Tool for fixed-point cutting of SIC chip

Abstract

The invention relates to the technical field of chip processing tools, in particular to an SIC chip fixed-point cutting tool which comprises a base and a cutting device installed on the base. Wherein a carrying table seat is further arranged above the base, a sample seat is connected to the upper portion of the carrying table seat in a sliding mode, and a driving assembly used for driving the sample seat to move is arranged on the carrying table seat; the tool comprises a sample base, a sample table is rotatably connected to the inner side of the sample base, and an adjusting assembly for controlling the sample table to rotate in the circumferential direction is arranged on the side edge of the sample base. The problem that the fixed-point cutting success rate of a micrometer left-right structure is low is solved, the whole structure is simple, cost is low, a wafer sample only needs to be placed in a containing groove, the height of a cutter is adjusted, and advancing of the sample table is controlled, and cutting operation control over the wafer is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of chip processing tools, and in particular to a tool for fixed-point cutting of a SIC chip. Background Art

[0002] In the field of semiconductor manufacturing, SiC (silicon carbide) wafers are widely used in high-temperature, high-frequency, and high-power electronic devices due to their excellent physical and chemical properties, such as high electron mobility, high thermal conductivity, high temperature resistance, and radiation resistance. However, there are some technical challenges in the production process of SiC wafers, especially in the cutting and processing of wafers.

[0003] Traditional SiC wafer cutting technologies, such as laser cutting and grinding wheel cutting, are limited to wafers with specific orientations (such as <100> direction) is more effective. However, for non <100> For SiC wafers with different directions, especially 4H-SiC wafers, these technologies have significant differences in the dissociation performance in the X and Y directions. Especially for tiny structures with a size of only about 20um, these traditional cutting technologies have difficulty in achieving precise point dissociation, and often require subsequent grinding processes for further processing, which is not allowed in some applications, such as in photoresist, PIM (plasma etching simulation) and other processes.

[0004] To solve this problem, the industry currently mainly uses two methods: the first is to observe with the naked eye and cut randomly. However, the success rate of this method is extremely low, especially in the Y direction of 4H-SiC wafers, the success rate is only about 10%. The second method is to use FIB (focused ion beam) technology to prepare samples. FIB technology can achieve high-precision cutting, but its equipment is expensive and complicated to operate. For semiconductor factories without FIB equipment, samples need to be sent out, which not only increases costs but also has poor timeliness.

[0005] Therefore, in order to achieve targeted cutting and dissociation of tiny structures and reduce costs, we propose a tool for targeted cutting of SIC chips. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art such as extremely low success rate and high processing cost, and to propose a tool for fixed-point cutting of SIC chips.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: Design a tool for SIC chip fixed-point cutting, including: A base and a cutting device mounted on the base; A stage seat is also provided above the base, a sample seat is slidably connected above the stage seat, and a driving component for driving the sample seat to move is provided on the stage seat; A sample stage is rotatably connected to the inner side of the sample holder, and an adjusting component for controlling the circumferential rotation of the sample stage is arranged on the side of the sample holder. The sample stage is located below the cutting device.

[0008] Furthermore, the carrier seat is of a frame structure and is detachably connected to the base. Two support plates are installed at intervals on the inner side of the carrier seat, and the sample holder is slidably connected above the two support plates via a guide rail and a slider assembly.

[0009] Furthermore, the driving assembly includes a shaft extending through both sides of the platform seat, and the shaft is rotatably connected to the platform seat; At least one gear is fixedly mounted on the outer side of the shaft, and a rack meshing with the gear is fixed on the bottom of the sample holder.

[0010] Furthermore, a grip sleeve is sleeved on the end of the shaft rod, and the grip sleeve is movably plugged with the shaft rod and circumferentially locked; A spring is fixedly connected between the inner side of the grip sleeve and the end of the shaft rod, and friction parts are provided on the end of the grip sleeve and the end surface of the carrier seat.

[0011] Furthermore, the end surface of the sample stage is provided with a receiving groove for receiving the chip; The sample holder is a frame structure, a fixing plate is fixedly installed on the inner side of the sample holder, and the sample holder is rotatably connected to the fixing plate via a shaft.

[0012] Furthermore, the adjustment assembly includes two screws threadedly connected to both sides of the sample holder, the two screws are respectively distributed on the upper and lower sides of the sample holder, the ends of the screws abut against the sides of the sample stage, and elastic structures are also provided on both sides of the sample stage.

[0013] Furthermore, the elastic structure includes a sleeve fixedly mounted on the side of the sample stage, a push rod movably inserted into the inner side of the sleeve, a compression spring fixedly connected between the inner end of the push rod and the inner wall of the sleeve, and the end of the push rod abuts against the inner wall of the sample holder.

