Wafer cutting machine and thickness detection method thereof

Abstract

The invention discloses a wafer cutting machine and a thickness detection method thereof, and relates to the technical field of wafer cutting. A cutting assembly is installed on the frame body in a matched mode. The cutting assembly comprises two symmetrical vertical plates mounted at the top of one end of the frame body; a first sliding rail is fixedly mounted between the two vertical plates; a laser controller is movably mounted on the first sliding rail; a laser transmitter is fixedly mounted at the bottom of the laser controller; during use, a wafer is placed in a counter bore formed in the placing plate through a mechanical arm, the distance between the wafer and the lower sensor and the distance between the wafer and the upper sensor are guaranteed, after the wafer is placed, the front-back position of the wafer is effectively adjusted through sliding of a sliding rod along a third sliding rail, meanwhile, the sliding plate can slide along a transverse rod, and therefore the wafer can be conveniently placed. Left-right adjustment of the wafer on the placing plate is achieved, and therefore irradiation measurement of the lower sensor and the upper sensor on the overall thickness of the wafer is effectively guaranteed.

Description

Technical Field

[0001] The present invention relates specifically to the technical field of wafer cutting, in particular to a wafer cutting machine and a thickness detection method thereof. Background Art

[0002] Semiconductor wafer dicing is a critical step in separating wafers that have completed front-end fabrication into individual chips. With the advancement of technologies such as chip size reduction, wafer thinning, material diversification (such as SiC and GaN), and 3D stacking, dicing technology continues to evolve, facing requirements for higher precision, less damage, higher efficiency, and more complex material compatibility. Mechanical blade dicing, due to its maturity and cost advantages, remains the mainstream choice for standard-thick silicon wafers, but is facing pressure to be eliminated in the areas of ultra-thin, hard and brittle materials, and narrow dicing streets. Laser ablation dicing is indispensable for dicing hard and brittle materials (SiC / GaN), complex structures (low-k / metal layers), and scenarios requiring non-contact / narrow dicing streets, but thermal effects are a key challenge. Stealth dicing (SD) is the gold standard for dicing ultra-thin silicon wafers, offering unparalleled edge quality and efficiency, making it the preferred choice for advanced packaging and thin devices, but it has requirements for internal wafer quality and equipment costs. Stealth dicing technology is increasingly being used in semiconductor wafer dicing. It uses a pulsed laser of a specific wavelength (typically near-infrared, such as 1064nm) focused inside the wafer (rather than on the surface). The laser energy is absorbed nonlinearly at the focal point inside the wafer, forming a modified layer (composed of tiny cracks or material-modified points) parallel to the wafer surface. After scanning along the dicing path to form a continuous internal modified layer, an externally applied expansion force (such as stretching a film) neatly separates the wafer along the modified layer into individual chips. The existing solution is to optimize the accuracy of grinding and polishing. Although laser stealth cutting has many advantages, it also has some disadvantages. The most troublesome problem is that the process parameters (focus depth, energy, scanning) are complicated to debug and need to be optimized for different wafer thicknesses / materials. After the wafer is ground and polished, the actual thickness deviates from the ideal thickness, resulting in the inability to position the laser focus of the stealth cutting machine in the center. Different thicknesses require different laser energies, and the modified layer must be uniform and continuous. Otherwise, additional stress will be generated, causing damage to the chip edge during film expansion and cracking, resulting in chip failure. Summary of the Invention

