Method for adjusting implantation uniformity of ion implantation equipment

Abstract

The present invention provides a method for adjusting the injection uniformity of an ion implantation machine, comprising: step S1: providing a test wafer, placing the test wafer on the target disk, and the surface of the target disk coincides with a reference surface; step S2: performing ion implantation on the test wafer according to preset ion implantation process parameters, and after the ion implantation is completed, scanning the test wafer to obtain a thermal wave value distribution diagram, obtaining the thermal wave value and position of the sampling point, and fitting the thermal wave value distribution curve using a quadratic function; step S3: judging whether the distance between the symmetry axis of the thermal wave value distribution curve and the Y axis of the thermal wave value distribution curve is less than a set value; step S4: judging whether the ion implantation uniformity of the test wafer meets the control requirements according to the thermal wave value of the sampling point; the present invention improves the injection uniformity of the ion implantation machine.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for adjusting the implantation uniformity of an ion implantation machine. Background Art

[0002] In the current applications of the integrated circuit manufacturing industry, ion implantation machines include single-wafer ion implantation machines and multi-wafer ion implantation machines. For a single-wafer ion implantation machine, only one wafer can be implanted with ions at a time. The wafer is placed on the target disk of the ion implantation machine, and the wafer performs linear scanning motion along with the target disk to implant ions into the wafer. In a single-wafer ion implantation machine, since the wafer is placed on the target disk and the target disk does not rotate, the uniformity of ion implantation can be guaranteed.

[0003] For a multi-wafer ion implantation machine, it is necessary to perform ion implantation on multiple wafers at the same time. The multi-wafer ion implantation machine has multiple target disks. When the multi-wafer ion implantation machine is working, the target disks will rotate and perform linear scanning motion. A wafer is placed on a target disk, and multiple wafers rotate with the target disk at the same time and perform linear scanning motion with the target disk, so as to perform ion implantation on multiple wafers at the same time. Since the wafer rotates with the target disk, the centripetal force required in the center area of ​​the wafer is provided by the internal stress of the wafer, which causes the wafer to present a certain curved surface shape, namely wafer warpage, and the wafer warpage will affect the ion implantation of the wafer, resulting in reduced uniformity of ion implantation. After ion implantation, the thermal wave value distribution diagram of the wafer shows that the ion implantation concentration of the wafer is distributed in a regular gradient. For example, the ion implantation concentration decreases or increases along a diameter direction of the wafer, resulting in a large difference in the ion implantation concentration on the wafer. That is, in a multi-wafer ion implantation machine, since the wafer rotates with the target disk, the centripetal force required in the center area of ​​the wafer causes the wafer to always present a certain curved shape. The ion implantation of the wafer cannot be guaranteed to be completely uniform, and the uniformity of ion implantation will affect product performance, especially when the critical dimension of the product is a relatively large process with a high depth. It is particularly important to improve the uniformity of ion implantation to improve the yield of the product. Summary of the invention

[0004] The object of the present invention is to provide a method for adjusting the implantation uniformity of an ion implantation machine, so as to improve the implantation uniformity of the ion implantation machine.

[0005] In order to achieve the above object, the present invention provides a method for adjusting the implantation uniformity of an ion implantation machine, wherein the ion implantation machine includes a plurality of target disks, and when performing ion implantation, the target disks rotate and move along a set direction to perform linear scanning, comprising:

[0006] Step S1: providing a test wafer, placing the test wafer on the target disk, the surface of the target disk coincides with the reference surface, and executing step S2;

[0007] Step S2: perform ion implantation on the test wafer according to preset ion implantation process parameters, and after the ion implantation is completed, scan the test wafer to obtain a thermal wave value distribution diagram, select a plurality of equally spaced sampling points on a straight line perpendicular to the notch direction of the test wafer on the test wafer, one of the sampling points is aligned with the notch, and the remaining sampling points are symmetrically distributed on both sides of the sampling point aligned with the notch, obtain the thermal wave value and position of the sampling point, take the sampling point aligned with the notch as the origin, the direction of the straight line as the X-axis, the thermal wave value of the sampling point as the Y coordinate, use a quadratic function to fit the thermal wave value distribution curve, and execute step S3;

[0008] Step S3: determine whether the distance between the symmetry axis of the thermal wave value distribution curve and the Y axis of the thermal wave value distribution curve is less than a set value; if not, adjust the angle between the target plate and the reference surface, and return to step S2; if yes, execute step S4;

[0009] Step S4: judging whether the ion implantation uniformity of the test wafer meets the control requirements according to the thermal wave value of the sampling point, and completing the adjustment of the ion implantation machine if it meets the control requirements; if it does not meet the control requirements, adjusting the rotation speed of the target disk and returning to step S2.

