A method for eliminating internal stress in semiconductor

Abstract

The present invention provides a method for eliminating internal stress of a semiconductor, comprising the following steps: (1) providing a semiconductor element and a ceramic plate, forming a protective film on the front of the semiconductor element and pasting the back of the semiconductor element to the front of the ceramic plate; (2) performing a first etching on the back of the ceramic plate after vacuuming in an ion etcher, wherein the etching gas is a mixed gas including oxygen and argon, and the volume ratio of oxygen to argon in the mixed gas is 1:5-1:2; (3) performing a second etching on the back of the ceramic plate after vacuuming in the ion etcher, wherein the etching gas is oxygen; (4) removing the protective film on the front of the semiconductor element. The method of the present invention can reduce the internal stress of the process of bonding the semiconductor element to the ceramic plate by glue during the semiconductor processing process, reduce the deformation of the semiconductor element, and improve the quality of the finished product of the semiconductor element.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor preparation, and in particular relates to a method for eliminating internal stress of a semiconductor. Background Art

[0002] During the semiconductor processing, internal stress will be formed inside the semiconductor element, causing various deformations of the semiconductor element. In particular, in the process of gluing the semiconductor element to the ceramic plate, internal stress will be formed inside the semiconductor element, causing the deformation of the component, thereby causing the position of the image to be shifted in the subsequent exposure and development. The existing solution to this problem is heat treatment, but heat treatment will loosen the glue that sticks the semiconductor element and the ceramic plate, causing inconvenience to the next step of processing. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for eliminating internal stress of a semiconductor.

[0004] To achieve the above object, the technical solution adopted by the present invention is: a method for eliminating internal stress of a semiconductor, the method comprising the following steps:

[0005] (1) providing a semiconductor element and a ceramic plate, forming a protective film on the front surface of the semiconductor element and adhering the back surface of the semiconductor element to the front surface of the ceramic plate to obtain a sample A;

[0006] (2) After the ion etcher is evacuated, the back side of the ceramic plate in sample A is subjected to a first etching, wherein the etching gas for the first etching is a mixed gas including oxygen and argon, the flow rate of the mixed gas is 790 sccm-810 sccm, and the volume ratio of oxygen to argon in the mixed gas is 1:5-1:2;

[0007] (3) After the ion etcher is evacuated, the back side of the ceramic plate in sample A is subjected to a second etching, wherein the etching gas for the second etching is oxygen gas, and the flow rate of the oxygen gas is 800 sccm-1000 sccm;

[0008] (4) Remove the protective film on the front side of the semiconductor element in Sample A.

[0009] The inventors have found through research that the above method can reduce the internal stress generated in the process of bonding semiconductor elements to ceramic plates by glue during semiconductor processing, reduce the deformation of semiconductor elements, and improve the quality of finished semiconductor elements.

[0010] Preferably, in step (2), the volume ratio of oxygen to argon in the mixed gas is 1:4-1:2.5.

[0011] The inventors have found through research that in step (2) of the above method, a volume ratio of oxygen to argon in the mixed gas of 1:4-1:2.5 is more effective in reducing the internal stress of semiconductor components.

[0012] Preferably, in step (2), the volume ratio of oxygen to argon in the mixed gas is 1:3.

[0013] The inventors have found through research that in step (2) of the above method, when the volume ratio of oxygen to argon in the mixed gas is 1:3, the effect of reducing the internal stress of the semiconductor element is significantly better.

[0014] Preferably, the bias RF power of the first etching is 195W-205W, and the bias RF power of the second etching is 1990W-2010W.

[0015] Preferably, before the first etching, the vacuum pressure is evacuated to 180 mTorr-200 mTorr (mTorr).

[0016] Preferably, the vacuum pressure is evacuated to 80 mTorr-120 mTorr before the second etching.

[0017] Preferably, the bias RF power of the first etching is 200W.

[0018] Preferably, the bias RF power of the second etching is 2000W.