[0003] The purpose of the present invention is to provide a wafer cutting machine and a thickness detection method thereof. In this device, the wafer thickness detection and wafer invisible cutting functions are combined into one machine, so that the wafer thickness and position data can be shared with the laser emitting device, so that the laser emitter can automatically adjust the focal depth and emission energy according to the wafer data, ensuring that the modified layer of the wafer maintains the same thickness and position after laser cutting; so as to solve the problems of the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions: A wafer cutting machine; comprising a frame; a cutting assembly mounted on the frame; the cutting assembly comprising two symmetrical vertical plates mounted on the top of one end of the frame; a first slide rail fixedly mounted between the two vertical plates; a laser controller movably mounted on the first slide rail; a laser emitter fixedly mounted on the bottom of the laser controller; The frame is also equipped with a transmission assembly; the transmission assembly includes two symmetrical second slide rails; the second slide rails are fixedly mounted to the frame; a movable plate is movably mounted on the second slide rails via a slider; a wafer stage is fixedly mounted on the movable plate; As a further technical solution of the present invention, the bottom of the movable plate is connected to the screw rod through a connecting block; both ends of the screw rod are movably mounted on the frame through seat bearings; wherein one end of the screw rod is fixedly mounted to the drive motor; As a further technical solution of the present invention, the movable plate is further equipped with a positioning assembly; the positioning assembly includes a double-rod cylinder; an L-shaped rod is fixedly mounted on the lever of each of the double-rod cylinders; a clamping plate is mounted on the bottom of the L-shaped rod; the inner side of the clamping plate is arranged in an arc shape; As a further technical solution of the present invention, a detection assembly is further provided inside the frame; the detection assembly includes two symmetrical third slide rails; the third slide rails are fixedly mounted on the inner sides of the side walls at both ends of the frame; a slide rod is slidably mounted on the third slide rails via a slider; As a further technical solution of the present invention, the two ends of the sliding rods are fixedly mounted on the two ends of the two cross bars; the cross bars are movably mounted with slides through sliders; As a further technical solution of the present invention, a placement plate is fixedly mounted on the bottom of the slide via a connecting rod; a countersunk hole is provided on the placement plate to facilitate wafer placement; As a further technical solution of the present invention, the detection component also includes a lower sensor and an upper sensor; wherein, the upper sensor is fixedly mounted on the bottom of the frame top plate; the lower sensor is fixedly mounted on the frame bottom plate through a support frame; the lower sensor and the upper sensor are at the same distance from the countersunk hole opened on the placement plate; in the wafer detection cavity, there are two upper and lower optical sensors, and the optical sensors are used to hit the laser on the wafer, and the distance is calculated by measuring the time or angle difference of the light traveling back and forth to the target; the wafer thickness can be obtained by subtracting the distance between the wafer and the sensor from the sensor distance fixed in the cavity; the machine will divide the wafer thickness data into areas, divided into thousands of small areas, and each small area will calculate the theoretical focal depth and laser power according to the system. When the laser cuts to the specified area, the machine will automatically switch the parameters, instead of cutting a complete wafer with one parameter, or manually switching the parameters. As a further technical solution of the present invention, the lower sensor and the upper sensor are both electrically connected to the signal converter via a transmission line; the signal converter is electrically connected to the master control box via a wire; the master control box is also electrically connected to the laser controller; the master control box is fixedly mounted on the top plate of the frame; As a further technical solution of the present invention, the detection method comprises the following steps: S1. Place the wafer into the countersunk hole on the placement plate through the robotic arm; slide the slide bar along the third slide rail, and slide the slide along the crossbar through the slider to effectively adjust the position of the wafer to be tested; S2. During the inspection, the lower sensor and the upper sensor are turned on by the second switch. The lower sensor and the upper sensor are at the same distance from the countersunk hole on the placement plate. The thickness of the wafer at different positions is automatically calculated by the signal converter through the refraction of the light emitted by the lower sensor and the upper sensor. S3. The signal converter transmits the calculated data to the master control box, which then transmits it to the laser controller. The laser controller automatically plans the cutting path based on the wafer data and automatically controls the laser emitter to adjust the focus depth and emission energy. S4. Place the inspected wafer on the wafer table. Use two clamping plates to effectively clamp and position the wafer. The first switch controls the lead screw to move the movable plate, so that the positioned wafer is transferred to the bottom of the laser emitter for cutting. Compared with the prior art, the present invention has the following beneficial effects: The present invention, when in use, places the wafer in the countersunk hole provided on the placement plate by a robotic arm, ensuring the spacing between the wafer and the lower sensor and the upper sensor. After the wafer is placed, the front and rear position of the wafer is effectively adjusted by sliding the slide bar along the third slide rail. At the same time, the left and right adjustment of the wafer on the placement plate can be achieved by sliding the slide plate along the cross bar, thereby effectively ensuring that the lower sensor and the upper sensor irradiate and measure the overall thickness of the wafer. The present invention, when measuring wafer thickness, synchronously turns on the lower sensor and the upper sensor through a second switch, effectively calculates the thickness of different positions of the wafer through the refraction of light emitted by the lower sensor and the upper sensor, and transmits the detection data of the lower sensor and the upper sensor to the main control box through a signal converter. When measuring thickness, the positions of the lower sensor and the upper sensor are fixed, and even if the wafer swings during the detection process, the efficiency of thickness detection can be effectively guaranteed. In the present invention, the signal converter shares the detected data with the laser controller. The laser controller effectively plans the cutting route based on the data detected by the lower and upper sensors. At the same time, it controls the laser emitter to automatically adjust the focus depth and emission energy to ensure that the modified layer of the wafer maintains the same thickness and position after laser cutting. In the present invention, after the debugging of the cutting component is completed, the wafer that has been inspected is transferred to the wafer table by the robotic arm. After the wafer is placed, the double-rod cylinder simultaneously drives the clamping plate at the bottom of the L-shaped rod to position and clamp the wafer. After the positioning is completed, the first switch is used to drive the motor to rotate the lead screw, and the lead screw drives the movable plate to slide along the second slide rail to move the wafer to the bottom of the laser emitter. When the laser emitter moves to the specified area, the laser controller automatically switches the parameters, rather than cutting a complete wafer with one parameter or manually switching the parameters, thereby effectively ensuring the cutting accuracy and cutting efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0006] Figure 2 In the present invention Figure 1 Schematic diagram of the rear structure.

