Semiconductor wafer cutting method

Abstract

The invention discloses a method for cutting a semiconductor wafer. The method comprises the following steps: placing the semiconductor wafer to be cut on a cutting machine table; after the grinding wheel is started, the grinding wheel is controlled to idle at a preset initial feeding speed and an initial main shaft rotating speed, and a laser generating device and the grinding wheel are controlled to move in the same direction at the same time, so that the semiconductor wafer is irradiated by laser generated by the laser generating device firstly and then cut by the grinding wheel; when the grinding wheel starts to make contact with the semiconductor wafer, the feeding speed of the grinding wheel is reduced to the preset cutting feeding speed, and the grinding wheel is controlled to cut the semiconductor wafer at the cutting feeding speed. According to the technical scheme, laser is used for assisting in cutting, the semiconductor wafer is irradiated by the laser firstly, heat is generated in the feeding position area of the semiconductor wafer, the temperature rises, then the semiconductor wafer is cut by the grinding wheel, the problems of edge breakage, cracking and the like generated when the semiconductor wafer is cut can be prevented, and therefore the product quality is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for cutting a semiconductor wafer. Background Art

[0002] In the semiconductor field, cutting is a very important process. As the processing size of semiconductor wafers becomes smaller and smaller, the processing difficulty gradually increases. To adapt to this situation, a grinding wheel with a relatively thin thickness needs to be used during cutting. However, as the thickness of the grinding wheel becomes thinner, its stiffness will also decrease. The traditional solution is to adjust the rotational speed and feed rate of the grinding wheel during cutting. However, this method will cause chipping on both sides of the entrance of the semiconductor wafer during cutting, thus causing losses to the product and affecting the product quality. Summary of the Invention

[0003] An object of an embodiment of the present invention is to provide a method for cutting a semiconductor wafer. By using laser-assisted cutting, the semiconductor wafer is first irradiated with laser, heat is generated in the feed position area, the temperature rises, and then it is cut by a grinding wheel, which can prevent problems such as chipping and cracking of the semiconductor wafer during cutting, thereby improving the product quality.

[0004] To achieve the above object, an embodiment of the present invention provides a method for cutting a semiconductor wafer, including:

[0005] Placing the semiconductor wafer to be cut on a cutting machine table;

[0006] After the grinding wheel is turned on, controlling the grinding wheel to rotate idly at a preset initial feed rate and initial spindle speed, and controlling the laser generating device to move in the same direction as the grinding wheel simultaneously, so that the semiconductor wafer is first irradiated with the laser generated by the laser generating device and then cut by the grinding wheel;

[0007] When the grinding wheel starts to contact the semiconductor wafer, reducing the feed rate of the grinding wheel to a preset cutting feed rate, and controlling the grinding wheel to cut the semiconductor wafer at the cutting feed rate.

[0008] Further, the initial feed rate is 20 cm / min, and the initial spindle speed is 600 - 1000 rpm.

[0009] Further, the energy of the laser generated by the laser generating device is 220 W, the spot diameter is 1.0 - 1.5 mm, and the spot diameter is the same as the width of the feed position area on the semiconductor wafer.

[0010] Further, the distance between the outer edge of the grinding wheel and the center of the spot is 5 cm.

[0011] Further, the cutting feed rate is 13 cm / min.

[0012] Further, the thickness of the semiconductor wafer is 2.5 mm, and the temperature of the semiconductor wafer after being irradiated by the laser is 100°C to 120°C.

[0013] Compared with the prior art, the embodiment of the present invention provides a method for cutting a semiconductor wafer. First, place the semiconductor wafer to be cut on the cutting machine table; then, after the grinding wheel is turned on, control the grinding wheel to rotate idly at a preset initial feed rate and initial spindle speed, and control the laser generating device and the grinding wheel to move in the same direction at the same time, so that the semiconductor wafer is first irradiated by the laser generated by the laser generating device and then cut by the grinding wheel; finally, when the grinding wheel starts to contact the semiconductor wafer, reduce the feed rate of the grinding wheel to the preset cutting feed rate, and control the grinding wheel to cut the semiconductor wafer at the cutting feed rate. By using laser-assisted cutting, the semiconductor wafer in the embodiment of the present invention is first irradiated by the laser, heat is generated in the feed position area, the temperature rises, and then it is cut by the grinding wheel, which can prevent problems such as chipping and cracking of the semiconductor wafer during cutting, thereby improving the product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a flowchart of a preferred embodiment of a method for cutting a semiconductor wafer provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art in the technical field of the present invention without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0016] The embodiment of the present invention provides a method for cutting a semiconductor wafer. Refer to Figure 1 As shown, it is a flowchart of a preferred embodiment of a method for cutting a semiconductor wafer provided by the present invention. The method includes steps S11 to S13:

