Thickness measuring device and wafer double-sided grinding equipment
By using ceramic brackets and ceramic measurement modules, and setting cooling channels and deflectors in the brackets, the measurement misalignment problem of contact thickness sensing devices during temperature changes is solved, and a more stable thickness measurement is achieved.
Patent Information
- Application Number
- CN202421177503.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-27
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-05-27
AI Technical Summary
When the temperature changes in the existing contact thickness sensing device, the bracket and sensing module will experience thermal expansion and contraction, resulting in misalignment of measurement, and when external airflow enters the grinding area, the measurement results will fluctuate greatly.
Using a ceramic bracket and a ceramic measurement module, a cooling channel is set inside the ceramic bracket to maintain the temperature stability by circulating the coolant, and the coolant is directed to the surface of the measurement module through the deflector to maintain the temperature stability quickly.
The thermal expansion deformation of the ceramic bracket and measurement module is reduced, the temperature of the measurement module is stabilized, the measurement error is reduced, and the accuracy of thickness measurement is improved.
Smart Images
Figure CN222644176U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a thickness measuring device and a double-sided wafer grinding device. Background Art
[0002] In the field of semiconductor manufacturing, real-time measurement of wafer thickness after grinding is of great significance for ensuring product quality, improving production efficiency, reducing material waste, maintaining product consistency, optimizing process parameters, reducing subsequent processing steps, avoiding equipment damage, complying with industry standards, and data recording and traceability.
[0003] In the field of double-sided wafer grinding technology, a contact thickness sensor is generally used to monitor the change in wafer thickness during double-sided grinding in real time. The sensor module of the contact thickness sensor is generally installed on an aluminum alloy bracket. Affected by the ambient temperature, the mounting bracket or mounting surface may be deformed due to thermal expansion and contraction, resulting in inaccurate measurement of the sensor module, and further inaccurate wafer thickness values.
[0004] At the same time, when the wafer is taken and placed, external airflow inevitably enters the grinding area, which may cause the temperature of the grinding environment to change, and also cause a certain degree of deformation of the bracket, sensor module, etc., resulting in large fluctuations in the numerical value of the measurement results. Utility Model Content
[0005] The purpose of the embodiments of the present application is to provide a thickness measuring device and a double-sided wafer grinding device, which improves the deformation problem of the measuring module and the bracket connected to the measuring module, thereby improving the instability of the double-sided grinding measurement thickness.
[0006] In a first aspect, a thickness measuring device is provided for measuring the thickness of a wafer in double-sided grinding in real time. The thickness measuring device comprises a support and two thickness measuring components.
[0007] The bracket is fixedly arranged, and at least part of the bracket is a ceramic bracket. Two thickness measurement components are mounted on the ceramic bracket; each thickness measurement component includes a measurement module and a sensor head, the measurement module is mounted on the bracket, and the sensor head is mounted on the measurement module; when double-sided grinding the wafer, the sensor heads of the two thickness measurement components are pressed on the two side surfaces of the wafer respectively; the measurement module is used to detect and output the position changes of the two sensor heads. A cooling channel for the coolant to flow through is set inside the ceramic bracket.
[0008] In an practicable solution, an overflow port is provided on the ceramic support, and the coolant overflows from the cooling channel through the overflow port;
[0009] The thickness measuring device also includes a guide plate for guiding flow, the guide plate is installed on the ceramic bracket, and the guide plate is used to guide the coolant flowing out of the overflow port to the surface of the measuring module.
[0010] In an practicable solution, two overflow ports are provided on the ceramic support, and are respectively provided near the two measuring modules;
[0011] The guide plate is provided with a through hole connected to the overflow port. When in use, the coolant flows out from the overflow port and overflows to the surface of the guide plate through the through hole.
[0012] In an practicable solution, there are two guide plates, and a guide plate is installed on each overflow port and the corresponding measurement module.
[0013] In an implementable solution, a guide groove is provided on the surface of the guide plate along the through hole to the measurement module.
