Photoresist layer defect detection method

Abstract

A photoresist layer defect detection method, comprising: a product wafer defect detection step (S100): forming a first photoresist layer (11) on the surface of a product wafer (10), and determining whether there is a defect (12); a test parameter determination step (S200): determining whether test parameters are normal; a test wafer defect detection step (S300): further forming a third photoresist layer (22) on the surface of a test wafer (20), and determining whether there is a defect; a large defect detection step (S400): using a strong light flashlight to irradiate the surface of the product wafer (10) to determine whether there is a large defect; a practice run step (S500): placing the test wafer (20) into each chamber of a photolithography tool, performing treatments other than photoresist coating, and determining whether there are large particles; a further detection step (S600): forming a fourth photoresist layer (13) on the surface of the product wafer (10), and determining whether there is a defect; and a determination step (S700): determining the cause of the defect (12). The detection method allows for quick and accurate identification of the cause of defects in photoresist layers.

Description

Photoresist layer defect detection method Technical Field

[0001] The present invention relates to the field of semiconductor integrated circuit manufacturing, and in particular to a method for detecting photoresist layer defects. Background Art

[0002] In existing technologies, the photolithography process first requires forming a PR (photoresist) layer on the wafer surface. However, for various reasons, defects may occur in certain locations within the PR layer, such as PR peeling. These defects can impact subsequent processes. To eliminate PR layer defects, the cause must first be identified. Therefore, how to quickly and accurately identify the cause of PR layer defects has become an urgent challenge for the industry. Technical issues

[0003] The present invention aims to provide a PR layer defect detection method capable of quickly and accurately finding the cause of defects in the PR layer. Technical Solutions

[0004] The detection method of the present invention comprises:

[0005] Product wafer defect detection step: forming a first photoresist layer on the surface of the product wafer using a photolithography machine, and inspecting the first photoresist layer using a detection machine to confirm whether there are defects;

[0006] Test machine parameter confirmation step: if the defect exists, confirm the previous test machine parameters to confirm whether the test machine parameters of the second photoresist layer on the surface of the test machine wafer are normal;

[0007] A test wafer defect detection step: if the test parameters of the second photoresist layer are normal, forming a third photoresist layer on the surface of the test wafer by the photolithography machine, and detecting the third photoresist layer by the detection machine to confirm whether there are defects;

[0008] Large defect detection step: if the third photoresist layer does not have defects, then use a strong flashlight to illuminate the surface of the product wafer to confirm whether there are large defects;

[0009] Dry run step: If there are no large defects on the surface of the product wafer, the test wafer is placed in each chamber of the photolithography machine and subjected to other treatments except photoresist coating. The test wafer is then tested for large particles by the inspection machine to confirm whether there are large particles.

[0010] Re-inspection step: if no large particles are present, removing the first photoresist layer on the surface of the product wafer, then forming a fourth photoresist layer on the surface of the product wafer using the photolithography machine, and inspecting the fourth photoresist layer using an inspection machine to confirm whether there are defects;

[0011] Judgment step: Determine the cause of the defect. Beneficial effects

[0012] The PR layer defect detection method of the present invention can quickly and accurately find out the cause of the PR layer defects, thereby ensuring that subsequent processes proceed smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG1 is a flow chart of a PR layer defect detection method according to the present invention;

[0014] FIG2 is a schematic cross-sectional view of the first PR layer of a product wafer of the present invention;

[0015] 3 is a schematic cross-sectional view of the second PR layer of the test wafer of the present invention;

[0016] FIG4 is a schematic cross-sectional view of the third PR layer of the test wafer of the present invention; and

[0017] FIG5 is a schematic cross-sectional view of the fourth PR layer of the product wafer of the present invention.

[0018] Explanation of symbols

[0019] 10 product wafers

[0020] 11 First PR layer

[0021] 12 Defects

[0022] 13 Fourth PR layer

[0023] 20 tester wafers

[0024] 21 Second PR layer

[0025] 22 Third PR layer Best Mode for Carrying Out the Invention

[0026] The PR layer defect detection method of the present invention will be described below with reference to FIG. 1 to FIG. 5 .

