Multi-channel film thickness measuring instrument with adjustable measuring position

Abstract

The utility model discloses a multi-channel film thickness measuring instrument with an adjustable measuring position. The multi-channel film thickness measuring instrument comprises a main shell, a voltage-stabilized power supply, a light source, a transmission optical fiber, a spectrograph and a measurement position adjusting module are arranged in the main shell; the light source is connected with the transmission fiber; the transmission optical fiber comprises a main optical fiber and a plurality of auxiliary optical fibers; one end of the main optical fiber is connected with the light source, the other end of the main optical fiber is connected with the auxiliary optical fibers, the tail end of each auxiliary optical fiber is connected with an optical fiber probe, and the measuring position adjusting module comprises an adjusting disc, an adjusting disc driving mechanism and a plurality of probe fixing pieces used for fixing the optical fiber probes. The adjusting disc driving mechanism drives the adjusting disc to rotate, and the adjusting disc drives the probe fixing piece to move through the connecting rod so as to adjust the measuring position. The measuring instrument provided by the utility model can be suitable for film materials with various sizes and different specifications, so that the measuring process is more accurate and flexible.

Description

Technical Field

[0001] The utility model relates to the technical field of thin film thickness measurement, in particular to a multi-channel thin film thickness measuring instrument with adjustable measuring position, which is applicable to the film thickness measurement of solar thin film batteries. Background Art

[0002] The improvement of the efficiency of crystalline silicon solar cells is one of the core topics in the photovoltaic industry. Since the concept of tunnel oxide passivated contact (TOPCon) was proposed by the Fraunhofer Institute in Germany at the 28th European Energy and Solar Photovoltaic Exhibition (EU-PVSEC) in 2013, through improving the passivation of the back surface of crystalline silicon cells, the efficiency of TOPCon technology can break through 26%, higher than the theoretical conversion efficiency limit (24.5%) of the current mainstream PERC cells. The specific production process of TOPCon cell wafers is as follows: First, a layer of ultra-thin silicon oxide (i.e., tunnel oxide layer) about 1.5 nm thick is grown on the back surface of the cell by using a wet chemical method; the tunnel oxide layer can eliminate the dangling bonds on the surface of crystalline silicon and play a role in chemical passivation; then a layer of about 30 nm thick phosphorus-doped amorphous silicon is deposited, and after high-temperature heat treatment, the amorphous silicon is transformed into polycrystalline silicon, and the doped phosphorus atoms are activated; due to the different doping levels (i.e., different Fermi levels) of polycrystalline silicon and crystalline silicon substrate, the energy band will bend to generate a field passivation effect, effectively preventing minority carriers from reaching the interface and collecting majority carriers. Relevant research shows that with the increase of the thickness of the polycrystalline silicon layer, the passivation effect will be improved, that is, the open circuit voltage will first increase and then tend to saturate. At the same time, the free carrier absorption will also increase, thereby reducing Jsc (short circuit current density), so the efficiency will first increase and then decrease with the thickness. Therefore, monitoring the thickness of the polycrystalline silicon layer is a key link to improve the photoelectric conversion efficiency of cell wafers.

[0003] At present, the methods for measuring the thickness of thin films are mainly divided into two categories: contact type and non-contact type. Among them, the contact type measuring instrument is mainly a step profiler, which is characterized by high test accuracy, and its disadvantage is that it has special requirements for the measured sample, requires special sample preparation, and cannot realize on-line testing. The non-contact type measuring instruments are mainly ellipsometers and reflection type film thickness measuring instruments. The testing principles of the two are different. The ellipsometer uses the ellipsometry method (polarized light method) to analyze the film thickness and optical constants of the thin film according to the change of the polarization state of light, and can test the film thickness, refractive index and extinction coefficient of the sample. The reflection type film thickness measuring instrument uses the optical interference principle to quickly and accurately measure information such as the film thickness by analyzing the reflection spectrum formed by the interference of the reflected light on the surface of the thin film and the reflected light at the interface between the thin film and the substrate. Since the light of the ellipsometer is incident at an angle and it is necessary to analyze the polarization and intensity of the reflected light, it requires expensive precision moving optical instruments and has a high cost. The reflection type spectroscopic measuring instrument has a relatively simple structure and a low cost, and is applicable to various thin film thickness test requirements.