[0010] Optionally, the distance is equal to the absolute value of the X coordinate of the axis of symmetry.

[0011] Optionally, the center line of the target disk is located on the reference plane, and when the angle between the target disk and the reference plane is adjusted, the target disk rotates clockwise or counterclockwise around its own center line.

[0012] Optionally, the angle between the target plate and the reference surface is equal to the ratio of the distance to the angle setting value.

[0013] Optionally, the angle setting value is an offset of the X coordinate of the symmetry axis when the included angle between the target plate and the reference plane is 1°.

[0014] Optionally, the step of judging whether the ion implantation uniformity of the test wafer meets the control requirements includes:

[0015] Obtaining an average value of the thermal wave values ​​of the sampling points;

[0016] Calculate the thermal wave difference between the maximum thermal wave value and the minimum thermal wave value of at least three sampling points on each side of the sampling point aligned with the notch and farthest from the sampling point aligned with the notch;

[0017] Determine whether the difference between the thermal wave difference on each side and the average value is less than the thermal wave set value. If so, determine that the ion implantation uniformity of the test wafer meets the control requirements. If not, determine that the ion implantation uniformity of the test wafer does not meet the control requirements.

[0018] Optionally, the heat wave setting value is 2% to 20% of the average value.

[0019] Optionally, when the ion implantation uniformity of the test wafer does not meet the control requirement, the rotation speed of the target disk is reduced.

[0020] Optionally, the number of sampling points is greater than or equal to 7.

[0021] Optionally, when the ion implantation uniformity of the test wafer meets the control requirement, the angle between the target disk and the reference surface and the rotation speed of the target disk are stored in the ion implantation machine to complete the adjustment of the ion implantation machine.

[0022] In the method for adjusting the implantation uniformity of an ion implantation machine provided by the present invention, step S1: providing a test wafer, placing the test wafer on a target disk, the surface of the target disk coincides with the reference surface, and executing step S2; step S2: performing ion implantation on the test wafer according to preset ion implantation process parameters, and after the ion implantation is completed, scanning the test wafer to obtain a thermal wave value distribution map, selecting a plurality of equally spaced sampling points on a straight line perpendicular to the notch direction of the test wafer on the test wafer, one of the sampling points is aligned with the notch, and the remaining sampling points are symmetrically distributed on both sides of the sampling point aligned with the notch, and obtaining the thermal wave value and position of the sampling point. Set, take the sampling point of the alignment notch as the origin, the direction of the straight line as the X-axis, the thermal wave value of the sampling point as the Y coordinate, use the quadratic function to fit the thermal wave value distribution curve, and execute step S3; step S3: determine whether the distance between the symmetry axis of the thermal wave value distribution curve and the Y-axis of the thermal wave value distribution curve is less than the set value, if not, adjust the angle between the target disk and the reference surface, and return to step S2; if so, execute step S4; step S4: according to the thermal wave value of the sampling point, determine whether the ion implantation uniformity of the test wafer meets the control requirements, when it meets, complete the adjustment of the ion implantation machine; when it does not meet, adjust the rotation speed of the target disk and return to step S2. In the present invention, after knowing that the distance between the symmetry axis of the thermal wave value distribution curve and the Y-axis of the thermal wave value distribution curve is less than the set value, adjust the rotation speed of the target disk, which can reduce the centripetal force on the central area of ​​the test wafer, so as to reduce the internal stress of the test wafer, and can improve the warping of the test wafer, thereby improving the implantation uniformity of the ion implantation machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A flow chart of a method for adjusting implantation uniformity of an ion implantation machine provided in one embodiment of the present invention;

[0024] Figure 2 An ion implantation concentration distribution diagram of a test wafer in a method for adjusting implantation uniformity of an ion implantation machine provided in an embodiment of the present invention;

