Ion implantation method, medium and system for semiconductor wafer

Abstract

The invention discloses an ion implantation method, medium and system for a semiconductor wafer, and the method comprises the following steps: S1, receiving dose ratio parameters of a plurality of concentric circle regions inputted by a user, and calculating the target dose of each region according to the total dose; s2, according to the calibration positions of the wafer target disc center and the beam current center, the beam current height and the radius parameter of each area, calculating the variable speed position coding value of each area in the vertical scanning direction; s3, based on the target dose, the injection speed of each region is calculated; s4, in a single vertical scanning process, dynamically adjusting the scanning speed of the wafer according to the variable-speed position coding value, and realizing variable-speed injection corresponding to different injection speeds in different areas; and S5, rotating the wafer to the next orientation, and repeating the step S4 until injection of all set orientations is completed, thereby realizing dose distribution of concentric circles or specific patterns. The method has the advantages that customizable dose distribution of specific graphs such as concentric circles can be realized, and the like.

Description

Technical Field

[0001] This invention relates primarily to the field of semiconductor technology, and specifically to an ion implantation method, medium, and system for semiconductor wafers. Background Technology

[0002] After semiconductor wafers undergo pre-fabrication processes such as photolithography and deposition, their surfaces are prone to uneven distribution of physical properties, such as localized thickness fluctuations and stress distribution differences. Traditional ion implantation scanning technology typically employs a "globally uniform" implantation strategy, applying the same ion dose across the entire wafer surface, without the ability to dynamically adjust the dose to address inherent physical differences in different regions. This results in significant in-plane dose deviations after implantation, impacting device performance consistency and yield.

[0003] In existing technologies, such as the strip beam implantation method used in HC (High-Intensity Concentration) machines, the process involves: drawing an ion beam from a narrow slit, or forming a strip beam with a width slightly larger than the wafer diameter through a deflection and focusing system; achieving uniform ion implantation across the entire wafer by controlling the beam's horizontal homogenization and combining this with the wafer's vertical scanning motion. While this method ensures overall dose uniformity across the wafer, it cannot achieve specific patterned dose distributions such as concentric circles according to process requirements.

[0004] Specifically, existing injection methods calculate the injection rate based on the dose of a single pass, with the entire pass scan at a fixed speed. Furthermore, the HC (High-Intensity Concentration) instrument uses a strip-shaped beam, which only guarantees the uniformity of the entire wafer and cannot achieve specific dose injection to a specific zone. Nevertheless, because the HC instrument's beam pattern is strip-shaped, relying solely on vertical scanning cannot achieve concentric circles or other customized dose distribution patterns in a single scan or unidirectional manner. This limits its ability to correct wafer surface non-uniformity and ultimately affects product yield. Summary of the Invention

[0005] To address the technical problems existing in the prior art, the present invention provides an ion implantation method, medium, and system for semiconductor wafers that enables customizable dose distribution for specific patterns such as concentric circles.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: An ion implantation method for semiconductor wafers includes the following steps: S1. Receive the dose percentage parameters of multiple concentric circle regions input by the user, and calculate the target dose of each region based on the total dose; S2. Based on the calibration position of the wafer target center and the beam center, the beam height, and the radius parameters of each region, calculate the variable speed position encoding value of each region in the vertical scanning direction; S3. Calculate the injection rate in each region based on the target dose; S4. During a single vertical scan, the scanning speed of the wafer is dynamically adjusted according to the variable speed position encoding value to achieve variable speed implantation with different implantation speeds for different regions; S5. Rotate the wafer to the next orientation and repeat S4 until implantation is completed in all set orientations to achieve a dose distribution of concentric circles or a specific pattern.

[0007] Preferably, in step S1, the target pattern is a concentric circle, consisting of a central circle (Zone 1), an intermediate ring (Zone 2), and an outer ring (Zone 3) from the center outwards, with the corresponding target standard dose being Dose. Zone1 =Dose*a, Dose Zone2 =Dose*b, Dose Zone3 =Dose*c; where Dose is the total dose; a, b, and c are the dose percentages of Zone1, Zone2, and Zone3, respectively.

[0008] Preferably, the specific process of step S2 is as follows: Given that the target center and beam center are horizontal, the Yscan coding value calibration value is zmm, the beam height is hmm, the radius of Zone 1 is 150mm, the radius of Zone 2 is Radius 1mm, and the radius of Zone 3 is Radius 2mm; The Yscan code value for the first gear shift position is zh / 2-Radius2, the Yscan code value for the second gear shift position is zh / 2-Radius1, the Yscan code value for the third gear shift position is zh / 2+Radius1, and the Yscan code value for the fourth gear shift position is zh / 2+Radius2.

