Electron beam detection method on semiconductor process line, cold field electron emission source emitter with nanoscale protruding structure applied to electron beam detection equipment on semiconductor process line and manufacturing method of cold field electron emission source emitter
By forming a nano-scale convex structure on the emitter of the cold-field electron-emitting source, the accumulation of gas molecules and pollutants is reduced, the problem of instability in electron beam emission is solved, the operation time of the equipment is extended and the detection efficiency is improved.
Patent Information
- Application Number
- CN202411043846.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-08-07
- Filing Date
- 2024-07-31
- Publication Date
- 2025-02-14
AI Technical Summary
In the prior art, when the emitter of the cold-field electron-emitting source operates in a vacuum environment, gas molecules or pollutants will still accumulate, resulting in unstable emission of electron beams, affecting detection accuracy, and frequent shutdowns and cleaning affecting the production capacity of semiconductor processes. and efficiency.
Using an emitter with a nano-scale convex structure, a nano-scale convex structure with an atomic stacked structure is formed on the surface of the needle tip of the emitter, reducing the adhesion opportunity of pollutants and gas molecules, and at 1×10-12 to 3 × 10-9 mbar operating in a vacuum environment.
It extends the operating time of the cold field electron source, improves the stability and accuracy of electron beam detection, reduces the equipment maintenance frequency, and improves the detection efficiency and production capacity on the semiconductor process line.
Smart Images
Figure CN119446866A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a cold field emission electron source emitter with a nanometer-level protruding structure and a manufacturing method thereof, and in particular to a cold field emission electron source emitter with a nanometer-level protruding structure used in electron beam detection equipment on a semiconductor process line and a manufacturing method thereof. Background Art
[0002] See also Figure 2A and Figure 2B , which is a schematic diagram of the prior art using an emitter to emit an electron source for electron beam inspection (E-beaminspection, referred to as E-beaminspection; EBI) and an enlarged view of the emitter tip. Electron beam inspection uses an electron beam emitted by an emitter 2 with a needle tip structure to detect defects in semiconductor devices, and through electron beam inspection, the defect status of semiconductor devices can be detected in real time online.
[0003] See also Figure 3A and Figure 3B , Figure 3A This is a schematic diagram of the use status of the emitter with a needle tip structure after a period of operation. Figure 3B It is an enlarged schematic diagram of the existing emitter tip surface being contaminated with gas molecules or pollutants. Electron beam detection uses an emitter 2 with a needle tip structure to emit an electron beam in a vacuum environment to perform defect detection on semiconductor devices. However, although the emitter operates in a vacuum environment, some gas molecules or pollutants D still exist in the vacuum operating environment. After a period of operation, the gas molecules or pollutants D will collide, accumulate and adhere to the surface of the emitter tip 21 with a needle tip structure. Even if a single atom adheres to the surface of the emitter of the emitter tip 21, it will still cause the emitter surface work function to change, affecting the emission of electrons, making the current emitted by the electron beam unstable, and further affecting the duration, efficiency, and stability of the emitter electron beam emission and the accuracy of electron beam detection. In addition, due to Figure 3B It can be seen that the electron beam emitted by the emitter 2 with a needle tip structure on the surface of the needle tip 21 is a large-scale electron beam. When the electron beam emission area is large, gas molecules or pollutants D will more easily collide, accumulate and adhere to the surface of the needle tip 21 of the emitter 2 with a needle tip structure.
[0004] In order to solve the above problem, the conventional method is to stop the operation of the cold field electron source and clean the surface of the emitter 2 having a needle tip structure. Figure 3AAs shown, the electron beam current will experience a decreasing period, a stable period and an unstable period as the use time increases. Under normal conditions, the cold field generator operates in a stable period. Therefore, when gas molecules or pollutants D collide and accumulate and adhere to the surface of the needle tip 21 of the emitter 2 with a needle tip structure after a period of operation, thereby affecting the electron beam current emitted by the emitter 2 with a needle tip structure, the operation of the cold field generator must be stopped to clean the emitter 2. The current cold field generator process must be shut down every 8 to 12 hours to clean the probe, which will greatly affect the overall production capacity and efficiency of the semiconductor process.