[0027] As shown in Figure 1 , the PR layer defect detection method of the present invention includes: a product wafer defect detection step ( S100 ), a tester parameter confirmation step ( S200 ), a tester wafer defect detection step ( S300 ), a large defect detection step ( S400 ), a dry run step ( S500 ), a re-test step ( S600 ), and a determination step ( S700 ). These steps are described in detail below.

[0028] Product wafer defect detection step S100: As shown in FIG1 and FIG2 , a first PR layer 11 is formed on the surface of the product wafer 10 by a photolithography machine, and the first PR layer 11 is inspected by an inspection machine to confirm whether there are defects 12 .

[0029] In this embodiment, the lithography machine is an XT-1950Hi from ASML of the Netherlands, and the inspection machine is an automatic optical inspection machine KT 89200 ADI. However, the present invention is not limited to this, and the lithography machine and inspection machine may also be other machines. The first PR layer can be formed using methods commonly used in the art. In this embodiment, the method for forming the first PR layer is to place the product wafer 10 into the various chambers of the lithography machine and sequentially perform cleaning, cooling, PR coating, baking, edge cleaning, exposure, baking, cooling, and development. The PR coating method may be to first apply a BAK (anti-reflective) layer to the surface of the product wafer 10, then apply a PR layer on the surface of the BAK layer, and finally apply an ITC (water-resistant) layer on the surface of the PR. Inspection steps may include exposure accuracy testing and defect detection. Furthermore, in this embodiment, defect 12 refers to PR peeling in certain locations.

[0030] Tester parameter confirmation step S200 : as shown in FIG. 1 and FIG. 3 , if there is a defect 12 , the previous tester parameters are confirmed to confirm whether the tester parameters of the second PR layer 21 on the surface of the tester wafer 20 are normal.

[0031] Before forming the first PR layer 11 on the product wafer 10, a test is typically performed. That is, a second PR layer 21 is formed on the surface of the test wafer 20 using a photolithography machine. The method and process parameters for forming the second PR layer 21 are exactly the same as those for forming the first PR layer 11. The test parameters of the second PR layer 21 are then tested to confirm that the photolithography machine is functioning properly. Therefore, when a defect 12 is found on the surface of the product wafer 10, the previous test parameters should be confirmed first. In this embodiment, the test parameters are all normal, indicating that the photolithography machine was functioning properly during the test.

[0032] Tester wafer defect detection step S300: As shown in Figures 1 and 4, if the tester parameters of the second PR layer 21 are normal, a third PR layer 22 is formed on the surface of the tester wafer 20 by a photolithography machine, and the third PR layer 22 is inspected by a detection machine to confirm whether there are defects.

[0033] In this step, in order to confirm whether the photolithography machine is normal at this time, the test machine wafer 20 is used to apply PR again and perform inspection. The method and process parameters used to form the third PR layer 22 are exactly the same as those used to form the first PR layer 11. This can better restore the situation when the first PR layer 11 is formed. In this embodiment, the third PR layer 22 is tested to have no defects. This shows that the photolithography machine is also normal at this time. Therefore, it can be judged that the defect 12 is not caused by the photolithography machine. In addition, the third PR layer 22 on the surface of the test machine wafer 20 must be removed at the end so that the test machine wafer 20 can be used next time.

[0034] Large defect detection step S400: If there is no defect in the third PR layer 22, a strong flashlight is used to illuminate the surface of the product wafer 10 to confirm whether there is a large defect.

[0035] This step can confirm whether there are defects such as large particles visible to the naked eye on the surface of the product wafer 10. In this embodiment, there are no large defects, that is, there are no defects such as large particles visible to the naked eye on the surface of the product wafer 10.

[0036] Empty run step S500: If there are no large defects on the surface of the product wafer 10, the test wafer 20 is placed in each chamber of the photolithography machine and subjected to other treatments except PR coating. The test wafer 20 is then inspected by the inspection machine to confirm whether there are large particles.

[0037] In this step, the test wafer 20 is placed in each chamber of the photolithography machine and is sequentially cleaned, cooled, baked, edge washed, exposed, baked, cooled, developed and other processes, except that PR coating is not performed. However, the test wafer 20 is also placed in the PR coating chamber of the photolithography machine for other processes, except that BAK, PR and ITC are not coated on the test wafer 20.

