A method for separating a semiconductor wafer

Abstract

The application discloses a semiconductor wafer separation method, comprising the following steps: ion etching the surface of a semiconductor wafer to separate the semiconductor wafer; and using a laser to correct the separation edge of the separated semiconductor wafer. The technical scheme of the application can effectively solve the problems of edge collapse and fragmentation in the separation process of the semiconductor wafer by ion etching and laser correction, greatly reduce the frequency of edge collapse and fragmentation, and reduce the size of edge collapse and the rate of collapse, thereby improving the processing quality of the semiconductor wafer.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more particularly to a method for separating semiconductor wafers. Background Technology

[0002] Currently, in the semiconductor wafer separation process, traditional separation techniques (e.g., cutting semiconductor wafers with grinding wheels or blades) easily cause edge chipping and breakage, which are key issues that need to be addressed in the separation process. Common solutions involve optimizing the grinding wheels or blades, such as adjusting the amplitude of the grinding wheel or blade and the cutting speed, to reduce the frequency of edge chipping and breakage; however, these methods are not very effective. Summary of the Invention

[0003] The purpose of this invention is to provide a method for separating semiconductor wafers, which can effectively solve the problems of edge chipping and breakage that occur during the separation process of semiconductor wafers through ion etching and laser correction, greatly reduce the frequency of edge chipping and breakage, and reduce the chipping size and the breakage rate, thereby improving the processing quality of semiconductor wafers.

[0004] To achieve the above objectives, embodiments of the present invention provide a method for separating semiconductor wafers, comprising:

[0005] The surface of the semiconductor wafer is ion-etched to separate the semiconductor wafer;

[0006] Lasers are used to correct the separation edges of the separated semiconductor wafers.

[0007] Furthermore, the ion etching of the semiconductor wafer surface specifically includes:

[0008] A semiconductor wafer is placed in a vacuum chamber, a preset mixed gas is introduced into the vacuum chamber, and the temperature in the vacuum chamber is adjusted to 25-30°C and the pressure to 75-100 mtorr.

[0009] Under preset source power and bias power conditions, the surface of the semiconductor wafer is subjected to ion etching.

[0010] Furthermore, the mixed gas is CF4 and O2, and the ratio of CF4 to O2 is 5:1.

[0011] Furthermore, the flow rate of the mixed gas is 1500–1800 sccm.

[0012] Furthermore, the source power is 2000-3000W, and the bias power is 180-240W.

[0013] Furthermore, the etching time for the ion etching is 30–45 min.

[0014] Furthermore, the step of using laser to correct the separation edges of the separated semiconductor wafers specifically includes:

[0015] Helium gas is introduced into the vacuum chamber at a flow rate of 40–50 L / min;

[0016] Under preset laser process parameters, the separation edges of the separated semiconductor wafers are corrected using lasers.

[0017] Furthermore, the laser process parameters include: laser power of 3kW, spot diameter of 0.01-0.03mm, defocusing amount of 5mm, and moving speed of 5-8mm / s.

[0018] Compared with existing technologies, this invention provides a method for separating semiconductor wafers. First, the surface of the semiconductor wafer is ion-etched to separate it; then, a laser is used to correct the separation edges of the separated semiconductor wafers. This invention effectively solves the problems of edge chipping and breakage during semiconductor wafer separation through ion etching and laser correction, significantly reducing the frequency of edge chipping and breakage, and decreasing the size and rate of chipping, thereby improving the processing quality of semiconductor wafers. Attached Figure Description

[0019] Figure 1 This is a flowchart of a preferred embodiment of a semiconductor wafer separation method provided by the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] This invention provides a method for separating semiconductor wafers, see [link to relevant documentation]. Figure 1 The diagram shown is a flowchart of a preferred embodiment of a semiconductor wafer separation method provided by the present invention, the method comprising steps S11 to S12:

[0022] Step S11: Perform ion etching on the surface of the semiconductor wafer to separate the semiconductor wafer;

[0023] Step S12: Use a laser to correct the separation edges of the separated semiconductor wafers.

[0024] In practice, the surface of the semiconductor wafer is first ion-etched to completely separate the semiconductor wafer into several independent parts; then, a laser is used to correct the separation edges (i.e., separation cross-sections) of the separated semiconductor wafer (i.e., each independent part after separation) so that the separation edges of the separated semiconductor wafer become smooth.