[0005] In addition, another method is to increase the vacuum degree of the cold field electron source in the vacuum operating environment to 1×10 -11 An extremely high vacuum (XHV) environment below millibar is used to reduce gas molecules or contaminants D in the operating environment. However, even in an extremely high vacuum environment, after a period of operation, gas molecules or contaminants D will still accumulate on the emitter surface. Compared with the above method of stopping the operation of the cold field emission electron source, this method can extend the time required to clean the emitter surface, but providing a strict vacuum operating environment will require higher equipment costs. Therefore, although the cold field emission electron source has the advantages of high brightness and high resolution, it is difficult to be widely used in electron beam detection equipment on semiconductor process lines.
[0006] Therefore, how to provide an improved method and structure has become a topic that urgently needs to be studied. Summary of the invention
[0007] The present invention provides a cold field emitting electron source emitter with a nano-scale protrusion structure for use in an electron beam detection device on a semiconductor process line, comprising a needle tip and a nano-scale protrusion structure. The needle tip is formed at the front end of the emitter. The nano-scale protrusion structure is formed on the surface of the needle tip, wherein the nano-scale protrusion structure is an atomic stacking structure, and wherein the nano-scale protrusion structure has a protrusion curvature radius, which is less than one third of the needle tip curvature radius of the needle tip, and the cold field emitting electron source operates at 1×10 -12 Up to 3×10 -9 Millibar vacuum environment.
[0008] The present invention further provides an electron beam detection method for a semiconductor process line, wherein the cold field electron generation originates from 1×10 -12 Up to 3×10 -9The invention relates to a method for producing a nanostructured emitter in a vacuum environment of 1000 mbar and comprising the following steps: providing an emitter having a nano-scale protrusion structure; applying a working voltage to the emitter having the nano-scale protrusion structure; and after a predetermined operating time, cleaning a needle tip surface of the emitter having the nano-scale protrusion structure and then reapplying the working voltage to the emitter having the nano-scale protrusion structure, wherein the predetermined operating time is between 48 hours and 4500 hours.
[0009] The present invention further provides a method for manufacturing a cold field electron source emitter having a nanoscale protrusion structure, wherein a nanoscale protrusion structure is formed on the surface of the needle tip of the emitter; wherein the nanoscale protrusion structure has a protrusion curvature radius, and the protrusion curvature radius is less than one third of the needle tip curvature radius of the needle tip.
[0010] As mentioned above, the cold field emitting electron source emitter with a nano-scale protruding structure is manufactured by the method of the present invention, which has the advantages of high brightness, extended operation time, improved performance, improved resolution and increased scanning speed. The high brightness is conducive to high-speed image scanning and high-resolution imaging. The nano-scale protruding structure has a small emission area, which reduces the probability of pollutants and gas molecules adhering to the emitter surface, thereby extending the operation time of the cold field emitting electron source and improving detection efficiency. It can be further more stably and widely used in electron beam detection equipment on semiconductor process lines. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1A and Figure 1B It is a schematic diagram and an enlarged diagram of the emitter of a cold field electron source with a nano-scale protruding structure applied to an electron beam detection device on a semiconductor process line according to the present invention;
[0012] Figure 1C It is an enlarged schematic diagram of the needle tip surface with nano-scale protrusion structure of the present invention being contaminated with gas molecules or pollutants;
[0013] Figure 1D A schematic diagram of the operating environment of electron beam detection on a semiconductor process line of the present invention;
[0014] Figure 2A and Figure 2B It is a schematic diagram of the prior art using an emitter to emit an electron source for electron beam detection and an enlarged diagram of the needle tip;
[0015] Figure 3A A schematic diagram of the use status of a conventional emitter with a needle tip structure after a period of operation; and
[0016] Figure 3B This is an enlarged schematic diagram of the existing emitter tip surface being contaminated with gas molecules or pollutants. DETAILED DESCRIPTION
[0017] See also Figures 1A to 1C , which is a schematic diagram of the emitter of the cold field emitting electron source with a nano-scale protrusion structure applied to the electron beam detection equipment on the semiconductor process line of the present invention, an enlarged diagram, and an enlarged schematic diagram of the needle tip surface with the nano-scale protrusion structure being contaminated with gas molecules or pollutants. The emitter 1 includes a needle tip 11 and a nano-scale protrusion structure 12. The needle tip 11 is formed at the front end of the emitter 1. The nano-scale protrusion structure 12 is formed on the surface of the needle tip 11, wherein the nano-scale protrusion structure 12 is an atomic stacking structure, and the cold field emitting electron source operates at 1×10 -12 Up to 3×10 -9 The nano-scale protrusion structure 12 has a protrusion curvature radius R2 (eg Figure 1C As shown), the protruding curvature radius is smaller than the tip curvature radius R1 of the needle tip portion 11 (as shown Figure 1B less than one third of that shown).
