Lightly doped drain electrode defect detection method
By preparing the deposited layer in the light-doped drain region and performing optical defect detection, the problem of low accuracy in the detection of defects with small sizes in the prior art is solved, and effective detection of light-doped drain defects is achieved, which improves the pass rate and performance of semiconductor devices.
Patent Information
- Application Number
- CN202311684776.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-07
- Publication Date
- 2025-06-10
AI Technical Summary
The prior art detects lightly doped drain defects, especially smaller defects, with low accuracy, which may cause abnormal silicon germanium deposition grooves or silicon germanium growth, affecting device performance and reliability.
By preparing a deposited layer on the surface of the element to be tested, covering the lightly doped drain region, and using an optical defect detection method, the reflected signal of the deposited layer is obtained to improve the detection signal ratio, thereby achieving effective detection of lightly doped drain defects of smaller size.
It improves the detection effect of lightly doped drain defects with small sizes, and improves the pass rate and performance of semiconductor device products.
Smart Images
Figure CN120127018A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a method for detecting lightly doped drain defects. Background Art
[0002] The lightly doped drain (LDD) structure is a common design in field-effect transistors (FETs) aimed at improving transistor performance, mainly used in metal-oxide-semiconductor field-effect transistors (MOSFETs) and other similar semiconductor devices. The main components of the LDD structure include the source, drain, and a lightly doped region between the source / drain. This structure helps alleviate the hot electron effect and leakage current problems, reducing power consumption, improving device reliability and lifespan. Currently, there are certain limitations in the LDD defect inspection methods, mainly manifested in the low detection accuracy for defects with smaller sizes. Defects with smaller sizes may cause silicon germanium deposition grooves (SIGE Recess Block) or abnormal silicon germanium growth in subsequent processes, thereby affecting the performance and reliability of the device. Summary of the Invention
[0003] The purpose of the present disclosure is to provide a method for detecting lightly doped drain defects to improve the detection effect for lightly doped drain defects with smaller sizes.
[0004] To achieve the above purpose, the present disclosure provides a method for detecting lightly doped drain defects, which includes:
[0005] Obtain a component to be measured, where the component to be measured has a lightly doped drain region;
[0006] Prepare a deposition layer on the surface of the component to be measured so that the deposition layer covers the lightly doped drain region, obtaining a component to be measured with a deposition layer formed thereon;
[0007] Perform optical defect detection on the component to be measured with the deposition layer formed thereon.
[0008] Optionally, the material of the deposition layer is silicon nitride and / or silicon oxide.
[0009] Optionally, the thickness of the deposition layer is 5 - 20 nm.
[0010] Optionally, the preparation method of the deposition layer is chemical vapor deposition and / or atomic layer deposition.
[0011] Optionally, the deposition layer is a silicon nitride layer, and the preparation conditions of the silicon nitride layer include: the deposition temperature is 500 - 650 °C, and the deposition time is 5 - 8 h.
[0012] Optionally, the method of the optical defect detection is bright field defect inspection method and / or dark field defect inspection method.
[0013] Optionally, the optical defect detection is a bright-field defect inspection method, and the detection conditions of the bright-field defect inspection method include: 50 nm pixels, blue-band light waves, and a reflected light collection mode.
[0014] Optionally, the optical defect detection of the element to be tested with a deposited layer formed thereon includes:
[0015] Obtaining a defect reflection signal of the lightly doped drain region;
[0016] According to the defect reflection signal, a detection result of the lightly doped drain defect is obtained.
[0017] Optionally, the size of the lightly doped drain defect is 20 - 100 nm.
[0018] Optionally, the method further includes a step of removing the deposited layer after the optical defect detection is completed.
[0019] Through the above technical solution, the present disclosure first prepares a deposited layer on the surface of the element to be tested, and then performs optical defect detection on the element to be tested with the deposited layer formed thereon. By improving the signal ratio obtained from the optical defect detection through the deposited layer reflection signal, the effective detection of lightly doped drain defects with smaller sizes is realized, thereby improving the qualification rate and performance of semiconductor device products.