[0004] Currently, commonly used reflection measuring instruments usually carry a probe at a fixed position to receive the light beam and the interference light signal formed after reflection. A single probe at a fixed position makes the measurement area relatively limited, and there are certain limitations on the size and specifications of the sample. Generally, it is only applicable to single-size thin film materials at fixed detection positions and cannot meet the thickness measurement requirements of thin film materials of various sizes and specifications. Summary of the Invention

[0005] To solve the above technical problems, the purpose of the present utility model is to provide a multi-channel thin film thickness measuring instrument with adjustable measurement position; the measuring instrument of the present utility model has a multi-channel probe position adjustable design, which can be applicable to battery wafers and other thin film materials of various sizes and different specifications, making the measurement process more accurate and flexible.

[0006] To achieve the above technical purpose and reach the above technical effect, the present utility model is realized through the following technical solutions:

[0007] A multi-channel thin film thickness measuring instrument with adjustable measurement position, including a main housing; a regulated power supply, a light source, a transmission optical fiber, a spectrometer, and a measurement position adjustment module are installed in the main housing;

[0008] The light source is connected to the transmission optical fiber; the transmission optical fiber includes a main optical fiber and multiple sub-optical fibers. One end of the main optical fiber is connected to the light source, and the other end is connected to the sub-optical fibers. Each sub-optical fiber includes an incident optical core and a reflected optical core. The incident optical core transmits the optical signal to the surface of the measured sample, and the optical signal reflected by the measured sample is collected by the reflected optical core and then transmitted to the spectrometer;

[0009] A fiber optic probe is respectively connected to the tail end of each sub-optical fiber. The measurement position adjustment module includes an adjustment disk, an adjustment disk driving mechanism, and multiple probe fixing parts for fixing the fiber optic probes. Each probe fixing part is respectively movably connected to the adjustment disk through a connecting rod. The adjustment disk driving mechanism drives the adjustment disk to rotate, and the adjustment disk drives the probe fixing parts to move through the connecting rod to adjust the measurement position.

[0010] Further, the number of the sub-optical fibers is set to 5. Each sub-optical fiber includes 6 incident optical cores and 1 reflected optical core, and the reflected optical core is located at the center of the sub-optical fiber.

[0011] Furthermore, corresponding to the number of the sub-optical fibers, the number of the fiber optic probes is 5; among the 5 fiber optic probes, one is located at the central position, and the remaining 4 fiber optic probes are distributed in a rectangle around the fiber optic probe at the central position.

[0012] Furthermore, the four fiber optic probes distributed in a rectangle are fixed on the probe fixing parts.

[0013] Further, the adjustment disk driving mechanism includes a rotating shaft and a gear transmission assembly. The rotating shaft passes through the main housing. The gear transmission assembly is connected to the rotating shaft and is in transmission connection with the adjustment disk.

[0014] Furthermore, the gear transmission assembly includes a driving gear and a driven gear. The driving gear is connected to the rotating shaft and is also in transmission connection with the driven gear. The adjustment disk is a bearing structure, and driving teeth are provided on the adjustment disk. The driven gear is in transmission connection with the driving teeth of the adjustment disk.

[0015] Further, the probe fixing member is fixedly connected to the slider, and the slider is slidably connected to the slide rail.

[0016] Further, a calibration platform is provided on the main housing. An incident light hole for the optical signal to pass through is provided on the calibration platform; a reflecting mirror is also provided on the calibration platform; the calibration platform can move the reflecting mirror onto the optical signal transmission path for light source calibration.

[0017] Further, a solid-state relay is also installed in the main housing.

[0018] Further, the film thickness measuring instrument can be spanned above the production line involving thin film thickness detection through a bracket for on-line detection.