[0018] Please also read Figure 1C and Figure 1D , Figure 1D This is a schematic diagram of the operating environment of electron beam detection on a semiconductor process line of the present invention. Figure 1C and Figure 1D As shown in FIG. 1 , since the nano-scale protrusion structure 12 on the surface of the emitter needle tip 11 is an atomic stacking structure, which has a very small area, even after the cold field emitting electron source has been operated for a period of time, the probability of gas molecules or pollutants D being contaminated on the nano-scale protrusion structure 12 will be greatly reduced. Therefore, the operating environment of the emitter with a nano-scale protrusion structure of the present invention applied to the cold field emitting electron source is 1×10 -12 Up to 3×10 -9 In a vacuum environment V of 100 mbar, the operating time can be extended before the emitter surface needs to be cleaned.
[0019] The present invention further provides a method for manufacturing a cold field electron source emitter having a nano-scale protrusion structure, wherein a nano-scale protrusion structure 12 is formed on the surface of the needle tip of the emitter. The nano-scale protrusion structure 12 has a protrusion curvature radius R2, and the protrusion curvature radius R2 is less than one third of the needle tip curvature radius R1 of the needle tip 11. In the embodiments of the present invention, the nano-scale protrusion structure 12 can be completed by the following various methods, which are not limited in the present invention.
[0020] In one embodiment of the present invention, the nano-scale protrusion structure 12 is formed by applying a high electric field in a vacuum environment. The electric field must be between and between.
[0021] In one embodiment of the present invention, the nano-scale protrusion structure 12 is formed by applying a high electric field in a vacuum environment and further heated at a predetermined temperature, wherein the predetermined temperature is between 600 degrees Celsius and 1500 degrees Celsius.
[0022] In one embodiment of the present invention, the nano-scale protrusion structure 12 is further formed by exposing the nano-scale protrusion structure 12 to a high electric field in a vacuum containing nitrogen.
[0023] In one embodiment of the present invention, the nano-scale protrusion structure 12 may be formed by being exposed to a vacuum containing oxygen and then heated and wrinkled.
[0024] In one embodiment of the present invention, the nano-scale protrusion structure 12 is formed by coating a noble metal on the surface of the tip of the emitter 1 and then heating and corrugating it.
[0025] In one embodiment of the present invention, the nano-scale protrusion structure 12 is formed by ion bombardment in a vacuum environment.
[0026] As mentioned above, the nano-scale protrusion structure 12 formed on the tip surface of the emitter 1 by the above-mentioned various methods contains at least thousands of atoms, or even tens of thousands of atoms, relative to the emission area on the tip surface of the emitter 1. Figure 1B The atomic stacking protrusions in the emitter 1, that is, each atomic stack protrudes from the tip surface of the emitter 1 to form an atomic stacking protrusion structure. Through this structure, the electron beam emitted by the emitter 1 can be more concentrated. In addition, Figure 1B and Figure 1C As shown, since the area of the electron-emitting region A2 of the nano-scale protrusion structure is more than 9 times smaller than the area of the electron-emitting region A1 of the tip surface of the emitter 1, the probability of the pollutants and gas molecules in the vacuum adhering to the nano-scale protrusion structure will be reduced by at least 9 times, thereby increasing the time for maintaining the emitter without cleaning to more than 9 times, that is, the cold field electron source needs to be cleaned only after a predetermined operating time of 48 hours to 4500 hours. In another embodiment of the present invention, the predetermined operating time is between 48 hours and 720 hours.
