A method and device for controlling the grinding thickness of a semiconductor silicon wafer with a substrate

Abstract

The present invention discloses a method and apparatus for controlling the grinding thickness of a semiconductor silicon wafer with a substrate. A method for controlling the grinding thickness of a semiconductor silicon wafer with a substrate includes, when grinding the silicon wafer layer of the silicon wafer to be ground, obtaining a first value detected by a contact probe and a second value detected by a non-contact infrared probe. Wherein, the silicon wafer to be ground includes a substrate layer and the silicon wafer layer, the first value is the total thickness of the silicon wafer to be ground, and the second value is the optical path of the silicon wafer layer; when the first value or the second value meets a first preset condition, stop grinding the silicon wafer layer to obtain a target ground silicon wafer.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor silicon wafer grinding, and particularly to a method and device for controlling the grinding thickness of a semiconductor silicon wafer with a substrate. Background Art

[0002] Existing silicon wafer grinding equipment is equipped with contact-type grinding thickness monitoring probes, such as micrometers (also known as screw gauges), with a monitoring accuracy of up to 2 μm. The grinding equipment control software can measure the height information of the upper surface of the silicon wafer being ground in real time, and then grind a silicon wafer with a smooth upper surface and uniform total thickness. However, when a substrate is bonded under the silicon wafer, in the same production batch, the thickness of the substrate is often not completely consistent. Then, even though the probe measurement of the existing grinding equipment and the grinding control software can accurately control the total thickness after grinding, they cannot ensure the thickness of the silicon wafer layer being ground, resulting in a low thickness accuracy of the silicon wafer layer being ground. Summary of the Invention

[0003] Based on this, in view of the above technical problems, a method and device for controlling the grinding thickness of a semiconductor silicon wafer with a substrate are provided to solve the problem of low thickness accuracy of the existing silicon wafer layer being ground.

[0004] In a first aspect, a method for controlling the grinding thickness of a semiconductor silicon wafer with a substrate, the method includes:

[0005] When grinding the silicon wafer layer of the silicon wafer to be ground, obtaining a first value detected by a contact-type probe and a second value detected by a non-contact infrared probe, wherein the silicon wafer to be ground includes a substrate layer and the silicon wafer layer, the first value is the total thickness of the silicon wafer to be ground, and the second value is the optical path of the silicon wafer layer;

[0006] When the first value or the second value meets a first preset condition, stopping the grinding of the silicon wafer layer to obtain a target ground silicon wafer;

[0007] Wherein, the total thickness of the silicon wafer to be ground is the sum of the thickness of the substrate layer and the thickness of the silicon wafer layer;

[0008] Wherein, the first value or the second value meeting the first preset condition includes any one of the following:

[0009] The first value is equal to the target thickness He of the silicon wafer to be ground;

[0010] The second value is equal to the target optical path Ie of the silicon wafer layer;

[0011] Wherein, He = h1 - (h1 - h2) / (i1 - i2) * i1 + Te, Ie = Te * (i1 - i2) / (h1 - h2);

[0012] Wherein, h1 is the first value detected by the contact probe at time t1, and h2 is the first value detected by the contact probe at time t2;

[0013] i1 is the second value detected by the non-contact infrared probe at time t1; i2 is the second value detected by the non-contact infrared probe at time t2;

[0014] Te is the thickness of the silicon layer of the target polished silicon wafer;

[0015] The time t1 and the time t2 are different times during the grinding process of the silicon layer.

[0016] In the above solution, optionally, when grinding the silicon layer of the silicon wafer to be ground, after obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe, the method further includes:

[0017] When both the first value and the second value do not meet the first preset condition, determine the thickness Ce of the silicon layer to be continuously ground and removed;

[0018] Continue to grind the silicon layer according to the thickness Ce of the silicon layer to be continuously ground and removed;

[0019] Wherein, Ce = (h1 - h2) / (i1 - i2) * i1 - Te.

[0020] In the above solution, further optionally, when grinding the silicon layer of the silicon wafer to be ground, after obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe, the method further includes:

[0021] When both the first value and the second value do not meet the first preset condition, determine the optical path Se of the silicon layer to be continuously ground and reduced;

[0022] Continue to grind the silicon layer according to the optical path Se of the silicon layer to be continuously ground and reduced;

[0023] Wherein, Se = i1 - Te * (i1 - i2) / (h1 - h2).

