Wafer surface component detection method and device thereof

Abstract

This invention discloses a method and apparatus for detecting the surface composition of a wafer, relating to the field of semiconductor wafer regeneration technology. The method includes the following steps: S1: Measuring the resistance of the wafer surface to obtain the surface metal content, and obtaining first-layer data based on the resistance value; S2: Illuminating the wafer surface and collecting refracted light wavelength data to obtain second-layer data, and inferring the wafer surface composition based on the first and second-layer data. The method involves obtaining first-layer data by measuring the resistance of the wafer surface, illuminating the wafer surface, collecting refracted light wavelength data to obtain second-layer data, and inferring the wafer surface composition based on the first and second-layer data.

Description

Technical Field

[0001] This invention relates to the field of semiconductor wafer regeneration technology, and in particular to a method and apparatus for detecting the composition of a wafer surface. Background Technology

[0002] Semiconductor silicon wafers are key materials for producing semiconductor products such as integrated circuits, discrete devices, and sensors. Among many semiconductor raw materials, silicon has significant advantages: a high melting point and a wide bandgap, making it widely applicable to high-temperature and high-pressure devices. With increasing demand and requirements, wafer surface treatment methods are becoming more widespread, and cost-effectiveness is also becoming increasingly important. Wafer recycling and reuse are now on the agenda. Traditional wafer recycling involves physical or chemical methods to remove the coating, followed by chemical or mechanical grinding and polishing, and finally cleaning.

[0003] In wafer regeneration technology, when processing the wafer surface, it is necessary to distinguish the types of impurities on the wafer surface in order to select appropriate physical or chemical methods for removal. However, how to distinguish the impurity composition of the wafer surface (currently, impurity composition is mainly classified into two categories: 1. metal film, 2. non-metal film, and non-metal film is further subdivided into Baer, ​​oxidation, nitridation, poly, etc.) has become a current problem. Therefore, this application provides a wafer surface composition detection method and apparatus to meet the requirements. Summary of the Invention

[0004] The purpose of this application is to provide a method and apparatus for detecting the composition of wafer surfaces, which solves the problem that the existing technology cannot distinguish the composition of impurities on the wafer surface.

[0005] To achieve the above objectives, this application provides the following technical solution: a method for detecting the composition of a wafer surface, comprising the following steps;

[0006] S1: Perform resistance measurement on the wafer surface to obtain the surface metal content, and obtain the first layer data based on the resistance value;

[0007] S2: Illuminate the wafer surface and collect the wavelength data of the refracted light to obtain the second layer of data. Based on the first and second layer data, infer the composition of the wafer surface.

[0008] Preferably, in step S1, resistance measurement is required on both sides of the wafer, and in step S2, illumination treatment is required on both sides of the wafer.

[0009] A wafer surface composition detection device includes six sets of wafer support units, detection units, and motion units;

[0010] Wafer carrier unit: used to load wafers;

[0011] Detection unit: used for resistance measurement and light detection of wafers in a static state;

[0012] Motion unit: Used to drive six sets of carrier units to simultaneously perform lateral rotation and longitudinal flipping movements, transporting the wafer to the next work station while performing wafer flipping operations.

[0013] Preferably, the motion unit includes a base with a positioning post fixed at its upper end, a guide cover fixedly sleeved on the positioning post, and six sets of guide cavities composed of figure-eight cavities and stopping cavities evenly distributed on the outer wall of the guide cover. Each guide cavity is provided with an isosceles triangular structure guide block adapted to the guide cavity below it. The lower ends of the six guide blocks are all located below the guide cover. The six guide blocks are all fixedly connected to the positioning post. The positioning post is penetrated by a rotating post. The rotating post and the positioning post are rotatably connected by a bearing. The lower end of the rotating post is geared to a servo motor. The upper end of the rotating post is fixedly sleeved with a mounting cover, and the guide cover is located inside the mounting cover.