[0014] Furthermore, the cutting device includes an upper support seat and a lower support seat, and support feet are respectively connected between the two sides of the upper support seat and the lower support seat, and the bottom ends of the support feet are connected to the base, wherein a cutter is passed between the upper support seat and the lower support seat, and an adjustment component for driving the cutter to move up and down is provided on the upper support seat.

[0015] Furthermore, the adjustment component includes a plurality of connecting arms fixed to the top of the upper support seat, and a mounting plate is fixedly connected between the tops of the plurality of connecting arms; The middle part of the mounting plate is threadedly connected with an adjusting screw, the bottom end of the adjusting screw is rotatably connected with a connecting sleeve, and the connecting sleeve is sleeved and locked with the top of the tool through a fastener.

[0016] Furthermore, a plurality of connecting rods are distributed at the four corners of the top of the base, and a positioning hole is opened on the end surface of the carrier seat. The connecting rods are plugged and adapted to the positioning hole and are locked and fixed by nuts.

[0017] The invention proposes a tool for spot cutting of SIC chips, which has the beneficial effects that: the tool in the invention is applicable to the spot cutting of square and irregular SiC fragments whose vertical sides of the dissociation surface are flat, and can solve the problem of low success rate of spot cutting of structures of about um in traditional SiC wafer cutting. The overall structure is simple and the cost is low. It only needs to place the wafer sample in the receiving groove, and the height of the tool is adjusted and the movement of the sample stage is controlled, so that the cutting operation of the wafer is conveniently controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A perspective view of the present invention; Figure 2 It is a schematic diagram of the base structure of the present invention; Figure 3 for Figure 2 A schematic diagram of the enlarged structure of area A; Figure 4 It is a structural schematic diagram of the present invention; Figure 5 It is a schematic diagram of the structure of the sample holder of the present invention; Figure 6 It is a schematic diagram of the grip structure of the present invention; Figure 7 It is a schematic diagram of the structure of the regulating component of the present invention; Figure 8 It is a schematic diagram of the structure of the cutting device of the present invention; Fig. 9 It is a schematic diagram of the cutting path of the present invention.

[0019] In the figure: 1. base; 11. connecting rod; 2. cutting device; 21. upper support seat; 22. lower support seat; 23. support foot; 24. tool; 25. connecting arm; 26. mounting plate; 27. adjusting screw; 28. connecting sleeve; 29. ​​fastener; 3. carrier seat; 31. support plate; 4. sample seat; 41. fixing plate; 5. driving assembly; 51. shaft; 52. gear; 53. rack; 54. grip sleeve; 55. spring; 56. friction member; 6. sample stage; 61. receiving groove; 7. adjusting assembly; 71. screw; 72. sleeve; 73. push rod; 74. compression spring. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] Reference Figure 1-8 An embodiment of the present invention discloses a tool for spot cutting of SIC chips, which is used to solve the problem of low success rate of spot cutting of SiC wafer structures of about 20um. Specifically, the tool includes a base 1 and a cutting device 2 installed on the base 1; A stage seat 3 is also provided above the base 1, and a sample seat 4 is slidably connected above the stage seat 3. The sample seat 4 in this embodiment slides along a first direction, and the first direction is the Y direction along the base 1. A driving component 5 for driving the sample seat 4 to move is provided on the stage seat 3; A sample stage 6 is rotatably connected to the inner side of the sample holder 4 , and an adjustment component 7 for controlling the circumferential rotation of the sample stage 6 is provided on the side of the sample holder 4 . The rotation direction of the sample stage 6 is the second direction, and the second direction is the R direction. The sample stage 6 is located below the cutting device 2 .

[0022] Reference Figure 1 In some embodiments, the carrier seat 3 of the present invention is of a frame structure and is detachably connected to the base 1. Specifically, in this embodiment, a plurality of connecting rods 11 are distributed at the four corners of the top of the base 1, and a positioning hole is provided on the end face of the carrier seat 3. Of course, there are four positioning holes in the matrix part, and they are respectively opposite to the four connecting rods 11. The connecting rods 11 are plugged and matched with the positioning holes and are locked and fixed by nuts. That is to say, in this embodiment, the connecting rods 11 are used to penetrate the positioning holes on the carrier seat 3 to achieve positioning, and the nuts are threadedly connected at the upper end of the connecting rods 11 to complete the connection and fixation of the carrier seat 3.

