A frequency measurement method for photolithography wafer tuning fork chip

Abstract

The invention discloses a frequency measurement method of a photolithography wafer tuning fork chip, wherein the measuring instrument comprises a positioning platform, a negative pressure pipeline connected to a negative pressure source is provided inside the positioning platform; a wafer is fixed on the positioning platform; a measuring system is arranged above the wafer, a probe of the measuring system is connected to a frequency meter, and the probe sequentially applies vibration to the root of each tuning fork chip on the wafer; a negative pressure hole is provided on the positioning platform and is connected to the negative pressure pipeline, and the negative pressure hole corresponds to the position of the tuning fork chip; the negative pressure hole is closed when the probe applies vibration, and the negative pressure hole is opened after the probe leaves the tuning fork chip. The present invention quickly consumes the vibration energy of the tuning fork chip, thereby ending the vibration of the tuning fork chip in the area, so that the probe can directly perform measurement when it reaches the tuning fork chip to be measured next, thereby greatly improving the measurement efficiency.

Description

Technical Field

[0001] The invention relates to the field of semiconductors, in particular to a frequency measurement method for a photolithography wafer tuning fork chip. Background Art

[0002] In the 21st century, with the advancement of technology and changes in market applications, quartz crystal resonators are showing a development trend of miniaturization, high precision and low power consumption. Secondly, quartz crystal resonators are developing towards higher precision and higher stability. Quartz crystal resonators are gradually miniaturized, thinned and sliced, posing greater challenges to improving their accuracy and stability. From the perspective of market application, quartz crystal resonators provide stable clock frequencies for electronic products, and their accuracy and stability have a vital impact on the quality, performance and subsequent maintenance costs of downstream products. Miniaturized, ultra-high frequency quartz crystal resonators are the technological development trend of future 5G applications. The photolithography tuning fork chip is one of the most important raw materials for ultra-small tuning fork crystal resonators and is the core component of small, low-power resonators. The quality of the chip will directly determine the performance of the device.

[0003] After the wafer is processed, the frequency of the tuning fork chip on the entire wafer needs to be measured. Currently, the frequency measurement needs to be performed through a probe. After the probe applies vibration to the tuning fork chip, a vibration wave will be generated, which will affect the vibration of adjacent products. It is necessary to wait until the adjacent products have finished oscillating before measuring, and the measurement efficiency is extremely low. At the same time, due to the extremely low thickness of the wafer, it is not easy to fix it during measurement, so it needs to be solved urgently. Summary of the invention

[0004] In order to avoid and overcome the technical problems existing in the prior art, the present invention provides a frequency measurement method for a photolithography wafer tuning fork chip, which greatly improves the measurement efficiency of the tuning fork chip.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for measuring the frequency of a photolithography wafer tuning fork chip, characterized in that it comprises the following steps:

[0007] S1. Complete the assembly of a measuring instrument, which includes a positioning platform, wherein a negative pressure pipeline connected to a negative pressure source is provided inside the positioning platform;

[0008] The wafer is fixed on the positioning platform;

[0009] The measuring system is arranged above the wafer. The probe of the measuring system is connected to the frequency meter. The probe sequentially applies vibration to the root of each tuning fork crystal on the wafer.

[0010] A negative pressure hole is provided on the positioning platform and is connected to the negative pressure pipeline, and the negative pressure hole corresponds to the position of the tuning fork wafer; the negative pressure hole is closed when the probe applies vibration, and the negative pressure hole is opened after the probe leaves the tuning fork wafer;

[0011] S2, placing the wafer on the positioning platform, making the wafer abut against each positioning protrusion, starting the negative pressure source to ensure that the wafer is fixed by negative pressure adsorption through the adsorption hole, and the solenoid valve is closed at this time;

[0012] S3, adjusting the positions of the X-axis slide, the Y-axis slide, and the Z-axis slide, so that the probe contacts the root of the first group of tuning fork chips, and the CCD recognition system recognizes and observes the tuning fork chips;

[0013] S4, the probe applies vibration to the root of the tuning fork wafer, and the frequency meter measures the vibration frequency of the tuning fork wafer. After the measurement is completed, the probe is driven to move to the root of the next tuning fork wafer through the relative movement of the X-axis slide, the Y-axis slide, and the Z-axis slide;

[0014] S5, in step S4, when the probe moves, the solenoid valve is opened, and instantaneous negative pressure is applied to the area where the measured tuning fork wafer is located through the negative pressure hole, and the solenoid valve is closed before the probe reaches the root of the next tuning fork wafer;

[0015] S6. After the probe reaches the root of the next tuning fork wafer, steps S4 and S5 are repeated to complete the measurement of all tuning fork wafers along the S-shaped measurement path, and the negative pressure source is turned off and the wafer is taken out.