[0014] Preferably, the wafer carrier unit includes a first carrier plate and a second carrier plate arranged vertically. The first carrier plate and the second carrier plate have through holes at their axial centers, and the inner cavities of the through holes are provided with blocking steps. A clamping cylinder is fixed to the upper end of the second carrier plate, and the output end of the clamping cylinder is connected to the first carrier plate. The side end of the first carrier plate is fixedly connected to one end of a rotating shaft, and the other end of the rotating shaft passes through the mounting cover and is fixedly connected to the axial center of the arc-shaped plate. Two limiting rods are symmetrically and rotatably arranged on the concave surface of the arc-shaped plate, and the axial centers of the two limiting rods are on the same straight line as the axial center of the arc-shaped plate. The outer ends of the two limiting rods contact the lower end of the guide cover.

[0015] Preferably, the detection unit includes a top plate and a bottom plate mounted on the positioning column. The top plate is fixed to the upper end of the column, and the column is fixed to the base. The upper end of the column passes through the rotating column and is rotatably connected to the rotating column through a bearing. The top plate and the bottom plate are connected by several support rods. The lower end of the top plate is equipped with two second light shields and two probe seats respectively through two first cylinders and two second cylinders. The two second light shields and the two probe seats are arranged adjacent to each other and corresponding to the wafer carrier unit. Each of the two second light shields is equipped with a hanging light source. The bottom plate is equipped with two first light shields through two first cylinders, and each of the two first light shields has a light wave receiver installed in its inner cavity. The first cylinders, second cylinders, light sources, light wave receivers, servo motors, clamping cylinders, and probe seats are all electrically connected to the PLC control cabinet.

[0016] Preferably, a pressure-bearing rod is fixed on one end of the first carrier plate opposite to the corresponding rotating shaft, and the end of the pressure-bearing rod is slidably disposed in the annular cavity of the pressure-bearing ring. The pressure-bearing ring is fixed on the support rod and is located on the periphery of the first carrier plate.

[0017] Preferably, the bearing rod is slidably mounted on the end of the inner cavity of the bearing ring and a bearing is fixedly sleeved thereon, and the size of the bearing is adapted to the inner cavity of the bearing ring, and the outer surface of the bearing is set as a smooth surface.

[0018] Preferably, the upper end of the pressure-bearing ring is located below the upper end of the first carrier plate.

[0019] In summary, the technical effects and advantages of this invention are as follows:

[0020] The present invention has a reasonable structure. By measuring the resistance of the wafer surface, the first layer of data is obtained. The wafer surface is then illuminated to collect the wavelength data of the refracted light waves, thereby obtaining the second layer of data. The composition of the wafer surface is inferred based on the first and second data.

[0021] In this invention, the wafer composition detection device can simultaneously perform front or side resistance detection and front or back illumination detection on multiple wafers individually, forming a continuous detection process, which can greatly improve work efficiency. At the same time, two robotic arms are added to perform loading and unloading operations respectively, avoiding any impact on detection efficiency.

[0022] In this invention, a pressure-bearing rod and a pressure-bearing ring are provided to ensure the stability of the first and second carrier plates, preventing them from shaking or completely swaying, which could cause the probes on the probe holder to fail to contact the wafer surface and thus prevent resistance detection. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0025] Figure 2 This is a schematic diagram of the rear view structure of the present invention;

[0026] Figure 3 For the present invention Figure 1 Enlarged structural diagram at point A in the middle;

[0027] Figure 4 For the present invention Figure 1Schematic diagram of the detection unit structure;

[0028] Figure 5 For the present invention Figure 1 Schematic diagram of the motion unit structure;

[0029] Figure 6 For the present invention Figure 5 A schematic diagram of the mid-motion unit from below;

[0030] Figure 7 This is a schematic diagram of the installation structure of the pressure-bearing rod and pressure-bearing ring of the present invention.

[0031] In the diagram: 1. Wafer carrier unit; 101. First carrier plate; 102. Second carrier plate; 103. Blocking step; 104. Clamping cylinder; 105. Rotating shaft; 106. Arc plate; 107. Limiting rod; 2. Detection unit; 21. Top plate; 22. Bottom plate; 23. Support rod; 24. First light shield; 25. Second light shield; 26. First cylinder; 27. Second cylinder; 28. Probe holder; 29. ​​Column; 3. Motion unit; 31. Mounting cover; 32. Base; 33. Servo motor; 34. Positioning column; 35. Guide block; 36. Guide cover; 37. Guide cavity; 38. Rotating column; 4. Pressure ring; 5. Pressure rod; 6. Column; 7. Ring groove; 8. Ball bearing. Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example: Reference Figure 1-4 The method for detecting the composition of a wafer surface shown includes the following steps;

[0034] S1: The resistance of the wafer surface is measured to obtain the surface metal content. The first layer of data is obtained based on the resistance value. Silicon wafers with metal impurities on the surface are conductive, while others are not. Therefore, the surface resistance of the wafer can be detected to determine whether it is conductive, and thus determine whether its surface contains metal impurities.