[0020] Other features and advantages of the present disclosure will be described in detail in the subsequent specific implementation section. Brief Description of the Drawings
[0021] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification. Together with the following specific implementation, they are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the drawings:
[0022] Figure 1 is a schematic flowchart of a specific implementation of the method for detecting lightly doped drain defects provided by the present disclosure.
[0023] Figure 2 is a schematic structural diagram of a specific implementation of the element to be tested in the method for detecting lightly doped drain defects provided by the present disclosure.
[0024] Figure 3 is a schematic structural diagram of a specific implementation of the element to be tested with a deposited layer formed thereon in the method for detecting lightly doped drain defects provided by the present disclosure.
[0025] Description of the Reference Numerals
[0026] 1 - lightly doped drain region, 2 - defect, 3 - deposited layer, 4 - substrate, 5 - polysilicon gate. Specific Implementation
[0027] The following will describe the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining and understanding the present disclosure, and are not used to limit the present disclosure.
[0028] The present disclosure provides a method for detecting light doped drain defects. Referring to Figure 1 , the method includes the following steps S101 to S103:
[0029] S101. Obtain a device under test, where the device under test has a light doped drain region;
[0030] S102. Prepare a deposition layer on the surface of the device under test so that the deposition layer covers the light doped drain region, obtaining a device under test with a deposition layer formed thereon;
[0031] S103. Perform optical defect detection on the device under test with the deposition layer formed thereon.
[0032] According to the present disclosure, the device under test can be various semiconductor devices with a need for detecting light doped drain defects, such as integrated circuit elements, etc. In the method of the present disclosure, a deposition layer is prepared on the surface of the device under test and then optical defect detection is performed on the device under test with the deposition layer formed thereon. By the reflection signal of the deposition layer at the light doped drain defect, the signal ratio obtained by optical defect detection is improved, thereby effectively detecting light doped drain defects with smaller sizes and improving the qualification rate and performance of semiconductor device products.
[0033] In step S101, there are no special restrictions on the preparation process and specific structure of the device under test, as long as it has a lightly doped drain (LDD) structure. For example, Figure 2 shows the device under test of an embodiment. The device includes a substrate 4, on which a light doped drain region 1 is formed. A polysilicon gate (Poly Gate) 5 is formed on the light doped drain region 1. There are no special restrictions on the specific structure of the light doped drain region 1. For example, it may include structures well-known in the art such as a source electrode, a drain electrode, and a lightly doped region, etc. The light doped drain region 1 may have a defect 2. The position of the defect 2 has no special restrictions, as long as it is within the region of the light doped drain region 1, it belongs to a light doped drain defect. The types of the defect 2 may be, for example, tiny particles, residues, etc.
[0034] In step S102, the material of the deposition layer may be silicon nitride (SiN) and / or silicon oxide (SiO 2) In one implementation, the material of the deposition layer is silicon nitride, that is, the deposition layer is a silicon nitride layer. The silicon nitride layer prepared on the surface of the device under test can be used as the deposition layer for the optical defect detection and also as a functional layer (such as a shielding layer, etc.) in the subsequent manufacturing process of the semiconductor device, without the need to be removed after the optical defect detection is completed.
[0035] Figure 3 FIG. is a schematic structural diagram of the device under test with a deposition layer formed thereon. The deposition layer 3 covering the lightly doped drain region 1 means that the deposition layer 3 covers the entire region of the lightly doped drain region 1, so that the deposition layer 3 covers the surface of the lightly doped drain defect 2. The thickness of the deposition layer 3 can be 5 - 20 nm.