[0016] As a further solution of the present invention: the positioning platform is provided with an adsorption hole that fits with the surface of the wafer, the negative pressure pipeline is split to form a first negative pressure channel connected to the adsorption hole and a second negative pressure channel connected to the negative pressure hole, and the second negative pressure channel is provided with a solenoid valve to control the opening and closing of the negative pressure hole.

[0017] As a further solution of the present invention: the surface of the positioning platform is provided with positioning protrusions which abut against the wafer and are distributed in an L shape, and the positioning protrusions cooperate with each other to form a positioning end for positioning the wafer at a right angle.

[0018] As a further solution of the present invention: the measuring system is provided with an observation port located above the probe, the CCD recognition system is fixed on the measuring system and the detection port of the CCD recognition system faces the direction of the probe.

[0019] As a further solution of the present invention: the positioning platform and the measuring system are both installed on a fixed seat, and the fixed seat is provided with an X-axis slide and a Y-axis slide arranged perpendicular to each other, and the positioning platform is fixed on the mounting seat of the X-axis slide; the Y-axis slide is also fixed with a Z-axis slide that moves in a vertical direction, and the measuring system is clamped and fixed by a fixed arm on the Z-axis slide.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention applies vibration to the tuning fork wafers on the wafer in sequence through the probe, and records the vibration frequency through the frequency meter, thereby completing the measurement process; when the probe leaves the tuning fork wafer whose measurement is completed and moves to the next wafer, the negative pressure hole opens to generate an instantaneous negative pressure, and the negative pressure hole instantly sucks in the airflow, and the fast-flowing airflow forms gas damping, which quickly consumes the vibration energy of the tuning fork wafer, thereby ending the vibration of the tuning fork wafer in this area, so that the probe can directly perform measurement when it reaches the tuning fork wafer to be measured next, thereby greatly improving the measurement efficiency.

[0022] 2. The present invention opens an adsorption hole on the surface of the positioning platform and connects it to a negative pressure source, thereby enabling the wafer to be adsorbed and fixed by negative pressure. The negative pressure pipeline connected to the negative pressure source can be split and connected to the adsorption hole through a first negative pressure channel and through a second negative pressure channel respectively. The adsorption hole can maintain continuous adsorption and fixation of the wafer to prevent rigid fixation from damaging an extremely thin wafer. Since an electromagnetic valve is provided on the second negative pressure channel, the flow rate of the inhaled gas at the negative pressure hole can be controlled by controlling the opening of the electromagnetic valve. Therefore, through a negative pressure source, the adsorption and fixation of the wafer and the solution to the vibration problem caused by measurement can be completed at the same time.

[0023] 3. The present invention arranges L-shaped positioning protrusions on the positioning platform so that the wafer can be positioned after contacting each positioning protrusion, which is easy to operate and will not damage the wafer during positioning.

[0024] 4. The present invention provides a CCD recognition system above the measuring system, which can magnify and observe the tuning fork wafer to be tested, making it easy to measure and locate as well as observe and pick out defective products; the coordinated arrangement of the X-axis slide, the Y-axis slide and the Z-axis slide facilitates the precise adjustment of the measuring system and the position of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention.

[0026] Figure 2 It is a schematic diagram of the structure of the measurement system in the present invention.

[0027] Figure 3 It is a structural schematic diagram of the positioning platform in the present invention.

[0028] Figure 4 It is an enlarged view of the tuning fork chip on the wafer of the present invention.

[0029] Figure 5 This is a simplified flow diagram of the negative pressure pipeline.