[0023] Reference Figure 4In addition, two support plates 31 are installed at intervals on the inner side of the carrier seat 3, and the sample holder 4 is slidably connected above the two support plates 31 through a guide rail and a slider assembly. The guide rail and slider assembly includes a guide rail and a slider. Two guide rails are provided and are respectively fixed above the two support plates 31. Of course, two sliders are also provided and fixed at intervals below the sample holder 4. The slider is adapted to slide with the guide rail to ensure that the sample holder 4 can move in the first direction.

[0024] Reference Figure 2 , Figure 3 as well as Figure 5 On the basis of the above-mentioned embodiment, the driving assembly 5 in the present invention comprises a shaft 51 penetrating through both sides of the platform seat 3, and the shaft 51 is rotatably connected to the platform seat 3; At least one gear 52 is fixedly installed on the outer side of the shaft 51, and a rack 53 meshing with the gear 52 is fixed to the bottom of the sample holder 4. Preferably, two gears 52 and two racks 53 are arranged at intervals in this embodiment. The design of the two gears 52 and the rack 53 is used to ensure the stability of the movement drive of the sample holder 4. In specific operations, the shaft 51 can be rotated to drive the two gears 52 to rotate, and the entire sample holder 4 can be driven to perform linear displacement by meshing with the rack 53.

[0025] Reference Figure 5 Considering that in the process of adjusting the position of the sample holder 4, in order to maintain its position locking ability after adjustment, the end of the shaft rod 51 in this embodiment is sleeved with a grip sleeve 54, and the grip sleeve 54 is movably plugged with the shaft rod 51 and circumferentially locked. The circumferential locking method can be achieved by opening a guide groove along the axial direction on the outer side of the shaft rod 51, and a convex block is formed on the inner side of the grip sleeve 54. The convex block and the guide groove are slidably matched to ensure the circumferential locking between the grip sleeve 54 and the shaft rod 51, so as to prevent the grip sleeve 54 from rotating. In addition, a spring 55 is fixedly connected between the inner side of the grip sleeve 54 and the end of the shaft rod 51, and a friction member 56 is provided on the end of the grip sleeve 54 and the end surface of the carrier seat 3. Specifically, the friction member 56 described in this embodiment can be set as a friction plate, and the two friction plates are respectively fixed to the grip sleeve 54 and the end surface of the carrier seat 3; In another embodiment, the technicians in the relevant field also know that the friction member 56 is set as a convex ring with latch teeth. When the two convex rings are in contact, the latch teeth are engaged with each other to achieve circumferential locking of the shaft 51, thereby ensuring the stability of the position of the sample holder 4. The technicians in the relevant field can select the specific structure according to actual needs, which will not be elaborated here.

[0026] That is, when the position of the sample holder 4 is moved and adjusted, the grip sleeve 54 is first pulled outward, and the friction member 56 at the end of the grip sleeve 54 is separated from the friction member 56 at the side of the stage holder 3, and then the grip sleeve 54 can be freely rotated to control the rotation of the shaft 51; When the shaft 51 rotates, the meshing connection between the gear 52 and the rack 53 is used to control the linear movement of the entire sample holder 4. After the movement control is completed, the pull on the grip sleeve 54 is released, and the grip sleeve 54 is reset under the pull of the spring 55. At this time, the two friction members 56 are locked to prevent the shaft 51 from further moving the sample holder 4 due to accidental contact. In this way, the position of the sample holder 4 can be stably adjusted, and the wafer can be driven to move linearly under the cutting device 2 during the cutting process to complete the cutting.

[0027] Reference Figure 6 In some embodiments, the end surface of the sample stage 6 of the present invention has a receiving groove 61 for receiving a chip. In this embodiment, the depth of the receiving groove 61 is 300um. The receiving groove 61 is located directly below the cutter 24 of the cutting device 2. When working, the wafer is placed in the receiving groove 61. When the sample holder 4 drives the sample stage 6 to move linearly, the cutter 24 cuts the wafer to complete the fixed-point dissociation of the wafer. The sample holder 4 is a frame structure, and a fixing plate 41 is fixedly installed on the inner side of the sample holder 4. The sample holder 4 is rotatably connected to the fixing plate 41 via an axle rod. That is, in this embodiment, the sample holder 4 is rotatably connected to the fixing plate 41 to achieve the rotation capability of the sample holder 4 in the second direction.

[0028] Reference Figure 6 , Figure 7 Furthermore, the adjustment assembly 7 in this embodiment includes two screws 71 threadedly connected to both sides of the sample holder 4, and the two screws 71 are respectively distributed on the upper and lower sides of both sides of the sample holder 4, and the ends of the screws 71 abut against the sides of the sample stage 6, wherein elastic structures are also provided on both sides of the sample stage 6.