[0027] The present invention further provides an electron beam detection method for a semiconductor process line, wherein the cold field electron generation originates from 1×10 -12 Up to 3×10 -9The vacuum environment of 10000 mbar comprises the following steps: in step S11, providing the emitter with the nano-scale protrusion structure. In step S12, applying a working voltage to the emitter with the nano-scale protrusion structure. In step S13, after a predetermined operation time, cleaning the tip surface of the emitter with the nano-scale protrusion structure, and then continuing the electron beam inspection on the semiconductor process line, wherein the predetermined operation time is between 48 hours and 4500 hours. In another embodiment of the present invention, the predetermined operation time is between 48 hours and 720 hours.
[0028] In summary, the cold field emitting electron source emitter with a nano-scale protruding structure is manufactured by the method of the present invention, which has the advantages of high brightness, extended operation time, improved performance, improved resolution and increased scanning speed. The high brightness is conducive to high-speed image scanning and high-resolution imaging. The nano-scale protruding structure has a small emission area, which reduces the probability of pollutants and gas molecules adhering to the emitter surface, thereby extending the operation time of the cold field emitting electron source and improving detection efficiency. It can be further more stably and widely used in electron beam detection on semiconductor process lines.
Claims
1. A cold field electron source emitter with a nano-scale protruding structure used in an electron beam detection device on a semiconductor process line, characterized in that: Include: A needle tip portion formed at a front end of an emitter; and A nanometer-scale protrusion structure is formed on a surface of the needle tip; The nanoscale protrusion structure is an atomic stacking structure; One of the cold field electron sources operates at 1×10 -12 Up to 3×10 -9 A vacuum environment of 1000 mbar; The nano-scale protrusion structure has a protrusion curvature radius, and the protrusion curvature radius is less than one third of a needle tip curvature radius of the needle tip portion.
2. The cold field emission electron source emitter with nanoscale protrusion structure according to claim 1, characterized in that: An electron emitting region of the nano-scale protruding structure is more than 9 times smaller than an electron emitting region on the surface of the needle tip of the emitter.
3. A method for electron beam detection on a semiconductor process line, characterized in that: The method uses the cold field emission electron source emitter with a nano-scale protrusion structure as claimed in claim 1, comprising the following steps: Applying a working voltage to the emitter having the nanoscale protrusion structure; and After a predetermined operation time has passed, cleaning a tip surface of the emitter having the nanoscale protrusion structure; The predetermined operation time is greater than 48 hours and between 4500 hours.
4. A method for manufacturing a cold field emission electron source emitter having a nanoscale protrusion structure, characterized in that: forming a nanometer-scale protrusion structure on a surface of a needle tip portion of an emitter; The nano-scale protrusion structure has a protrusion curvature radius, and the protrusion curvature radius is less than one third of a needle tip curvature radius of the needle tip portion.
5. The method for manufacturing a cold field emission electron source emitter having a nanoscale protrusion structure according to claim 4, characterized in that: The nanoscale protrusion structure is formed by applying a high electric field in a vacuum environment, wherein the high electric field must be between and between.
6. The method for manufacturing a cold field emission electron source emitter having a nanoscale protrusion structure according to claim 5, characterized in that: The nano-scale protrusion structure is further formed by heating at a preset temperature, wherein the preset temperature is between 600 degrees Celsius and 1500 degrees Celsius.
7. The method for manufacturing a cold field emission electron source emitter having a nano-scale protrusion structure according to claim 4, characterized in that: The nano-scale protrusion structure is formed by ion bombardment in a vacuum environment.
8. The method for manufacturing a cold field emission electron source emitter having a nano-scale protrusion structure according to claim 4, characterized in that: The nanometer-scale protrusion structure is exposed to a vacuum environment containing nitrogen and a high electric field is applied to form the structure.
9. The method for manufacturing a cold field emission electron source emitter having a nano-scale protrusion structure according to claim 4, characterized in that: The nano-scale protrusion structure is exposed to a vacuum environment containing oxygen and heated to wrinkle.
10. The method for manufacturing a cold field emission electron source emitter having a nano-scale protrusion structure according to claim 4, characterized in that: The nano-scale protruding structure is formed by coating a noble metal on the surface of the emitter needle tip and then heating and wrinkling it in a vacuum environment.