[0030] In the figure:

[0031] 1. Positioning platform; 11. Negative pressure interface; 12. Positioning protrusion;

[0032] 13. Adsorption hole; 14. Negative pressure hole; 15. Negative pressure pipeline;

[0033] 151, first negative pressure channel; 152, second negative pressure channel; 153, solenoid valve;

[0034] 2. wafer chip; 21. Tuning fork chip;

[0035] 3. Measurement system; 31. Probe; 32. Observation port;

[0036] 4. CCD recognition system;

[0037] 5. Fixed seat; 51. X-axis slide table;

[0038] 52. Z-axis slide; 521. Fixed arm;

[0039] 53. Y-axis slide table; 531. mounting seat. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] See also Figures 1 to 5 In an embodiment of the present invention, a frequency measurement method of a photolithography wafer tuning fork chip is provided, and the measurement method comprises the following steps:

[0042] S1, placing the wafer 2 on the positioning platform 1, making the wafer 2 abut against each positioning protrusion 12, starting the negative pressure source to ensure that the wafer 2 is fixed by negative pressure adsorption through the adsorption holes 13, and at this time, the solenoid valve 153 is closed;

[0043] S2, adjusting the positions of the X-axis slide 51, the Y-axis slide 53, and the Z-axis slide 52, so that the probe 31 abuts against the root of the first group of tuning fork wafers 21, and the CCD recognition system 4 recognizes and observes the tuning fork wafers 21;

[0044] The X-axis slide 51, the Y-axis slide 53, and the Z-axis slide 52 are all driven by servo motors. If defective products are found during observation, they will be directly marked and removed.

[0045] S3, the probe 31 applies vibration to the root of the tuning fork wafer 21, and the frequency meter measures the vibration frequency of the tuning fork wafer 21. After the measurement is completed, the probe 31 is driven to move to the root of the next tuning fork wafer 21 through the relative movement of the X-axis slide 51, the Y-axis slide 53, and the Z-axis slide 52;

[0046] S4, in step S3, when the probe 31 moves, the solenoid valve 153 is opened, and negative pressure is applied to the area where the measured tuning fork wafer 21 is located through the negative pressure hole 14, and the solenoid valve 153 is closed before the probe 31 reaches the root of the next tuning fork wafer 21;

[0047] S5. After the probe 31 reaches the root of the next tuning fork wafer 21, steps S3 and S4 are repeated until the measurement of all tuning fork wafers 21 is completed, the negative pressure source is turned off, and the wafer 2 is taken out and sent to the next station.

[0048] Usually, the probe 31 performs measurement along an S-shaped trajectory.

[0049] The measuring instrument includes a fixed base 5 on which an X-axis slide 51 and a Y-axis slide 53 arranged perpendicular to each other are installed. A Z-axis slide 52 arranged along a plumb direction is fixed to the Y-axis slide 53, and the Z-axis slide 52 can slide along the length direction of the Y-axis slide 53.

[0050] A horizontally suspended fixed arm 521 is fixed on the slide seat of the Z-axis slide table 52, and the measurement system 3 and the CCD recognition system 4 are both installed at the end of the fixed arm 521. The measurement system 3 is in the shape of a plate, and an observation port 32 is opened at the center. The probe 31 is fixed below the observation port 32, and the probe 31 is connected to the frequency meter through a line. After the probe 31 abuts against the root of the tuning fork wafer 21, vibration can be applied to the tuning fork wafer 21, and the vibration frequency is recorded by the frequency meter.

[0051] The CCD recognition system 4 is fixed above the measuring system 3 , with its detection port facing the location of the probe 31 so as to magnify and observe the location of the probe 31 .

[0052] The mounting seat 531 is fixed on the slide seat of the X-axis slide 51, and the positioning platform 1 is fixed on the mounting seat 531. The X-axis slide 51, the Y-axis slide 53 and the Z-axis slide 52 can make rough adjustments to the positions of the measuring system 3 and the positioning platform 1, and the mounting seat 531 can drive the positioning platform 1 to make fine adjustments.

[0053] The positioning platform 1 is a horizontally arranged square platform. The wafer 2 is placed on the top of the positioning platform 1 and abuts against the positioning protrusions 12 spaced apart on the top of the positioning platform 1, thereby achieving position positioning.

[0054] The positioning protrusions 12 are preferably distributed in an L-shape, and after cooperating with each other, they form a right-angled positioning end to complete the positioning of the wafer 2.