[0007] Figure 3 In the present invention Figure 1 main view.

[0008] Figure 4 In the present invention Figure 1 side view.

[0009] Figure 5 In the present invention Figure 1 Another perspective structural diagram.

[0010] Figure 6 In the present invention Figure 5 main view.

[0011] Figure 7 In the present invention Figure 5 Schematic diagram of the internal structure of the middle frame.

[0012] Figure 8 In the present invention Figure 1 Schematic diagram of the splitting.

[0013] Figure 9 In the present invention Figure 8 Bottom view of the bottom structure of the detection component.

[0014] Figure 10 In the present invention Figure 5 A magnified view of the local structure at point A.

[0015] In the figure: 1-frame, 2-movable door, 3-cutting assembly, 30-vertical plate, 31-first slide rail, 32-laser controller, 33-laser transmitter, 4-master control box, 5-transmission assembly, 50-second slide rail, 51-wafer table, 52-screw rod, 53-moving plate, 54-drive motor, 6-first switch, 7-second switch, 8-positioning assembly, 80-double-rod cylinder, 81-L-shaped rod, 82-clamping plate, 9-detection assembly, 90-slide plate, 91-cross bar, 92-placement plate, 93-lower sensor, 94-upper sensor, 95-slide bar, 96-third slide rail, 97-signal converter, 98-support frame. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] See also Figure 1-9 In an embodiment of the present invention, a wafer cutting machine and a thickness detection method thereof include a frame 1; a cutting assembly 3 is mounted on the frame 1; the cutting assembly 3 includes two symmetrical vertical plates 30 mounted on the top of one end of the frame 1; a first slide rail 31 is fixedly mounted between the two vertical plates 30; a laser controller 32 is movably mounted on the first slide rail 31; a laser emitter 33 is fixedly mounted on the bottom of the laser controller 32; The frame 1 is also equipped with a transmission assembly 5; the transmission assembly 5 includes two symmetrical second slide rails 50; the second slide rails 50 are fixedly mounted to the frame 1; a movable plate 53 is movably mounted on the second slide rails 50 via a slider; and a wafer stage 51 is fixedly mounted on the movable plate 93; The bottom of the movable plate 93 is connected to the screw rod 52 through a connecting block; both ends of the screw rod 52 are movably mounted on the frame 1 through seat bearings; one end of the screw rod 52 is fixedly mounted to the drive motor 54.