[0024] In the above solution, further optionally, when grinding the silicon layer of the silicon wafer to be ground, obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe includes:

[0025] When grinding the silicon layer of the silicon wafer to be ground, at the first target time, continuously obtain p first value candidates detected by the contact probe;

[0026] Take the median value of p first numerical candidates as the first numerical value at the first target time;

[0027] At the second target time, continuously obtain q second numerical candidates detected by the non-contact infrared probe;

[0028] Take the median value of q second numerical candidates as the second numerical value at the second target time.

[0029] In the above solution, further optionally, when grinding the silicon layer of the silicon wafer to be ground, after obtaining the first numerical value detected by the contact probe and the second numerical value detected by the non-contact infrared probe, the method further includes:

[0030] When grinding the silicon layer of the silicon wafer to be ground, take t1 as the starting time, continuously obtain n first numerical values h1 and second numerical values i1, and obtain n groups (h1, i1);

[0031] Take t2 as the starting time, continuously obtain m first numerical values h2 and second numerical values i2, and obtain m groups (h2, i2);

[0032] Perform quadratic linear fitting on n groups (h1, i1), and eliminate the (h1, i1) that do not meet the second preset condition in n groups (h1, i1), to obtain the target quadratic fitting curve at t1;

[0033] Perform quadratic linear fitting on m groups (h2, i2), and eliminate the (h2, i2) that do not meet the third preset condition in m groups (h2, i2), to obtain the target quadratic fitting curve at t2.

[0034] In the above solution, further optionally, the second preset condition is that the distance from a group (h1, i1) to the quadratic fitting curve at t1 is less than 3 times the root mean square of the distances from n (h1, i1) to the quadratic fitting curve.

[0035] In the above solution, further optionally, the third preset condition is that the distance from a group (h2, i2) to the quadratic fitting curve at t2 is less than 3 times the root mean square of the distances from m (h2, i2) to the quadratic fitting curve.

[0036] In a second aspect, a grinding thickness control device for a semiconductor silicon wafer with a substrate, characterized in that the device includes a grinding platform and a measuring mechanism arranged on the grinding platform;

[0037] At least one installation groove for installing the silicon wafer to be ground is opened on the grinding platform, and the silicon wafer to be ground includes a substrate layer and a silicon layer;

[0038] The measuring mechanism includes a contact probe and a non-contact infrared probe;

[0039] The contact probe is used to measure the sum of the thickness of the substrate layer and the thickness of the silicon wafer layer;

[0040] The non-contact infrared probe is located directly above the silicon wafer layer, and there is a gap between the non-contact infrared probe and the silicon wafer layer. The non-contact infrared probe is used to measure the optical path of the silicon wafer layer.

[0041] In a third aspect, a computer-readable storage medium stores a computer program thereon. When the computer program is executed by a processor, the following steps are implemented:

[0042] When grinding the silicon wafer layer of the silicon wafer to be ground, obtain a first value detected by the contact probe and a second value detected by the non-contact infrared probe. Wherein, the silicon wafer to be ground includes a substrate layer and the silicon wafer layer, the first value is the total thickness of the silicon wafer to be ground, and the second value is the optical path of the silicon wafer layer;

[0043] When the first value or the second value meets a first preset condition, stop grinding the silicon wafer layer to obtain a target ground silicon wafer;

[0044] Wherein, the total thickness of the silicon wafer to be ground is the sum of the thickness of the substrate layer and the thickness of the silicon wafer layer;

[0045] Wherein, the first value or the second value meeting the first preset condition includes any one of the following:

[0046] The first value is equal to the target thickness He of the silicon wafer to be ground;

[0047] The second value is equal to the target optical path Ie of the silicon wafer layer;

[0048] Wherein, He = h1 - (h1 - h2) / (i1 - i2)*i1 + Te, Ie = Te*(i1 - i2) / (h1 - h2);

[0049] Wherein, h1 is the first value detected by the contact probe at time t1, and h2 is the first value detected by the contact probe at time t2;

[0050] i1 is the second value detected by the non-contact infrared probe at time t1; i2 is the second value detected by the non-contact infrared probe at time t2;

[0051] Te is the thickness of the silicon wafer layer of the target ground silicon wafer;

[0052] The time t1 and the time t2 are different times during the grinding process of the silicon wafer layer, respectively.

