Real-time detection equipment applied to FIB photoetching technology

Abstract

The invention discloses real-time detection equipment applied to an FIB photoetching technology, which comprises N ion guns used for ion beam photoetching and N electron guns I used for detection after ion beam photoetching to ensure photoetching quality, N is greater than or equal to 1, and the real-time detection equipment is characterized in that the ion guns and the electron guns I are respectively controlled and synchronously work. Compared with the prior art, the invention has the following beneficial effects: the electrons and the ion gun are spaced at a certain distance, so that the electrons and the ion gun can work synchronously and do not interfere with each other (especially the electron gun does not interfere with the work of the ion gun), real-time detection is realized, and the efficiency of ion beam photoetching and detection is greatly improved; the electron gun and the ion gun are respectively and independently controlled, so that better real-time monitoring can be realized; and the electronic gun is independently controlled and works, so that a better monitoring effect can be obtained.

Description

Technical Field

[0001] The invention relates to a follow-up type real-time detection device applied in FIB lithography technology. Background Art

[0002] like Figure 1 As shown, the current detection method of traditional lithography process is to first perform lithography (resin coating, exposure, and development) in a lithography machine (unit), and then send the semiconductor wafer to a separate detection device to detect the lithography effect. For example, whether the lithography size meets the standard is detected in the CDSEM, which cannot achieve the effect of real-time monitoring.

[0003] FIB lithography technology equipped with secondary electron probes or independent electron guns can achieve real-time monitoring. FIB lithography technology is a completely new type of lithography technology used in chip manufacturing. Figure 2 As shown in the figure, the current detection scheme of FIB lithography technology equipped with independent electron guns is that the electron gun and ion gun are concentrated at the same point. Figure 2 In the scheme shown, first turn off the electron gun and turn on the ion gun so that the ion gun focuses on the focus point A. After that, turn off the ion gun, switch to the electron gun, turn on the electron gun, and the electron gun is also focused on the focus point A to take pictures for detection. After that, turn off the electron gun, turn on the ion gun, and switch from focus point A to the next focus point in the process to continue working. That is, the detection scheme of the existing FIB lithography technology is to stop the ion gun after the FIB processing is completed, and use the electron gun to image at the same focus point. The efficiency of this detection method is extremely low, which affects the efficiency of ion beam lithography. Of course, the electron gun and the ion gun can also be turned on at the same time, but the two will interfere with each other.

[0004] like Figure 3 As shown in the figure, in the existing detection scheme, the ion gun can also be equipped with a secondary electron probe to collect the secondary electron signal excited by the ion beam for real-time imaging, so that real-time imaging can be achieved when the ion gun is working. However, the ion beam signal has large noise, and the image effect is as follows Figure 4 As shown, the clarity is poor. It is also possible to stop the ion gun lithography action and use the secondary electron probe for imaging alone, but the imaging effect is also poor. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the detection scheme of FIB lithography technology equipped with an independent electron gun is extremely inefficient.

[0006] In order to solve the above technical problems, the technical solution of the present invention is to disclose a real-time detection device applied to FIB lithography technology, comprising N ion guns for ion beam lithography and N electron guns one for detection after ion beam lithography to ensure the lithography quality, N ≥ 1, characterized in that the ion gun and the electron gun one are controlled separately;

[0007] At the current moment, the ion gun and the electron gun 1 focus on the current N focus points and the previous N focus points adjacent to the current N focus points in the process, respectively. While the ion gun completes ion beam lithography at the current focus point, the electron gun 1 completes detection at the previous N focus points.

[0008] At the next moment, the ion gun focuses on the next N focus points adjacent to the current focus point in the process, and the electron gun focuses on the current focus point. After traversing all the focus points of the current process row on the semiconductor wafer, the ion gun and the electron gun switch to the next row to continue working.

