Thin film deposition method

Abstract

The present application provides a thin film deposition method and thin film deposition equipment, by measuring the thickness of the first substrate, the maximum thickness position and the minimum thickness position are obtained, and the first angle between the maximum thickness position and the baseline and the second angle between the minimum thickness position and the baseline are calculated, the position difference between the maximum thickness position and the minimum thickness position before the substrate rotation working angle is calculated by using the first angle and the second angle, which is used as the substrate rotation correction angle of the second substrate for the thin film deposition process. The second substrate first deposits a part of the material with the target thin film thickness in the thin film deposition process, then rotates the working angle by the first rotation axis, and then rotates 180 degrees and the substrate rotation correction angle by the second rotation axis, so that the maximum thickness position is rotated to the position coinciding with the minimum thickness position when the first half process is performed. In this way, when the subsequent process is performed, the deposition state at the maximum thickness position and the minimum thickness position of the thin film is complementary, and finally a thin film with uniform thickness is produced.

Description

Technical Field

[0001] This application relates to the technical field of depositing thin films on substrates, and in particular to a thin film deposition method and a thin film deposition apparatus. Background Technology

[0002] Existing copper interconnect processes involve forming a thin film (SiCN / SiCOH / TEOS) on a substrate using chemical vapor deposition (CVD), then etching trenches and vias into the thin film, depositing a copper layer on the substrate, and finally polishing the copper layer using chemical mechanical polishing to obtain the metal wiring layer. When the width of the metal wiring layer is equal, the cross-sectional area (depth) of the metal wiring layer affects its on-resistance.

[0003] The thin film layer formed by chemical vapor deposition (CVD) has the problem of uneven thickness. Therefore, after the trenches and vias are formed by etching, the trenches and vias at different locations have different depths. This results in different cross-sectional areas of the metal wiring layer, and thus different on-resistance at different locations.

[0004] Due to factors such as differences in gas distribution or electric field distribution within the reaction chamber, Figure 1 As shown, this results in a problem where the film thickness near the sidewall of the deposition chamber is greater than that near the center of the deposition chamber after the film has been deposited to the target thickness on the substrate surface. This causes differences in the on-resistance of the subsequently formed metal wiring layer at various locations. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a thin film deposition method and a thin film deposition apparatus to improve the problem of uneven surface thickness of thin films deposited on substrates in the prior art.

[0006] To achieve the above and other related objectives, this application provides a thin film deposition method applied to a thin film deposition apparatus. The apparatus includes a deposition cavity, a turntable disposed within the deposition cavity, and multiple deposition stations disposed on the turntable. The turntable is provided with a first rotation axis, and each deposition station has a second rotation axis at its bottom. The thin film deposition method includes: A portion of the target thin film thickness is deposited on a first substrate to form a first intermediate thin film; Rotate the first substrate around the first rotation axis by a working angle; Repeat the steps of forming the first intermediate film and rotating the first substrate by the working angle to form the first target film; A marking structure is defined at the edge of the first substrate, and the marking structure is defined as a baseline through a line connecting the center of the first substrate to the opposite side; The thickness of the first target film is measured to obtain the positions of maximum and minimum thickness. Calculate the first angle formed between the first line connecting the location of maximum thickness and the center, and the baseline; Calculate the second angle formed between the second line connecting the minimum thickness position and the center and the baseline; The substrate turning correction angle is obtained from the first included angle and the second included angle by subtracting the second included angle from the first included angle. A portion of the target film thickness is deposited on a second substrate to form a second intermediate film, the second substrate having the same shape and structure as the first substrate; The second substrate is rotated about the first rotation axis by a working angle; The difference between rotating the second substrate 180 degrees around the second rotation axis and the substrate orientation correction angle; Repeat the steps of forming the second intermediate film and rotating the second substrate by the working angle to form the second target film.

[0007] Optionally, the first substrate and the second substrate are wafers, and the marking structure is a notch formed at the edge of the wafer.

[0008] Optionally, the first rotation axis is located outside the first substrate and the second substrate.

[0009] Optionally, the first included angle is defined as positive when the first connecting line is formed from the baseline in a clockwise direction and negative when it is formed in a counterclockwise direction, and the second included angle is defined as positive when the second connecting line is formed from the baseline in a clockwise direction and negative when it is formed in a counterclockwise direction.

[0010] Optionally, the substrate orientation correction angle is greater than -180 degrees and less than +180 degrees.

[0011] Optionally, with the center of the first substrate as the origin, the coordinates of the position with the maximum thickness are (X, Y), and the first included angle is the inverse cosine function value of the quotient of the absolute value of the Y coordinate divided by the square root of the sum of the squares of the X coordinate and the Y coordinate.