[0053] The present invention has at least the following beneficial effects:

[0054] Based on further analysis and research of the problems of the existing technology, it is recognized that the probe measurement and grinding control software of the existing grinding equipment can accurately control the total thickness of the silicon wafer to be ground after grinding, but cannot guarantee the accuracy of the thickness of the silicon wafer layer to be ground in the silicon wafer to be ground.

[0055] In the case of grinding the silicon wafer layer of the silicon wafer to be ground, the total thickness of the silicon wafer to be ground is detected by an existing contact probe as a first value, and the optical path of the silicon wafer layer of the silicon wafer to be ground is detected by an additional non-contact infrared probe as a second value. When the first value is equal to the target thickness of the silicon wafer to be ground, or the second value is equal to the target optical path of the silicon wafer layer, the grinding of the silicon wafer layer is stopped, and a target ground silicon wafer can be obtained. The thickness of the silicon wafer layer of the target ground silicon wafer is equal to the thickness of the silicon wafer layer expected by the user. Through the grinding thickness control method of the present application, the real-time monitoring and precise control of the grinding thickness of the silicon wafer layer can be realized, and it is not affected by the inaccurate thickness of the substrate layer. According to the characteristic that the infrared ray of the non-contact infrared probe can penetrate the silicon wafer, the non-contact infrared probe is used to obtain the optical path information of the infrared ray passing through the ground silicon wafer layer in real time, so as to grind a semiconductor silicon wafer with a substrate whose surface silicon material meets the precise requirements, and the grinding thickness accuracy is high; and it will not damage the structure of the existing grinding equipment, which is convenient for popularization and use. Description of the Drawings

[0056] Figure 1 It is a schematic flowchart of a method for controlling the grinding thickness of a semiconductor silicon wafer with a substrate provided by an embodiment of the present invention;

[0057] Figure 2 It is a schematic cross-sectional view of the thickness of a silicon wafer to be ground provided by an embodiment of the present invention;

[0058] Figure 3 It is a schematic structural diagram of a device for controlling the grinding thickness of a semiconductor silicon wafer with a substrate provided by an embodiment of the present invention;

[0059] Figure 4 It is a timing relationship diagram of probe readings of a method for controlling the grinding thickness of a semiconductor silicon wafer provided by an embodiment of the present invention. Detailed Embodiments

[0060] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0061] A method for controlling the grinding thickness of a semiconductor silicon wafer with a substrate includes the following steps:

[0062] When grinding the silicon wafer layer of the silicon wafer to be ground, obtain a first value detected by a contact probe and a second value detected by a non-contact infrared probe. Wherein, the silicon wafer to be ground includes a substrate layer and the silicon wafer layer, the first value is the total thickness of the silicon wafer to be ground, and the second value is the optical path of the silicon wafer layer;

[0063] When the first value or the second value meets a first preset condition, stop grinding the silicon wafer layer to obtain a target ground silicon wafer;

[0064] Wherein, the total thickness of the silicon wafer to be ground is the sum of the thickness of the substrate layer and the thickness of the silicon wafer layer;

[0065] Wherein, the first value or the second value meeting the first preset condition includes any one of the following:

[0066] The first value is equal to the target thickness He of the silicon wafer to be ground;

[0067] The second value is equal to the target optical path Ie of the silicon wafer layer;

[0068] Wherein, He = h1 - (h1 - h2) / (i1 - i2)*i1 + Te, Ie = Te*(i1 - i2) / (h1 - h2);

[0069] Wherein, h1 is the first value detected by the contact probe at time t1, and h2 is the first value detected by the contact probe at time t2;

[0070] The i1 is the second value detected by the non-contact infrared probe at time t1; the i2 is the second value detected by the non-contact infrared probe at time t2;

[0071] Te is the thickness of the silicon wafer layer of the target ground silicon wafer;

[0072] The time t1 and the time t2 are different times during the grinding process of the silicon wafer layer.