[0009] Preferably, it also includes N electron guns 2 for detection before ion beam lithography to ensure that the pre-conditions of ion beam lithography meet the expectations, and the ion gun, the electron gun 1 and the electron gun 2 are controlled separately;

[0010] At the current moment, the ion gun focuses on the current focus point, the electron gun 1 focuses on the upper N focus points adjacent to the current focus point in the process, and the electron gun 2 focuses on the lower N focus points adjacent to the current focus point in the process. While the ion gun completes ion beam lithography at the current focus point, the electron gun 1 completes detection at the upper N focus points, and the electron gun 2 completes detection at the lower N focus points;

[0011] At the next moment, the ion gun focuses on the next N focus points, the electron gun 1 focuses on the current focus point, and the electron gun 2 focuses on the next N focus points that are adjacent to the next N focus points in the process.

[0012] Preferably, the ion gun is a multi-array ion gun.

[0013] Preferably, the first electron gun and / or the second electron gun is a multi-array electron gun.

[0014] Preferably, the ion gun is equipped with a secondary electron probe, a backscattered electron probe, an EDX probe or a SIMS probe.

[0015] Preferably, when the ion gun is equipped with the SIMS probe, the composition information obtained by the SIMS probe is used to determine whether the etching depth during photolithography is sufficient.

[0016] Preferably, when the ion gun is equipped with the EDX probe, it is determined whether the etching depth during photolithography is sufficient by using the depth information obtained by the EDX probe.

[0017] Preferably, the electron gun one and / or the electron gun two are equipped with a secondary electron probe or a backscattered electron probe.

[0018] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0019] 1) The electrons and ion guns are separated by a certain distance, which can achieve synchronous operation while ensuring that they do not interfere with each other (especially the electron gun does not interfere with the operation of the ion gun). This allows for real-time detection while greatly improving the efficiency of ion beam lithography and detection.

[0020] 2) The electron gun and ion gun are controlled separately, which can achieve better "real-time monitoring";

[0021] 3) The electron gun is controlled and operated separately, which can achieve better monitoring effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The current traditional lithography detection method is illustrated;

[0023] Figure 2 The current FIB lithography technology with independent electron gun is shown.

[0024] Figure 3 The scheme of the existing ion gun equipped with a secondary electron probe is illustrated;

[0025] Figure 4 The imaging effect after collecting the secondary electron signal excited by the ion beam for ion beam imaging is illustrated;

[0026] Figure 5 A configuration method of a real-time detection device applied to FIB lithography technology disclosed in the present invention is illustrated;

[0027] Figure 6 The imaging effect after collecting the secondary electron signal excited by the electron beam for ion beam imaging is shown;

[0028] Figure 7 Another configuration of the real-time detection device disclosed in the present invention and applied to FIB lithography technology is illustrated. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0030] Example 1

[0031] The real-time detection device used in FIB lithography disclosed in the embodiment of the present invention includes at least one electron gun and one ion gun. The electron gun and the ion gun are separated by a certain distance and are controlled separately. The distance between the electron gun and the ion gun is equivalent to the distance between two adjacent focus points (for example, 100um). Furthermore, at the same time, the electron gun and the ion gun do not focus on the same focus point, but focus on two adjacent focus points. Figure 5 As shown, the ion gun and the electron gun are turned on at the same time. Assume that the ion gun is focused on the focus point B, and at the same time, the electron gun is focused on the focus point A. The ion gun works at the focus point B to complete the photolithography. While the ion gun is working, the electron gun works at the focus point A to detect the part of the semiconductor wafer that has completed the photolithography to ensure the photolithography quality of the focus point A. Subsequently, the electron gun switches to focus point B, and the ion gun switches to the next focus point (such as focus point C) adjacent to focus point B in the process. In this way, the FIB photolithography of all focus points in any row on the semiconductor wafer is completed. It should be noted that: first, in FIB lithography technology, semiconductor wafers are lithographically processed row by row, and each row has multiple focus points. Assuming that each row of focus points is arranged in a horizontal position, then for each row of focus points, according to the process design, the lithography can be completed from left to right or from right to left. The order is not limited in the present invention; secondly, there will be a certain distance of "empty cut points" in each row. When the ion gun works at the first focus point that is not an "empty cut point" in the current row, the electron gun works at the "empty cut point". At this time, the electron gun is in "empty" operation, and the electron gun at the "empty cut point" is turned off. When the electron gun switches to the focus point where the original ion gun is located, the electron gun is turned on again; and when the ion gun completes working at the last focus point in the current row, the ion gun is turned off, and the same is true for the electron gun.