[0019] Preferably, in step (1), the protective film is a carbonized film.

[0020] The beneficial effects of the present invention are as follows: the present invention provides a method for eliminating internal stress of a semiconductor, which can reduce the internal stress of the process of bonding the semiconductor element to the ceramic plate by glue during the semiconductor processing, reduce the deformation of the semiconductor element, and improve the finished product quality of the semiconductor element. DETAILED DESCRIPTION

[0021] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0022] Example 1

[0023] As a method for eliminating internal stress in a semiconductor according to an embodiment of the present invention, the method comprises the following steps:

[0024] (1) providing a semiconductor element and a ceramic plate, forming a protective film on the front surface of the semiconductor element and adhering the back surface of the semiconductor element to the front surface of the ceramic plate to obtain a sample A;

[0025] (2) placing sample A in an ion etcher and evacuating the vacuum to a vacuum pressure of 180 mTorr-200 mTorr, performing a first etching on the back side of the ceramic plate in sample A after the ion etcher is evacuated, wherein the conditions for the first etching are as follows: maintaining the bias RF power at 200 W, the etching gas being a mixed gas of oxygen and argon, the flow rate of the mixed gas being 800 sccm, and the volume ratio of oxygen to argon in the mixed gas being 1:5;

[0026] (3) Evacuate to a vacuum pressure of 80mTorr-120mTorr, and perform a second etching on the back of the ceramic plate in sample A after evacuating the vacuum in the ion etcher. The conditions of the second etching are: maintain the bias RF power at 2000W, use oxygen as the etching gas, and the flow rate of the oxygen is 800sccm-1000sccm;

[0027] (4) Remove the protective film on the front side of the semiconductor element in Sample A.

[0028] Example 2

[0029] As a method for eliminating internal stress in a semiconductor according to an embodiment of the present invention, the method comprises the following steps:

[0030] (1) providing a semiconductor element and a ceramic plate, forming a protective film on the front surface of the semiconductor element and adhering the back surface of the semiconductor element to the front surface of the ceramic plate to obtain a sample A;

[0031] (2) placing sample A in an ion etcher and evacuating the vacuum to a vacuum pressure of 180 mTorr-200 mTorr, performing a first etching on the back of the ceramic plate in sample A after the ion etcher is evacuated, wherein the conditions for the first etching are as follows: maintaining the bias RF power at 200 W, the etching gas being a mixed gas of oxygen and argon, the flow rate of the mixed gas being 800 sccm, and the volume ratio of oxygen to argon in the mixed gas being 1:4;

[0032] (3) Evacuate to a vacuum pressure of 80mTorr-120mTorr, and perform a second etching on the back of the ceramic plate in sample A after evacuating the vacuum in the ion etcher. The conditions of the second etching are: maintain the bias RF power at 2000W, use oxygen as the etching gas, and the flow rate of the oxygen is 800sccm-1000sccm;

[0033] (4) Remove the protective film on the front side of the semiconductor element in Sample A.

[0034] Example 3

[0035] As a method for eliminating internal stress in a semiconductor according to an embodiment of the present invention, the method comprises the following steps:

[0036] (1) providing a semiconductor element and a ceramic plate, forming a protective film on the front surface of the semiconductor element and adhering the back surface of the semiconductor element to the front surface of the ceramic plate to obtain a sample A;

[0037] (2) placing sample A in an ion etcher and evacuating the vacuum to a vacuum pressure of 180 mTorr-200 mTorr, performing a first etching on the back side of the ceramic plate in sample A after the ion etcher is evacuated, wherein the conditions for the first etching are as follows: maintaining the bias RF power at 200 W, the etching gas being a mixed gas of oxygen and argon, the flow rate of the mixed gas being 800 sccm, and the volume ratio of oxygen to argon in the mixed gas being 1:3;

[0038] (3) Evacuate to a vacuum pressure of 80mTorr-120mTorr, and perform a second etching on the back of the ceramic plate in sample A after evacuating the vacuum in the ion etcher. The conditions of the second etching are: maintain the bias RF power at 2000W, use oxygen as the etching gas, and the flow rate of the oxygen is 800sccm-1000sccm;

[0039] (4) Remove the protective film on the front side of the semiconductor element in Sample A.