[0029] That is, in this embodiment, two screws 71 arranged on both sides of the sample holder 4 are used to resist the sample stage 6 for rotational movement during adjustment, and the elastic structure is arranged to maintain its stability in the adjustment position to prevent the sample stage 6 from further rotating.

[0030] Reference Figure 7Preferably, the elastic structure in the present invention includes a sleeve 72 fixedly mounted on the side of the sample stage 6, a push rod 73 is movably inserted into the inner side of the sleeve 72, a compression spring 74 is fixedly connected between the inner end of the push rod 73 and the inner wall of the sleeve 72, and the end of the push rod 73 abuts against the inner wall of the sample holder 4, that is, the retractable push rod 73 provided in the present invention is used to abut against the inner wall of the sample holder 4, and when the sample stage 6 is rotated and adjusted, the two push rods 73 on both sides respectively abut against the inner walls on both sides of the sample holder 4, and the reverse thrust generated by the compression spring 74 on the push rod 73 is used to ensure the stability of its position adjustment.

[0031] Reference Figure 8 It should be noted that the cutting device 2 in the present invention includes an upper support seat 21 and a lower support seat 22, and legs 23 are respectively connected between the two sides of the upper support seat 21 and the lower support seat 22, and the bottom ends of the legs 23 are connected to the base 1. Specifically, the legs 23 described in this embodiment are connected and fixed to the base 1 by bolts; It should be noted that, in this embodiment, the two legs 23 can be slidably connected to the top of the base 1 along the third direction, and the third direction is the X direction along the base 1. The specific sliding method can also adopt the cooperation method of the guide rail and the slider, and a locking nut is threadedly connected to the leg 23 to contact the base 1 to achieve the lateral position locking of the leg 23, thereby achieving the lateral position adjustment and locking function of the leg 23; That is, in the present invention, the third direction movement of the cutting device 2, the first direction movement of the sample holder 4 and the third direction movement of the sample stage 6 can be used to ensure the adjustable adaptability of the wafer cutting position during the cutting process.

[0032] A tool 24 is provided between the upper support seat 21 and the lower support seat 22. The tool 24 is a diamond pen with its tip facing the wafer to achieve cutting and separation after contacting the wafer. An adjustment component for driving the tool 24 to move up and down is provided on the upper support seat 21.

[0033] Reference Figure 8 On the basis of the above embodiment, the adjustment component in the present invention includes a plurality of connecting arms 25 fixed to the top of the upper support seat 21, and a mounting plate 26 is fixedly connected between the tops of the plurality of connecting arms 25; The middle part of the mounting plate 26 is threadedly connected with an adjusting screw 27, and the bottom end of the adjusting screw 27 is rotatably connected with a connecting sleeve 28. The connecting sleeve 28 is sleeved and locked with the top of the tool 24 through a fastener 29. The fastener 29 described in this embodiment is configured as a bolt. When making a specific connection, the top end of the tool 24 is first inserted into the inside of the connecting sleeve 28, and then the prop 24 can be locked and fixed by the fastener 29 threadedly connected to the connecting sleeve 28, thereby completing the connection and assembly of the tool 24.

[0034] In addition, in a further embodiment, the present invention may also have a locking bolt threadedly connected to the side of the upper support seat 21 and the lower support seat 22, and the locking bolt is used to fix and lock the tool 24 in the adjusted position, thereby further improving the position stability of the tool 24.

[0035] The following takes the cutting of a 20um wafer structure in the receiving groove 61 as an example: Cut out a sample containing a target test structure from the SiC wafer. The target test structure is about 1 cm away from the flat side and is located in the middle of the sample. Place the sample in the receiving groove 61 and align the flat side of the sample with the bottom side of the receiving groove 61; The sample stage 6 is controlled to rotate by adjusting the screw 71 until the wafer scribe line is as shown in FIG. Fig. 9 The position indicated by the grey line is perpendicular to the base of the sample stage 6; Turn the adjusting screw 27 to drive the tool 24 to move vertically. Fig. 9 , until the tool 24 contacts the gray point and continues to press down, the distance between the gray point and the black point is the key, and the distance is preferably set to about 50-100um, which determines the direction of the separation surface; Hold the stage 3 and the gripping sleeve 54 on its side with both hands, and drive the sample stage 6 to move by rotating the gripping sleeve 54, so that the tool 24 can move from the Fig. 9 The medium grey dots are drawn to the thickened line at the bottom edge of the sample; Finally, the SiC sample can be dissociated using conventional failure analysis dissociation methods.