[0025] In one optional embodiment, the ion etching of the semiconductor wafer surface specifically includes:

[0026] A semiconductor wafer is placed in a vacuum chamber, a preset mixed gas is introduced into the vacuum chamber, and the temperature in the vacuum chamber is adjusted to 25-30°C and the pressure to 75-100 mtorr.

[0027] Under preset source power and bias power conditions, the surface of the semiconductor wafer is subjected to ion etching.

[0028] Specifically, in conjunction with the above embodiments, when performing ion etching on the surface of a semiconductor wafer, the semiconductor wafer can first be placed in a vacuum chamber, and a preset mixed gas can be introduced into the vacuum chamber. Then, the temperature in the vacuum chamber is adjusted to 25°C to 30°C, and the pressure in the vacuum chamber is adjusted to 75 mtorr to 100 mtorr. After that, under preset source power and bias power conditions, ion etching is performed on the surface of the semiconductor wafer until the semiconductor wafer is completely separated.

[0029] For example, the temperature inside the vacuum chamber can be 25°C, 26°C, 27°C, 28°C, 29°C or 30°C, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0030] For example, the pressure inside the vacuum chamber can be 75 mtorr, 76 mtorr, 77 mtorr, 78 mtorr, 79 mtorr, 80 mtorr, 81 mtorr, 82 mtorr, 83 mtorr, 84 mtorr, 85 mtorr, 86 mtorr, 87 mtorr, 88 mtorr, 89 mtorr, 90 mtorr, 91 mtorr, 92 mtorr, 93 mtorr, 94 mtorr, 95 mtorr, 96 mtorr, 97 mtorr, 98 mtorr, 99 mtorr, or 100 mtorr, and can also be set according to actual needs. This embodiment of the invention does not impose specific limitations.

[0031] In one alternative embodiment, the mixed gas is CF4 and O2, and the ratio of CF4 to O2 is 5:1.

[0032] Specifically, in conjunction with the above embodiments, when performing ion etching on the surface of a semiconductor wafer, the mixed gas introduced into the vacuum chamber is CF4 and O2, and the ratio of CF4 to O2 in the mixed gas is 5:1.

[0033] In one alternative embodiment, the flow rate of the mixed gas is 1500–1800 sccm.

[0034] Specifically, in conjunction with the above embodiments, when performing ion etching on the surface of a semiconductor wafer, the flow rate of the mixed gas introduced into the vacuum chamber is 1500 sccm to 1800 sccm.

[0035] For example, the flow rate of the mixed gas can be 1500 sccm, 1510 sccm, 1520 sccm, 1530 sccm, 1540 sccm, 1550 sccm, 1560 sccm, 1570 sccm, 1580 sccm, 1590 sccm, 1600 sccm, 1610 sccm, 1620 sccm, 1630 sccm, 1640 sccm, 1650 sccm, 1660 sccm, 1670 sccm, 1680 sccm, 1690 sccm, 1700 sccm, 1710 sccm, 1720 sccm, 1730 sccm, 1740 sccm, 1750 sccm, 1760 sccm, 1770 sccm, 1780 sccm, 1790 sccm, or 1800 sccm, and can also be set according to actual needs. This embodiment of the invention does not impose specific limitations.

[0036] In one optional embodiment, the source power is 2000-3000W and the bias power is 180-240W.

[0037] Specifically, in conjunction with the above embodiments, when performing ion etching on the surface of a semiconductor wafer, the source power is 2000W to 3000W and the bias power is 180W to 240W. That is, under the conditions of a source power of 2000W to 3000W and a bias power of 180W to 240W, ion etching is performed on the surface of the semiconductor wafer until the semiconductor wafer is completely separated.

[0038] It should be noted that source power refers to the power of the plasma source, which is mainly used to generate plasma. When the source power increases, more plasma will be generated in the vacuum chamber, thereby increasing the etching rate.

[0039] It should be noted that bias power refers to the power applied to the lower electrode, also known as substrate bias. The greater the bias power, the faster the plasma bombards the semiconductor wafer surface. Especially in physical etching (such as IBE), the increase in bias power will significantly improve the etching rate.

[0040] For example, the source power can be 2000W, 2100W, 2200W, 2300W, 2400W, 2500W, 2600W, 2700W, 2800W, 2900W or 3000W, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0041] For example, the bias power can be 180W, 190W, 200W, 210W, 220W, 230W or 240W, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0042] In one optional embodiment, the etching time of the ion etching is 30 to 45 minutes.