[0040] Example 4

[0041] As a method for eliminating internal stress in a semiconductor according to an embodiment of the present invention, the method comprises the following steps:

[0042] (1) providing a semiconductor element and a ceramic plate, forming a protective film on the front surface of the semiconductor element and adhering the back surface of the semiconductor element to the front surface of the ceramic plate to obtain a sample A;

[0043] (2) placing sample A in an ion etcher and evacuating the vacuum to a vacuum pressure of 180 mTorr-200 mTorr, performing a first etching on the back side of the ceramic plate in sample A after the ion etcher is evacuated, wherein the conditions for the first etching are as follows: maintaining the bias RF power at 200 W, the etching gas being a mixed gas of oxygen and argon, the flow rate of the mixed gas being 800 sccm, and the volume ratio of oxygen to argon in the mixed gas being 1:2.5;

[0044] (3) Evacuate to a vacuum pressure of 80mTorr-120mTorr, and perform a second etching on the back of the ceramic plate in sample A after evacuating the vacuum in the ion etcher. The conditions of the second etching are: maintain the bias RF power at 2000W, use oxygen as the etching gas, and the flow rate of the oxygen is 800sccm-1000sccm;

[0045] (4) Remove the protective film on the front side of the semiconductor element in Sample A.

[0046] Example 5

[0047] As a method for eliminating internal stress in a semiconductor according to an embodiment of the present invention, the method comprises the following steps:

[0048] (1) providing a semiconductor element and a ceramic plate, forming a protective film on the front surface of the semiconductor element and adhering the back surface of the semiconductor element to the front surface of the ceramic plate to obtain a sample A;

[0049] (2) placing sample A in an ion etcher and evacuating the vacuum to a vacuum pressure of 180 mTorr-200 mTorr, performing a first etching on the back side of the ceramic plate in sample A after the ion etcher is evacuated, wherein the conditions for the first etching are as follows: maintaining the bias RF power at 200 W, the etching gas being a mixed gas of oxygen and argon, the flow rate of the mixed gas being 800 sccm, and the volume ratio of oxygen to argon in the mixed gas being 1:2;

[0050] (3) Evacuate to a vacuum pressure of 80mTorr-120mTorr, and perform a second etching on the back of the ceramic plate in sample A after evacuating the vacuum in the ion etcher. The conditions of the second etching are: maintain the bias RF power at 2000W, use oxygen as the etching gas, and the flow rate of the oxygen is 800sccm-1000sccm;

[0051] (4) Remove the protective film on the front side of the semiconductor element in Sample A.

[0052] Comparative Example 1

[0053] As a method for eliminating internal stress in a semiconductor as a comparative example of the present invention, the method comprises the following steps:

[0054] (1) providing a semiconductor element and a ceramic plate, forming a protective film on the front surface of the semiconductor element and adhering the back surface of the semiconductor element to the front surface of the ceramic plate to obtain a sample A;

[0055] (2) placing sample A in an ion etcher and evacuating the vacuum to a vacuum pressure of 180 mTorr-200 mTorr, performing a first etching on the back side of the ceramic plate in sample A after the ion etcher is evacuated, wherein the conditions for the first etching are as follows: maintaining the bias RF power at 200 W, the etching gas being a mixed gas of oxygen and argon, the flow rate of the mixed gas being 800 sccm, and the volume ratio of oxygen to argon in the mixed gas being 1:1;

[0056] (3) Evacuate to a vacuum pressure of 80mTorr-120mTorr, and perform a second etching on the back of the ceramic plate in sample A after evacuating the vacuum in the ion etcher. The conditions of the second etching are: maintain the bias RF power at 2000W, use oxygen as the etching gas, and the flow rate of the oxygen is 800sccm-1000sccm;

[0057] (4) Remove the protective film on the front side of the semiconductor element in Sample A.