[0018] By adopting the above technical solution, when in use, the wafer is placed in the countersunk hole opened on the placement plate 92 by the robotic arm, ensuring the distance between the wafer and the lower sensor 93 and the upper sensor 94. After the wafer is placed, the sliding rod 95 slides along the third slide rail 96 to effectively adjust the front and rear position of the wafer. At the same time, the slide plate 90 can also slide along the cross bar 91 to achieve left and right adjustment of the wafer on the placement plate 92, thereby effectively ensuring that the lower sensor 93 and the upper sensor 94 can irradiate and measure the overall thickness of the wafer. See also Figure 1-10 In this embodiment, the movable plate 53 is further provided with a positioning assembly 8; the positioning assembly 8 comprises a double-rod cylinder 80; an L-shaped rod 81 is fixedly mounted on the lever of each of the double-rod cylinders 80; a clamping plate 82 is provided at the bottom of the L-shaped rod 81; the inner side of the clamping plate 82 is arc-shaped; In this embodiment, a detection assembly 9 is further provided inside the frame 1; the detection assembly 9 includes two symmetrical third slide rails 96; the third slide rails 96 are fixedly mounted on the inner sides of the side walls at both ends of the frame 1; a slide rod 95 is slidably mounted on the third slide rails 96 via a slider; Furthermore, the two ends of the slide rod 95 are fixedly mounted on the two ends of the two cross bars 91; the slide plate 90 is movably mounted on the cross bar 91 through a slider; By adopting the above technical solution, when measuring the thickness of the wafer, the lower sensor 93 and the upper sensor 94 are turned on synchronously through the second switch 7. The thickness of different positions of the wafer is effectively calculated through the refraction of light emitted by the lower sensor 93 and the upper sensor 94. The lower sensor 93 and the upper sensor 94 transmit the detection data to the main control box 4 through the signal converter 97. When measuring the thickness, the positions of the lower sensor 93 and the upper sensor 94 are fixed. Even if the wafer swings during the detection process, the efficiency of the thickness detection can be effectively guaranteed. In this embodiment, a placement plate 92 is fixedly mounted on the bottom of the slide plate 90 via a connecting rod; a countersunk hole is provided on the placement plate 92 for facilitating wafer placement; The detection assembly 9 further includes a lower sensor 93 and an upper sensor 94; wherein the upper sensor 94 is fixedly mounted on the bottom of the top plate of the frame 1; the lower sensor 93 is fixedly mounted on the bottom plate of the frame 1 via a support frame 98; the lower sensor 93 and the upper sensor 94 are at the same distance from the countersunk hole provided on the placement plate 92; By adopting the above technical solution, the signal converter 97 shares the detected data with the laser controller 32. The laser controller 32 effectively plans the cutting route based on the data detected by the lower sensor 93 and the upper sensor 94. At the same time, it controls the laser emitter 33 to automatically adjust the focus depth and emission energy to ensure that the modified layer of the wafer maintains the same thickness and position after laser cutting. In this embodiment, the lower sensor 93 and the upper sensor 94 are electrically connected to the signal converter 97 through a transmission line; the signal converter 97 is electrically connected to the main control box 4 through a wire; the main control box 4 is also electrically connected to the laser controller 32; the main control box 4 is fixedly mounted on the top plate of the frame 1; The detection method includes the following steps: S1. Place the wafer into the countersunk hole on the placement plate 92 by the robotic arm; slide the slide bar 95 along the third slide rail 96 and slide the slide plate 90 along the crossbar 91 by the slider, thereby effectively adjusting the position of the wafer to be tested; S2. During detection, the lower sensor 93 and the upper sensor 94 are turned on by the second switch 7. The lower sensor 93 and the upper sensor 94 are at the same distance from the countersunk hole provided on the placement plate 92. The thickness of the