[0017] Step S11: Place the semiconductor wafer to be cut on the cutting machine table;

[0018] Step S12: After the grinding wheel is turned on, control the grinding wheel to rotate idly at a preset initial feed rate and initial spindle speed, and control the laser generating device and the grinding wheel to move in the same direction at the same time, so that the semiconductor wafer is first irradiated by the laser generated by the laser generating device and then cut by the grinding wheel;

[0019] Step S13: When the grinding wheel starts to contact the semiconductor wafer, reduce the feed rate of the grinding wheel to a preset cutting feed rate, and control the grinding wheel to cut the semiconductor wafer at the cutting feed rate.

[0020] In specific implementation, first, place the semiconductor wafer to be cut on the cutting machine table; then, control the grinding wheel to start up. After the grinding wheel starts up, control the grinding wheel to rotate idly at a preset initial feed rate and a preset initial spindle speed. At the same time, prepare a laser generating device, and control the laser generating device to move in the same direction as the grinding wheel simultaneously, so that the semiconductor wafer is first irradiated by the laser generated by the laser generating device to increase the temperature, and then cut by the grinding wheel; finally, when the grinding wheel passes through the groove and the main body of the grinding wheel starts to contact the semiconductor wafer, reduce the feed rate of the grinding wheel from the initial feed rate to a preset cutting feed rate, and control the grinding wheel to cut the semiconductor wafer at the adjusted cutting feed rate.

[0021] It should be noted that when irradiating the surface of the semiconductor wafer with the laser generated by the laser generating device, it is mainly to irradiate the feed position area on the surface of the semiconductor wafer; in the actual cutting process, the laser and the grinding wheel move in the same direction simultaneously, and the laser is in front and the grinding wheel is behind. The feed position area on the surface of the semiconductor wafer is first irradiated by the laser, and after the temperature rises, it is then cut by the grinding wheel, which can prevent chipping from occurring on both sides of the entrance of the grinding wheel cutting the semiconductor wafer, thereby reducing the edge chipping of the semiconductor wafer.

[0022] It should be noted that through experimental tests, it can be known that by adopting the cutting solution provided by the embodiment of the present invention, the incidence rate of chipping drops from 2% - 3% to 0.1% - 0.2%.

[0023] In one optional embodiment, the initial feed rate is 20 cm / min, and the initial spindle speed is 600 - 1000 rpm.

[0024] Specifically, in combination with the above embodiment, during the idle rotation of the grinding wheel, the feed rate of the grinding wheel is the preset initial feed rate, and the initial feed rate is 20 cm / min. The spindle speed of the grinding wheel is the preset initial spindle speed, and the initial spindle speed is 600 rpm - 1000 rpm.

[0025] Exemplarily, the value of the initial spindle speed can be 600 rpm, 700 rpm, 800 rpm, 900 rpm or 1000 rpm, or it can also be set according to actual requirements, and the embodiment of the present invention does not make specific limitations.

[0026] In one optional embodiment, the laser generated by the laser generating device has an energy of 220W, a spot diameter of 1.0 - 1.5mm, and the spot diameter is the same as the width of the feed position area on the semiconductor wafer.

[0027] Specifically, in combination with the above embodiment, the laser energy generated by the laser generating device is 220W, the spot diameter of the laser is 1.0mm - 1.5mm, and the spot diameter is consistent with the width of the feed position area on the semiconductor wafer to ensure that the feed position area can be completely covered by the laser spot.

[0028] Exemplarily, the value of the spot diameter can be 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm or 1.5mm, or it can be set according to actual requirements, and the embodiments of the present invention do not make specific limitations.

