Wafer resistivity nondestructive testing equipment based on laser calibration inductance method
By integrating a laser rangefinder and an inductor sensor into a wafer resistivity testing device, the problems of damage, low efficiency, and high cost in wafer testing have been solved, achieving high-precision non-destructive testing and low-cost resistivity measurement.
Patent Information
- Application Number
- CN202422793254.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-15
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2034-11-15
AI Technical Summary
Existing wafer resistivity testing methods suffer from problems such as damaging the wafer surface, low testing efficiency, low accuracy, and high cost, especially the high cost of traditional four-probe methods and high-precision mechanical positioning systems.
A laser-calibrated inductive method detection device is adopted, which integrates a laser rangefinder and an inductive sensor to detect the distance between the inductor coil and the wafer surface in real time, and corrects the resistivity detection results based on the distance value, thus avoiding the use of a high-precision positioning system.
It achieves high-precision, non-destructive testing, reduces testing costs, improves testing efficiency, and is applicable to various conductive materials, including ferromagnetic and non-ferromagnetic materials.
Smart Images
Figure CN223727911U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of detection, and particularly relates to a wafer resistivity nondestructive testing equipment based on laser calibration inductance method. BACKGROUND
[0002] Wafer is the basic material of integrated circuit manufacturing and the cornerstone of integrated circuit development. At present, most integrated circuit chips are manufactured on wafers through bulk silicon technology. In the manufacturing process of integrated circuits, the resistivity of the wafer is an important process parameter. Therefore, it is necessary to detect the wafer resistivity with high precision and high efficiency.
[0003] At present, traditional detection methods such as the four-probe method are widely used in wafer resistivity detection due to their high precision and high stability. However, the four-probe method is a contact detection method, and the contact between the probe and the wafer may cause damage and contamination to the wafer surface during the detection process. In addition, the four-probe method has low detection efficiency and small detection range, and is difficult to adapt to work scenes with high requirements for wafer surface integrity. Therefore, it is necessary to develop high-precision and high-efficiency nondestructive detection technology to solve the problems existing in traditional detection methods.
[0004] Non-contact wafer resistivity detection methods include inductance method, microwave method, and laser method. These methods provide a fast and nondestructive method for detecting the resistivity of the wafer. Among these methods, the inductance method is widely used due to its fast speed, high precision, and low cost. In the inductance method, an inductance coil is driven by an alternating current signal to generate an alternating induced current in the wafer. The alternating induced current changes the impedance value of the inductance coil through mutual inductance. Different wafer resistivities correspond to different alternating induced current intensities, and the mutual inductance causes different changes in the coil impedance. Therefore, by detecting the impedance value of the inductance coil, the resistivity of the wafer can be measured.
[0005] The precision of the inductance method is mainly affected by the variation of lift-off distance (LOD), which is the distance between the inductance coil and the wafer surface. The variation of LOD during the detection process will increase the detection error. Due to environmental vibration and positional errors during detection, the variation of LOD is inevitable. In order to improve the precision of inductance method detection, a high-precision mechanical positioning system is usually used in traditional inductance method wafer resistivity detection to keep the LOD unchanged. Although this significantly improves the detection precision, the high-precision mechanical positioning system also dramatically increases the manufacturing cost of the detection equipment. UTILITY MODEL CONTENTS
[0006] The utility model discloses to solve the problem of the existing wafer detection technology's damage wafer surface, low detection efficiency, low detection precision, high manufacturing cost, provide a kind of wafer resistivity nondestructive testing equipment based on laser calibration inductance method, the equipment will inductance coil and laser ranging sensor are integrated and synchronous work, when inductance coil carries out resistivity detection, laser ranging sensor will real-time detection LOD value, and according to LOD value, the resistivity value measured is corrected, the equipment can significantly improve the precision of inductance method resistivity detection under the condition of not using high-precision positioning system, and the cost of wafer resistivity detection equipment is greatly reduced.
[0007] The utility model is realized through the following technical schemes:
[0008] A kind of inductance method wafer high-precision nondestructive testing equipment based on laser calibration function, including XY two-axis workbench and the detection probe of being installed on the XY two-axis workbench;
[0009] The detection probe is provided with laser ranging sensor and inductance sensor, wherein the inductance sensor is used to detect the resistivity of wafer by inductance method, and the laser ranging sensor is used to detect the distance between inductance sensor and wafer surface.