[0025] Figure 3A to Figure 3C A distribution curve diagram of thermal wave values ​​and positions of sampling points in a method for adjusting the implantation uniformity of an ion implantation machine provided in one embodiment of the present invention;

[0026] Figure 4A and Figure 4B A top view of a target plate for adjusting the angle between the target plate and a reference surface in a method for adjusting the implantation uniformity of an ion implantation machine provided in an embodiment of the present invention;

[0027] Wherein, the accompanying drawings are marked as follows:

[0028] D-sampling point; N-notch; S-target plate. DETAILED DESCRIPTION

[0029] The specific implementation of the present invention will be described in more detail below in conjunction with the schematic diagram. The advantages and features of the present invention will become clearer based on the following description. It should be noted that the drawings are all in a very simplified form and are not in exact proportions, and are only used to facilitate and clearly assist in explaining the purpose of the embodiments of the present invention.

[0030] Figure 1 This is a flow chart of a method for adjusting the implantation uniformity of an ion implantation machine provided in this embodiment. This embodiment provides a method for adjusting the implantation uniformity of an ion implantation machine. The ion implantation machine includes a plurality of target disks. When performing ion implantation, the target disks rotate and move along a set direction to perform linear scanning. Please refer to Figure 1 ,include:

[0031] Step S1: providing a test wafer, placing the test wafer on a target disk, with the surface of the target disk overlapping with the reference surface, and executing step S2;

[0032] Step S2: perform ion implantation on the test wafer according to preset ion implantation process parameters, and after the ion implantation is completed, scan the test wafer to obtain a thermal wave value distribution diagram, select a plurality of equally spaced sampling points on a straight line perpendicular to the notch direction of the test wafer on the test wafer, one of the sampling points is aligned with the notch, and the remaining sampling points are symmetrically distributed on both sides of the sampling point aligned with the notch, obtain the thermal wave value and position of the sampling point, take the sampling point aligned with the notch as the origin, the direction of the straight line as the X-axis, the thermal wave value of the sampling point as the Y coordinate, use a quadratic function to fit the thermal wave value distribution curve, and execute step S3;

[0033] Step S3: determine whether the distance between the symmetry axis of the thermal wave value distribution curve and the Y axis of the thermal wave value distribution curve is less than a set value. If not, adjust the angle between the target plate and the reference surface and return to step S2; if yes, execute step S4;

[0034] Step S4: According to the thermal wave value of the sampling point, determine whether the ion implantation uniformity of the test wafer meets the control requirements. If yes, complete the adjustment of the ion implantation machine; if not, adjust the rotation speed of the target disk and return to step S2.

[0035] Figure 2 An ion implantation concentration distribution diagram of a test wafer in the method for adjusting implantation uniformity of an ion implantation machine provided in this embodiment; Figure 3A to Figure 3C A distribution curve diagram of thermal wave values ​​and positions of the thermal wave values ​​of the sampling points in the method for adjusting the implantation uniformity of the ion implantation machine provided in this embodiment; Figure 4A and Figure 4B A top view of a target plate for adjusting the angle between the target plate and the reference surface in the method for adjusting the implantation uniformity of an ion implantation machine provided in this embodiment. Figure 2 , Figure 3A to Figure 3C , Figure 4A and Figure 4B The method for adjusting the implantation uniformity of the ion implantation machine provided in this embodiment is described in detail.

[0036] Execute step S1: The ion implantation machine in this embodiment includes multiple target disks, which can realize ion implantation of multiple wafers at the same time. In order to adjust the implantation uniformity of the ion implantation machine, a test wafer is provided to test and adjust the ion implantation machine, and the test wafer is placed on the target disk. The surface of the target disk coincides with the reference surface. In this embodiment, the reference surface is a vertical plane, and the ion beam of the ion implantation machine can be vertically incident on the reference surface. At this time, the angle between the target disk and the reference surface is 0°, and step S2 is executed.

[0037] Execute step S2: perform ion implantation on the test wafer according to the preset ion implantation process parameters. In this embodiment, the ion implantation process parameters include ion implantation type, ion implantation energy and ion implantation dose. For example, the ion implantation type may be P ion, the ion implantation energy may be 90 KeV, and the ion implantation dose may be 7.0x10 -12 Specific ion implantation process parameters are determined according to actual conditions. When ion implantation is performed on the test wafer, the surface of the target disk continues to coincide with the reference surface, and the target disk rotates and moves along a set direction for linear scanning. The set direction can be a direction on the reference surface.