[0035] S2: Illuminate the wafer surface and collect the wavelength data of the refracted light to obtain the second layer of data. Based on the first and second layer data, the composition of the wafer surface can be inferred. According to the wavelength formula λ=C / f, where C is the speed of light (light travels at different speeds in different media) and f is the frequency of light (which does not change), the collected wavelength data of the refracted light can be compared with the wavelength data of the corresponding wafer surface containing impurities in the data system to infer the composition of the wafer surface.

[0036] In a preferred embodiment of this invention, in step S1, resistance measurement is required on both sides of the wafer, and in step S2, illumination treatment is required on both sides of the wafer.

[0037] A wafer surface composition detection device, reference Figure 1 It includes six sets of wafer carrier units 1, detection units 2, and motion units 3;

[0038] Wafer carrier unit 1: Used to load wafers;

[0039] Detection unit 2: Used for resistance measurement and light detection of wafers in a static state;

[0040] Motion unit 3: Used to drive six sets of carrier units to perform horizontal rotation and vertical flipping movements simultaneously, transporting the wafer to the next work station while performing wafer flipping operations.

[0041] As a preferred embodiment of this example, Figure 1-6As shown, the motion unit 3 includes a base 32 with a positioning post 34 fixed to its upper end. A guide cover 36 is fixedly sleeved on the positioning post 34. The outer wall of the guide cover 36 has six sets of guide cavities 37, each consisting of a figure-eight shaped cavity and a stopping cavity, evenly distributed around its circumference. Below each guide cavity 37, there is an isosceles triangular guide block 35 adapted to the guide cavity 37. The lower ends of the six guide blocks 35 are all located below the guide cover 36. All six guide blocks 35 are fixedly connected to the positioning post 34. The positioning post 34 is penetrated by a rotating post 38. The rotating post 38 and the positioning post 34 are rotatably connected by a bearing. The lower end of the rotating post 38 is connected to a servo motor via a gear. The motor 33 is geared, and the upper end of the rotating column 38 is fixedly fitted with a mounting cover 31. The guide cover 36 is located in the inner cavity of the mounting cover 31. The wafer carrier unit 1 includes a first carrier plate 101 and a second carrier plate 102 arranged vertically. The first carrier plate 101 and the second carrier plate 102 are provided with through holes at their axial centers, and the inner cavities of the through holes are provided with blocking steps 103. The upper end of the second carrier plate 102 is fixedly fitted with a clamping cylinder 104, and the output end of the clamping cylinder 104 is connected to the first carrier plate 101. The side end of the first carrier plate 101 is fixedly connected to one end of the rotating shaft 105, and the other end of the rotating shaft 105 passes through the mounting cover 31 and is curved. The plate 106 is fixedly connected at its axis. Two limiting rods 107 are symmetrically rotated on the concave surface of the arc plate 106, and the axes of the two limiting rods 107 and the axis of the arc plate 106 are on the same straight line. The outer ends of the two limiting rods 107 contact the lower end of the guide cover 36. The detection unit 2 includes a top plate 21 and a bottom plate 22 mounted on the positioning column 34. The top plate 21 is fixed to the upper end of the column 29. The column 29 is fixed to the base 32. The upper end of the column 29 passes through the rotating column 38 and is rotatably connected to the rotating column 38 through a bearing. The top plate 21 and the bottom plate 22 are connected by several support rods 23. At the lower end, two second light shields 25 and two probe seats 28 are respectively installed by two first cylinders 26 and two second cylinders 27. The two second light shields 25 and two probe seats 28 are arranged adjacently and corresponding to the wafer carrier unit 1. Each of the two second light shields 25 is equipped with a light source. Two first light shields 24 are installed on the base plate 22 by two first cylinders 26, and each of the two first light shields 24 is equipped with a light wave receiver. The first cylinders 26, second cylinders 27, light source, light wave receiver, servo motor 33, clamping cylinder 104 and probe seats 28 are all electrically connected to the PLC control cabinet.