[0009] Preferably, the specific process of step S4 is as follows: When the wafer is scanned upwards, it moves sequentially from the first region speed to the first variable speed position, then switches to the second region speed to the second variable speed position, then switches to the third region speed to the third variable speed position, then switches back to the second region speed, and finally switches back to the first region speed to complete the upward scan. When the wafer is scanned downwards, the speed switching sequence is symmetrical to that of scanning upwards.

[0010] Preferably, in step S5, the number of directions is n, where n is 1, 2, 4, 8, 16, or 32.

[0011] Preferably, the specific process of step S5 is as follows: The wafer is placed at 0 degrees and an upward scan is performed once; the wafer is rotated 360° / n and a downward scan is performed once; the wafer is rotated 360° / n degrees again and an upward scan is performed, and so on, to complete the injection in a total of n different orientations.

[0012] Preferably, in step S3, the injection rate of each region is inversely proportional to the corresponding target dose.

[0013] The present invention also discloses a computer program product, comprising a computer program that, when executed by a processor, performs the steps of the method described above.

[0014] The present invention further discloses a computer-readable storage medium having a computer program stored thereon, the computer program executing the steps of the method described above when run by a processor.

[0015] The present invention also discloses an ion implantation system for semiconductor wafers, comprising an interconnected memory and a processor, wherein the memory stores a computer program that, when run by the processor, executes the steps of the method described above.

[0016] Compared with the prior art, the advantages of the present invention are as follows: The ion implantation method of this invention combines real-time speed variation based on a preset pattern region with multi-directional rotational implantation during a single vertical scan, successfully achieving customizable dose distribution for specific patterns such as concentric circles on a strip beam apparatus. First, it can accurately compensate for in-plane non-uniformity of the wafer due to thickness, stress, etc., caused by previous processes, and improve implantation uniformity to a new level by setting differentiated doses for areas such as the outer ring and center. Second, it can actively suppress edge dose accumulation effects, optimizing edge device performance without the need for additional physical shielding. Third, it significantly improves process flexibility and adaptability, enabling rapid response to the patterned implantation requirements of different devices. Fourth, it can be implemented through control software upgrades, requiring minimal modification to existing hardware, exhibiting high compatibility and low implementation cost, providing an effective uniformity control solution for advanced semiconductor manufacturing. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing the division of regions, injection dose, and injection rate in this invention.

[0018] Figure 2 This is one of the 16 different injection distribution process diagrams in this invention.

[0019] Figure 3 This is one of the overall effect diagrams of the injection distribution in 16 different directions in this invention.

[0020] Figure 4 This is the second of 16 diagrams showing the injection distribution process at different locations in this invention.

[0021] Figure 5 This is the second of the overall effect diagrams of the injection distribution in 16 different directions in this invention.

[0022] Figure 6 This is a flowchart of an embodiment of the ion implantation method for semiconductor wafers according to the present invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 6 As shown, the ion implantation method for semiconductor wafers provided in this embodiment of the invention includes the following steps: S1. Receive the dose percentage parameters of multiple concentric circle regions input by the user, and calculate the target admission dose for each region based on the total dose; S2. Based on the calibration position of the wafer target center and the beam center, the beam height, and the radius parameters of each region, calculate the variable speed position encoding value of each region in the vertical scanning direction; S3. Calculate the injection rate for each region based on the target standard injection dose; S4. During a single vertical scan, the wafer scanning speed is dynamically adjusted according to the variable speed position encoding value to achieve variable speed implantation for different regions with different implantation speeds; S5. Rotate the wafer to the next orientation and repeat S4 until implantation is completed in all set orientations to achieve a dose distribution of concentric circles or a specific pattern.

[0025] This invention achieves differentiated dose application to different regions in a single scan by dynamically changing the mechanical scanning speed of the wafer in real time according to the preset pattern region boundaries during a single vertical scan. By rotating the wafer in multiple orientations and repeating the variable-speed scanning process, the desired two-dimensional dose distribution pattern (such as concentric circles) is finally synthesized. This method overcomes the limitation of traditional strip beam injection technology, which can only achieve globally uniform injection.