[0038] After the test wafer completes ion implantation, the test wafer is scanned at a set temperature to obtain a thermal wave value distribution diagram. The thermal wave value distribution diagram can reflect the distribution of ion implantation concentration of the test wafer, that is, the ion implantation concentration and the thermal wave value have a mapping relationship. In this embodiment, the set temperature can be 500°C, depending on the actual situation.

[0039] As the target plate rotates, the test wafer rotates with the target plate. The centripetal force required in the center area of ​​the test wafer generates stress inside the test wafer, causing the test wafer to present a certain curved surface shape, i.e., the test wafer is warped. In addition, the test wafer has a notch, which is generally used for positioning and alignment. Although the uniformity of ion implantation will be affected when the test wafer rotates with the target plate, in order to make the ion implantation of the test wafer more uniform, under ideal conditions, after the ion implantation, the distribution of the ion implantation concentration of the test wafer is required to gradually increase or decrease in the direction perpendicular to the notch of the test wafer and centered on the notch direction of the test wafer toward the edge of the test wafer.

[0040] Please refer to Figure 2 , Figure 2 N in is the notch of the test wafer. Figure 2 Different filling patterns represent different ion implantation concentrations. In fact, the ion implantation concentration should be more gradual. Figure 2 The following only briefly shows the gradient of ion implantation concentration. Figure 2 It can be seen from the figure that the distribution of the ion implantation concentration of the test wafer gradually increases or decreases in the direction perpendicular to the notch of the test wafer and centered on the notch direction of the test wafer. Figure 2 What is shown is the distribution of the ion implantation concentration of the test wafer under ideal conditions, but in actual conditions, it is very likely that the distribution of the ion implantation concentration of the test wafer does not gradually increase or decrease with the notch direction of the test wafer as the center axis toward the edge of the test wafer, that is, the distribution of the ion implantation concentration of the test wafer is not symmetrically distributed with the notch direction of the test wafer as the center axis. It should also be noted that in this embodiment, the distribution of the ion implantation concentration of the test wafer is set to be symmetrically distributed with the notch direction of the test wafer as the center axis according to the position of the ion implantation machine and the test wafer. In actual conditions, the distribution of the ion implantation concentration of the test wafer may be symmetrically distributed with any diameter direction of the test wafer as the center axis.

[0041] Therefore, multiple sampling points distributed equidistantly on a straight line perpendicular to the notch direction of the test wafer are selected, one of the sampling points is aligned with the notch of the test wafer, that is, in the notch direction of the test wafer, and the remaining sampling points are symmetrically distributed on both sides of the sampling point aligned with the notch. In this embodiment, the number of sampling points is greater than or equal to 7, and the specific number depends on the actual situation.

[0042] Please continue to refer to Figure 2,exist Figure 2 There are 13 sampling points D in the dotted box, one of which coincides with the center of the test wafer, i.e., aligned with the notch N of the test wafer. The remaining sampling points D are evenly divided into two groups and symmetrically distributed on both sides of the sampling points D aligned with the notch N. Figure 2 The middle dotted line shows the direction of the notch N. In this embodiment, the straight line may pass through the center of the test wafer or may not pass through the center of the test wafer.

[0043] According to the thermal wave value distribution diagram, the thermal wave value of the sampling point is obtained, with the sampling point aligned with the notch as the origin, the direction of the straight line as the X-axis, the thermal wave value of the sampling point as the Y coordinate, the position of the sampling point as the X coordinate of the sampling point, the origin as 0, and the X coordinate of the sampling point from the origin can be obtained according to the actual distance between the sampling point and the origin, or the X coordinate of the sampling point can be set by itself. The thermal wave value distribution curve is fitted using a quadratic function according to the thermal wave value and position of the sampling point, and step S3 is executed. In this embodiment, since one sampling point is aligned with the notch of the test wafer, the remaining sampling points are symmetrically distributed on both sides of the sampling point aligned with the notch. Ideally, the distribution of the ion implantation concentration of the test wafer should be centered on the notch direction of the test wafer and gradually increase or decrease axially to the edge of the test wafer, that is, the thermal wave values ​​of the sampling points symmetrically distributed on both sides of the sampling point aligned with the notch should correspond one to one and be roughly equal.