[0036] The deposition layer 3 can be prepared on the surface of the device under test by common methods in the art. Specifically, the preparation method of the deposition layer 3 can be chemical vapor deposition and / or atomic layer deposition. In one implementation, the deposition layer 3 is a silicon nitride layer, and the silicon nitride layer is prepared by chemical vapor deposition. Further, the preparation conditions of the silicon nitride layer include: deposition temperature is 500 - 650 °C, and deposition time is 5 - 8 h.
[0037] In step S103, the method of the optical defect detection can be a common method in the art for detecting defects of semiconductor devices. For example, the method of the optical defect detection can be bright - field inspection and / or dark - field inspection.
[0038] In one implementation, the optical defect detection is bright - field inspection. The detection equipment and specific operation steps used can be common and well - known in the art. For example, the detection conditions can include: 50 nm pixel, blue - band light wave, and reflection light collection mode.
[0039] According to the present disclosure, since the deposition layer 3 covers the lightly doped drain region 1, when the lightly doped drain region 1 has a defect 2, the lightly doped drain defect is also covered by the deposition layer 3. In this way, when the optical defect detection is performed, the presence of the deposition layer 3 covering the lightly doped drain defect is beneficial to obtaining an increased defect reflection signal, thereby realizing the effective detection of lightly doped drain defects with smaller sizes. Specifically, the optical defect detection of the device under test with a deposition layer formed thereon includes:
[0040] Obtaining the defect reflection signal of the lightly doped drain region;
[0041] Obtaining the detection result of the lightly doped drain defect according to the defect reflection signal.
[0042] Among them, the detection results of the lightly doped drain defects may include results such as whether there are lightly doped drain defects and the size of the lightly doped drain defects. The present disclosure can effectively detect lightly doped drain defects with smaller sizes. Specifically, the size of the lightly doped drain defects can be 30 to 500 nm.
[0043] Furthermore, the method may further include the step of removing the deposition layer after the detection of the lightly doped drain defects is completed. Especially when the material of the deposition layer cannot be used to form the functional layer of the device under test, removing the deposition layer can avoid affecting the subsequent manufacturing process and device performance while realizing the detection of the lightly doped drain defects. The method of removing the deposition layer can be well-known in the art. For example, pickling, dry etching and other methods can be used to remove the deposition layer.
[0044] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.
[0045] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.
[0046] In addition, any combination can be made between various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.
Claims
1. A method for detecting light - doped drain defects, characterized in that, the method includes: obtaining a device under test, where the device under test has a light - doped drain region; preparing a deposition layer on the surface of the device under test so that the deposition layer covers the light - doped drain region, obtaining a device under test with a deposition layer formed thereon; performing optical defect detection on the device under test with the deposition layer formed thereon.
2. The method according to claim 1, wherein, the material of the deposition layer is silicon nitride and / or silicon oxide.
3. The method according to claim 1, wherein, the thickness of the deposition layer is 5 - 20 nm.
4. The method according to claim 1, wherein, the preparation method of the deposition layer is chemical vapor deposition and / or atomic layer deposition.
5. The method according to claim 1, wherein, the deposition layer is a silicon nitride layer, and the preparation conditions of the silicon nitride layer include: deposition temperature is 500 - 650 °C, deposition time is 5 - 8 h.
6. The method according to claim 1, wherein, the method of optical defect detection is bright - field defect inspection method and / or dark - field defect inspection method.
7. The method according to claim 1, wherein, the optical defect detection is the bright - field defect inspection method, and the detection conditions of the bright - field defect inspection method include: 50 nm pixel, blue - band light wave, and reflection light collection mode.
8. The method according to claim 1, wherein, performing optical defect detection on the device under test with the deposition layer formed thereon includes: obtaining a defect reflection signal of the light - doped drain region; obtaining a detection result of light - doped drain defects according to the defect reflection signal.
9. The method according to claim 8, wherein, the size of the light - doped drain defects is 20 - 100 nm.
10. The method according to claim 1, wherein, the method further includes a step of removing the deposition layer after the optical defect detection is completed.