TWI734216B - Apparatus and method for cutting electronic device on substrate - Google Patents

Abstract

A method and apparatus for cutting an electronic device is disclosed. In one embodiment, an apparatus for cutting an electronic device on a substrate is described that includes a stage for supporting the substrate having the electronic device thereon, a focused ion beam column fixed in a position over the stage, the focused ion beam column adapted to emit a beam path at an acute angle relative to a plane of a major surface of the substrate, and a microscope positioned adjacent to the focused ion beam column, wherein the stage is limited to movement in an X-Y plane during cutting of the electronic device.

Description

Apparatus and method for cutting electronic device on substrate

The disclosed embodiments generally relate to a focused ion beam (FIB) system for analyzing electronic devices on a large-area substrate. More particularly, it relates to a method and apparatus for analyzing thin film transistors on a large-area substrate on which a plurality of thin film transistors (TFT) are formed.

Electronic devices, such as thin film transistors, photovoltaic (PV) devices, or solar cells, and other electronic devices, have been manufactured on large-area substrates (such as thin, flexible media) for many years. The substrate may be made of glass, polymer, or other materials suitable for forming electronic devices. The work in progress is about manufacturing electronic devices on substrates with a surface area much larger than one square meter (e.g., two square meters or more) to produce larger-sized final products, and/or reducing individual devices (e.g. It is the manufacturing cost of pixels, thin-film transistors, photovoltaics, or solar cells, etc.).

It is often necessary to analyze discrete devices that have been determined to be defective, such as a thin film transistor. For example, the transistor for switching a single pixel may be defective, which will cause the pixel to be always on or always off.

Focused ion beam systems have been used as an increasingly analytical technique in the semiconductor industry, materials science, and biological fields. In the semiconductor industry, focused ion beam systems use ion beams to perform spot analysis on a part of a die on a wafer (for example, a "sample"). The wafer with a sample on it is attached to a movable platform. This platform is usually used to tilt and/or rotate so that the main surface of the platform is at an angle of about 45 degrees with respect to a horizontal plane (for example, the plane of the floor of a manufacturing facility). The ions from the focused ion beam system usually cut a two-dimensional rectangle in the sample, and the area of interest is at an angle relative to the main surface of the wafer. Next, use a scanning electron microscope (SEM) to analyze the region of interest.

However, large-area substrates used in thin-film transistor manufacturing are highly elastic at room temperature. This leads to processing challenges, so that the conventional focused ion beam system and method may not be used.

There is a need for a method and equipment that can apply focused ion beam technology to large-area substrates.

A method and equipment for cutting an electronic device are disclosed. In one embodiment, a device for cutting an electronic device on a substrate is described. The device includes a platform for supporting the substrate, the electronic device is mounted on the substrate, and the device is fixed at a position above the platform. A focused ion beam column on the upper surface, the focused ion beam column is adapted to emit a beam path at an acute angle relative to a plane of a major surface of the substrate, and a focused ion beam column placed adjacent to the A microscope, where the platform is limited to moving in an XY plane during the cutting of the electronic device.

In another embodiment, an apparatus for cutting an electronic device on a substrate is disclosed. This equipment includes a platform for supporting the substrate with the electronic device; a focused ion beam column fixed at a position above the platform, and the focused ion beam column is suitable for emitting a beam path and A three-dimensional notch is cut in the electronic device; and a microscope placed adjacent to the focused ion beam column, wherein the platform is limited to moving in an XY plane during the cutting of the electronic device.

In another embodiment, a method for cutting an electronic device on a substrate is disclosed. The method includes placing the substrate on a platform; emitting a beam path from a focused ion beam column that is fixed at an angle of about 45 degrees with respect to a major surface of the substrate; and The platform is moved in a single horizontal plane to create a three-dimensional notch in the electronic device.