[0044] Execute step S3: Since the X coordinate of the Y axis of the thermal wave value distribution curve is 0, the distance between the symmetry axis of the thermal wave value distribution curve and the Y axis of the thermal wave value distribution curve is the absolute value of the X coordinate of the symmetry axis of the thermal wave value distribution curve. Determine whether the absolute value of the X coordinate of the symmetry axis of the thermal wave value distribution curve is less than the set value. If not, adjust the angle between the target plate and the reference surface and repeat step S2; if so, execute step S4.

[0045] Please refer to Figure 3A to Figure 3C , where the X-axis is the location of the sampling point and the Y-axis is the thermal wave value of the sampling point. Figure 3A In the example, the symmetric axis Z1 of the thermal wave value distribution curve is located on the right side of the Y axis. If the absolute value of the X1 coordinate of the symmetric axis Z1 of the thermal wave value distribution curve is greater than the set value, adjust the angle between the target disk and the reference surface and return to step S2; if the absolute value of the X1 coordinate of the symmetric axis Z1 of the thermal wave value distribution curve is less than the set value, execute step S4. Figure 3B In the above example, the symmetric axis Z2 of the thermal wave value distribution curve is located on the left side of the Y axis. If the absolute value of the X2 coordinate of the symmetric axis Z2 of the thermal wave value distribution curve is greater than the set value, adjust the angle between the target disk and the reference surface and return to step S2; if the absolute value of the X2 coordinate of the symmetric axis Z2 of the thermal wave value distribution curve is less than the set value, execute step S4. Figure 3CIn the embodiment, the symmetry axis Z3 of the thermal wave value distribution curve coincides with the Y axis, which is an ideal situation in this embodiment, and step S4 is executed. In this embodiment, after adjusting the angle between the target disk and the reference surface, before executing step S2, a new test wafer, that is, a test wafer that has not been ion-implanted, is provided, and a test wafer that has not been ion-implanted is re-placed on the target disk for ion implantation, so as to observe the ion implantation concentration distribution of the test wafer.

[0046] In this embodiment, a first set value and a second set value are provided, the first set value is a positive value, the second set value is a negative value, the absolute values ​​of the first set value and the second set value are equal, the set value is the absolute value of the first set value and the second set value, the X coordinate of the symmetric axis of the thermal wave value distribution curve is greater than the first set value and the X coordinate of the symmetric axis of the thermal wave value distribution curve is less than the second set value, both of which represent that the distance between the symmetric axis of the thermal wave value distribution curve and the Y axis of the thermal wave value distribution curve is greater than the set value, and the angle between the target disk and the reference surface is adjusted by whether the X coordinate of the symmetric axis of the thermal wave value distribution curve is on the left or right side of the Y axis of the thermal wave value distribution curve. When the X coordinate of the symmetric axis of the thermal wave value distribution curve is greater than the first set value or less than the second set value, it represents that the distance is greater than the set value, and the angle between the target disk and the reference surface needs to be adjusted.

[0047] Please refer to Figure 4A and Figure 4B Specifically, the center line of the target disk is located on the reference plane. When the angle between the target disk and the reference plane is adjusted, the target disk rotates clockwise or counterclockwise around its own center line. Figure 4A In , the dotted line is the reference surface. If the X coordinate of the symmetric axis of the thermal wave value distribution curve is less than the second set value, the target plate S can be adjusted to rotate clockwise around its own center line so that the angle between the target plate S and the reference surface is θ°; Figure 4B In , the dotted line is the reference surface. If the X coordinate of the symmetric axis of the thermal wave value distribution curve is greater than the first set value, the target plate S can be adjusted to rotate counterclockwise around its own center line so that the angle between the target plate S and the reference surface is θ°. Figure 4A and Figure 4B The above is only an example, and it depends on the specific situation in actual application. For example, the angle between the target plate and the reference surface is adjusted clockwise or counterclockwise according to the actual application. In this embodiment, the distribution of the ion implantation concentration of the adjusted ion implantation machine can be changed by adjusting the angle between the target plate and the reference surface, so that the distribution of the ion implantation concentration of the subsequent test wafer is symmetrically distributed with the notch direction of the test wafer as the central axis.

