser chip peeling system, comprising a base (1), characterized in that: On the base (1), there is provided a wafer stage (2) for placing a chip; a template fixing frame (3) located above the wafer stage (2); a peeling template (4) located on the template fixing frame (3) opposite to the wafer stage (2), and a peeling groove (41) corresponding to the peeling area on the chip is provided on the peeling template (4); a laser module (5) located above the peeling template (4), and a laser focusing lens is provided at the light outlet of the laser module (5).

2. The laser chip peeling system according to claim 1, wherein: The wafer stage (2) includes a y-axis adjustment base (21) horizontally slidably connected to the base (1), an x-axis adjustment base (22) horizontally slidably connected to the y-axis adjustment base (21), the sliding direction of the x-axis adjustment base (22) is perpendicular to the sliding direction of the y-axis adjustment base (21), a rotating base (23) is rotatably connected to the x-axis adjustment base (22), and a vacuum chuck (24) is provided on the rotating base (23).

3. The laser chip peeling system according to claim 2, characterized in that: The template fixing frame (3) includes a fixing rod (31) fixedly connected to the base (1) and a lifting frame (32) vertically slidably connected to the fixing rod (31), and a plurality of vacuum adsorption holes (321) are provided on the lifting frame (32).

4. A laser chip peeling system according to claim 3, characterized in that: A plurality of adsorption channels (42) are provided in the peeling template (4), communication holes (43) communicating with the adsorption channels (42) are provided at the edge of the lower surface of the peeling template (4), the communication holes (43) are communicated with one of the vacuum adsorption holes (321), and a plurality of impurity removal holes (44) communicating with the adsorption channels (42) are provided on the lower surface of the peeling template (4).

5. A laser chip peeling system according to claim 4, characterized in that: A positioning block (45) bulging downward is provided at the edge of the peeling template (4), and a positioning groove (322) corresponding to the positioning block (45) is provided on the lifting frame (32).

6. The laser chip peeling system according to claim 4, wherein: The vacuum chuck (24) is connected with an adsorption hose (25), a impurity removal cavity (323) is provided on the lifting frame (32), the impurity removal cavity (323) is communicated with the vacuum adsorption holes (321), an adsorption net (324) is provided in the impurity removal cavity (323), the end of the impurity removal cavity (323) far from the vacuum adsorption holes (321) is connected with an external negative pressure device through a vacuum tube (325), the adsorption hose (25) is communicated with the vacuum adsorption holes (321), and a one-way valve is provided at the connection between the vacuum adsorption holes (321) and the adsorption hose (25).

7. A laser chip peeling system according to claim 1, characterized in that: A vertically arranged lifting rod (6) is connected to the base (1), and a laser fixing frame (61) is provided at the upper end of the lifting rod (6), and the laser module (5) is fixed on the laser fixing frame (61).

8. A laser chip peeling system according to claim 7, characterized in that: The laser fixing frame (61) is horizontally rotatably connected to the lifting rod (6), and a microscope (62) is provided at one end of the laser fixing frame (61) far from the laser module (5).

9. The laser chip peeling system according to claim 1, characterized in that: The laser module (5) selects a semiconductor laser of 405 nm or 450 nm.

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