Semiconductor substrate and method for preparing the same

Abstract

The present invention provides a semiconductor substrate and a preparation method thereof, the preparation method comprising the following steps: providing a substrate, the substrate comprising a functional area and a measurement area; using the same process steps to form at least one functional film layer in the functional area of ​​the substrate, and forming at least one measurement film layer in the measurement area, wherein in a top view direction, the measurement film layer is divided into at least one measurement unit, the shape of the measurement unit is a polygon, and the internal angle of the polygon is greater than 90 degrees. In the process of preparing a semiconductor substrate of the present invention, a polygonal measurement unit is formed in the measurement area, the measurement unit of this shape has a small force moment, is not easy to fall off, and will not become a defect source, thereby avoiding the measurement unit affecting the process quality and the final yield of the semiconductor substrate; at the same time, the stress distribution of the polygonal measurement unit is relatively more uniform, and the structure is more stable.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a semiconductor substrate and a preparation method thereof. Background Art

[0002] In the process of manufacturing semiconductor substrates, a corrosive etching solution is often used to perform various treatments on the substrate with an insulating film. For example, the prior art discloses a method of treating a semiconductor substrate with a SPM (sulfuric acid / hydrogen peroxide mixture) solution.

[0003] In the process of semiconductor substrate manufacturing, the measurement unit is used to simulate the behavior of the array area or the periphery area, and can be used to measure and monitor the critical dimensions of the process, which is of great significance.

[0004] However, the measurement unit may become a defect source, affecting the process quality and the final yield. Therefore, designing a semiconductor substrate with a reasonable measurement unit is an effective way to avoid defects. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a semiconductor substrate and a preparation method thereof, which can prevent the measurement unit from falling off, improve the process quality and the final yield of the semiconductor substrate.

[0006] In order to solve the above problems, the present invention provides a method for preparing a semiconductor substrate, the preparation method comprising the following steps: providing a substrate, the substrate comprising a functional area and a measurement area; forming at least one functional film layer in the functional area of ​​the substrate and forming at least one measurement film layer in the measurement area using the same process steps, in the top view direction, the measurement film layer is divided into at least one measurement unit, the shape of the measurement unit is a polygon, and the internal angle of the polygon is greater than 90 degrees.

[0007] Furthermore, the polygon is a regular polygon.

[0008] Furthermore, the polygon is a regular octagon.

[0009] Furthermore, the measurement area is arranged at the edge of the functional area.

[0010] Furthermore, the measuring film layer is divided into a plurality of measuring units, and the measuring units are arranged in a matrix.

[0011] Furthermore, the measuring film layer is divided into a plurality of measuring units, and the measuring units are independent of each other.

[0012] Furthermore, the method for forming the measurement unit in the measurement area includes the following steps: providing a mask plate, the mask plate having a polygonal opening in an area corresponding to the measurement unit, and the inner angle of the polygonal opening is greater than 90 degrees; in the step of forming a measurement film layer, the measurement film layer is deposited through the polygonal opening to form the measurement unit.

[0013] The present invention also provides a semiconductor substrate, which includes a functional area and a measurement area, the functional area has at least one functional film layer, the measurement area has at least one measurement film layer, in the top view direction, the measurement film layer is divided into at least one measurement unit, the shape of the measurement unit is a polygon, and the internal angle of the polygon is greater than 90 degrees.