[0073] In one embodiment, after obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe when grinding the silicon wafer layer of the silicon wafer to be ground, the method further includes:

[0074] When the first value and the second value do not meet the first preset condition, determine the thickness Ce of the silicon wafer layer to be continuously ground and removed;

[0075] According to the thickness Ce of the silicon wafer layer to be continuously ground and removed, continue to grind the silicon wafer layer;

[0076] Wherein, Ce = (h1 - h2) / (i1 - i2)*i1 - Te.

[0077] In one embodiment, when grinding the silicon wafer layer of the silicon wafer to be ground, after obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe, the method further includes:

[0078] When both the first value and the second value do not meet the first preset condition, determine the optical path Se of the silicon wafer layer to be continuously ground and reduced;

[0079] According to the optical path Se of the silicon wafer layer to be continuously ground and reduced, continue to grind the silicon wafer layer;

[0080] Wherein, Se = i1 - Te*(i1 - i2) / (h1 - h2).

[0081] In one embodiment, when grinding the silicon wafer layer of the silicon wafer to be ground, obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe includes:

[0082] When grinding the silicon wafer layer of the silicon wafer to be ground, at the first target moment, continuously obtain p first value candidates detected by the contact probe;

[0083] Take the median value of the p first value candidates as the first value at the first target moment;

[0084] At the second target moment, continuously obtain q second value candidates detected by the non-contact infrared probe;

[0085] Take the median value of the q second value candidates as the second value at the second target moment.

[0086] In this embodiment, it should be noted that the acquisition frequencies of the first value candidates and the second value candidates can be the same or different, and this embodiment does not make specific limitations on this.

[0087] When the acquisition frequencies of the first value candidates and the second value candidates are the same, p = q; when the acquisition frequencies of the first value candidates and the second value candidates are different, p ≠ q. In practical applications, the time used to continuously obtain the p first value candidates detected by the contact probe can be one-thousandth of a second; the time used to continuously obtain the q second value candidates detected by the non-contact infrared probe can be one-thousandth of a second.

[0088] In one embodiment, when grinding the silicon wafer layer of the silicon wafer to be ground, after obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe, the method further includes:

[0089] When grinding the silicon wafer layer of the silicon wafer to be ground, taking the t1 moment as the starting moment, continuously obtaining n first values h1 and second values i1, and obtaining n groups of (h1, i1);

[0090] Taking the t2 moment as the starting moment, continuously obtaining m first values h2 and second values i2, and obtaining m groups of (h2, i2);

[0091] Performing quadratic linear fitting on the n groups of (h1, i1), and eliminating the (h1, i1) that do not meet the second preset condition among the n groups of (h1, i1), so as to obtain the target quadratic fitting curve at the t1 moment;

[0092] Performing quadratic linear fitting on the m groups of (h2, i2), and eliminating the (h2, i2) that do not meet the third preset condition among the m groups of (h2, i2), so as to obtain the target quadratic fitting curve at the t2 moment.

[0093] In one embodiment, the second preset condition is that the distance from a group of (h1, i1) to the quadratic fitting curve at the t1 moment is less than 3 times the root mean square of the distances from the n groups of (h1, i1) to the quadratic fitting curve.

[0094] In one embodiment, the third preset condition is that the distance from a group of (h2, i2) to the quadratic fitting curve at the t2 moment is less than 3 times the root mean square of the distances from the m groups of (h2, i2) to the quadratic fitting curve.

[0095] In one embodiment, to eliminate the environmental interference at the silicon wafer grinding site and the probe reading error, the data reading and processing adopt the following steps:

[0096] (1) Median filtering for single-point data reading, that is: selecting the median from several continuously read data (such as 3 times, 5 times) to prevent interference in data reading and eliminate invalid noise points.

[0097] (2) Continuous reading mode, that is:

[0098] Starting from the t1 moment, continuously obtaining the median-filtered readings of two probes (contact probe and infrared laser interferometer probe) n times, and obtaining n groups of (h1, i1) readings;

[0099] Then, starting from the t2 moment, continuously obtaining the median-filtered readings of the two probes m times, and obtaining m groups of (h2, i2) readings;

[0100] The rotation speed of general grinding production equipment can reach 2400 rpm, that is, 40 revolutions per second. If the reading is taken once every 10 degrees of rotation, then the number of readings per second can be 360 / 10*40 = 1440 times; if the reading is taken once every 5 degrees, the number of readings per second is 2880 times.