[0043] Specifically, in conjunction with the above embodiments, when performing ion etching on the surface of a semiconductor wafer, the etching time is 30 min to 45 min, that is, under the conditions of source power of 2000W to 3000W and bias power of 180W to 240W, the surface of the semiconductor wafer is ion etched for 30 min to 45 min until the semiconductor wafer is completely separated.

[0044] For example, the etching time can be 30 minutes, 31 minutes, 32 minutes, 33 minutes, 34 minutes, 35 minutes, 36 minutes, 37 minutes, 38 minutes, 39 minutes, 40 minutes, 41 minutes, 42 minutes, 43 minutes, 44 minutes or 45 minutes, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0045] In one optional embodiment, the step of using a laser to correct the separation edges of the separated semiconductor wafers specifically includes:

[0046] Helium gas is introduced into the vacuum chamber at a flow rate of 40–50 L / min;

[0047] Under preset laser process parameters, the separation edges of the separated semiconductor wafers are corrected using lasers.

[0048] Specifically, in conjunction with the above embodiments, when using a laser to correct the separation edge of the separated semiconductor wafer, helium can be selected as the protective gas, with a gas flow rate of 40L / min to 50L / min. Correspondingly, helium can be introduced into the vacuum chamber at a gas flow rate of 40L / min to 50L / min first, and then, under the preset laser process parameters, the separation edge of the separated semiconductor wafer can be corrected using a laser, so that the separation edge of the separated semiconductor wafer becomes smooth.

[0049] For example, the flow rate of helium gas can be 40L / min, 41L / min, 42L / min, 43L / min, 44L / min, 45L / min, 46L / min, 47L / min, 48L / min, 49L / min or 50L / min, and can also be set according to actual needs. This embodiment of the invention does not make specific limitations.

[0050] In one optional embodiment, the laser process parameters include: laser power of 3kW, spot diameter of 0.01-0.03mm, defocusing amount of 5mm, and moving speed of 5-8mm / s.

[0051] Specifically, in conjunction with the above embodiments, when using a laser to correct the separation edge of the separated semiconductor wafer, the laser power is 3kW, the spot diameter is 0.01mm to 0.03mm, the defocusing amount is 5mm, and the moving speed is 5mm / s to 8mm / s. That is, under the conditions of laser power of 3kW, spot diameter of 0.01mm to 0.03mm, defocusing amount of 5mm, and moving speed of 5mm / s to 8mm / s, the laser is used to correct the separation edge of the separated semiconductor wafer, making the separation edge of the separated semiconductor wafer smooth.

[0052] For example, the laser spot diameter can be 0.01mm, 0.02mm or 0.03mm, or it can be set according to actual needs. This embodiment of the invention does not impose specific limitations.

[0053] For example, the laser's movement speed can be 5mm / s, 6mm / s, 7mm / s, or 8mm / s, and can also be set according to actual needs. This embodiment of the invention does not impose specific limitations.

[0054] It should be noted that after ion etching of the semiconductor wafer surface, the chipping rate of the separated semiconductor wafer is 0.03%. After using laser to correct the separation edge of the separated semiconductor wafer, the chipping rate drops to below 0.01%. At the same time, the implementation of this invention can also soften the semiconductor wafer, reduce the number of chipped edges, and reduce the size of the chipped edges (the chipped edge size can be reduced to below 2 micrometers).

[0055] Based on all the above embodiments, the implementation process of this solution is described below through the first specific embodiment, including: (1) placing the semiconductor wafer in a vacuum chamber; (2) introducing a mixed gas of CF4 and O2 into the vacuum chamber, wherein the ratio of CF4 to O2 in the mixed gas is 5:1, the flow rate of the mixed gas is 1500 sccm, adjusting the temperature in the vacuum chamber to 25°C, and adjusting the pressure in the vacuum chamber to 75 mtorr; (3) performing ion etching on the surface of the semiconductor wafer under the conditions of source power of 2000W and bias power of 180W, the etching time is 45 min, until the semiconductor wafer is completely separated; (4) introducing helium into the vacuum chamber at a gas flow rate of 40 L / min, and using laser to correct the separation edge of the separated semiconductor wafer under the conditions of laser power of 3kW, spot diameter of 0.01mm, defocusing amount of 5mm, and moving speed of 5mm / s, so that the separation edge of the separated semiconductor wafer becomes flat.