[0014] The advantage of the present invention is that in the process of preparing a semiconductor substrate, a polygonal measuring unit is formed in the measuring area. The measuring unit of this shape is subjected to a small force torque, is not easy to fall off, and will not become a source of defects, thereby avoiding the measuring unit affecting the process quality and the final yield of the semiconductor substrate; at the same time, the stress distribution of the polygonal measuring unit is relatively more uniform and the structure is more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the steps of a specific embodiment of the method for preparing a semiconductor substrate of the present invention;

[0016] Figure 2A to Figure 2C is a process flow chart of a specific embodiment of the method for preparing a semiconductor substrate of the present invention, wherein: Figure 2A and Figure 2C A top view diagram is shown. Figure 2B It is a side view schematic diagram;

[0017] Figure 3 is a schematic top view of another specific embodiment of the method for preparing a semiconductor substrate of the present invention;

[0018] Figure 4 is a schematic diagram of a top view structure of a measurement unit of a semiconductor substrate;

[0019] Figure 5 It is a SEM image of the corner of a measurement unit in the shape of a quadrilateral;

[0020] Fig. 6A It is a schematic diagram of a top view structure of a semiconductor substrate measuring area in which the measuring unit is a regular quadrilateral after an etching process is performed;

[0021] Figure 6B yes Fig. 6A A schematic diagram of the side structure of

[0022] Fig. 7AIt is a schematic diagram of a top view structure of a semiconductor substrate measuring area in which the measuring unit is a regular octagon after an etching process is performed;

[0023] Figure 7B yes Fig. 7A A schematic diagram of the side structure of

[0024] Figure 8 It is a schematic top view of a semiconductor substrate. DETAILED DESCRIPTION

[0025] The specific implementation manner of the semiconductor substrate and the preparation method thereof provided by the present invention is described in detail below with reference to the accompanying drawings.

[0026] Figure 1 Schematic diagram of a specific embodiment of the method for preparing a semiconductor substrate of the present invention. Figure 1 The method for preparing a semiconductor substrate of the present invention comprises the following steps: step S10, providing a substrate, wherein the substrate comprises a functional area and a measurement area; step S11, forming at least one functional film layer in the functional area of ​​the substrate and forming at least one measurement film layer in the measurement area by using the same process steps, wherein in a top view direction, the measurement film layer is divided into at least one measurement unit, and the shape of the measurement unit is a polygon, and the internal angle of the polygon is greater than 90 degrees.

[0027] Figure 2A to Figure 2C is a process flow chart of a specific embodiment of the method for preparing a semiconductor substrate of the present invention, wherein: Figure 2A and Figure 2C A top view diagram is shown. Figure 2B It is a side view schematic diagram.

[0028] Please refer to step S10 and Figure 2A , a substrate 100 is provided, wherein the substrate 100 includes a functional area A and a measurement area B.

[0029] The substrate 100 includes but is not limited to a silicon-based substrate, a glass substrate or a flexible substrate.

[0030] In this specific embodiment, the semiconductor substrate includes a functional area A and a measurement area B, and the measurement area B is arranged at the edge of the functional area A. In other specific embodiments of the present invention, Figure 3 As shown, the semiconductor substrate of the present invention includes a plurality of functional areas A and a plurality of measurement areas B, and one functional area A corresponds to one or more measurement areas B.

[0031] Please refer to step S11 and Figure 2B , at least one functional film layer 101 is formed in the functional area A of the substrate 100, and at least one measurement film layer 102 is formed in the measurement area B by the same process steps. Specifically, in this specific embodiment, Figure 2BOnly four functional film layers 101 and four measurement film layers 102 are schematically shown. The present invention does not limit the number of the functional film layers 101 and the measurement film layers 102, which can be determined according to the process of the semiconductor substrate.

[0032] In this step, the use of the same process steps to form the functional film layer 101 and the measurement film layer 102 means that the functional film layer 101 and the measurement film layer 102 are not only deposited and formed by the same process steps, but also photolithography and etching are performed by the same process steps. Figure 2B In the embodiment, after four functional film layers 101 and four measurement film layers 102 are formed by the same deposition process, part of the functional film layers 101 and part of the measurement film layers 102 are removed by the same photolithography and etching process.

[0033] The present invention adopts the same process steps to form the functional film layer 101 and the measurement film layer 102, so the measurement area B simulates the behavior of the array area or the edge area of ​​the corresponding functional area A, and the critical dimensions of the process can be measured and monitored in the measurement area B, so that the critical dimensions of the process in the functional area A can be known.