[0101] Generally, it takes about 5 minutes to grind a silicon wafer. The time length experienced for reading n groups of data can be selected to be in seconds.

[0102] (3) Quadratic linear fitting filtering of sampled data

[0103] Perform quadratic linear fitting on n (h1, i1) sampled starting from time t1 and m (h2, i2) sampled starting from time t2 respectively, and eliminate the sampling points that deviate from the quadratic fitting curve by more than 3 times the deviation mean square error as invalid data; continuously iterate fitting and elimination until all the remaining sampling points participating in the fitting deviate from the quadratic fitting curve within 3 times the deviation mean square error range.

[0104] (4) Randomly select a point on the quadratic fitting curve starting from time t1, and obtain its reading as (H1, I1); randomly select a point on the quadratic fitting curve starting from time t2, and obtain its reading as (H2, I2), then:

[0105] When the silicon wafer layer grinding reaches the expected thickness Te, the total thickness (including the substrate) of the silicon wafer being ground is:

[0106] He = H1 - (H1 - H2) / (I1 - I2)*I1 + Te

[0107] The infrared optical path of the silicon wafer layer is:

[0108] Ie = Te*(I1 - I2) / (H1 - H2)

[0109] (5) After obtaining the m (h2, i2) data sampled starting from time t2, continue to read the reading I of the infrared probe and the reading H of the contact probe, monitor the continuous decrease of the I and H values, and stop grinding when I is close to Ie or H is close to He (the proximity threshold can be set according to actual needs), that is, obtain the substrate wafer with the grinding thickness of the silicon wafer layer meeting the precise requirements.

[0110] It should be understood that although Figure 1 the steps in the flowchart of Figure 1At least a part of the steps may include multiple steps or multiple stages. These steps or stages are not necessarily executed and completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0111] In one embodiment, the present application further provides a grinding thickness control device for a semiconductor silicon wafer with a substrate, as Figure 3 shown. The grinding thickness control device includes a grinding platform 1 and a measuring mechanism arranged on the grinding platform 1;

[0112] At least one mounting groove 1-1 for mounting the silicon wafer to be ground is formed on the grinding platform. The silicon wafer to be ground includes a substrate layer and a silicon wafer layer 3;

[0113] The measuring mechanism includes a contact probe 2-1 and a non-contact infrared probe 2-2;

[0114] The contact probe 2-1 is used to measure the sum of the thickness of the substrate layer and the thickness of the silicon wafer layer 3;

[0115] The non-contact infrared probe 2-2 is located directly above the silicon wafer layer 3, and a gap is provided between the non-contact infrared probe 2-2 and the silicon wafer layer 3. The non-contact infrared probe 2-2 is used to measure the optical path of the silicon wafer layer 3.

[0116] In one embodiment, the contact probe 2-1 is fixedly connected to the grinding platform 1 through a connector, and the probe surface of the contact probe 2-1 is attached to the upper surface of the silicon wafer layer 3.

[0117] In one embodiment, the device further includes a grinding disc 4. The diameter of the grinding disc 4 is larger than the radius of the mounting groove 1-1. The grinding disc 4 is used to grind the silicon wafer layer 3;

[0118] In this embodiment, the non-contact infrared probe 2-2 is an infrared laser interferometer probe.

[0119] For the specific limitations of the grinding thickness control device, reference can be made to the limitations on the grinding thickness control method in the foregoing text, which will not be elaborated here.

[0120] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0121] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for controlling the grinding thickness of a semiconductor silicon wafer with a substrate, characterized in that, The method includes: When grinding the silicon layer of the silicon wafer to be ground, obtaining a first value detected by a contact probe and a second value detected by a non-contact infrared probe, where the silicon wafer to be ground includes a substrate layer and the silicon layer, the first value is the total thickness of the silicon wafer to be ground, and the second value is the optical path of the silicon layer; When the first value or the second value satisfies a first preset condition, stop grinding the silicon layer to obtain a target ground silicon wafer; Wherein, the total thickness of the silicon wafer to be ground is the sum of the thickness of the substrate layer and the thickness of the silicon layer; Wherein, the first value or the second value satisfying the first preset condition includes any one of the following: The first value is equal to the target thickness He of the silicon wafer to be ground; The second value is equal to the target optical path Ie of the silicon layer; Wherein, He = h1 - (h1 - h2) / (i1 - i2)*i1 + Te, Ie = Te*(i1 - i2) / (h1 - h2); Wherein, h1 is the first value detected by the contact probe at time t1, and h2 is the first value detected by the contact probe at time t2; The i1 is the second value detected by the non-contact infrared probe at time t1; the i2 is the second value detected by the non-contact infrared probe at time t2; Te is the thickness of the silicon layer of the target ground silicon wafer; The time t1 and the time t2 are different times during the grinding process of the silicon layer respectively.