[0026] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0027] Taking differentiated dose implantation of three annular regions on a 300mm wafer with 16 orientations as an example. The target pattern is concentric circles, with Zone 1 (center circle), Zone 2 (middle ring), and Zone 3 (outer ring) from the center outwards. The implantation system is an HC-type ion implanter with precise vertical scanning (Y-scan) and wafer rotation (Twist) functions. The specific steps are as follows: S1. Based on process requirements, input the dose ratios of Zone1, Zone2, and Zone3 as a, b, and c, respectively, which is the Dose... Zone1 =Dose*a, Dose Zone2 =Dose*b, Dose Zone3 =Dose*c; S2. Given that the Yscan coding value is zmm when the target disk center is horizontal with the beam center, the beam height is hmm, the radius of Zone 1 (wafer radius) is 150mm, the radius of Zone 2 is Radius1 (mm), and the radius of Zone 3 is Radius2 (mm). Therefore, during the top-down vertical scan (Y-scan) of the wafer, the coordinates of the four key positions where the speed changes (corresponding to...) Figure 1 (The four dotted lines from top to bottom in the middle). The Yscan code value for the first gear position (first dashed line) is zh / 2-Radius2, the Yscan code value for the second gear position (second dashed line) is zh / 2-Radius1, the Yscan code value for the third gear position (third dashed line) is zh / 2+Radius1, and the Yscan code value for the fourth gear position (fourth dashed line) is zh / 2+Radius2.

[0028] S3. Calculate the injection rate V1 for Zone 1, the injection rate V2 for Zone 2, and the injection rate V3 for Zone 3 based on the target dose for each zone (the rate is inversely proportional to the target dose). S4. During a complete vertical scan, the speed calculated in S3 is dynamically switched according to the coordinates of S2. If the wafer moves upwards: it first moves at speed V1 to the first dotted line position and then changes speed to V2; it moves to the second dotted line and then changes speed to V3; it moves to the third dotted line and then changes speed to V2; it moves to the fourth dotted line and then changes speed to V1; it moves to the injection high position to complete an upward pass injection (e.g., Figure 1 (as shown) If the wafer is moving downwards: it first moves at speed V1 to the fourth dotted line position and then changes speed to V2; it moves to the third dotted line position and then changes speed to V3; it moves to the second dotted line position and then changes speed to V2; it moves to the first dotted line position and then changes speed to V1; finally, it moves to the injection low position, completing one downward pass injection (e.g., ...). Figure 1 ).

[0029] This process can create differentiated dose bands in the vertical direction in a single scan; S5. To synthesize the above vertical dose bands into a circularly symmetrical pattern, perform multi-directional implantation: Place the wafer at 0 degrees and perform one upward scan; rotate the wafer 22.5 degrees (360° / 16) and perform one downward scan; continue rotating 22.5 degrees and perform an upward scan, alternating in this manner; repeat the above steps to complete a total of 16 implantations at different orientations (distribution process as follows). Figure 2 The overall effect is as follows Figure 3 ).

[0030] Explanation of supperscan for other graphs: If Radius1 and Radius2 are equal, Dose Zone1 and Dose Zone2 If they are equal, the injection effect is two concentric circles (the distribution process is as follows). Figure 4 The overall effect is as follows Figure 5 ).

[0031] This invention enables multi-directional ion implantation by rotating a target disk, while simultaneously varying the implantation speed of a single pass. This allows for the implantation of a specific dose into a specific region in the vertical direction of a single pass, with a linear dose transition region. Through multi-directional (2, 4, 8, 16, 32...) implantation, specific patterns can be achieved.

[0032] The present invention achieves different ion concentrations by varying the injection speed of a single pass; it completes concentric supperscan injection through multi-directional variable-speed injection to meet customer needs; concentric injection can set differentiated doses for annular regions of different radii, such as increasing the injection dose for the outer ring with thicker film thickness and fine-tuning the dose parameters for the central high-stress region, which can control the dose deviation within the wafer plane within a more stringent range and solve the problem of insufficient uniformity caused by the "global one-size-fits-all" approach of traditional high-current injection; concentric injection precisely offsets edge dose redundancy by setting a gradient decreasing dose parameter for the outermost ring, avoiding problems such as abnormal leakage current in edge devices, while eliminating the need for additional shielding components.

[0033] The ion implantation method of this invention combines real-time speed variation based on a preset pattern region with multi-directional rotational implantation during a single vertical scan, successfully achieving customizable dose distribution for specific patterns such as concentric circles on a strip beam apparatus. First, it can accurately compensate for in-plane non-uniformity of the wafer due to thickness, stress, etc., caused by previous processes, and improve implantation uniformity to a new level by setting differentiated doses for areas such as the outer ring and center. Second, it can actively suppress edge dose accumulation effects, optimizing edge device performance without the need for additional physical shielding. Third, it significantly improves process flexibility and adaptability, enabling rapid response to the patterned implantation requirements of different devices. Fourth, it can be implemented through control software upgrades, requiring minimal modification to existing hardware, exhibiting high compatibility and low implementation cost, providing an effective uniformity control solution for advanced semiconductor manufacturing.