wafer at different positions is automatically calculated by the signal converter 97 through the refraction of the light emitted by the lower sensor 93 and the upper sensor 94. S3, the signal converter 97 transmits the calculated data to the main control box 4, and then the main control box 4 transmits it to the laser controller 32. The laser controller 32 automatically plans the cutting path according to the wafer data, and automatically controls the laser emitter 33 to adjust the focus depth and emission energy. S4. Place the inspected wafer on the wafer stage 51. Use the two clamping plates 82 to effectively clamp and position the wafer. The first switch 6 controls the lead screw to move the movable plate 53, so that the positioned wafer is transferred to the bottom of the laser emitter 33 for cutting. By adopting the above technical solution, after the debugging of the cutting assembly 3 is completed, the wafer that has been inspected is transferred to the wafer table 51 by the robotic arm. After the wafer is placed, the double-rod cylinder 80 simultaneously drives the clamping plate 82 at the bottom of the L-shaped rod 81 to position and clamp the wafer. After the positioning is completed, the first switch 6 is used to drive the motor 54 to drive the screw rod 52 to rotate, and the screw rod 52 drives the moving plate 53 to slide along the second slide rail 50 to move the wafer to the bottom of the laser emitter 33. When the laser emitter 33 moves to the designated area, the laser controller 32 automatically switches the parameters, rather than cutting a complete wafer with one parameter or manually switching the parameters, thereby effectively ensuring the cutting accuracy and cutting efficiency. The working principle of the present invention is as follows: when in use, the wafer is placed in the countersunk hole opened on the placement plate 92 by the robotic arm, ensuring the distance between the wafer and the lower sensor 93 and the upper sensor 94. After the wafer is placed, the sliding rod 95 slides along the third slide rail 96 to effectively adjust the front and rear position of the wafer. At the same time, the slide plate 90 can also slide along the cross bar 91 to achieve left and right adjustment of the wafer on the placement plate 92, thereby effectively ensuring that the lower sensor 93 and the upper sensor 94 can irradiate and measure the overall thickness of the wafer. When measuring the thickness of the wafer, the lower sensor 93 and the upper sensor 94 are turned on synchronously through the second switch 7. The thickness of different positions of the wafer is effectively calculated through the refraction of light emitted by the lower sensor 93 and the upper sensor 94. The lower sensor 93 and the upper sensor 94 transmit the detection data to the main control box 4 through the signal converter 97. When measuring the thickness, the positions of the lower sensor 93 and the upper sensor 94 are fixed. Even if the wafer swings during the detection process, the efficiency of the thickness detection can be effectively guaranteed. The signal converter 97 shares the detected data with the laser controller 32. The laser controller 32 effectively plans the cutting route based on the data detected by the lower sensor 93 and the upper sensor 94. At the same time, it controls the laser emitter 33 to automatically adjust the focus depth and emission energy to ensure that the modified layer of the wafer maintains the same thickness and position after laser cutting. After the debugging of the cutting component 3 is completed, the wafer that has been inspected is transferred to the wafer table 51 by the robotic arm. After the wafer is placed, the double-rod cylinder 80 drives the clamping plate 82 at the bottom of the L-shaped rod 81 to position and clamp the wafer. After the positioning is completed, the first switch 6 is used to drive the motor 54 to drive the screw rod 52 to rotate, and the screw rod 52 drives the moving plate 53 to slide along the second slide rail 50 to move the wafer to the bottom of the laser emitter 33. When the laser emitter 33 moves to the designated area, the laser controller 32 automatically switches the parameters, instead of cutting a complete wafer with one parameter, or manually switching the parameters, thereby effectively ensuring the cutting accuracy and cutting efficiency.

