CN116810636A - A method and device for controlling the grinding thickness of semiconductor silicon wafers containing a substrate - Google Patents

Abstract

The application discloses a method and a device for controlling the grinding thickness of a semiconductor silicon wafer containing a substrate, wherein the method for controlling the grinding thickness of the semiconductor silicon wafer containing the substrate comprises the steps of acquiring a first numerical value detected by a contact probe and a second numerical value detected by a non-contact infrared probe under the condition of grinding a silicon wafer layer of the silicon wafer to be ground, wherein the silicon wafer to be ground comprises a substrate layer and the silicon wafer layer, the first numerical value is the total thickness of the silicon wafer to be ground, and the second numerical value is the optical path of the silicon wafer layer; and stopping grinding the silicon wafer layer under the condition that the first numerical value or the second numerical value meets a first preset condition to obtain the target ground silicon wafer.

Description

A method and device for controlling the grinding thickness of semiconductor silicon wafers containing a substrate

Technical field

The present application relates to the technical field of semiconductor silicon wafer grinding, and in particular to a method and device for controlling the grinding thickness of semiconductor silicon wafers containing a substrate.

Background technique

Existing silicon wafer grinding equipment is equipped with contact grinding thickness monitoring probes, such as spiral micrometers (also called micrometers), with monitoring accuracy up to 2um; grinding equipment control software can measure the height information of the upper surface of the polished silicon wafer in real time , and then grind the silicon wafer with a smooth upper surface and uniform thickness. However, when a substrate is bonded underneath the silicon wafer, the thickness of the substrate is often not completely consistent within the same production batch. So even though the probe measurement and grinding control software of existing grinding equipment can accurately control the total thickness after grinding, it cannot guarantee the thickness of the silicon wafer layer being ground, resulting in low thickness accuracy of the silicon wafer layer being ground.

Contents of the invention

Based on this, in view of the above technical problems, a method and device for controlling the polishing thickness of a semiconductor silicon wafer containing a substrate are provided to solve the existing problem of low thickness accuracy of the polished silicon wafer layer.

In a first aspect, a method for controlling the grinding thickness of a semiconductor silicon wafer containing a substrate, the method includes:

In the case of grinding the silicon wafer layer of the silicon wafer to be ground, the first value detected by the contact probe and the second value detected by the non-contact infrared probe are obtained, wherein the silicon wafer to be polished 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 the first preset condition, stop grinding the silicon wafer layer to obtain the target polished 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 wafer layer;

Wherein, the first numerical value or the second numerical 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 wafer layer;

Among them, He=h ₁ -(h ₁ -h ₂ )/(i ₁ -i ₂ )*i ₁ +Te, Ie=Te*(i ₁ -i ₂ )/(h ₁ -h ₂ );

Wherein, h ₁ is the first value detected by the contact probe at time t ₁ , and h ₂ is the first value detected by the contact probe at time t ₂ ;

The i ₁ is the second value detected by the non-contact infrared probe at time t ₁ ; the i ₂ is the second value detected by the non-contact infrared probe at time t ₂ ;

Te is the thickness of the silicon wafer layer of the target polished silicon wafer;

The time t ₁ and the time t ₂ are respectively different times during the grinding process of the silicon wafer layer.

In the above scheme, optionally, after obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the Methods also include:

In the case where neither the first value nor the second value meets the first preset condition, determine the thickness Ce of the silicon wafer layer to be continued to be removed by grinding;

Continue to grind the silicon wafer layer according to the thickness Ce of the silicon wafer layer to be further removed by grinding;

Among them, Ce=(h ₁ -h ₂ )/(i ₁ -i ₂ )*i ₁ -Te.

In the above scheme, further optionally, after the first value detected by the contact probe and the second value detected by the non-contact infrared probe are obtained in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the The above methods also include:

When neither the first value nor the second value meets the first preset condition, determine the optical path Se of the silicon wafer layer to be reduced by continuing grinding;

Continue to polish the silicon wafer layer according to the optical path Se of the silicon wafer layer that is to be further reduced by polishing;

Where, Se=i ₁ -Te*(i ₁ -i ₂ )/(h ₁ -h ₂ ).

In the above solution, further optionally, in the case of 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 include:

In the case of grinding the silicon wafer layer of the silicon wafer to be ground, at the first target time, continuously obtain p first numerical candidate values detected by the contact probe;

Use the median value of the p first numerical candidate values as the first numerical value of the first target time;

At the second target moment, continuously acquire q second numerical candidate values detected by the non-contact infrared probe;

The median value of the q second value candidate values is used as the second value of the second target time.