[0029] In one optional embodiment, the distance between the outer edge of the grinding wheel and the center of the spot is 5cm.

[0030] Specifically, in combination with the above embodiment, during the actual cutting process, the distance between the point where the outer edge of the grinding wheel contacts the semiconductor wafer and the center of the laser spot is 5cm, that is, the laser and the grinding wheel move in the same direction at the same time, and the laser is in front and the grinding wheel is behind, and the distance between the center of the laser spot and the front end of the grinding wheel is 5cm.

[0031] In one optional embodiment, the cutting feed speed is 13cm / min.

[0032] Specifically, in combination with the above embodiment, when the main body of the grinding wheel starts to contact the semiconductor wafer, the feed speed of the grinding wheel needs to be reduced from the initial feed speed of 20cm / min to the preset cutting feed speed of 13cm / min, and the grinding wheel is controlled to cut the semiconductor wafer at a cutting feed speed of 13cm / min.

[0033] It can be understood that 13cm / min is also the moving speed of the laser.

[0034] In one optional embodiment, the thickness of the semiconductor wafer is 2.5mm, and the temperature of the semiconductor wafer after being irradiated by the laser is 100℃ - 120℃.

[0035] Specifically, in combination with the above embodiment, the thickness of the semiconductor wafer to be cut is 2.5mm. During the cutting process at a moving speed of 13cm / min, after the semiconductor wafer is irradiated by the laser, the temperature inside it will rise to 100℃ - 120℃.

[0036] It should be noted that if the moving speed is greater than 13 cm / min, the temperature inside the semiconductor wafer is relatively low and cannot reach 100 °C, which will affect the cutting effect; if the moving speed is less than 13 cm / min, the temperature inside the semiconductor wafer is relatively high and will be higher than 120 °C, thus damaging the coils inside the semiconductor wafer, resulting in defective products, and even causing cracks on the surface of the semiconductor wafer, increasing the surface cracks.

[0037] Combining all the above embodiments, the implementation process of this solution is described below through the first specific embodiment, including: (1) Place the semiconductor wafer to be cut on the cutting machine table; wherein, the thickness of the semiconductor wafer is 2.5 mm; (2) Control the grinding wheel to start up. After the grinding wheel starts up, control the grinding wheel to rotate idly at an initial feed speed of 20 cm / min and an initial spindle speed of 600 rpm. At the same time, prepare a laser generating device, control the laser generating device to move in the same direction as the grinding wheel simultaneously, and the distance between the outer edge of the grinding wheel and the center of the laser spot is 5 cm, so that the semiconductor wafer is first irradiated by the laser generated by the laser generating device to increase the temperature, and then cut by the grinding wheel; wherein, the laser energy generated by the laser generating device is 220 W, the spot diameter is 1.0 mm, and this spot diameter is consistent with the width of the feed position area on the semiconductor wafer. The temperature inside the semiconductor wafer rises to 100 °C after being irradiated by the laser; (3) When the grinding wheel passes through the groove and the main body of the grinding wheel starts to contact the semiconductor wafer, reduce the feed speed of the grinding wheel from 20 cm / min to 13 cm / min, and control the grinding wheel to cut the semiconductor wafer at a cutting feed speed of 13 cm / min.

[0038] Combining all the above embodiments, the implementation process of this solution is described below through the second specific embodiment, including: (1) Place the semiconductor wafer to be cut on the cutting machine table; wherein, the thickness of the semiconductor wafer is 2.5 mm; (2) Control the grinding wheel to start up. After the grinding wheel starts up, control the grinding wheel to rotate idly at an initial feed speed of 20 cm / min and an initial spindle speed of 800 rpm. At the same time, prepare a laser generating device, control the laser generating device to move in the same direction as the grinding wheel simultaneously, and the distance between the outer edge of the grinding wheel and the center of the laser spot is 5 cm, so that the semiconductor wafer is first irradiated by the laser generated by the laser generating device to increase the temperature, and then cut by the grinding wheel; wherein, the laser energy generated by the laser generating device is 220 W, the spot diameter is 1.2 mm, and this spot diameter is consistent with the width of the feed position area on the semiconductor wafer. The temperature inside the semiconductor wafer rises to 110 °C after being irradiated by the laser; (3) When the grinding wheel passes through the groove and the main body of the grinding wheel starts to contact the semiconductor wafer, reduce the feed speed of the grinding wheel from 20 cm / min to 13 cm / min, and control the grinding wheel to cut the semiconductor wafer at a cutting feed speed of 13 cm / min.