[0034] The present invention also discloses a computer program product, including a computer program that, when run by a processor, performs the steps of the method described above. The present invention further discloses a computer-readable storage medium storing a computer program that, when run by a processor, performs the steps of the method described above. The present invention also discloses an ion implantation system for semiconductor wafers, including an interconnected memory and a processor, wherein the memory stores a computer program that, when run by a processor, performs the steps of the method described above.

[0035] The products, media, and systems of the present invention, corresponding to the methods described above, also possess the advantages described above.

[0036] The present invention can implement all or part of the processes in the methods of the above embodiments, or it can be implemented by hardware related to computer program instructions. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium includes: any entity or device capable of carrying computer program code, recording media, USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. The memory is used to store computer programs and / or modules. The processor implements various functions by running or executing the computer programs and / or modules stored in the memory, and by calling data stored in the memory. The memory may include high-speed random access memory, as well as non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital (SD) cards, flash cards, at least one disk storage device, flash memory device, or other volatile solid-state storage devices.

[0037] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. An ion implantation method for semiconductor wafers, characterized in that, Includes the following steps: S1. Receive the dose percentage parameters of multiple concentric circle regions input by the user, and calculate the target dose of each region based on the total dose; S2. Based on the calibration position of the wafer target center and the beam center, the beam height, and the radius parameters of each region, calculate the variable speed position encoding value of each region in the vertical scanning direction; S3. Calculate the injection rate in each region based on the target dose; S4. During a single vertical scan, the scanning speed of the wafer is dynamically adjusted according to the variable speed position encoding value to achieve variable speed implantation with different implantation speeds for different regions; S5. Rotate the wafer to the next orientation and repeat S4 until implantation is completed in all set orientations to achieve a dose distribution of concentric circles or a specific pattern.

2. The ion implantation method for semiconductor wafers according to claim 1, characterized in that, In step S1, the target pattern is a concentric circle, with the three rings arranged from the center outwards as: central circle Zone 1, middle ring Zone 2, and outer ring Zone 3. The corresponding target standard dose is Dose. Zone1 =Dose*a, Dose Zone2 =Dose*b, Dose Zone3 =Dose*c; where Dose is the total dose; a, b, and c are the dose percentages of Zone1, Zone2, and Zone3, respectively.

3. The ion implantation method for semiconductor wafers according to claim 2, characterized in that, The specific process of step S2 is as follows: Given that the target center and beam center are horizontal, the Yscan coding value calibration value is zmm, the beam height is hmm, the radius of Zone 1 is 150mm, the radius of Zone 2 is Radius 1mm, and the radius of Zone 3 is Radius 2mm; The Yscan code value for the first gear shift position is zh / 2-Radius2, the Yscan code value for the second gear shift position is zh / 2-Radius1, the Yscan code value for the third gear shift position is zh / 2+Radius1, and the Yscan code value for the fourth gear shift position is zh / 2+Radius2.

4. The ion implantation method for semiconductor wafers according to claim 3, characterized in that, The specific process of step S4 is as follows: When the wafer is scanned upwards, it moves sequentially from the first region speed to the first variable speed position, then switches to the second region speed to the second variable speed position, then switches to the third region speed to the third variable speed position, then switches back to the second region speed, and finally switches back to the first region speed to complete the upward scan. When the wafer is scanned downwards, the speed switching sequence is symmetrical to that of scanning upwards.

5. The ion implantation method for semiconductor wafers according to any one of claims 1-4, characterized in that, In step S5, the number of directions is n, where n is 1, 2, 4, 8, 16, or 32.

6. The ion implantation method for semiconductor wafers according to claim 5, characterized in that, The specific process of step S5 is as follows: The wafer is placed at 0 degrees and an upward scan is performed once; the wafer is rotated 360° / n and a downward scan is performed once; the wafer is rotated 360° / n degrees again and an upward scan is performed, and so on, to complete the injection in a total of n different orientations.

7. The ion implantation method for semiconductor wafers according to any one of claims 1-4, characterized in that, In step S3, the injection rate of each region is inversely proportional to the corresponding target dose.

8. A computer program product, comprising a computer program, characterized in that, The computer program is executed by the processor to perform the steps of the method as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program, when run by a processor, performs the steps of the method as described in any one of claims 1-7.

10. An ion implantation system for semiconductor wafers, comprising an interconnected memory and a processor, wherein the memory stores a computer program, characterized in that... The computer program, when run by a processor, performs the steps of the method as described in any one of claims 1-7.

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