[0042] At each of the two workstations where no second light shield or probe holder 28 is provided, a set of robotic arms is installed to perform unloading and loading operations respectively. During operation, the servo motor 33 can be controlled to work intermittently. When the servo motor 33 is in operation... Figure 1When the system is in operation, the servo motor 33 drives the mounting cover 31 to rotate via the rotating column 38, while the first carrier plate 101 rotates circumferentially. When one of the limiting rods 107 on the arc-shaped plate 106 moves into the figure-eight cavity, the first carrier plate 101, which is undergoing circumferential motion, will flip over. When the limiting rod 107 moves into the stopping cavity, the other limiting rod 107 can rotate past the guide block 35 from below and contact the lower end of the guide cover 36 again. As the first carrier plate 101 continues its circular motion, the limiting rod 107 located in the dwell cavity will enter the figure-eight cavity and eventually move out of the figure-eight cavity to contact the lower end face of the guide cover 36, completing one flipping operation. When the first carrier plate 101 moves to below the probe seat 28 or the second light shield 25, the servo motor 33 stops working. At this time, through the cooperation of the first cylinder 26 and the second cylinder 27, the four crystals clamped and fixed by the first carrier plate 101 and the second carrier plate 103 are simultaneously... The wafers undergo front resistance testing, back resistance testing, front light wave testing, and back light wave testing respectively. After the testing is completed, the servo motor 33 starts working again to drive the carrier plate 101 to move in a circle and flip it over. When the front and back resistance and front and back light wave testing of a wafer are completed, it will be transported to the unloading area (the clamping cylinder 104 drives the second carrier plate 102 to move relative to the first carrier plate 101, while other wafers are being tested). The first robot's robotic arm reaches into the gap between the first carrier plate 101 and the second carrier plate 102 to remove the wafer and classify and place it according to the obtained data. Since this operation takes a certain amount of time (while the resistance testing and light wave testing require less time), in order to ensure the efficient and orderly operation of the entire equipment, a loading robot is also set up. When the empty carrier plate moves to the loading area, the loading robot performs the loading operation, which can avoid reducing the testing efficiency of this device.

[0043] It should be noted that: First, the two probe holders 28 can be arranged symmetrically, reducing the number of working positions from six to five, which can further improve work efficiency; Second, during optical detection, the wafer is placed within the sealed space formed by the first light shield 24 and the second light shield 25, which can prevent external light from affecting the detection; Third, a strong light source, such as a laser light source, is selected as the light source, which has good light transmission effect on the wafer; Fourth, a limiting post is provided on the first carrier plate 101, which penetrates the second carrier plate 102, and the second carrier plate 102 is slidably connected to the limiting post, which helps to ensure the stability of the first carrier plate 101 and the second carrier plate 102.

[0044] As a preferred embodiment of this example, Figure 1 and Figure 5As shown, a pressure-bearing rod 5 is fixed on one end of the first carrier plate 101 opposite to the corresponding rotating shaft 105, and the end of the pressure-bearing rod 5 is slidably disposed in the annular cavity of the pressure-bearing ring 4. The pressure-bearing ring 4 is fixed on the support rod 23. The pressure-bearing ring 4 is located on the periphery of the first carrier plate 101, which can ensure the stability of the first carrier plate 101 and the second carrier plate 102, and prevent them from shaking or completely causing the probe on the probe holder 28 to fail to contact the wafer surface, thus making it impossible to perform resistance detection.

[0045] As a preferred embodiment of this example, Figure 7 As shown, the bearing rod 5 is slidably mounted on the end of the bearing ring 4 and a bearing is fixedly sleeved thereon. The size of the bearing is adapted to the inner cavity of the bearing ring 4. The outer surface of the bearing is set as a smooth surface. The end of the bearing rod 5 is rolledly connected to the bearing ring 4 through the bearing. The smooth surface of the outer surface is set to reduce friction.

[0046] As a preferred embodiment of this example, Figure 1 As shown, the upper end of the pressure ring 4 is located below the upper end of the first carrier plate 101 to avoid occupying the operating space of the robot's robotic arm for loading and unloading.