[0014] In an practicable solution, on each guide plate, the guide groove diverges into a plurality of channels at one end close to the measuring module and extends to the edge of the guide plate.
[0015] In an implementable solution, the thickness measuring device further includes a spray temperature control device, which is disposed above the bracket and the thickness measuring assembly.
[0016] In an implementable solution, each thickness measuring component also includes a swing rod, one end of which is connected to the measuring module, and the other end of which is connected to a sensing head; when double-sided grinding the wafer, the sensing heads of the two thickness measuring components are respectively pressed on the two side surfaces of the wafer; the measuring module is used to detect and output the opening angles of the two sensing heads.
[0017] In an implementable solution, the bracket includes an aluminum alloy bracket, and the ceramic bracket is mounted on the aluminum alloy bracket.
[0018] According to a second aspect of the present application, a double-side wafer grinding device is also provided, comprising the thickness measuring device in the aforementioned solution.
[0019] Compared with the prior art, the beneficial effects of this application include at least:
[0020] In the present application, since the ceramic material has a lower thermal expansion coefficient than the aluminum alloy material, this means that the volume or length of the ceramic bracket changes very little when the temperature changes, the deformation of the mounting surface of the measuring module and the ceramic bracket is also very small, and the deformation or displacement caused to the measuring module is also very small. This can reduce the deformation of the bracket and the measuring module, reduce the measurement error of the measuring module, and improve the accuracy of thickness measurement.
[0021] At the same time, since the ceramic bracket is provided with a cooling channel inside, a circulating coolant with a constant temperature is always introduced into the cooling channel of the ceramic bracket during operation. In this way, even if external airflow enters, causing the ambient temperature of the grinding area to change, the ceramic bracket can adjust its own temperature and the temperature of the measuring module under the action of the coolant in the cooling channel, thereby ensuring the temperature stability of the measuring module, reducing the possibility of deformation of the measuring module, reducing the irregular fluctuation of the thickness measurement value caused by the deformation of the measuring module, and improving the accuracy of the thickness measurement.
[0022] In a further solution, an overflow port may be provided on the ceramic bracket, and the coolant overflows from the cooling channel through the overflow port. A guide plate is installed on the ceramic bracket, and the guide plate is used to guide the coolant flowing out of the overflow port to the surface of the measuring module, thereby maintaining the temperature stability of the measuring module more quickly, reducing the influence of the external temperature on the measuring module, keeping the temperature basically constant, reducing the possibility of deformation, reducing the measurement value fluctuation caused by deformation caused by temperature changes during thickness measurement, and improving measurement accuracy.
[0023] In summary, the thickness measuring device of the present application reduces the influence of external temperature, improves the deformation problem of the measuring module and the bracket connected to the measuring module, and further improves the instability of the thickness measurement during double-sided grinding. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.
[0025] Figure 1 The fluctuation of the average thickness of a wafer measured in the prior art;
[0026] Figure 2 It is a structural schematic diagram of a thickness measuring device using a ceramic bracket and an aluminum alloy bracket at the same time according to an embodiment of the present application;
[0027] Figure 3 It is a structural schematic diagram of a thickness measuring device using an all-ceramic bracket according to an embodiment of the present application;
[0028] Figure 4 is a schematic structural diagram of a thickness measuring device having a first guide plate according to an embodiment of the present application;
[0029] Figure 5The fluctuation of the average thickness of a wafer measured by the thickness measuring device according to the embodiment of the present application;
[0030] Figure 6 is a schematic structural diagram of a thickness measuring device having a second guide plate according to an embodiment of the present application;
[0031] Figure 7 This is a schematic structural diagram of a guide plate of a thickness measuring device according to an embodiment of the present application;
[0032] Figure 8 It is a schematic structural diagram of a thickness measuring device with a spray temperature control device according to an embodiment of the present application.