[0039] Combining all the above embodiments, the implementation process of this solution is described below through a third specific embodiment, including: (1) Place the semiconductor wafer to be cut on the cutting machine table; wherein, the thickness of the semiconductor wafer is 2.5 mm; (2) Control the grinding wheel to start up. After the grinding wheel starts up, control the grinding wheel to rotate idly at an initial feed rate of 20 cm / min and an initial spindle speed of 1000 rpm. At the same time, prepare a laser generating device, control the laser generating device to move in the same direction as the grinding wheel simultaneously, and the distance between the outer edge of the grinding wheel and the center of the laser spot is 5 cm, so that the semiconductor wafer is first irradiated by the laser generated by the laser generating device to increase the temperature, and then cut by the grinding wheel; wherein, the laser energy generated by the laser generating device is 220 W, the spot diameter is 1.5 mm, and this spot diameter is consistent with the width of the feed position area on the semiconductor wafer. After the semiconductor wafer is irradiated by the laser, the internal temperature rises to 120 °C; (3) When the grinding wheel passes through the groove and the main body of the grinding wheel begins to contact the semiconductor wafer, reduce the feed rate of the grinding wheel from 20 cm / min to 13 cm / min, and control the grinding wheel to cut the semiconductor wafer at a cutting feed rate of 13 cm / min.

[0040] In summary, for a cutting method of a semiconductor wafer provided by an embodiment of the present invention, first, place the semiconductor wafer to be cut on the cutting machine table; then, after the grinding wheel starts up, control the grinding wheel to rotate idly at a preset initial feed rate and an initial spindle speed, and control the laser generating device to move in the same direction as the grinding wheel simultaneously, so that the semiconductor wafer is first irradiated by the laser generated by the laser generating device and then cut by the grinding wheel; finally, when the grinding wheel begins to contact the semiconductor wafer, reduce the feed rate of the grinding wheel to a preset cutting feed rate, and control the grinding wheel to cut the semiconductor wafer at the cutting feed rate. By using laser-assisted cutting in the embodiment of the present invention, the semiconductor wafer is first irradiated by the laser, heat is generated in its feed position area, the temperature rises, and then it is cut by the grinding wheel, which can prevent problems such as chipping and cracking of the semiconductor wafer during cutting, thereby improving the product quality.

[0041] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A method for cutting a semiconductor wafer, characterized in that, Including: Placing the semiconductor wafer to be cut on the cutting machine table; After the grinding wheel is started, controlling the grinding wheel to rotate idly at a preset initial feed speed and initial spindle speed, and controlling the laser generating device and the grinding wheel to move in the same direction simultaneously, so that the semiconductor wafer is first irradiated by the laser generated by the laser generating device and then cut by the grinding wheel; When the grinding wheel starts to contact the semiconductor wafer, reducing the feed speed of the grinding wheel to a preset cutting feed speed, and controlling the grinding wheel to cut the semiconductor wafer at the cutting feed speed.

2. The cutting method of the semiconductor wafer as described in claim 1, characterized in that, The initial feed speed is 20 cm / min, and the initial spindle speed is 600 - 1000 rpm.

3. The cutting method of a semiconductor wafer as described in claim 1, characterized in that, The energy of the laser generated by the laser generating device is 220 W, the spot diameter is 1.0 - 1.5 mm, and the spot diameter is the same as the width of the feed position area on the semiconductor wafer.

4. The cutting method of a semiconductor wafer as claimed in claim 3, wherein The distance between the outer edge of the grinding wheel and the center of the spot is 5 cm.

5. The cutting method of a semiconductor wafer as described in claim 1, characterized in that, The cutting feed speed is 13 cm / min.

6. The cutting method of a semiconductor wafer as described in claim 1, characterized in that, The thickness of the semiconductor wafer is 2.5 mm, and the temperature of the semiconductor wafer after being irradiated by the laser is 100°C - 120°C.

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