In the above scheme, further optionally, after the first value detected by the contact probe and the second value detected by the non-contact infrared probe are obtained in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the The above methods also include:

In the case of polishing the silicon wafer layer of the silicon wafer to be polished, time t ₁ is used as the starting time, and n first numerical values h ₁ and second numerical values i ₁ are continuously obtained to obtain n groups (h ₁ , i ₁ ) ;

Taking time t ₂ as the starting time, continuously obtain m first values h ₂ and second values i ₂ to obtain m groups (h ₂ , i ₂ );

Perform quadratic linear fitting on n groups (h ₁ , i ₁ ), and eliminate those (h ₁ , i ₁ ) in n groups (h ₁ , i ₁ ) that do not meet the second preset condition to obtain t ₁ The target quadratic fitting curve at time;

Perform quadratic linear fitting on the m group (h ₂ , i ₂ ), and eliminate those (h ₂ , i ₂ ) that do not meet the third preset condition in the m group (h ₂ , i ₂ ) to obtain t ₂ target quadratic fit curve at time.

In the above scheme, further optionally, the second preset condition is that the distance between a set of (h ₁ , i ₁ ) and the quadratic fitting curve at time t ₁ is less than n (h ₁ , i ₁ ) to all The distance of the quadratic fitting curve is 3 times the root mean square.

In the above scheme, further optionally, the third preset condition is that the distance between a set of (h ₂ , i ₂ ) and the quadratic fitting curve at time t ₂ is less than m (h ₂ , i ₂ ) to all The distance of the quadratic fitting curve is 3 times the root mean square.

In a second aspect, a device for controlling the grinding thickness of a semiconductor silicon wafer containing a substrate is characterized in that the device includes a grinding platform and a measuring mechanism arranged on the grinding platform;

The grinding platform is provided with at least one mounting slot for installing the silicon wafer to be ground, and the silicon wafer to be ground includes a substrate layer and a silicon wafer layer;

The measurement 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. The non-contact infrared probe is used to measure the silicon wafer layer. The optical path of the slice.

In a third aspect, a computer-readable storage medium has a computer program stored thereon. The computer program implements the following steps when executed by a processor:

In the case of grinding the silicon wafer layer of the silicon wafer to be ground, the first value detected by the contact probe and the second value detected by the non-contact infrared probe are obtained, wherein the silicon wafer to be polished 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 the first preset condition, stop grinding the silicon wafer layer to obtain the target polished 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 wafer layer;

Wherein, the first numerical value or the second numerical 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 wafer layer;

Among them, He=h ₁ -(h ₁ -h ₂ )/(i ₁ -i ₂ )*i ₁ +Te, Ie=Te*(i ₁ -i ₂ )/(h ₁ -h ₂ );

Wherein, h ₁ is the first value detected by the contact probe at time t ₁ , and h ₂ is the first value detected by the contact probe at time t ₂ ;

The i ₁ is the second value detected by the non-contact infrared probe at time t ₁ ; the i ₂ is the second value detected by the non-contact infrared probe at time t ₂ ;

Te is the thickness of the silicon wafer layer of the target polished silicon wafer;

The time t ₁ and the time t ₂ are respectively different times during the grinding process of the silicon wafer layer.

The present invention has at least the following beneficial effects:

Based on further analysis and research on existing technical problems, the present invention realizes that the probe measurement and grinding control software of existing grinding equipment can accurately control the total thickness of the silicon wafer to be ground, but cannot guarantee the thickness of the silicon wafer to be ground. The accuracy of the thickness of the silicon wafer layer being ground.

In this application, when grinding the silicon wafer layer of the silicon wafer to be ground, the total thickness of the silicon wafer to be ground is detected as the first value through the existing contact probe, and the additional non-contact infrared probe is used to detect the thickness of the silicon wafer to be ground. The optical path of the silicon wafer layer of the silicon wafer is used as the second value, and 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 processing of the silicon wafer layer is stopped. After grinding, the target ground silicon wafer can be obtained, wherein the silicon wafer layer thickness of the target ground silicon wafer is equal to the silicon wafer layer thickness expected by the user. Through the grinding thickness control method of the present application, real-time monitoring and precise control of the grinding thickness of the silicon wafer layer can be achieved, without being affected by the inaccurate thickness of the substrate layer. According to the characteristics of the infrared rays of the non-contact infrared probe that can penetrate the silicon wafer, a non-contact infrared probe is adopted. The contact infrared probe acquires the optical path information of infrared light passing through the silicon wafer layer to be ground in real time to grind out the semiconductor silicon wafer containing the substrate whose surface silicon material meets the precise requirements. The grinding thickness is highly accurate; and it will not damage the existing grinding equipment. structure, easy to promote and use.