[0056] Based on all the above embodiments, the implementation process of this solution is described below through a second specific embodiment, including: (1) placing the semiconductor wafer in a vacuum chamber; (2) introducing a mixed gas of CF4 and O2 into the vacuum chamber, wherein the ratio of CF4 to O2 in the mixed gas is 5:1, the flow rate of the mixed gas is 1650 sccm, adjusting the temperature in the vacuum chamber to 28°C, and adjusting the pressure in the vacuum chamber to 88 mtorr; (3) performing ion etching on the surface of the semiconductor wafer under the conditions of source power of 2500W and bias power of 210W, with an etching time of 38 min, until the semiconductor wafer is completely separated; (4) introducing helium into the vacuum chamber at a gas flow rate of 45 L / min, and using a laser to correct the separation edge of the separated semiconductor wafer under the conditions of laser power of 3kW, spot diameter of 0.02mm, defocusing amount of 5mm, and moving speed of 6mm / s, so that the separation edge of the separated semiconductor wafer becomes flat.

[0057] Based on all the above embodiments, the implementation process of this solution is described below through a third specific embodiment, including: (1) placing the semiconductor wafer in a vacuum chamber; (2) introducing a mixed gas of CF4 and O2 into the vacuum chamber, wherein the ratio of CF4 to O2 in the mixed gas is 5:1, the flow rate of the mixed gas is 1800 sccm, adjusting the temperature in the vacuum chamber to 30°C, and adjusting the pressure in the vacuum chamber to 100 mtorr; (3) performing ion etching on the surface of the semiconductor wafer under the conditions of a source power of 3000W and a bias power of 240W, with an etching time of 30 min, until the semiconductor wafer is completely separated; (4) introducing helium into the vacuum chamber at a gas flow rate of 50 L / min, and using a laser to correct the separation edge of the separated semiconductor wafer under the conditions of a laser power of 3kW, a spot diameter of 0.03mm, a defocusing amount of 5mm, and a moving speed of 8mm / s, so that the separation edge of the separated semiconductor wafer becomes flat.

[0058] In summary, the semiconductor wafer separation method provided by this invention first performs ion etching on the surface of the semiconductor wafer to separate it; then, a laser is used to correct the separation edges of the separated semiconductor wafer. This invention effectively solves the problems of edge chipping and breakage that occur during semiconductor wafer separation through ion etching and laser correction, significantly reducing the frequency of edge chipping and breakage, and decreasing the size and rate of chipping, thereby improving the processing quality of the semiconductor wafer.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for separating semiconductor wafers, characterized in that, include: The surface of the semiconductor wafer is ion-etched to separate the semiconductor wafer; Lasers are used to correct the separation edges of the separated semiconductor wafers.

2. The semiconductor wafer separation method as described in claim 1, characterized in that, The ion etching of the semiconductor wafer surface specifically includes: A semiconductor wafer is placed in a vacuum chamber, a preset mixed gas is introduced into the vacuum chamber, and the temperature in the vacuum chamber is adjusted to 25-30°C and the pressure to 75-100 mtorr. Under preset source power and bias power conditions, the surface of the semiconductor wafer is subjected to ion etching.

3. The semiconductor wafer separation method as described in claim 2, characterized in that, The mixed gas is CF4 and O2, and the ratio of CF4 to O2 is 5:

1.

4. The semiconductor wafer separation method as described in claim 3, characterized in that, The flow rate of the mixed gas is 1500–1800 sccm.

5. The semiconductor wafer separation method as described in claim 2, characterized in that, The source power is 2000-3000W, and the bias power is 180-240W.

6. The semiconductor wafer separation method as described in claim 2, characterized in that, The etching time for the ion etching is 30–45 min.

7. The semiconductor wafer separation method as described in claim 2, characterized in that, The method of using laser to correct the separation edges of the separated semiconductor wafers specifically includes: Helium gas is introduced into the vacuum chamber at a flow rate of 40–50 L / min; Under preset laser process parameters, the separation edges of the separated semiconductor wafers are corrected using lasers.

8. The semiconductor wafer separation method as described in claim 7, characterized in that, The laser process parameters include: laser power of 3kW, spot diameter of 0.01-0.03mm, defocusing amount of 5mm, and moving speed of 5-8mm / s.

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