[0012] Optionally, with the center of the first substrate as the origin, the coordinates of the position with the minimum thickness are (x, y), and the second included angle is the inverse cosine function value of the quotient of the absolute value of the y coordinate divided by the square root of the sum of the squares of the x and y coordinates.

[0013] Optionally, the first substrate is deposited twice to form the first target film, and the second substrate is deposited twice to form the second target film, wherein the working angle is 180°.

[0014] Optionally, the first substrate is deposited four times to form the first thin film, and the second substrate is deposited four times to form the second thin film, wherein the working angle is 90°.

[0015] As described above, the improved surface uniformity of the substrate deposited thin film in this application has the following beneficial effects: By measuring the film thickness of the first substrate, the positions of maximum and minimum thickness are obtained. The first angle between the maximum thickness position and the baseline, and the second angle between the minimum thickness position and the baseline are calculated. Using these angles, the positional difference between the maximum and minimum thickness positions is calculated after the substrate rotates 180 degrees around its center, following a rotation around the first axis. This difference is used as the substrate orientation correction angle for the second substrate's thin film deposition process. The second substrate first deposits a portion of the target film thickness using the thin film deposition process. Then, the second substrate rotates 180 degrees around the first axis, followed by the substrate orientation correction angle, so that the maximum thickness position coincides with the minimum thickness position from the first half of the process. This ensures that the deposition states at the maximum and minimum thickness positions are complementary during the first half of the process, resulting in a film with uniform thickness. Attached Figure Description

[0016] Figure 1 This is a state diagram showing the thickness of thin films formed on a substrate using existing technology; Figure 2 The diagram shown is a schematic of a thin film deposition apparatus used in this application.

[0017] Figure 3A and Figure 3B The flowchart shown is a thin film deposition method according to an embodiment of this application; Figures 4 to 6 The diagram shown illustrates a method for calculating the substrate orientation correction angle using a thin film deposition method according to an embodiment of this application. Figure 7 This diagram shows the thickness of the thin film formed on the substrate after the thin film deposition method described in this application.

[0018] Component labeling explanation First substrate S1; Marking structure A11; Second substrate S2; First rotation axis A; Deposition cavity C; Baseline L; First connection L1; Second connection L2; First servo motor M1; Second servo motor M2; Substrate rotation correction angle n; Second rotation axis O; Station P; Maximum thickness position P1; Position P1'; Minimum thickness position P2; Turntable R; First included angle α; Second included angle θ Detailed Implementation

[0019] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application.

[0020] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one component or feature shown in the accompanying drawings and other components or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the accompanying drawings for devices in use or operation.

[0021] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] Please see Figure 2 This refers to a thin film deposition apparatus used in an embodiment of this application. The thin film deposition apparatus includes a reaction chamber C and a turntable R. Four workstations P are arranged within the reaction chamber, and the four workstations P are mounted on a turntable R. The turntable R is rotatable about a first rotation axis A. Each workstation P is itself a turntable, rotatable about its own second rotation axis O. The turntable R is connected to a first servo motor M1, and the turntable of each workstation P is connected to a second servo motor M2. The first servo motor M1 rotates the turntable R by a working angle, for example, 180 degrees or 90 degrees. The second servo motor M2 rotates the turntable of workstation P by 180 degrees and a substrate orientation correction angle n, described later.

[0023] Please see Figure 3A and Figure 3BThis is a flowchart of a thin film deposition method according to an embodiment of this application. The thin film deposition method of this embodiment is implemented based on a thin film deposition equipment. The thin film deposition equipment of this application uses a 2*2 mode or a 4*1 mode for deposition. In the 2*2 mode, deposition is completed after two wafer depositions, with two new wafers fed in for each deposition. In the 4*1 mode, deposition is completed after four wafer depositions, with one new wafer fed in for each deposition. This application uses the 2*2 mode as an example for explanation, where each deposition in the 2*2 mode requires a 180-degree rotation.

[0024] In step S1, a material equal to half the thickness of the target thin film is deposited on the first substrate to form a first intermediate thin film. Then, the process proceeds to step S2.

[0025] In step S2, the first substrate is rotated around a first rotation axis by a working angle. In this embodiment, the deposition process is performed using a LAMVector Extreme instrument, so the working angle is 180 degrees. Then, proceed to step S3.

[0026] In step S3, half the thickness of the target film is deposited on the first substrate to form the first target film. Then, proceed to step S4.

[0027] Please refer to step S4 as well. Figure 4 A marking structure A11 is defined at the edge of the first substrate S1. The line connecting the marking structure A11 through the center O of the first substrate S1 and extending to the other edge is defined as the baseline L. In this embodiment, the first substrate S1 is a wafer with a circular shape, and the marking structure A11 is a notch formed at the edge of the wafer. Then proceed to step S5.