[0019] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0020] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A wafer cutting machine, characterized in that: The invention comprises a frame (1); a cutting assembly (3) is mounted on the frame (1); the cutting assembly (3) comprises two symmetrical vertical plates (30) mounted on the top of one end of the frame (1); a first slide rail (31) is fixedly mounted between the two vertical plates (30); a laser controller (32) is movably mounted on the first slide rail (31); a laser emitter (33) is fixedly mounted on the bottom of the laser controller (32); The frame (1) is also equipped with a transmission component (5); the transmission component (5) includes two symmetrical second slide rails (50); the second slide rails (50) are fixedly installed on the frame (1); a movable plate (53) is movably installed on the second slide rails (50) through a slider; a wafer table (51) is fixedly installed on the movable plate (93).

2. The wafer cutting machine according to claim 1, wherein: The bottom of the movable plate (93) is connected to the screw rod (52) through a connecting block; both ends of the screw rod (52) are movably mounted on the frame (1) through seat bearings; and one end of the screw rod (52) is fixedly mounted on the drive motor (54).

3. The wafer cutting machine according to claim 1, wherein: The movable plate (53) is also equipped with a positioning assembly (8); the positioning assembly (8) includes a double-rod cylinder (80); an L-shaped rod (81) is fixedly mounted on the lever of the double-rod cylinder (80); a clamping plate (82) is equipped with a bottom of the L-shaped rod (81); the inner side of the clamping plate (82) is arranged in an arc shape.

4. The wafer cutting machine according to claim 3, wherein: A detection assembly (9) is also provided inside the frame (1); the detection assembly (9) includes two symmetrical third slide rails (96); the third slide rails (96) are fixedly mounted on the inner sides of the side walls at both ends of the frame (1); a slide rod (95) is slidably mounted on the third slide rail (96) via a slider.

5. The wafer cutting machine according to claim 4, characterized in that: The two ends of the slide rod (95) are fixedly mounted on the two ends of the two cross bars (91); the slide plate (90) is movably mounted on the cross bar (91) via a slider.

6. The wafer cutting machine according to claim 5, characterized in that: A placement plate (92) is fixedly mounted on the bottom of the slide plate (90) via a connecting rod; a countersunk hole is provided on the placement plate (92) for facilitating wafer placement.

7. The wafer cutting machine according to claim 4, characterized in that: The detection assembly (9) further comprises a lower sensor (93) and an upper sensor (94); wherein the upper sensor (94) is fixedly mounted on the bottom of the top plate of the frame (1); the lower sensor (93) is fixedly mounted on the bottom plate of the frame (1) via a support frame (98); the lower sensor (93) and the upper sensor (94) are at the same distance from the countersunk hole provided on the placement plate (92).

8. The wafer cutting machine according to claim 7, characterized in that: The lower sensor (93) and the upper sensor (94) are both electrically connected to the signal converter (97) via a transmission line; the signal converter (97) is electrically connected to the master control box (4) via a wire; the master control box (4) is also electrically connected to the laser controller (32); the master control box (4) is fixedly mounted on the top plate of the frame (1).

9. A wafer thickness detection method for a wafer cutting machine according to claims 1-8, characterized in that: The detection method includes the following steps: S1, placing the wafer into the countersunk hole opened on the placement plate (92) by the robotic arm; sliding the slide bar (95) along the third slide rail (96), and the slide plate (90) sliding along the cross bar (91) by the slider, thereby effectively adjusting the position of the wafer to be tested; S2. When performing the detection, the lower sensor (93) and the upper sensor (94) are turned on by the second switch (7). The distances between the lower sensor (93) and the upper sensor (94) and the countersunk hole opened on the placement plate (92) are the same. The thickness of the wafer at different positions is automatically calculated by the signal converter (97) through the refraction of the light emitted by the lower sensor (93) and the upper sensor (94); S3, the signal converter (97) transmits the calculated data to the main control box (4), and the main control box (4) transmits it to the laser controller (32), and the laser controller (32) automatically plans the cutting path according to the wafer data, and automatically controls the laser emitter (33) to automatically adjust the focus depth and emission energy through the laser controller (32); S4. Place the wafer that has been inspected on the wafer table (51), and effectively clamp and position the wafer through two clamping plates (82). The first switch (6) controls the screw rod to drive the moving plate (53) to move, so that the wafer that has been positioned is transferred to the bottom of the laser emitter (33) for cutting.

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