[0032] Under the technical enlightenment given by the present invention, those skilled in the art can also set more than two ion guns as needed, and set a corresponding number of electron guns. Multiple ion guns can perform photolithography at multiple points of interest at the same time, while multiple electron guns can perform detection work at multiple points of interest at the same time, which is more efficient. Those skilled in the art can also use array electron guns and array ion guns as needed, which can also improve work efficiency.

[0033] In such Figure 5 In the technical solution shown, the electron gun and the ion gun can each be equipped with a secondary electron probe. The secondary electron probe carried by the ion gun is used to collect the secondary electron signal excited when the ion beam is working, ensuring more real-time monitoring. The secondary electron probe carried by the electron gun is used to collect the secondary electron signal excited when the electron beam is working, such as Figure 6 As shown, a clearer image result can be guaranteed.

[0034] At the same time, the ion gun can be equipped with a variety of probes other than the secondary electron probe, such as backscattered electron probe, EDX probe, SIMS probe, etc. When the ion gun is equipped with an EDX probe or a SIMS probe, the etching depth can be judged according to the composition information, that is, whether the ion beam lithography (lithography + etching) reaches the etching stop layer (stop layer), to decide whether to stop the ion beam. In the traditional etching process, the etching is controlled to stop at the etching stop layer by controlling the etching selectivity. The technical solution disclosed in the embodiment of the present invention can monitor the composition in real time through the EDX probe or the SIMS probe to control the etching to stop at the etching stop layer.

[0035] Specifically: If the ion gun is equipped with a SIMS probe, the secondary ions escaped by etching will be collected by the SIMS probe. If the SIMS probe only detects Si / O signals and no Cu signals, it means that the etching depth is not enough; if the SIMS probe detects Cu signals, it means that the etching depth is sufficient and etching (photolithography) can be stopped. Compared with traditional solutions, the technical solution disclosed in the embodiment of the present invention is more accurate in sensing and controlling the entire etching (photolithography) Etch.

[0036] The EDX probe will collect information at a certain depth. If the ion gun is equipped with an EDX probe, the strength of the received signal will be used to determine whether the etching depth is sufficient. Similarly, compared with the traditional solution, the technical solution disclosed in the embodiment of the present invention is more accurate in sensing and controlling the entire etching (photolithography) Etch.

[0037] Example 2

[0038] like Figure 2 As shown, a real-time detection device applied to FIB lithography technology disclosed in an embodiment of the present invention includes two electron guns and one ion gun, and the two electron guns are defined as a front electron gun and a delayed electron gun, a front electron gun, an ion gun, and a delayed electron gun. The front electron gun and the ion gun, and the ion gun and the delayed electron gun are separated by a certain distance, and are controlled separately, and the distance between the front electron gun and the ion gun and the distance between the ion gun and the delayed electron gun are equivalent to the distance between two adjacent focus points (for example, 100um). Furthermore, at the same time, the front electron gun, the ion gun, and the delayed electron gun are not focused on the same focus point, but on three adjacent focus points. The front electron gun, the ion gun, and the delayed electron gun are turned on at the same time. Assuming that the front electron gun, the ion gun, and the delayed electron gun are focused on focus point C, focus point B, and focus point A respectively at the current moment, then at the next moment, the front electron gun, the ion gun, and the delayed electron gun are focused on focus point D (the next focus point adjacent to focus point C in the process), focus point C, and focus point B respectively.