Description of the drawings

Figure 1 is a schematic flow chart of a method for controlling the polishing thickness of a semiconductor silicon wafer containing a substrate provided by one embodiment of the present invention;

Figure 2 is a schematic cross-sectional view of the thickness of a silicon wafer to be ground according to an embodiment of the present invention;

Figure 3 is a schematic structural diagram of a device for controlling the polishing thickness of a semiconductor silicon wafer containing a substrate provided by one embodiment of the present invention;

Figure 4 is a probe reading timing diagram of a method for controlling the polishing thickness of semiconductor silicon wafers provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clear, 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 here are only used to explain the present application and are not used to limit the present application.

This application provides a method for controlling the grinding thickness of semiconductor silicon wafers containing a substrate, which includes the following steps:

In the case of grinding the silicon wafer layer of the silicon wafer to be ground, the first value detected by the contact probe and the second value detected by the non-contact infrared probe are obtained, wherein the silicon wafer to be polished 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 the first preset condition, stop grinding the silicon wafer layer to obtain the target polished 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 wafer layer;

Wherein, the first numerical value or the second numerical 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 wafer layer;

Among them, He=h ₁ -(h ₁ -h ₂ )/(i ₁ -i ₂ )*i ₁ +Te, Ie=Te*(i ₁ -i ₂ )/(h ₁ -h ₂ );

Wherein, h ₁ is the first value detected by the contact probe at time t ₁ , and h ₂ is the first value detected by the contact probe at time t ₂ ;

The i ₁ is the second value detected by the non-contact infrared probe at time t ₁ ; the i ₂ is the second value detected by the non-contact infrared probe at time t ₂ ;

Te is the thickness of the silicon wafer layer of the target polished silicon wafer;

The time t ₁ and the time t ₂ are respectively different times during the grinding process of the silicon wafer layer.

In one embodiment, after obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the method further include:

In the case where neither the first value nor the second value meets the first preset condition, determine the thickness Ce of the silicon wafer layer to be continued to be removed by grinding;

Continue to grind the silicon wafer layer according to the thickness Ce of the silicon wafer layer to be further removed by grinding;

Among them, Ce=(h ₁ -h ₂ )/(i ₁ -i ₂ )*i ₁ -Te.

In one embodiment, after obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the method further include:

When neither the first value nor the second value meets the first preset condition, determine the optical path Se of the silicon wafer layer to be reduced by continuing grinding;

Continue to polish the silicon wafer layer according to the optical path Se of the silicon wafer layer that is to be further reduced by polishing;

Where, Se=i ₁ -Te*(i ₁ -i ₂ )/(h ₁ -h ₂ ).

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 include:

In the case of grinding the silicon wafer layer of the silicon wafer to be ground, at the first target time, continuously obtain p first numerical candidate values detected by the contact probe;

Use the median value of the p first numerical candidate values as the first numerical value of the first target time;

At the second target moment, continuously acquire q second numerical candidate values detected by the non-contact infrared probe;

The median value of the q second value candidate values is used as the second value of the second target time.

In this embodiment, it should be noted that the acquisition frequency of the first numerical candidate value and the acquisition frequency of the second numerical candidate value may be the same or different, and this embodiment does not specifically limit this.

When the acquisition frequency of the first numerical candidate value and the acquisition frequency of the second numerical candidate value are the same, p=q; when the acquisition frequency of the first numerical candidate value and the acquisition frequency of the second numerical candidate value are different, p≠q. In practical applications, the time it takes to continuously acquire p first numerical candidate values detected by the contact probe can be one thousandth of a second; the time it takes to continuously acquire q second numerical candidate values detected by the non-contact infrared probe The time can be one thousandth of a second.

In one embodiment, after obtaining the first value detected by the contact probe and the second value detected by the non-contact infrared probe in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the method further include:

In the case of polishing the silicon wafer layer of the silicon wafer to be polished, time t ₁ is used as the starting time, and n first numerical values h ₁ and second numerical values i ₁ are continuously obtained to obtain n groups (h ₁ , i ₁ ) ;

Taking time t ₂ as the starting time, continuously obtain m first values h ₂ and second values i ₂ to obtain m groups (h ₂ , i ₂ );

Perform quadratic linear fitting on n groups (h ₁ , i ₁ ), and eliminate those (h ₁ , i ₁ ) in n groups (h ₁ , i ₁ ) that do not meet the second preset condition to obtain t ₁ The target quadratic fitting curve at time;

Perform quadratic linear fitting on the m group (h ₂ , i ₂ ), and eliminate those (h ₂ , i ₂ ) that do not meet the third preset condition in the m group (h ₂ , i ₂ ) to obtain t ₂ target quadratic fit curve at time.