2. The method according to claim 1, wherein After obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe when grinding the silicon layer of the silicon wafer to be ground, the method further includes: When the first value and the second value do not satisfy the first preset condition, determining the thickness Ce of the silicon layer to be continuously ground and removed; Continuing to grind the silicon layer according to the thickness Ce of the silicon layer to be continuously ground and removed; Wherein, Ce = (h1 - h2) / (i1 - i2)*i1 - Te.

3. The method according to claim 1, characterized in that, After obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe when grinding the silicon layer of the silicon wafer to be ground, the method further includes: When the first value and the second value do not satisfy the first preset condition, determining the optical path Se of the silicon layer to be continuously ground and reduced; Continuing to grind the silicon layer according to the optical path Se of the silicon layer to be continuously ground and reduced; Wherein, Se = i1 - Te*(i1 - i2) / (h1 - h2).

4. The method according to claim 1, characterized in that, The step of obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe when grinding the silicon layer of the silicon wafer to be ground includes: When grinding the silicon layer of the silicon wafer to be ground, at a first target time, continuously obtaining p first value candidate values detected by the contact probe; Taking the median value of the p first value candidate values as the first value at the first target time; At a second target time, continuously obtaining q second value candidate values detected by the non-contact infrared probe; Use the median value of q second numerical candidates as the second numerical value at the second target moment.

5. The method according to claim 1, wherein When grinding the silicon wafer layer of the silicon wafer to be ground, after obtaining the first numerical value detected by the contact probe and the second numerical value detected by the non-contact infrared probe, the method further includes: When grinding the silicon wafer layer of the silicon wafer to be ground, use t1 moment as the starting moment, continuously obtain n first numerical values h1 and second numerical values i1, and obtain n groups (h1, i1); Use t2 moment as the starting moment, continuously obtain m first numerical values h2 and second numerical values i2, and obtain m groups (h2, i2); Perform quadratic linear fitting on n groups (h1, i1), and eliminate (h1, i1) that do not meet the second preset condition in n groups (h1, i1) to obtain the target quadratic fitting curve at t1 moment; Perform quadratic linear fitting on m groups (h2, i2), and eliminate (h2, i2) that do not meet the third preset condition in m groups (h2, i2) to obtain the target quadratic fitting curve at t2 moment.

6. The method according to claim 5, characterized in that, The second preset condition is that the distance from a group (h1, i1) to the quadratic fitting curve at t1 moment is less than 3 times the root mean square of the distances from n (h1, i1) numerical groups to the quadratic fitting curve.

7. The method according to claim 5, wherein The third preset condition is that the distance from a group (h2, i2) to the quadratic fitting curve at t2 moment is less than 3 times the root mean square of the distances from m (h2, i2) numerical groups to the quadratic fitting curve.

8. A grinding thickness control device for a semiconductor silicon wafer with a substrate, characterized in that, The device includes a grinding platform and a measuring mechanism arranged on the grinding platform, and executes the method according to any one of claims 1 to 7; At least one installation groove for installing the silicon wafer to be ground is provided on the grinding platform, and the silicon wafer to be ground includes a substrate layer and a silicon wafer layer; The measuring mechanism includes a contact probe and a non-contact infrared probe; The contact probe is used to measure the sum of the thickness of the substrate layer and the thickness of the silicon wafer layer; The non-contact infrared probe is located directly above the silicon wafer layer, and a gap is provided between the non-contact infrared probe and the silicon wafer layer, and the non-contact infrared probe is used to measure the optical path of the silicon wafer layer.

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