[0039] In the embodiment of the present invention, the pre-electron gun is used for detection before ion beam lithography to ensure that the pre-conditions of ion beam lithography meet expectations, and preventive, remedial and compensatory measures can be taken in a timely manner for any problems found. Specifically, before the pre-electron gun and the ion gun are operated, a preliminary inspection is performed to ensure that there are no quality problems such as particles, contamination, cracks, scratches, misalignment, etc., and to ensure that the site is clear. Specifically, it can be judged by image comparison. The ion gun is mainly used for lithography, and can be used with a secondary electron probe to monitor the status of the lithography process in real time. The delayed electron gun is used for detection after ion beam lithography to ensure the quality of lithography, and corresponding processing and compensation measures can also be taken for the problems found.

[0040] Under the technical enlightenment given by the present invention, those skilled in the art can also set more than two ion guns as needed, and set a corresponding number of pre-electron guns and delayed electron guns. Multiple ion guns can perform photolithography at multiple points of interest at the same time, while multiple pre-electron guns and multiple delayed electron guns can perform detection work at multiple points of interest at the same time, with higher work efficiency. Those skilled in the art can also use array electron guns as pre-electron guns and delayed electron guns as needed, and use array ion guns, which can also improve work efficiency.

[0041] The other structures and working principles of this embodiment are the same as those of Embodiment 1 and will not be described in detail here.

Claims

1. A real-time detection device used in FIB lithography technology, comprising N ion guns for ion beam lithography and N electron guns for detection after ion beam lithography to ensure lithography quality, N≥1, characterized in that: The ion gun and electron gun are controlled separately; At the current moment, the ion gun and the electron gun 1 focus on the current N focus points and the previous N focus points adjacent to the current N focus points in the process, respectively. While the ion gun completes ion beam lithography at the current focus point, the electron gun 1 completes detection at the previous N focus points. At the next moment, the ion gun focuses on the next N focus points adjacent to the current focus point in the process, and the electron gun focuses on the current focus point. After traversing all the focus points of the current process row on the semiconductor wafer, the ion gun and the electron gun switch to the next row to continue working.

2. A real-time detection device applied to FIB lithography technology as claimed in claim 1, characterized in that: It also includes N electron guns 2 for detection before ion beam lithography to ensure that the pre-conditions of ion beam lithography meet the expectations, and the ion gun, the electron gun 1 and the electron gun 2 are controlled separately; At the current moment, the ion gun focuses on the current focus point, the electron gun 1 focuses on the upper N focus points adjacent to the current focus point in the process, and the electron gun 2 focuses on the lower N focus points adjacent to the current focus point in the process. While the ion gun completes ion beam lithography at the current focus point, the electron gun 1 completes detection at the upper N focus points, and the electron gun 2 completes detection at the lower N focus points; At the next moment, the ion gun focuses on the next N focus points, the electron gun 1 focuses on the current focus point, and the electron gun 2 focuses on the next N focus points that are adjacent to the next N focus points in the process.

3. A real-time detection device applied to FIB lithography technology as claimed in claim 1 or 2, characterized in that: The ion gun is a multi-array ion gun.

4. A real-time detection device applied to FIB lithography technology as claimed in claim 1 or 2, characterized in that: The electron gun one and / or the electron gun two is a multi-array electron gun.

5. A real-time detection device applied to FIB lithography technology as claimed in claim 1 or 2, characterized in that: The ion gun is equipped with a secondary electron probe, a backscattered electron probe, an EDX probe or a SIMS probe.

6. A real-time detection device applied to FIB lithography technology as claimed in claim 3, characterized in that: When the ion gun is equipped with the SIMS probe, it is determined whether the etching depth during photolithography is sufficient based on the composition information obtained by the SIMS probe.

7. A real-time detection device applied to FIB lithography technology as claimed in claim 3, characterized in that: When the ion gun is equipped with the EDX probe, it is determined whether the etching depth during photolithography is sufficient by using the depth information obtained by the EDX probe.

8. A real-time detection device applied to FIB lithography technology as claimed in claim 1 or 2, characterized in that: The electron gun 1 and / or the electron gun 2 is equipped with a secondary electron probe or a backscattered electron probe.

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