[0036] In summary, the tool in the present invention can be used for the fixed-point cutting of square and irregular SiC fragments with flat edges vertical to the dissociation surface, and can solve the problem of low success rate of fixed-point cutting of structures around 20um in traditional SiC wafer cutting. The overall structure is simple, and it is only necessary to place the wafer sample in the receiving groove 61, and the height of the tool 24 can be adjusted and the movement of the sample stage 6 can be controlled, so as to facilitate the control of the wafer cutting operation.

[0037] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A tool for SIC chip fixed-point cutting, characterized in that: include: A base (1) and a cutting device (2) mounted on the base (1); A stage seat (3) is also provided above the base (1), a sample seat (4) is slidably connected above the stage seat (3), and a driving component (5) for driving the sample seat (4) to move is provided on the stage seat (3); A sample stage (6) is rotatably connected to the inner side of the sample holder (4), and an adjustment component (7) for controlling the circumferential rotation of the sample stage (6) is provided on the side of the sample holder (4). The sample stage (6) is located below the cutting device (2).

2. A tool for SIC chip fixed-point cutting according to claim 1, characterized in that: The stage seat (3) is of a frame structure and is detachably connected to the base (1). Two support plates (31) are installed at intervals on the inner side of the stage seat (3). The sample seat (4) is slidably connected above the two support plates (31) via a guide rail and a slider assembly.

3. A tool for SIC chip fixed-point cutting according to claim 2, characterized in that: The driving assembly (5) comprises a shaft (51) penetrating through two sides of the carrier seat (3), and the shaft (51) is rotatably connected to the carrier seat (3); At least one gear (52) is fixedly mounted on the outer side of the shaft (51), and a rack (53) meshing with the gear (52) is fixed on the bottom of the sample holder (4).

4. A tool for cutting SIC chips at a fixed point according to claim 3, characterized in that: The end of the shaft rod (51) is sleeved with a grip sleeve (54), and the grip sleeve (54) is movably plugged into the shaft rod (51) and circumferentially locked; A spring (55) is fixedly connected between the inner side of the grip sleeve (54) and the end of the shaft rod (51), and a friction piece (56) is provided on the end of the grip sleeve (54) and the end surface of the carrier seat (3).

5. The tool for cutting SIC chips at a fixed point according to claim 1, characterized in that: The end surface of the sample stage (6) is provided with a receiving groove (61) for receiving a chip; The sample holder (4) is of a frame-type structure, a fixing plate (41) is fixedly mounted on the inner side of the sample holder (4), and the sample holder (4) is rotatably connected to the fixing plate (41) via a shaft.

6. A tool for spot cutting of SIC chips according to claim 5, characterized in that: The adjustment assembly (7) comprises two screw rods (71) threadedly connected to both sides of the sample holder (4), the two screw rods (71) being respectively distributed on the upper side and the lower side of both sides of the sample holder (4), the ends of the screw rods (71) abutting against the side edges of the sample stage (6), wherein elastic structures are also provided on both sides of the sample stage (6).

7. A tool for spot cutting of SIC chips according to claim 6, characterized in that: The elastic structure comprises a sleeve (72) fixedly mounted on the side of the sample stage (6), a push rod (73) movably inserted into the inner side of the sleeve (72), a compression spring (74) fixedly connected between the inner end of the push rod (73) and the inner wall of the sleeve (72), and the end of the push rod (73) contacts the inner wall of the sample holder (4).

8. The tool for cutting SIC chips at a fixed point according to claim 1, characterized in that: The cutting device (2) comprises an upper support seat (21) and a lower support seat (22), wherein legs (23) are respectively connected between the two sides of the upper support seat (21) and the lower support seat (22), and the bottom ends of the legs (23) are connected to the base (1), wherein a cutter (24) is inserted between the upper support seat (21) and the lower support seat (22), and an adjustment component for driving the cutter (24) to move up and down is arranged on the upper support seat (21).

9. A tool for spot cutting of SIC chips according to claim 8, characterized in that: The adjustment component comprises a plurality of connecting arms (25) fixed to the top of the upper support seat (21), and a mounting plate (26) is fixedly connected between the tops of the plurality of connecting arms (25); The middle part of the mounting plate (26) is threadedly connected to an adjusting screw (27), the bottom end of the adjusting screw (27) is rotatably connected to a connecting sleeve (28), and the connecting sleeve (28) is sleeved and locked with the top of the tool (24) via a fastener (29).

10. A tool for spot cutting of SIC chips according to any one of claims 1 to 9, characterized in that: A plurality of connecting rods (11) are distributed at the four corners of the top of the base (1), and a positioning hole is opened on the end surface of the carrier seat (3). The connecting rods (11) are plugged into and fitted into the positioning hole and are locked and fixed by nuts.

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