[0038] This is done to confirm whether there are large particles in the chamber of the photolithography machine. If there are large particles, then after the test wafer 20 enters the various chambers of the photolithography machine, these large particles will fall on the surface of the test wafer 20 and be detected in the subsequent steps. This means that the large particles in the various chambers of the photolithography machine caused the defect 12 on the surface of the product wafer 10. In this embodiment, after testing, no large particles are found on the surface of the test wafer 20. This shows that there are no large particles in the various chambers of the photolithography machine. Therefore, it can be judged that the defect 12 is not caused by the presence of large particles in the various chambers of the photolithography machine.

[0039] Re-inspection step S600: If there are no large particles, remove the first PR layer 11 on the surface of the product wafer 10, then form a fourth PR layer 13 on the surface of the product wafer 10 using a photolithography machine, and inspect the fourth PR layer 13 using an inspection machine to confirm whether there are defects 12'.

[0040] In this embodiment, the method and process parameters for forming the fourth PR layer 13 are exactly the same as those for forming the first PR layer 11. Inspection of the fourth PR layer 13 then reveals that a defect 12' still exists, and the location of the defect 12' is exactly the same as that of the previous defect 12.

[0041] Determination step S700: Determine the cause of defect 12.

[0042] In this embodiment, defect 12' is located in exactly the same position as defect 12, indicating that the defect is not caused by the PR layer, but by the surface of the product wafer 10 beneath it. If the PR layer itself were to be the cause, the location of the defect would be random. However, the two defects are located in exactly the same position, indicating that the problem lies at the location on the surface of the product wafer 10 corresponding to defect 12. This could be due to oil stains or uneven surface conditions on the product wafer 10, preventing the PR from adhering to this location on the surface of the product wafer 10, leading to PR peeling at this location.

[0043] From this, we can conclude that defect 12 is caused by a previous process, namely, the process of forming the top layer of product wafer 10. In this embodiment, the top layer of product wafer 10 is a TiN (titanium nitride) layer. Therefore, a problem occurred in the TiN layer formation process, resulting in oil stains or unevenness in the TiN layer at the location corresponding to defect 12. This has identified the cause of the PR layer defect.

[0044] Therefore, the PR layer defect detection method of the present invention can quickly and accurately find out the cause of the PR layer defects, thereby ensuring that subsequent processes proceed smoothly.

[0045] Although the present invention has been disclosed in the form of embodiments as described above, they are not intended to limit the present invention. Any professional and technical personnel in this field may make various necessary changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the attached claims.

Claims

1. A method for detecting photoresist layer defects, comprising: Product wafer defect detection step S100: forming a first photoresist layer (11) on the surface of the product wafer (10) by a photolithography machine, and detecting the first photoresist layer (11) by a detection machine to confirm whether there are defects (12); Test machine parameter confirmation step S200: if the defect (12) exists, confirm the previous test machine parameters to confirm whether the test machine parameters of the second photoresist layer (21) on the surface of the test machine wafer (20) are normal; Test wafer defect detection step S300: if the test parameters of the second photoresist layer (21) are normal, a third photoresist layer (22) is formed on the surface of the test wafer (20) by the photolithography machine, and the third photoresist layer (22) is detected by the detection machine to confirm whether there are defects; Large defect detection step S400: if the third photoresist layer (22) does not have defects, using a strong flashlight to illuminate the surface of the product wafer (10) to confirm whether there are large defects; Empty run step S500: if there are no large defects on the surface of the product wafer (10), the test wafer (20) is placed in each chamber of the photolithography machine, and other treatments are performed except for photoresist coating, and the test wafer (20) is tested for large particles by the detection machine to confirm whether there are large particles; Re-detection step S600: if no large particles exist, removing the first photoresist layer (11) on the surface of the product wafer (10), then forming a fourth photoresist layer (13) on the surface of the product wafer (10) by the photolithography machine, and detecting the fourth photoresist layer (13) by the detection machine to confirm whether there are defects; Determination step S700: Determine the cause of the defect (12).

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