[0033] In the figure: 1. bracket; 11. ceramic bracket; 111. cooling channel; 112. overflow port; 12. aluminum alloy bracket; 2. thickness measurement component; 21. measurement module; 22. sensor head; 23. swing rod; 3. guide plate; 31. through hole; 32. guide groove; 4. spray temperature control device. DETAILED DESCRIPTION
[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.
[0035] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.
[0036] In actual work, the inventors found that when placing and removing wafers, external airflow inevitably enters the grinding area, which may cause the temperature of the grinding environment to change, and also cause a certain degree of deformation of the bracket, sensor module, etc., resulting in fluctuations in the measurement results. Figure 1 The thickness fluctuation of a certain type of wafer is shown in Figure 1 It can be seen that the thickness of the processed product fluctuates within the range of 795.0±2.0um, and the fluctuation is large. It should be noted that the fluctuation here refers to the change of the value from large to small.
[0037] like Figure 2As shown, this embodiment provides a thickness measuring device for measuring the thickness of a wafer during double-sided grinding in real time. The thickness measuring device includes a bracket 1 and two thickness measuring components 2 .
[0038] The bracket 1 can be fixedly mounted on the internal frame of the double-sided wafer grinding equipment, and at least part of the bracket 1 is a ceramic bracket 11. Two thickness measuring components 2 are mounted on the ceramic bracket 11. Each thickness measuring component 2 includes a measuring module 21 and a sensor head 22, the measuring module 21 is mounted on the bracket 1, and the sensor head 22 is mounted on the measuring module 21. When double-sided grinding the wafer, the sensor heads 22 of the two thickness measuring components 2 are respectively pressed on the two side surfaces of the wafer, and the measuring module 21 is used to detect and output the position changes of the two sensor heads 22 and then calculate the wafer thickness. A cooling channel 111 for the coolant to flow through is arranged inside the ceramic bracket 11.
[0039] In this embodiment, since the ceramic material has a lower thermal expansion coefficient than the aluminum alloy material, this means that the volume or length of the ceramic bracket 11 changes very little when the temperature changes, and the deformation of the mounting surface of the measuring module 21 and the ceramic bracket 11 is also very small, and the deformation or displacement caused to the measuring module 21 is also very small, thereby reducing the measurement error of the measuring module 21 and improving the accuracy of thickness measurement.
[0040] At the same time, since the ceramic bracket 11 is provided with a cooling channel 111, during operation, a circulating coolant with a constant temperature is always introduced into the cooling channel 111 of the ceramic bracket 11. In this way, even if an external airflow enters, causing the ambient temperature of the grinding area to change, the ceramic bracket 11 can adjust its own temperature and the temperature of the measuring module 21 under the action of the coolant in the cooling channel 111, thereby ensuring the temperature stability of the measuring module 21, reducing the possibility of deformation of the measuring module 21, reducing the irregular fluctuation of the thickness measurement value caused by the deformation of the measuring module 21, and improving the accuracy of the thickness measurement.
[0041] In summary, the thickness measuring device of this embodiment reduces the influence of external temperature on the bracket 1 of the measuring module 21, improves the deformation problem of the measuring module 21 and the bracket 1 connected to the measuring module 21, and further improves the instability of the double-sided grinding measurement thickness.
[0042] In this embodiment, if Figure 2 As shown, each thickness measuring component 2 may also include a swing rod 23, one end of the swing rod 23 is connected to the measuring module 21, and the other end of the swing rod 23 is connected to the sensor head 22; when double-sided grinding the wafer, the sensor heads 22 of the two thickness measuring components 2 are respectively pressed on the two side surfaces of the wafer; the measuring module 21 is used to detect and output the opening angles of the two sensor heads 22.
[0043] The measuring module 21 may include an angle sensor mechanism, for example, a resistive angle sensor mechanism, a capacitive angle sensor mechanism, an optical angle sensor mechanism or any other suitable sensor mechanism. The angle sensor mechanism is used to detect the angles of the two relative swinging rods 23 relative to the wafer surface, and then the wafer thickness is calculated.