[0055] The top of the positioning platform 1 is also provided with an adsorption hole 13 corresponding to the wafer 2, and the top of the positioning platform 1 is also provided with a negative pressure hole 14 corresponding to the position of the tuning fork chip 21 on the wafer 2. A negative pressure interface 11 is provided at the front end of the positioning platform 1, and the negative pressure source is connected to the negative pressure pipeline 15 inside the positioning platform 1 through the negative pressure interface 11. The negative pressure source is usually a vacuum pump. There are two branches in the negative pressure pipeline 15, namely a first negative pressure channel 151 connected to the adsorption hole 13 and a second negative pressure channel 152 connected to the negative pressure hole 14.

[0056] A group of solenoid valves 153 are used at each negative pressure hole 14 to control the opening and closing of all negative pressure holes 14 at the same time, or a group of solenoid valves 153 are set at each negative pressure hole 14 to control the opening and closing thereof respectively. The first negative pressure channel 151 has no valve to control the opening and closing, and continuously adsorbs and fixes the wafer 2. The second negative pressure channel 152 is controlled by the solenoid valve 153, and opens and closes instantly after the probe 31 leaves the tuning fork wafer 21, generating an instantaneous negative pressure, thereby sucking airflow from the negative pressure hole 14, and consuming the vibration energy of the tuning fork wafer 21 through the fast-flowing airflow.

[0057] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0058] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0059] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0060] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0061] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A method for measuring the frequency of a photolithography wafer tuning fork, characterized in that: The steps include: S1. Complete the assembly of a measuring instrument, which includes a positioning platform, wherein a negative pressure pipeline connected to a negative pressure source is provided inside the positioning platform; The wafer is fixed on the positioning platform; The measuring system is arranged above the wafer. The probe of the measuring system is connected to the frequency meter. The probe sequentially applies vibration to the root of each tuning fork crystal on the wafer. A negative pressure hole is provided on the positioning platform and is connected to the negative pressure pipeline, and the negative pressure hole corresponds to the position of the tuning fork wafer; the negative pressure hole is closed when the probe applies vibration, and the negative pressure hole is opened after the probe leaves the tuning fork wafer; S2, placing the wafer on the positioning platform, making the wafer abut against each positioning protrusion, starting the negative pressure source to ensure that the wafer is fixed by negative pressure adsorption through the adsorption hole, and the solenoid valve is closed at this time; S3, adjusting the positions of the X-axis slide, the Y-axis slide, and the Z-axis slide, so that the probe contacts the root of the first group of tuning fork chips, and the CCD recognition system recognizes and observes the tuning fork chips; S4, the probe applies vibration to the root of the tuning fork wafer, and the frequency meter measures the vibration frequency of the tuning fork wafer. After the measurement is completed, the probe is driven to move to the root of the next tuning fork wafer through the relative movement of the X-axis slide, the Y-axis slide, and the Z-axis slide; S5, in step S4, when the probe moves, the solenoid valve is opened, and an instantaneous negative pressure is applied to the area where the measured tuning fork wafer is located through the negative pressure hole, and the solenoid valve is closed before the probe reaches the root of the next tuning fork wafer; S6. After the probe reaches the root of the next tuning fork wafer, repeat steps S4 and S5, complete the measurement of all tuning fork wafers along the S-shaped measurement path, turn off the negative pressure source and take out the wafer; The positioning platform is provided with an adsorption hole that fits with the surface of the wafer, and the negative pressure pipeline is divided to form a first negative pressure channel connected to the adsorption hole and a second negative pressure channel connected to the negative pressure hole. The second negative pressure channel is provided with a solenoid valve to control the opening and closing of the negative pressure hole.

2. The frequency measurement method of a photolithography wafer tuning fork according to claim 1, characterized in that: The surface of the positioning platform is provided with positioning protrusions which are in contact with the wafer and are distributed in an L shape. The positioning protrusions cooperate with each other to form a positioning end for positioning the wafer at a right angle.

3. The frequency measurement method of a photolithography wafer tuning fork according to claim 1, characterized in that: The measuring system is provided with an observation port located above the probe, and the CCD recognition system is fixed on the measuring system with the detection port of the CCD recognition system facing the direction of the probe.

4. The frequency measurement method of a photolithography wafer tuning fork according to claim 1, characterized in that: The positioning platform and the measuring system are both installed on a fixed seat, on which an X-axis slide and a Y-axis slide arranged perpendicular to each other are provided. The positioning platform is fixed on the mounting seat of the X-axis slide. A Z-axis slide moving in a vertical direction is also fixed on the Y-axis slide, and the measuring system is clamped and fixed by a fixed arm on the Z-axis slide.

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