[0034] See also Figure 2C , in the top view direction, the measurement film layer 102 is divided into at least one measurement unit 110. In this specific embodiment, the measurement film layer 102 is divided into a plurality of measurement units 110, and the measurement units 110 are arranged in a matrix. Specifically, the measurement units 110 are arranged in sequence along the edge of the functional area A. Preferably, the measurement units 110 are independent of each other to facilitate the measurement and monitoring of the critical dimensions of the process.

[0035] Figure 4 is a schematic diagram of the top view of the measurement unit, please refer to Figure 4 In the top-view direction (ie, in the direction perpendicular to the semiconductor substrate), the shape of the measuring unit 110 is a polygon, and the internal angle α of the polygon is greater than 90 degrees, that is, the internal angle of the polygon is an obtuse angle.

[0036] Preferably, in the top view, the shape of the measuring unit 110 is a regular polygon, which can further prevent the corners of the measuring unit 110 from falling off during the process. In this specific embodiment, in the top view, the shape of the measuring unit 110 is a regular octagon, and its internal angle α is 135 degrees.

[0037] Preferably, in the process of forming the measuring film layer 102, the measuring unit 110 is directly formed into a polygonal shape. Specifically, in this specific embodiment, the method for forming the polygonal measuring unit 110 in the measuring area B is to form the measuring unit 110 using a mask plate with a polygonal opening. Specifically, a mask plate is provided, and the mask plate has a polygonal opening in the area corresponding to the measuring unit 110, and the inner angle of the polygonal opening is greater than 90 degrees, wherein the polygonal opening can be formed on the mask plate by photolithography and etching methods; in the step of forming the measuring film layer 102, the measuring film layer 102 is deposited through the polygonal opening to form the measuring unit 110. It can be understood that in the functional area A, the mask plate also has a patterned opening to form the functional film layer 101.

[0038] Figure 5 This is a SEM image of a corner of a quadrilateral measurement unit. Figure 5 From the SEM image, the inventors found that during the preparation of the semiconductor substrate, the corners of the measuring unit are prone to fall off (e.g. Figure 5 The measurement unit is damaged, and the damaged measurement unit becomes a defect source, affecting the process quality and the final yield of the semiconductor substrate. However, the corners of the polygonal measurement unit 110 of the present invention are not easy to peel off, and will not become a defect source, and the measurement unit will not affect the process quality and the final yield of the semiconductor substrate.

[0039] The advantages of the semiconductor substrate preparation method of the present invention are described below by taking the shapes of the measurement units as regular quadrilaterals and regular octagons as examples.

[0040] Fig. 6A It is a schematic diagram of a top view of the structure after the etching process is implemented in the semiconductor substrate measurement area where the measurement unit is a regular quadrilateral. Figure 6B yes Fig. 6A Schematic diagram of the side structure, Fig. 7A It is a schematic diagram of a top view of the structure after the etching process is implemented in the measurement area of ​​the semiconductor substrate where the measurement unit is a regular octagon. Figure 7B yes Fig. 7A Schematic diagram of the side structure of FIG. In the figure, only two measuring film layers are schematically drawn, namely the top layer and the insulating layer (ie, the etched layer) located below the top layer. Fig. 6A and Fig. 7A The insulating layer is depicted using a dotted frame and shadows.