[0058] Experimental Example 1

[0059] The methods of Examples 1-5 and Comparative Example 1 were applied, and the height differences on both sides of the semiconductor samples after being processed by the methods were measured by a height measuring instrument. Ten samples were processed by each method, and the results are shown in Table 1.

[0060] Table 1 Effects of the methods of Examples 1-5 and Comparative Example 1 on eliminating internal stress in semiconductors

[0061] method Volume ratio of oxygen to argon Height difference μm Example 1 1:5 3-5 Example 2 1:4 2-3 Example 3 1:3 0.5-1 Example 4 1:2.5 1-1.5 Example 5 1:2 2-4.5 Comparative Example 1 1:1 5-7 Before treatment 4-5

[0062] It can be seen from Table 1 that before the semiconductor is treated, the height difference between the two sides of the 60 semiconductor samples used in the experiment is in the range of 4-5μm, and it is found that the height difference between the two sides of the semiconductor samples treated by the method of Comparative Example 1 is in the range of 5-7μm, indicating that the method of Comparative Example 1 cannot solve the problem of eliminating internal stress of the semiconductor; the height difference between the two sides of the semiconductor samples treated by the methods of Examples 1 to 5 is smaller than that before the semiconductor is treated, indicating that the methods of Examples 1 to 5 reduce the internal stress of the semiconductor and reduce the deformation of the semiconductor, and combined with Comparative Example 1, it is shown that in step (2), the volume ratio of oxygen and argon in the mixed gas is an important factor of the method. An inappropriate volume ratio not only cannot reduce the internal stress of the semiconductor and reduce the deformation of the semiconductor, but also increases the deformation of the semiconductor; further comparing the height difference between the two sides of the semiconductor samples treated by the methods of Examples 1 to 5, it is found that in step (2), the volume ratio of oxygen and argon in the mixed gas is 1:3, which is the best effect on reducing semiconductor deformation and reducing semiconductor internal stress.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for eliminating internal stress in a semiconductor, characterized in that: The method comprises the following steps: (1) providing a semiconductor element and a ceramic plate, forming a protective film on the front surface of the semiconductor element and adhering the back surface of the semiconductor element to the front surface of the ceramic plate to obtain a sample A; (2) After the ion etcher is evacuated, the back side of the ceramic plate in sample A is subjected to a first etching, wherein the etching gas for the first etching is a mixed gas including oxygen and argon, the flow rate of the mixed gas is 790 sccm-810 sccm, and the volume ratio of oxygen to argon in the mixed gas is 1:3-1:2.5; (3) After the ion etcher is evacuated, the back side of the ceramic plate in sample A is subjected to a second etching, wherein the etching gas for the second etching is oxygen gas, and the flow rate of the oxygen gas is 800 sccm-1000 sccm; (4) Remove the protective film on the front side of the semiconductor element in Sample A.

2. The method according to claim 1, characterized in that In the step (2), the volume ratio of oxygen to argon in the mixed gas is 1:

3.

3. The method according to any one of claims 1-2, characterized in that: The bias RF power of the first etching is 195W-205W, and the bias RF power of the second etching is 1990W-2010W.

4. The method according to any one of claims 1-2, characterized in that: Before the first etching, the vacuum pressure is evacuated to 180mTorr-200mTorr.

5. The method according to any one of claims 1-2, characterized in that: Before the second etching, the vacuum pressure is evacuated to 80mTorr-120mTorr.

6. The method according to any one of claims 1-2, characterized in that: The bias RF power of the first etching is 200W.

7. The method according to any one of claims 1-2, characterized in that: The bias RF power of the second etching is 2000W.

8. The method according to any one of claims 1-2, characterized in that: In the step (1), the protective film is a carbonized film.