[0028] In step S5, the thickness of the first target thin film on the first substrate S1 is measured to obtain the position of maximum thickness P1 and the position of minimum thickness P2. Then proceed to step S6.

[0029] In step S6, the first angle α formed between the first line L1 connecting the maximum thickness position P1 and the center O, and the baseline L, is calculated. Taking the center O of the first substrate A1 as the origin, the coordinates of the maximum thickness position P1 are (X, Y), and the first angle α = arccos(|Y| / √(X)). 2 +(Y) 2 That is, the first included angle α is the inverse cosine function value of the quotient of the absolute value of the Y coordinate divided by the square root of the sum of the squares of the X and Y coordinates. Then proceed to step S7.

[0030] In step S7, a second included angle θ formed between a second connecting line L2 formed by the minimum thickness position P2 and the center O and the base line L is calculated. Taking the center O of the first substrate S1 as the origin, the coordinates of the minimum thickness position P2 are (x, y), and the second included angle θ=arccos(|y| / √(x) 2 +(y) 2 ), that is, the second included angle θ is the arccosine value of the quotient obtained by dividing the absolute value of the y-coordinate by the square root of the sum of the square of the x-coordinate and the square of the y-coordinate. Then the process proceeds to step S8.

[0031] In step S8, the substrate rotation correction angle n=α–θ is obtained from the first included angle α and the second included angle θ. For the first included angle α, that formed by the first connecting line L1 clockwise from the base line L is defined as a positive value, and that formed counterclockwise from the base line L is defined as a negative value. For the second included angle θ, that formed by the second connecting line L2 clockwise from the base line L is defined as a positive value, and that formed counterclockwise from the base line L is defined as a negative value. Moreover, the range of the substrate rotation correction angle n is -180°<n<+180°, that is, the substrate rotation correction angle n is greater than -180° and less than +180°. As Figure 6 shows, for example, the first included angle α is 30° clockwise from the base line L, and the second included angle θ is 15° clockwise from the base line L, so n=α–θ=30°–15°=15°. In another embodiment, the first included angle α is 30° clockwise from the base line L, the second included angle θ is 15° counterclockwise from the base line L, and n=α–θ=30°–(-15°)=45°. If the value of n is positive, it means that the substrate is first rotated by 180° and then rotated counterclockwise by n degrees for compensation during rotation correction; if the value of n is negative, it means that the substrate is first rotated by 180° and then rotated clockwise by n degrees for compensation during rotation correction. In an extreme case, if the maximum thickness position P1 is adjacent to the minimum thickness position P2, the substrate is first rotated by 180° and then rotated by another 180° clockwise or counterclockwise for compensation during rotation correction, and the value of n is close to +180° or -180°. If the maximum thickness position P1 and the minimum thickness position P2 are at two ends of the same straight line, the compensation is completed after the substrate is rotated by 180° during rotation correction, and the value of n is 0°. Then the process proceeds to step S9.

[0032] In step S9, a material accounting for 1 / 2 of the target film thickness is deposited on a second substrate to form a second midway film, wherein the second substrate has the same shape and structure as the first substrate. In this embodiment, the second substrate is a perfectly circular wafer and is provided with a notch-shaped marking structure at the edge. The deposition process of the second substrate is performed based on the position of Figure 6 the first substrate S1 as shown to form the second midway film. Then the process proceeds to step S10.

[0033] In step S10, the second substrate S2 is rotated around the first rotation axis by a working angle. In this embodiment, the deposition process is performed using a LAMVector Extreme machine, so the working angle is 180 degrees. Then, proceed to step S11.

[0034] Please refer to the following: Figure 5 In step S11, the second substrate A2 is rotated 180 degrees around its center O. Then, proceed to step S12.

[0035] Please refer to step S12 as well. Figure 3B and Figure 6 Then rotate the second substrate A2 about its center O by n degrees. For example, from... Figure 6 If the substrate orientation correction angle n = +15 degrees is calculated based on the state of the first substrate S1, then the second substrate S2 is rotated 15 degrees counterclockwise, so that the position P1' corresponding to the maximum thickness position P1 of the second intermediate film and the first substrate S1 is rotated to the position P2' corresponding to the minimum thickness position P2 of the first substrate S1. Then proceed to step S13.

[0036] In step S13, half the thickness of the target film is deposited on the second substrate S2 to form a second target film.