[0041] See also Fig. 6A , Figure 6B , Fig. 7A and Figure 7BIn the semiconductor process, the insulating layers 601 and 701 need to be etched. After etching, the most prominent dimensions of the regular quadrilateral measurement unit and the regular octagonal measurement unit are at the corners. Assuming that the etching depth of the insulating layer is L, the distance from the corner of the insulating layer 601 to the corner of the top layer 600 after etching is ΔL1, and the distance from the corner of the insulating layer 701 to the corner of the top layer 700 is ΔL2. Among them, ΔL1=1.414L, ΔL2=1.08L. It can be seen that when the etching depth is the same, ΔL1>ΔL2. This shows that when the etching gas flows in the process and causes the film layer of the measurement unit to be stressed, under the same stress, the force torque of the regular octagonal measurement unit is smaller, it is not easy to fall off, and it will not become a defect source, thereby avoiding the measurement unit affecting the process quality and the final yield of the semiconductor substrate. In addition, the internal angles of the shape of the measuring unit of a regular quadrilateral are right angles, and some polygons have acute internal angles. When the internal angles of a polygon are acute or right angles, it is more likely to cause stress concentration, while the internal angles of the measuring unit of a regular octagon are obtuse angles, and its stress distribution is relatively more uniform and the structure is more stable.

[0042] The present invention also provides a semiconductor substrate prepared by the above preparation method. Figure 8 is a top view of a semiconductor substrate. Figure 8 , the semiconductor substrate includes a functional area A and a measurement area B. In the direction perpendicular to the semiconductor substrate, the functional area A has at least one functional film layer, and the measurement area B has at least one measurement film layer. In the top view direction, the measurement film layer is divided into at least one measurement unit 800. In this specific embodiment, the measurement film layer is divided into a plurality of measurement units 800. The shape of the measurement unit 800 is a polygon, and the internal angle α of the polygon is greater than 90 degrees. Preferably, refer to Figure 4 In this specific implementation, the shape of the measuring unit 800 is a regular octagon, and the internal angle α of the regular octagon is 135 degrees.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a semiconductor substrate, It is characterized in that The steps include: Providing a substrate, wherein the substrate comprises a functional area and a measurement area; At least one functional film layer is formed in the functional area of ​​the substrate and at least one measurement film layer is formed in the measurement area by the same process steps. The functional film layer and the measurement film layer are deposited by the same process steps and are photolithographically and etched by the same steps. In the top-view direction, the measurement film layer is divided into at least one measurement unit. The measurement unit is in the shape of a regular octagon with an internal angle of 135 degrees. The measurement unit has a top layer, and an insulating layer is provided between the top layers of the upper and lower adjacent measurement units. After the etching, the etching depth of the insulating layer is L, and the distance from the corner of the insulating layer to the corner of the top layer is ΔL2, and ΔL2=1.08L.

2. The method for preparing a semiconductor substrate according to claim 1, It is characterized in that The measuring area is arranged at the edge of the functional area.

3. The method for preparing a semiconductor substrate according to claim 1, It is characterized in that The measuring film layer is divided into a plurality of measuring units, and the measuring units are arranged in a matrix.

4. The method for preparing a semiconductor substrate according to claim 1, It is characterized in that The measuring film layer is divided into a plurality of measuring units, and the measuring units are independent of each other.

5. A semiconductor substrate, It is characterized in that It includes a functional area and a measurement area, the functional area has at least one functional film layer, the measurement area has at least one measurement film layer, the functional film layer and the measurement film layer are deposited and formed by the same process steps, and are also photolithographically and etched by the same steps; in the top-view direction, the measurement film layer is divided into at least one measurement unit, the measurement unit is in the shape of a regular octagon, and the internal angle of the regular octagon is 135 degrees; the measurement unit has a top layer, and an insulating layer is provided between the top layers of the upper and lower adjacent measurement units; after the etching, the etching depth of the insulating layer is L, and the distance from the corner of the insulating layer to the corner of the top layer is ΔL2, and ΔL2=1.08L.

6. The semiconductor substrate according to claim 5, It is characterized in that The measuring area is arranged at the edge of the functional area.

7. The semiconductor substrate according to claim 5, It is characterized in that The measuring film layer is divided into a plurality of measuring units, and the measuring units are arranged in a matrix.

8. The semiconductor substrate according to claim 5, It is characterized in that The measuring film layer is divided into a plurality of measuring units, and the measuring units are independent of each other.

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