[0010] In the above technical scheme, the XY two-axis workbench includes base, X-axis moving mechanism and Y-axis moving mechanism, X-axis moving mechanism is installed on base, Y-axis moving mechanism is installed on X-axis moving mechanism, Y-axis moving mechanism is driven to move along X-axis direction by X-axis moving mechanism, and the detection probe is installed on Y-axis moving mechanism, and the detection probe is driven to move along Y-axis direction by Y-axis moving mechanism.
[0011] In the above technical scheme, one end of X-axis moving mechanism is provided with first driving motor as the driving source of X-axis moving mechanism;One end of Y-axis moving mechanism is provided with second driving motor as the driving source of Y-axis moving mechanism.
[0012] In the above technical scheme, wafer table is further provided on the XY two-axis workbench, and the wafer table is fixedly installed on the base of the XY two-axis workbench by bolts, and a U-shaped groove is provided on the wafer table for placing the wafer to be detected in the U-shaped groove.
[0013] In the above technical scheme, control system is further provided on the XY two-axis workbench for controlling the operation of the equipment.
[0014] The utility model has the advantages and beneficial effects that:
[0015] High sensitivity: can detect the resistivity change in the range of 1x10-5-1x102Ω·cm.
[0016] Automatic calibration: the laser ranging sensor can automatically detect and calibrate the detection results when the LOD changes.
[0017] No contact required: no direct contact with the wafer during detection, avoiding potential damage to the material surface.
[0018] Fast and efficient: can realize overall rapid detection, improve detection efficiency.
[0019] Instant results: results can be obtained immediately after detection, without waiting.
[0020] Wide applicability: suitable for various conductive materials, including ferromagnetic and non-ferromagnetic materials. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 is the structure diagram of the inductance method wafer high-precision nondestructive testing equipment based on laser calibration function of the utility model.
[0022] Figure 2 is the detection method flow chart of the nondestructive testing equipment.
[0023] Figure 3 is the detection result of the inductance sensor under the calibration of the laser ranging sensor.
[0024] Figure 4 is the detection result of the inductance sensor without the calibration of the laser ranging sensor.
[0025] For ordinary skilled persons in the art, other related drawings can be obtained according to the above drawings without creative labor. DETAILED DESCRIPTION
[0026] The technical scheme of the utility model will be further illustrated below in combination with specific embodiments.
[0027] The patent proposes an inductance method wafer high-precision nondestructive testing equipment based on laser calibration function, referring to the attached Figure 1 , including XY two-axis workbench 1 and detection probe 2 installed on the XY two-axis workbench, through XY two-axis workbench 1, the detection probe 2 can be controlled in any detection position of XY plane, so as to scan and detect the wafer on the XY two-axis workbench, and detect the resistivity of the wafer.
[0028] Specifically, the XY two-axis workbench 1 includes a base 101, an X-axis moving mechanism 102 and a Y-axis moving mechanism 103, the X-axis moving mechanism 102 is installed on the base 101, the Y-axis moving mechanism 103 is installed on the X-axis moving mechanism 102, the Y-axis moving mechanism 103 is driven as a whole to move along the X-axis direction through the X-axis moving mechanism 102, the detection probe 2 is installed on the Y-axis moving mechanism 103, the detection probe 2 is driven to move along the Y-axis direction through the Y-axis moving mechanism 103, and then the detection probe 2 is moved to any position on the XY plane through the combined action of the X-axis moving mechanism 102 and the Y-axis moving mechanism 103.
[0029] The detection probe 2 is provided with a laser ranging sensor 201 and an inductance sensor 202, wherein the inductance sensor 202 is used for detecting the resistivity of the wafer through the inductance method (the inductance method is that an alternating current is generated in the wafer by driving an inductance coil through an alternating signal, and the alternating current changes the impedance value of the inductance coil through mutual inductance. Different wafer resistivities correspond to different alternating current intensities, and the mutual inductance causes different changes in the impedance of the coil, so that the resistivity of the wafer can be measured by detecting the impedance value of the inductance coil); the laser ranging sensor 201 is used for detecting the distance between the inductance sensor 202 and the surface of the wafer, i.e. the lift-off height (LOD). When the inductance sensor detects the resistivity, the laser ranging sensor 201 detects the LOD value in real time, and corrects the resistivity value detected by the inductance sensor according to the LOD value, and after the detection is completed, the data is sent to the PC end, so that the wafer resistivity is detected quickly.