[0048] In this embodiment, the angle between the target plate and the reference surface is equal to the ratio of the distance to the angle setting value, and this distance is the distance between the symmetry axis of the thermal wave value distribution curve and the Y axis of the thermal wave value distribution curve; wherein the angle setting value is the offset of the X coordinate of the symmetry axis when the angle between the target plate and the reference surface is 1°, that is, the absolute value of the difference between the X coordinate of the symmetry axis when the angle between the target plate and the reference surface is 1° and when the angle between the target plate and the reference surface is 0°.

[0049] Executing step S4: judging whether the ion implantation uniformity of the test wafer meets the control requirements according to the thermal wave value of the sampling point includes: obtaining the average value of the thermal wave value of the sampling point. In this embodiment, the sampling point can be reselected, that is, the sampling point selected in step S4 can be different from the sampling point selected in step S2, but the sampling points selected are all located on a straight line perpendicular to the notch direction of the test wafer and are equidistantly distributed, one of the sampling points is aligned with the notch, and the remaining sampling points are symmetrically distributed on both sides of the sampling point aligned with the notch; further, the sampling point on each side of the sampling point aligned with the notch, which is farthest from the notch, is calculated. The thermal wave difference between the maximum thermal wave value and the minimum thermal wave value in at least three sampling points of the sampling points of the mouth; and, whether the difference between the thermal wave difference value on each side and the average value is less than the thermal wave setting value, if so, it is determined that the ion implantation uniformity of the test wafer meets the control requirements, when the ion implantation uniformity of the test wafer meets the control requirements, the angle between the target disk and the reference surface and the rotation speed of the target disk are stored in the ion implantation machine to complete the adjustment of the ion implantation machine; if not, it is determined that the ion implantation uniformity of the test wafer does not meet the control requirements, indicating that the ion implantation is not uniform enough and cannot meet the process requirements, then the rotation speed of the target disk is reduced. Since the rotation speed of the target disk will affect the centripetal force required in the central area of ​​the test wafer, the smaller the rotation speed of the target disk, the smaller the centripetal force required in the central area of ​​the test wafer, the smaller the stress inside the test wafer, the warping degree of the test wafer can be reduced, and the ion implantation concentration of the test wafer is more uniform. In this embodiment, the thermal wave setting value is 2% to 20% of the average value, which depends on the actual situation.

[0050] Furthermore, after reducing the rotation speed of the target disk, return to step S2, and before executing step S2, provide a new test wafer, that is, a test wafer that has not been ion-implanted, and place a new test wafer that has not been ion-implanted on the target disk for ion implantation, so as to observe the ion implantation concentration distribution of the test wafer. Execute steps S2 to S4 until the ion implantation uniformity of the test wafer meets the control requirements, thereby improving the implantation uniformity of the ion implantation machine.

[0051] In summary, in the method for adjusting the implantation uniformity of the ion implantation machine provided by the present invention, step S1: provide a test wafer, place the test wafer on a target disk, the surface of the target disk coincides with the reference surface, and execute step S2; step S2: perform ion implantation on the test wafer according to preset ion implantation process parameters, and after the ion implantation is completed, scan the test wafer to obtain a thermal wave value distribution map, select a plurality of equidistantly distributed sampling points on a straight line perpendicular to the notch direction of the test wafer on the test wafer, one of the sampling points is aligned with the notch, and the remaining sampling points are symmetrically distributed on both sides of the sampling point aligned with the notch, and obtain the thermal wave value and Position, take the sampling point of the alignment notch as the origin, the direction of the straight line as the X-axis, the thermal wave value of the sampling point as the Y-coordinate, use the quadratic function to fit the thermal wave value distribution curve, and execute step S3; step S3: determine whether the distance between the symmetry axis of the thermal wave value distribution curve and the Y-axis of the thermal wave value distribution curve is less than the set value, if not, adjust the angle between the target disk and the reference surface, and return to step S2; if so, execute step S4; step S4: according to the thermal wave value of the sampling point, determine whether the ion implantation uniformity of the test wafer meets the control requirements, when it meets, complete the adjustment of the ion implantation machine; when it does not meet, adjust the rotation speed of the target disk and return to step S2. In the present invention, after knowing that the distance between the symmetry axis of the thermal wave value distribution curve and the Y-axis of the thermal wave value distribution curve is less than the set value, adjust the rotation speed of the target disk, which can reduce the centripetal force on the central area of ​​the test wafer, so as to reduce the internal stress of the test wafer, and improve the warping of the test wafer, thereby improving the implantation uniformity of the ion implantation machine.