In one embodiment, the second preset condition is that the distance between a set of (h ₁ , i ₁ ) and the quadratic fitting curve at time t ₁ is less than n (h ₁ , i ₁ ) to the quadratic fitting curve. The distance of the fitted curve is 3 times the root mean square.

In one embodiment, the third preset condition is that the distance between a set of (h ₂ , i ₂ ) and the quadratic fitting curve at time t ₂ is less than m (h ₂ , i ₂ ) to the quadratic fitting curve. The distance of the fitted curve is 3 times the root mean square.

In one embodiment, in order to eliminate environmental interference and probe reading errors at the silicon wafer grinding site, the following steps are used for data reading and processing:

(1) Median filtering for single-point data reading, that is, selecting the median value from several consecutive data reads (such as 3 times and 5 times) to prevent interference during data reading and eliminate invalid noise points.

(2) Continuous reading mode, that is:

Starting from time t1, continuously obtain the median filtered readings of the two probes (contact probe and infrared laser interference probe) n times, and obtain n sets of (h1, i1) readings;

Then, starting from time t2, the median filtered readings of the two probes are continuously obtained m times, and m sets of (h2, i2) readings are obtained;

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

Generally, silicon wafer grinding takes about 5 minutes. The length of time it takes to read n sets of data can be selected to the second level.

(3) Quadratic linear fitting filtering of sampled data

Perform quadratic linear fitting on the n (h1, i1) samples started at t1 and the m (h2, i2) samples started on t2, respectively. For sampling points that deviate from the quadratic fitting curve by more than 3 times the mean square error Eliminate as invalid data; continue iterative fitting and elimination until all remaining sampling points participating in the fitting deviate from the quadratic fitting curve within 3 times of the mean square error.

(4) Randomly pick a point on the quadratic fitting curve sampled starting from time t1, and get its reading (H1, I1); randomly pick a point on the quadratic fitting curve sampled starting from time t2, and get its reading. is (H2, I2), then:

When the silicon wafer layer is polished to the desired thickness Te, the total thickness of the polished silicon wafer (including the substrate) is:

He＝H1-(H1-H2)/(I1-I2)*I1+Te

The infrared optical path length of the silicon wafer layer is:

Ie＝Te*(I1-I2)/(H1-H2)

(5) After obtaining m (h2, i2) data that started sampling at t2, continue to read the reading I of the infrared probe and the reading H of the contact probe, and monitor the decreasing values of I and H until I is already at When Ie approaches or H approaches He (the proximity threshold can be set according to actual needs), the grinding is stopped, and a substrate wafer whose polished thickness of the silicon wafer layer meets the precise requirements is obtained.

It should be understood that although various steps in the flowchart of FIG. 1 are shown in sequence as indicated by arrows, these steps are not necessarily executed in the order indicated by arrows. Unless explicitly stated in this article, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in Figure 1 may include multiple steps or stages. These steps or stages are not necessarily executed at the same time, but may be executed at different times. The execution order of these steps or stages is also It does not necessarily need to be performed sequentially, but may be performed in turn or alternately with other steps or at least part of steps or stages in other steps.

In one embodiment, the present application also provides a grinding thickness control device for semiconductor silicon wafers containing a substrate. As shown in Figure 3, the grinding thickness control device includes a grinding platform 1 and a grinding plate disposed on the grinding platform 1. measuring mechanism on

The grinding platform is provided with at least one mounting slot 1-1 for installing the silicon wafer to be ground, and the silicon wafer to be ground includes a substrate layer and a silicon wafer layer 3;

The measurement mechanism includes a contact probe 2-1 and a non-contact infrared probe 2-2;

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;

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

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 in contact with the upper surface of the silicon wafer layer 3 .

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;

In this embodiment, the non-contact infrared probe 2-2 is an infrared laser interference probe.

For specific limitations on the grinding thickness control device, please refer to the above limitations on the grinding thickness control method, which will not be described again here.

The technical features of the above embodiments can be combined in any way. To simplify the 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, all possible combinations should be used. It is considered to be within the scope of this manual.