[0047] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wafer surface composition detection device, characterized in that: It includes six sets of wafer carrier units (1), detection units (2) and motion units (3); Wafer carrier unit (1): used to load wafers; Detection unit (2): used for resistance measurement and light detection of wafers in a static state; Motion unit (3): used to drive six sets of carrier units to perform horizontal rotation and vertical flipping motion simultaneously, and transport the wafer to the next work station while performing wafer flipping operation; The motion unit (3) includes a base (32) with a positioning post (34) fixed at the upper end. A guide cover (36) is fixedly sleeved on the positioning post (34). The outer wall of the guide cover (36) has six sets of guide cavities (37) evenly distributed in a circular pattern, each consisting of a figure-eight shaped cavity and a stopping cavity. Each guide cavity (37) has an isosceles triangular structure guide block (35) adapted to the guide cavity (37) below it. The lower ends of the six guide blocks (35) are all located at the bottom of the guide cavity (37). Below the cover (36), the six guide blocks (35) are all fixedly connected to the positioning post (34). The positioning post (34) is penetrated by the rotating post (38). The rotating post (38) and the positioning post (34) are rotatably connected by bearings. The lower end of the rotating post (38) is geared to the servo motor (33). The upper end of the rotating post (38) is fixedly fitted with a mounting cover (31). The guide cover (36) is located in the inner cavity of the mounting cover (31).

2. The wafer surface composition detection device of claim 1, wherein: The wafer carrier unit (1) includes a first carrier plate (101) and a second carrier plate (102) arranged vertically. A through hole is provided at the axial center of both the first carrier plate (101) and the second carrier plate (102), and a blocking step (103) is provided within the cavity of each through hole. A clamping cylinder (104) is fixed to the upper end of the second carrier plate (102), and the output end of the clamping cylinder (104) is connected to the first carrier plate (101). The side of the first carrier plate (101)... One end of the shaft (105) is fixedly connected to the other end of the mounting cover (31) and fixedly connected to the axis of the arc plate (106). Two limiting rods (107) are symmetrically rotated on the concave surface of the arc plate (106), and the axis of the two limiting rods (107) is on the same straight line as the axis of the arc plate (106). The outer ends of the two limiting rods (107) are in contact with the lower end of the guide cover (36).

3. The wafer surface composition detection apparatus according to claim 2, characterized by: The detection unit (2) includes a top plate (21) and a bottom plate (22) mounted on the positioning column (34). The top plate (21) is fixed to the upper end of the column (29), and the column (29) is fixed to the base (32). The upper end of the column (29) passes through the rotating column (38) and is rotatably connected to the rotating column (38) through a bearing. The top plate (21) and the bottom plate (22) are connected by several support rods (23). The lower end of the top plate (21) is equipped with two second light shields (25) and two second light shields (26 and 27) respectively through two first cylinders (26) and two second cylinders (27). The probe holder (28), two second light shields (25) and two probe holders (28) are arranged adjacently and corresponding to the wafer carrier unit (1). A light source is provided in each of the two second light shields (25). Two first light shields (24) are installed on the base plate (22) through two first cylinders (26). A light wave receiver is installed in the inner cavity of each of the two first light shields (24). The first cylinder (26), the second cylinder (27), the light source, the light wave receiver, the servo motor (33), the clamping cylinder (104) and the probe holder (28) are all electrically connected to the PLC control cabinet.

4. The wafer surface composition detection apparatus according to claim 2, characterized by: A pressure rod (5) is fixed on one end of the first carrier plate (101) opposite to the corresponding rotating shaft (105), and the end of the pressure rod (5) is slidably disposed in the annular cavity of the pressure ring (4). The pressure ring (4) is fixed on the support rod (23) and is located on the periphery of the first carrier plate (101).

5. The wafer surface composition detection device according to claim 4, characterized in that: The pressure rod (5) is slidably disposed on the end of the inner cavity of the pressure ring (4) and a bearing is fixedly sleeved thereon. The size of the bearing is adapted to the inner cavity of the pressure ring (4), and the outer surface of the bearing is set as a smooth surface.

6. The wafer surface composition detection device according to claim 4, characterized in that: The upper end of the pressure ring (4) is located below the upper end of the first carrier plate (101).

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