[0037] In this embodiment, there are two first substrates A1 and two second substrates A2. The first substrate S1 and the second substrate S2 can perform thin film deposition processes in the same reaction chamber. After the first substrate S1 completes the thin film of the target thickness, the substrate turning correction angle n is calculated and used for the thin film deposition process of the second substrate S2.

[0038] In the embodiment of a four-station process with four 90-degree rotations each, the first and second substrates deposit material equal to 1 / 4 of the target film thickness in each deposition step, and the working angle around the first rotation axis is 90 degrees. The remaining substrates undergo the same process as in the previous embodiment, where they are first rotated 180 degrees and then n degrees for compensation during orientation correction.

[0039] Please see Figure 7 After adjusting the position of the second substrate using the thin film deposition method of this application, a uniform thin film thickness is obtained.

[0040] By measuring the film thickness of the first substrate, the positions of maximum and minimum thickness are obtained. The first angle between the maximum thickness position and the baseline, and the second angle between the minimum thickness position and the baseline are calculated. Using these angles, the positional difference between the maximum and minimum thickness positions is calculated after the substrate rotates 180 degrees around its center, following a rotation around the first axis. This difference is used as the substrate orientation correction angle for the second substrate's thin film deposition process. The second substrate first deposits a portion of the target film thickness using the thin film deposition process. Then, the second substrate rotates 180 degrees around the first axis, followed by the substrate orientation correction angle, so that the maximum thickness position coincides with the minimum thickness position from the first half of the process. This ensures that the deposition states at the maximum and minimum thickness positions are complementary during the first half of the process, resulting in a film with uniform thickness.

[0041] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A thin film deposition method, applied to a thin film deposition apparatus, the thin film deposition apparatus having a deposition cavity, a turntable disposed in the deposition cavity, and multiple deposition stations disposed on the turntable, the turntable being provided with a first rotation axis, and each deposition station having a second rotation axis disposed at its bottom, characterized in that... ,include: A portion of the target film thickness is deposited on a first substrate to form a first intermediate film; Rotate the first substrate around the first rotation axis by a working angle; Repeat the steps of forming the first intermediate film and rotating the first substrate by the working angle to form the first target film; A marking structure is defined at the edge of the first substrate, and a baseline is defined by a line connecting the marking structure through the center of the first substrate and extending to the other edge. The thickness of the first target film is measured to obtain the positions of maximum and minimum thickness. Calculate the first angle formed between the first line connecting the location of maximum thickness and the center, and the baseline; Calculate the second angle formed between the second line connecting the minimum thickness position and the center and the baseline; The substrate turning correction angle is obtained from the first included angle and the second included angle by subtracting the second included angle from the first included angle; A portion of the target film thickness is deposited on a second substrate to form a second intermediate film, the second substrate having the same shape and structure as the first substrate; Rotate the second substrate around the first rotation axis by the working angle; Rotate the second substrate 180 degrees around the second rotation axis and subtract the substrate orientation correction angle; Repeat the steps of forming the second intermediate film and rotating the second substrate by the working angle to form the second target film.

2. The thin film deposition method as described in claim 1, characterized in that... The first substrate and the second substrate are wafers, and the marking structure is a notch formed at the edge of the wafer.

3. The thin film deposition method as described in claim 1, characterized in that... The first rotation axis is located outside the first substrate and the second substrate.

4. The thin film deposition method as described in claim 1, characterized in that... The first included angle α is defined as positive when the first connecting line is formed from the baseline in a clockwise direction and negative when it is formed in a counterclockwise direction. The second included angle θ is defined as positive when the second connecting line is formed from the baseline in a clockwise direction and negative when it is formed in a counterclockwise direction.

5. The thin film deposition method as described in claim 1, characterized in that... The substrate orientation correction angle is greater than -180 degrees and less than +180 degrees.

6. The thin film deposition method as described in claim 1, characterized in that... With the center of the first substrate as the origin, the coordinates of the position with the maximum thickness are (X, Y), and the first included angle is the inverse cosine function value of the quotient of the absolute value of the Y coordinate divided by the square root of the sum of the squares of the X and Y coordinates.

7. The thin film deposition method as described in claim 6, characterized in that... With the center of the first substrate as the origin, the coordinates of the position with the minimum thickness are (x, y), and the second included angle is the inverse cosine function value of the quotient of the absolute value of the y coordinate divided by the square root of the sum of the squares of the x and y coordinates.

8. The thin film deposition method as described in claim 1, characterized in that... The first substrate is deposited twice to form the first target film, and the second substrate is deposited twice to form the second target film. The working angle is 180°.

9. The thin film deposition method as described in claim 1, characterized in that... The first substrate is deposited in four stages to form the first thin film, and the second substrate is deposited in four stages to form the second thin film. The working angle is 90°.

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