[0030] A wafer table 3 is further arranged on the XY two-axis workbench 1, and the wafer table 3 is fixedly installed on the base 101 of the XY two-axis workbench 1 through bolts, and a U-shaped groove is arranged on the wafer table 3, and the wafer to be detected is placed in the U-shaped groove.
[0031] A control system 4 is further arranged on the XY two-axis workbench 1, and is used for controlling the operation of the device.
[0032] The detection method of the inductance method wafer high-precision nondestructive detection equipment based on the laser calibration function of the utility model is as follows: Figure 2
[0033] 1, first use calibration: select a standard wafer sample for calibration, the resistivity of the sample is known; then the detection equipment of the utility model is used to detect the sample, the sample is fixed on the wafer table 3, the voltage value output by the inductance sensor 202 under different LOD values is detected and recorded, so that the relationship between the resistivity and the inductance sensor output voltage value under different LOD values is obtained.
[0034] 2, detection: for the wafer to be detected, the sample is fixed on the wafer table 3, the position of the detection probe 2 is adjusted by controlling the XY two-axis workbench 1, single point or multi-point global detection at any position is carried out, the inductance sensor 202 detects the wafer in real time and outputs the voltage value, the laser ranging sensor 201 detects the LOD value in real time, and the resistivity value measured by the inductance sensor is corrected according to the LOD value: that is, according to the relationship between the resistivity and the inductance sensor output voltage value under different LOD values obtained by calibration, the resistivity of the wafer to be detected corresponding to the LOD value detected by the laser ranging sensor 201 in real time is obtained.
[0035] Reference is made to the accompanying drawings Figure 3 , the detection result of the inductance sensor under the calibration of the laser ranging sensor of the utility model, it can be seen that there is no difference in the detection result under static and dynamic conditions; while Figure 4 , the detection result of the inductance sensor without the calibration of the laser ranging sensor, it can be seen that the dynamic condition has a significant influence on the detection result.
[0036] The above is only to explain the utility model by drawing, and is not used to limit the utility model in the structure and use range shown and described, so any corresponding modification and equivalent within the spirit and principles of the utility model belongs to the patent range applied by the utility model.
Claims
1. A wafer resistivity non-destructive testing device based on laser calibration inductance method, characterized in that: The XY two-axis workbench and a detection probe mounted on the XY two-axis workbench are comprised; The detection probe is provided with a laser ranging sensor and an inductance sensor, wherein the inductance sensor is used to detect the resistivity of the wafer by inductance method, and the laser ranging sensor is used to detect the distance between the inductance sensor and the surface of the wafer; The XY two-axis workbench comprises a base, an X-axis moving mechanism and a Y-axis moving mechanism, the X-axis moving mechanism is mounted on the base, the Y-axis moving mechanism is mounted on the X-axis moving mechanism, the Y-axis moving mechanism is driven by the X-axis moving mechanism to move along the X-axis direction, and the detection probe is mounted on the Y-axis moving mechanism and is driven by the Y-axis moving mechanism to move along the Y-axis direction.
2. The wafer resistivity non-destructive testing device based on laser calibration inductance method according to claim 1, characterized in that: One end of the X-axis moving mechanism is provided with a first driving motor as a driving source of the X-axis moving mechanism, and one end of the Y-axis moving mechanism is provided with a second driving motor as a driving source of the Y-axis moving mechanism.
3. The wafer resistivity non-destructive testing equipment based on laser calibration inductance method according to claim 1, characterized in that: A wafer table is further provided on the XY two-axis workbench for placing the wafer.
4. The wafer resistivity non-destructive testing device based on laser calibration inductance method according to claim 3, characterized in that: The wafer table is fixedly installed on the base of the XY two-axis workbench by bolts.
5. The wafer resistivity non-destructive testing device based on laser calibration inductance method according to claim 3, characterized in that: A U-shaped groove is provided on the wafer table for placing the wafer to be detected in the U-shaped groove.
6. The wafer resistivity non-destructive testing device based on laser calibration inductance method according to claim 1, characterized in that: A control system is further provided on the XY two-axis workbench.