100: Focused ion beam system

105A: Cutting process

105B: Analysis process

110: Large area substrate

115: Transistor

120: platform

125: main surface

130: main surface

135: Plane

140: Focused ion beam column

145: beam path

150: three-dimensional space

155: Microscope

160: Observation Path

200: electronic device

205: two-dimensional notch

210: wall

215: Inclined surface

300: three-dimensional notch

305: first inclined surface

310: second inclined surface

315: single wall

320: Angle

400: Metrology System

405: Vacuum chamber

410: Vacuum Pump

415: Auxiliary Electronic Detector

α: Angle

In order to understand the details of the above-mentioned features of the present disclosure, one may refer to the embodiments to obtain a more detailed description of the present disclosure briefly summarized above, some examples of which are shown in the accompanying drawings. However, it should be noted that the drawings only show exemplary embodiments, and therefore should not be considered as a limitation of their scope, and other equivalent embodiments may be allowed.

Figure 1A is a schematic cross-sectional view showing an embodiment of a focused ion beam system.

FIG. 1B is another schematic cross-sectional view showing the focused ion beam system of FIG. 1A.

2A-2B show various views of the electronic device cut by the conventional method.

3A-3C are various views of the electronic device cut by the method and device as disclosed herein.

Figure 4 is a schematic cross-sectional view of a metrology system.

To make it easier to understand, consistent component symbols have been used as much as possible to mark the same components in the drawings. It is expected that the elements disclosed in one embodiment can be advantageously applied to other embodiments, and will not be described again.

The present disclosure generally relates to a focused ion beam system for analyzing electronic devices on large-area substrates. The large-area substrate used here includes a major surface, and a surface area of the major surface is greater than one square meter, for example, two square meters or more. The focused ion beam system as described herein is exemplarily disclosed for analyzing thin film transistors on large-area substrates. However, the focused ion beam system and method described herein can be used to analyze other electronic devices on large-area substrates.

FIG. 1A is a schematic cross-sectional view showing an embodiment of a focused ion beam system 100. FIG. FIG. 1B is another schematic cross-sectional view showing the focused ion beam system of FIG. 1A. The focused ion beam system 100 shown in FIG. 1A is performing a cutting process 105A, in which a large area substrate 110 with a transistor 115 on it is cut. The focused ion beam system 100 shown in FIG. 1B is performing an analysis process 105B, in which the cut transistor 115 is analyzed.

The large-area substrate 110 is positioned on a platform 120. The platform 120 has a main surface 125 that supports the large-area substrate 110 in a direction such that a plane of the main surface 125 is parallel to the Y direction.

The platform 120 can move in at least one lateral direction (in the X direction and/or the Y direction). The platform 120 supports the large-area substrate 110 so that the large-area substrate A major surface 130 of the 110 is parallel to the major surface 125 of the platform 120. Therefore, a plane 135 of the main surface 130 of the large-area substrate 110 is parallel to the Y direction.

The focused ion beam system 100 also includes a focused ion beam (FIB) column 140 that emits an ion beam. The focused ion beam column 140 is supported such that a beam path 145 of the focused ion beam column 140 is oriented at an angle α with respect to the plane 135 of the main surface 130 of the large area substrate 110. The angle α of the beam path 145 with respect to the plane 135 of the main surface 130 of the large-area substrate 110 is an acute angle, for example, about 40 degrees to about 50 degrees. In one example, with respect to the plane 135 of the main surface 130 of the large-area substrate 110, the angle α is approximately 45 degrees.

The beam path 145 of the focused ion beam column 140 is configured to cut a three-dimensional space 150 in the transistor 115 and/or the large-area substrate 110. The three-dimensional space 150 is formed by a moving platform 120 having a large-area substrate 110 in the lateral direction (X direction and Y direction) relative to the focused ion beam column 140. The three-dimensional space 150 is cut in a plane (XY plane).

The focused ion beam system 100 also includes a microscope 155. As shown in FIG. 1B, the microscope 155 is used to analyze the three-dimensional space 150 of the transistor 115. The microscope 155 may be a scanning electron microscope with an observation path 160. The observation path 160 is oriented at an angle orthogonal to the plane 135 of the main surface 130 of the large area substrate 110.