[0044] In this embodiment, the measuring module 21 also includes a retracting mechanism (not shown in the figure), which is arranged in the measuring module 21 and is movably connected to the swing rod 23. The retracting mechanisms in the two measuring modules 21 are used to apply a force to the swing rods 23 to move closer to each other, so that the sensor head 22 at the front end of the swing rod 23 can always fit on the surface of the wafer. As the thickness of the wafer changes, the distance between the two sensor heads 22 changes, and then the angle between the two swing rods 23 will also change. The thickness of the wafer can be calculated by detecting this angle change through the angle sensing mechanism. For example, the retracting mechanism can be a pneumatically controlled retracting mechanism, a motor-controlled retracting mechanism, etc., and the pneumatically controlled retracting mechanism, the motor-controlled retracting mechanism, etc. are used to realize the movement of the swing rod 23 in the direction close to the wafer, so that the sensor head 22 can always fit on the surface of the wafer. For example, the retracting mechanism can also be an elastic structure, such as a spring, an elastic rope, etc., with the help of the spring, elastic rope and other structures, a pulling force is applied to the swing rod 23 in the direction of the wafer, so that the sensor head 22 at the end of the swing rod 23 can always fit the wafer surface.
[0045] In this embodiment, the tip of the sensor head 22 that contacts the wafer is generally made of a wear-resistant material to increase the service life of the sensor head 22 , such as diamond.
[0046] In this embodiment, if Figure 2 As shown, the support 1 of the thickness measuring device may include an aluminum alloy support 12 in addition to the ceramic support 11, and the ceramic support 11 is mounted on the aluminum alloy support 12. Figure 3 As shown, the brackets 1 of the thickness measuring device may also all be ceramic brackets 11. In actual production and manufacturing, a suitable solution may be reasonably selected according to requirements such as cost and structural strength.
[0047] In this embodiment, if Figure 4 As shown, the ceramic bracket 11 may be provided with an overflow port 112, and the coolant overflows from the cooling channel 111 through the overflow port 112. The thickness measuring device may also include a guide plate 3 for guiding flow, the guide plate 3 is installed on the ceramic bracket 11, and the guide plate 3 is used to guide the coolant flowing out of the overflow port 112 to the surface of the measuring module 21, so that the temperature stability of the measuring module 21 can be maintained more quickly, so as to reduce the fluctuation of the measurement value caused by temperature deformation during thickness measurement and improve the measurement accuracy. For example, in the measurement after adopting the above scheme, if Figure 5 As shown, for Figure 1 For the same wafer product, the thickness value at the measurement point fluctuates within 795.0±1.5um, the fluctuation becomes smaller, and the measurement accuracy is improved.
[0048] In this embodiment, if Figure 4 As shown, the edge of the guide plate 3 is at a certain distance from the edge of the measuring module 21 to facilitate cooling heat flow to the surface of the measuring module 21 .
[0049] In this embodiment, the guide plate 3 may be provided with a certain slope in the direction from the overflow port 112 to the measuring module 21 , so as to facilitate the coolant to flow from the overflow port 112 to the surface of the measuring module 21 .
[0050] In this embodiment, if Figure 4 As shown, the ceramic bracket 11 may be provided with two overflow ports 112, which are respectively provided near the two measuring modules 21. The guide plate 3 may be provided with a through hole 31 connected to the overflow port 112. When in use, the coolant flows out of the overflow port 112 and overflows to the surface of the guide plate 3 through the through hole 31.
[0051] In this embodiment, if Figure 6 As shown, the number of guide plates 3 can be two, and a guide plate 3 is installed on each overflow port 112 and the corresponding measurement module 21, and the coolant can be guided to the surfaces of the two measurement modules 21 through the two guide plates 3. The two guide plates 3 can guide the coolant to the upper surface and side of the measurement module 21, and the temperature control effect is better.