[0052] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A method for adjusting the implantation uniformity of an ion implantation machine, wherein the ion implantation machine comprises a plurality of target disks, and when performing ion implantation, the target disks rotate and move along a set direction to perform linear scanning, wherein: include: Step S1: providing a test wafer, placing the test wafer on the target disk, the surface of the target disk coincides with the reference surface, and executing step S2; Step S2: perform ion implantation on the test wafer according to preset ion implantation process parameters, and after the ion implantation is completed, scan the test wafer to obtain a thermal wave value distribution diagram, select a plurality of equally spaced sampling points on a straight line perpendicular to the notch direction of the test wafer on the test wafer, one of the sampling points is aligned with the notch, and the remaining sampling points are symmetrically distributed on both sides of the sampling point aligned with the notch, obtain the thermal wave value and position of the sampling point, take the sampling point aligned with the notch as the origin, the direction of the straight line as the X-axis, the thermal wave value of the sampling point as the Y coordinate, use a quadratic function to fit the thermal wave value distribution curve, and execute step S3; Step S3: determine whether the distance between the symmetry axis of the thermal wave value distribution curve and the Y axis of the thermal wave value distribution curve is less than a set value; if not, adjust the angle between the target plate and the reference surface, and return to step S2; if yes, execute step S4; Step S4: judging whether the ion implantation uniformity of the test wafer meets the control requirements according to the thermal wave value of the sampling point, and completing the adjustment of the ion implantation machine if it meets the control requirements; if it does not meet the control requirements, adjusting the rotation speed of the target disk and returning to step S2.

2. The method for adjusting implantation uniformity of an ion implantation apparatus according to claim 1, wherein: The distance is equal to the absolute value of the X coordinate of the axis of symmetry.

3. The method for adjusting implantation uniformity of an ion implantation apparatus according to claim 1, wherein: The center line of the target disk is located on the reference surface. When the angle between the target disk and the reference surface is adjusted, the target disk rotates clockwise or counterclockwise around its own center line.

4. The method for adjusting implantation uniformity of an ion implantation apparatus according to claim 1 or 3, characterized in that: The included angle between the target plate and the reference surface is equal to the ratio of the distance to the angle setting value.

5. The method for adjusting implantation uniformity of an ion implantation apparatus according to claim 4, wherein: The angle setting value is the offset of the X coordinate of the symmetry axis when the included angle between the target plate and the reference surface is 1°.

6. The method for adjusting implantation uniformity of an ion implantation apparatus according to claim 1, wherein: The step of judging whether the ion implantation uniformity of the test wafer meets the control requirements comprises: Obtaining an average value of the thermal wave values ​​of the sampling points; Calculate the thermal wave difference between the maximum thermal wave value and the minimum thermal wave value of at least three sampling points on each side of the sampling point aligned with the notch and farthest from the sampling point aligned with the notch; Determine whether the difference between the thermal wave difference on each side and the average value is less than the thermal wave set value. If so, determine that the ion implantation uniformity of the test wafer meets the control requirements. If not, determine that the ion implantation uniformity of the test wafer does not meet the control requirements.

7. The method for adjusting implantation uniformity of an ion implantation apparatus according to claim 6, wherein: The heat wave setting value is 2% to 20% of the average value.

8. The method for adjusting implantation uniformity of an ion implantation apparatus according to claim 1 or 6, wherein: When the ion implantation uniformity of the test wafer does not meet the control requirement, the rotation speed of the target disk is reduced.

9. The method for adjusting implantation uniformity of an ion implantation apparatus according to claim 1, wherein: The number of the sampling points is greater than or equal to 7.

10. The method for adjusting implantation uniformity of an ion implantation apparatus according to claim 1, wherein: When the ion implantation uniformity of the test wafer meets the control requirement, the angle between the target disk and the reference surface and the rotation speed of the target disk are stored in the ion implantation machine to complete the adjustment of the ion implantation machine.

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