After performing the cutting process 105A as shown and described in FIG. 1A, the platform 120 is moved in the Y direction so that the three-dimensional space 150 of the transistor 115 is located under the microscope 155, as shown in FIG. 1B. In the analysis process 105B, the platform 120 can move laterally, so that the observation path 160 of the microscope 155 scans the three-dimensional space 150. In the three-dimensional space 150, the microscope 155 can observe the transistor 115 Cross-section. For example, the microscope 155 can observe the source and drain regions, the active layer, and the cross-section of the large-area substrate 110. The movement of the platform 120 may be limited to the movement on the X-Y plane during the cutting process 105A.

2A-2B show various views of the electronic device 200 cut by a conventional method. The conventional method is to tilt and/or rotate the underlying substrate (not shown) with the electronic device 200 thereon relative to the level on the platform (not shown). The electronic device 200 is also rotated and/or tilted relative to a fixed focused ion beam column (not shown). The focused ion beam column cuts the electronic device 200 to produce a two-dimensional notch 205. During this cutting process, the angle of the beam path (not shown) of the focused ion beam column relative to the main surface of the electronic device 200 is about 90 degrees at most.

The two-dimensional notch 205 is more clearly seen in the cross-sectional view of FIG. 2B. The two-dimensional recess 205 includes walls 210 on each side of an inclined surface 215. The inclined surface 215 is a plane generally observed by a microscope (not shown). The surface roughness (average surface roughness (Ra)) of the wall 210 has a higher surface roughness because the wall 210 is not parallel to the scanning direction of the focused ion beam, but is determined by the position of the scanning start and the scanning end. Define the wall 210. The roughness (Ra) of the inclined surface 215 may be about 5 nanometers to about 10 nanometers or more. The wall 210 is at an angle of 90 degrees with respect to the main surface of the electronic device 200, and due to the oblique viewing angle, it can be observed with a microscope with reduced resolution or image quality. Therefore, with full microscope resolution and low surface roughness, the only plane that can be observed is the inclined surface 215.

3A-3C are various views of the electronic device 200 cut by the method and device as disclosed herein. Figure 1A shows a device for cutting the electronic device 200.

According to the embodiment described here, the method of cutting the electronic device 200 produces a three-dimensional notch 300. The three-dimensional notch 300 is the same as the three-dimensional space 150 shown in FIGS. 1A and 1B. The three-dimensional recess 300 includes a plurality of inclined surfaces, such as a first inclined surface 305 and a second inclined surface 310. The first inclined surface 305 and the second inclined surface 310 are planes observed by a microscope (not shown). The first inclined surface 305 and the second inclined surface 310 may be adjacent to each other. In addition, the three-dimensional recess 300 includes a single wall 315.

Each of the first inclined surface 305 and the second inclined surface 310 includes an angle 320. The angle 320 of both the first inclined surface 305 and the second inclined surface 310 may be the same. The angle 320 may be approximately 45 degrees. The single wall 315 may be at an angle of approximately 90 degrees with respect to the main surface of the electronic device 200 and cannot be observed by a microscope. The roughness (Ra) of the first inclined surface 305 and the second inclined surface 310 may be about 2 nanometers to about 0.1 nanometers or less.

Figure 4 is a schematic cross-sectional view of a metrology system 400. The metrology system 400 includes a vacuum chamber 405, and the vacuum chamber 405 has the platform 120 described in FIGS. 1A and 1B. The platform 120 supports a large-area substrate 110 with an electronic device (not shown) thereon. The vacuum chamber 405 is fluidly coupled with a vacuum pump 410, and the vacuum pump 410 maintains the negative pressure in the vacuum chamber 405.