[0052] In this embodiment, if Figure 7 As shown, the surface of the guide plate 3 may be provided with a guide groove 32 along the through hole 31 to the measuring module 21, which is more conducive to guiding the coolant to flow to the position of the measuring module 21. And on each guide plate 3, the guide groove 32 at one end close to the measuring module 21 may diverge into multiple channels and extend to the edge of the guide plate 3, so that the coolant can contact more surfaces of the measuring module 21 more evenly.
[0053] In this embodiment, if Figure 8 As shown, the thickness measuring device may further include a spray temperature control device 4, which is arranged above the bracket 1 and the thickness measuring component 2. The spray temperature control device 4 may include multiple spray heads, and the multiple spray heads may cover multiple structures such as the sensing head 22, the measuring module 21, and the ceramic bracket 11 to achieve a spray temperature control effect in a larger range.
[0054] This embodiment also provides a double-side wafer grinding device, including the thickness measuring device in the above-mentioned solution.
[0055] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A thickness measuring device, characterized in that: Used to measure the thickness of a wafer during double-sided grinding in real time, the thickness measuring device comprises: A support (1) is fixedly arranged, and at least a portion of the support (1) is a ceramic support (11); Two thickness measurement assemblies (2) are mounted on the ceramic bracket (11); each of the thickness measurement assemblies (2) comprises a measurement module (21) and a sensor head (22); the measurement module (21) is mounted on the bracket (1), and the sensor head (22) is mounted on the measurement module (21); when double-sided grinding of a wafer, the sensor heads (22) of the two thickness measurement assemblies (2) are respectively pressed against the two side surfaces of the wafer; the measurement module (21) is used to detect and output position changes of the two sensor heads (22); Wherein, a cooling channel (111) for cooling liquid to flow through is arranged inside the ceramic bracket (11); The ceramic support (11) is provided with an overflow port (112), and the coolant flows from the cooling channel (111) and overflows through the overflow port (112) to the surface of the measuring module (21).
2. The thickness measuring device according to claim 1, characterized in that: The thickness measuring device further comprises a guide plate (3) for guiding flow, wherein the guide plate (3) is mounted on the ceramic bracket (11), and the guide plate (3) is used to guide the coolant flowing out of the overflow port (112) to the surface of the measuring module (21).
3. The thickness measuring device according to claim 2, characterized in that: The ceramic support (11) is provided with two overflow ports (112), which are respectively arranged near the two measuring modules (21); The guide plate (3) is provided with a through hole (31) connected to the overflow port (112); when in use, the coolant flows out from the overflow port (112) and overflows onto the surface of the guide plate (3) through the through hole (31).
4. The thickness measuring device according to claim 3, characterized in that: The number of the guide plates (3) is two, and one guide plate (3) is installed on each overflow port (112) and the corresponding measurement module (21).
5. The thickness measuring device according to claim 3 or 4, characterized in that: The surface of the guide plate (3) is provided with a guide groove (32) extending from the through hole (31) to the measurement module (21).
6. The thickness measuring device according to claim 5, characterized in that: On each of the guide plates (3), the guide groove (32) diverges into a plurality of channels at an end close to the measurement module (21) and extends to the edge of the guide plate (3).
7. The thickness measuring device according to claim 1, characterized in that: The thickness measuring device further comprises a spray temperature control device (4) which is arranged above the bracket (1) and the thickness measuring component (2).
8. The thickness measuring device according to claim 1, characterized in that: Each thickness measurement assembly (2) further comprises a swing rod (23), one end of the swing rod (23) being connected to the measurement module (21), and the other end of the swing rod (23) being connected to the sensor head (22); the measurement module (21) being used to detect and output the opening angles of the two sensor heads (22).
9. The thickness measuring device according to claim 1, characterized in that: The support (1) comprises an aluminum alloy support (12), and the ceramic support (11) is mounted on the aluminum alloy support (12).
10. A double-sided wafer grinding device, characterized in that: Comprising the thickness measuring device as claimed in any one of claims 1 to 9.