The above-described embodiments only express several implementation modes of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all fall within the protection scope of the present application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims (8)

1. A method for controlling the grinding thickness of semiconductor silicon wafers containing a substrate, characterized in that the method includes: In the case of grinding the silicon wafer layer of the silicon wafer to be ground, the first value detected by the contact probe and the second value detected by the non-contact infrared probe are obtained, wherein the silicon wafer to be polished 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 the first preset condition, stop grinding the silicon wafer layer to obtain the target polished 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 wafer layer; Wherein, the first numerical value or the second numerical 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 wafer layer; Among them, He=h ₁ -(h ₁ -h ₂ )/(i ₁ -i ₂ )*i ₁ +Te, Ie=Te*(i ₁ -i ₂ )/(h ₁ -h ₂ ); Wherein, h ₁ is the first value detected by the contact probe at time t ₁ , and h ₂ is the first value detected by the contact probe at time t ₂ ; The i ₁ is the second value detected by the non-contact infrared probe at time t ₁ ; the i ₂ is the second value detected by the non-contact infrared probe at time t ₂ ; Te is the thickness of the silicon wafer layer of the target polished silicon wafer; The time t ₁ and the time t ₂ are respectively different times during the grinding process of the silicon wafer layer. 2. The method according to claim 1, characterized in that, in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the first value detected by the contact probe and the first value detected by the non-contact infrared probe are obtained. After the second value, the method further includes: In the case where neither the first value nor the second value meets the first preset condition, determine the thickness Ce of the silicon wafer layer to be continued to be removed by grinding; Continue to grind the silicon wafer layer according to the thickness Ce of the silicon wafer layer to be further removed by grinding; Among them, Ce=(h ₁ -h ₂ )/(i ₁ -i ₂ )*i ₁ -Te. 3. The method according to claim 1, characterized in that, in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the first value detected by the contact probe and the first value detected by the non-contact infrared probe are obtained. After the second value, the method further includes: When neither the first value nor the second value meets the first preset condition, determine the optical path Se of the silicon wafer layer to be reduced by continuing grinding; Continue to polish the silicon wafer layer according to the optical path Se of the silicon wafer layer that is to be further reduced by polishing; Where, Se=i ₁ -Te*(i ₁ -i ₂ )/(h ₁ -h ₂ ). 4. The method according to claim 1, characterized in that, in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the first value detected by the contact probe and the third value detected by the non-contact infrared probe are obtained. Binary values, including: In the case of grinding the silicon wafer layer of the silicon wafer to be ground, at the first target time, continuously obtain p first numerical candidate values detected by the contact probe; Use the median value of the p first numerical candidate values as the first numerical value of the first target time; At the second target moment, continuously acquire q second numerical candidate values detected by the non-contact infrared probe; The median value of the q second value candidate values is used as the second value of the second target time. 5. The method according to claim 1, characterized in that, in the case of grinding the silicon wafer layer of the silicon wafer to be ground, the first value detected by the contact probe and the first value detected by the non-contact infrared probe are obtained. After the second value, the method further includes: In the case of polishing the silicon wafer layer of the silicon wafer to be polished, time t ₁ is used as the starting time, and n first numerical values h ₁ and second numerical values i ₁ are continuously obtained to obtain n groups (h ₁ , i ₁ ) ; Taking time t ₂ as the starting time, continuously obtain m first values h ₂ and second values i ₂ to obtain m groups (h ₂ , i ₂ ); Perform quadratic linear fitting on n groups (h ₁ , i ₁ ), and eliminate those (h ₁ , i ₁ ) in n groups (h ₁ , i ₁ ) that do not meet the second preset condition to obtain t ₁ The target quadratic fitting curve at time; Perform quadratic linear fitting on the m group (h ₂ , i ₂ ), and eliminate those (h ₂ , i ₂ ) that do not meet the third preset condition in the m group (h ₂ , i ₂ ) to obtain t ₂ target quadratic fit curve at time. 6. The method according to claim 5, characterized in that the second preset condition is that the distance from a set of (h ₁ , i ₁ ) to the quadratic fitting curve at time t ₁ is less than n (h ₁ , i ₁ ) 3 times the root mean square of the distance between the numerical value group and the quadratic fitting curve. 7. The method according to claim 5, characterized in that the third preset condition is that the distance from a set of (h ₂ , i ₂ ) to the quadratic fitting curve at time t ₂ is less than m (h ₂ , i ₂ ) 3 times the root mean square of the distance between the numerical value group and the quadratic fitting curve. 8. A device for controlling the grinding thickness of semiconductor silicon wafers containing a substrate, characterized in that the device includes a grinding platform and a measuring mechanism arranged on the grinding platform; The grinding platform is provided with at least one mounting slot for installing the silicon wafer to be ground, and the silicon wafer to be ground includes a substrate layer and a silicon wafer layer; The measurement 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. The non-contact infrared probe is used to measure the silicon wafer layer. The optical path of the slice.