The focused ion beam column 140 and the microscope 155 are at least partially positioned in the vacuum chamber 405 above the platform 120. The metrology system 400 also includes an auxiliary electronic detector 415. The auxiliary electron detector 415 is used for imaging when the focused ion beam column 140 is used to cut the electronic device.

The method and equipment described herein can cut an electronic device without tilting and/or rotating the electronic device and the underlying substrate. The method and equipment described here also Create multiple surfaces that can be observed by a microscope. The three-dimensional notch 300 as disclosed herein allows the cross-section of the source and drain regions, the active layer, and a portion of the underlying substrate to be viewed in three dimensions.

Although the above content is about embodiments, other and further embodiments can be designed without departing from the basic scope, and the scope is determined by the scope of the following patent applications.

200: electronic device

300: three-dimensional notch

305: first inclined surface

310: second inclined surface

Claims (17)

A device for cutting an electronic device on a substrate, the device comprising: a platform for supporting the substrate, the substrate having the electronic device; a focused ion beam column fixed on a position above the platform , The focused ion beam column is adapted to emit a beam path at an acute angle relative to a plane of a main surface of the substrate; and a microscope placed adjacent to the focused ion beam column, wherein the electronic device During the cutting, the platform is movable in an XY plane, wherein the microscope has an observation path oriented at approximately 90 degrees relative to the plane of the main surface of the substrate. The device described in item 1 of the scope of patent application, wherein the beam path cuts a three-dimensional notch in the electronic device. The device described in item 2 of the scope of patent application, wherein the three-dimensional notch includes a plurality of inclined surfaces that can be observed by the microscope. The device described in item 3 of the scope of patent application, wherein each of the inclined surfaces is approximately 45 degrees with respect to the plane of the main surface of the substrate. The device according to any one of items 2 to 4 in the scope of the patent application, wherein the three-dimensional recess includes a single wall that cannot be observed by the microscope. The device according to claim 5, wherein the single wall is at an angle of about 90 degrees with respect to the plane of the main surface of the substrate. A device for cutting an electronic device on a substrate, the device comprising: a platform for supporting the substrate, and the electronic device on the substrate; A focused ion beam column fixed at a position above the platform, the focused ion beam column is suitable for emitting a beam path and cutting a three-dimensional notch in the electronic device; and corresponding to the focused ion beam column A microscope placed next to each other, wherein the platform is limited to moving in an XY plane during the cutting of the electronic device, wherein the microscope has a plane with respect to a major surface of the substrate and an observation with an orientation of about 90 degrees path. The device according to item 7 of the scope of patent application, wherein the beam path is fixed at an acute angle of the plane with respect to the main surface of the substrate. The device according to item 7 of the scope of patent application, wherein the three-dimensional notch includes a plurality of inclined surfaces that can be observed by the microscope. The device according to claim 9, wherein each of the inclined surfaces is approximately 45 degrees with respect to the plane of the main surface of the substrate. The device described in item 7 of the scope of patent application, wherein the three-dimensional notch includes a single wall that cannot be observed by the microscope. The device according to claim 11, wherein the single wall is at an angle of about 90 degrees with respect to the plane of the main surface of the substrate. The device as described in item 7 of the scope of patent application, wherein the electronic device is a transistor. A method for cutting an electronic device on a substrate, the method comprising: placing the substrate on a platform; emitting a beam path from a focused ion beam column, the focused ion beam column being fixed relative to the substrate At an angle of about 45 degrees on one of the major surfaces; and The platform is moved in a single lateral plane to create a three-dimensional notch in the electronic device, wherein the microscope has an observation path at an angle of approximately 90 degrees with respect to a plane of the main surface of the substrate. The method described in item 14 of the scope of the patent application further includes: moving the platform on the single lateral plane adjacent to a microscope. The method described in item 15 of the scope of the patent application further includes using the microscope to observe a plurality of inclined surfaces in the three-dimensional recess. The method according to claim 16, wherein each of the inclined surfaces has an angle of about 45 degrees with respect to the plane of the main surface of the substrate.

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