[0019] The beneficial effects of the present utility model are as follows:

[0020] Based on the optical interference principle, the present utility model designs the positions of multi-channel probes to be adjustable. When measuring the film thickness, the measurement area is selected according to actual needs, and the reflection spectrum formed by the interference of the reflected light on the thin film surface and the reflected light at the interface between the thin film and the substrate is obtained, realizing the rapid and accurate measurement of information such as the thin film thickness. Compared with the conventional reflectivity film thickness instrument equipped with a single probe with a fixed probe position, the design of the multi-channel adjustable probe position can be applied to the film thickness test of battery wafers of various sizes and specifications, and the test position can be adjusted, making the measurement process more accurate and flexible.

[0021] The present utility model is equipped with a reflecting mirror for optical calibration. By simply axially moving and controlling the calibration platform through software, the switching between calibration and testing can be realized. While realizing the integration of calibration and testing, it also ensures the accuracy and stability of the test data points. When the present utility model is testing, the incident light can be perpendicularly irradiated onto the polysilicon film layer through optical fiber transmission, and the instrument and the sample are fixed through a bracket with a trapezoidal structure, which can effectively avoid the influence of external light on the test.

[0022] The utility model can realize multi-channel testing, and the testing position is flexibly adjustable. The testing area can be selected and adjusted according to actual needs, so that it is applicable to thin film materials of different sizes. When applied to the detection of the thickness of polysilicon film layers, the measuring instrument can be applicable to cell wafers of different sizes, realizing controllable global monitoring of the polysilicon layers of samples, which is beneficial to quickly monitoring the film layer uniformity after the CVD process section. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. is a schematic diagram of the overall structure of the thin film thickness measuring instrument of the utility model.

[0024] Figure 2 FIG. is a schematic diagram of the structure of another perspective of the thin film thickness measuring instrument of the utility model, in which the calibration platform is removed.

[0025] Figure 3 FIG. is a schematic diagram of the internal structure of the thin film thickness measuring instrument of the utility model.

[0026] Figure 4 FIG. is a schematic diagram of the structure of the measurement position adjustment module in the thin film thickness measuring instrument of the utility model.

[0027] Figure 5 FIG. is a schematic diagram of the structure of the transmission optical fiber in the utility model.

[0028] Figure 6 FIG. is a schematic diagram of the arrangement structure of the reflected optical core and the incident optical core in the utility model.

[0029] Figure 7 FIG. is a schematic diagram of the cooperation between the thin film thickness measuring instrument of the utility model and the cell production line.

[0030] In the figures, 1: main housing, 11: test port; 2: regulated power supply; 3: light source; 4: transmission optical fiber, 41: main optical fiber, 42: secondary optical fiber, 421: incident optical core, 422: reflected optical core, 43: optical fiber probe; 5: spectrometer; 6: measurement position adjustment module, 61: rotating shaft, 611: knob, 62: driving gear, 63: driven gear, 631: bevel gear part, 632: spur gear part, 633: connecting shaft part, 64: adjustment disc, 65: connecting rod, 66: probe fixing member, 67: slider, 68: slide rail; 7: calibration platform; 8: air cylinder; 9: solid state relay: 10: receiving optical fiber. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The following describes in detail the preferred embodiments of the utility model with reference to the accompanying drawings, so that the advantages and features of the utility model can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the utility model.

[0032] AsFigures 1 to 7 A preferred embodiment of a multi-channel thin film thickness measuring instrument with adjustable measuring position is shown, which includes a main housing 1; a regulated power supply 2, a light source 3, a transmission optical fiber 4, a spectrometer 5 and a measuring position adjustment module 6 are installed in the main housing 1.

[0033] The regulated power supply 2 provides a constant current for modules such as the light source and spectrometer inside the instrument to ensure the stability of the light source and the normal operation of other modules.

[0034] A solid-state relay 9 is also installed in the main housing 1. The solid-state relay 9 has functions of short-circuit protection, overload protection and overheat protection. Through the set combined logic solidification and encapsulation, the intelligent control of the optical path system can be realized.

[0035] The light source 3 is connected to the transmission optical fiber 4; the light source 3 can stably and continuously output a stable light source within a certain wavelength range; the transmission optical fiber 4 includes a main optical fiber 41 and auxiliary optical fibers 42. One end of the main optical fiber 41 is connected to the light source 3, and the other end is connected to the auxiliary optical fibers. There are 5 auxiliary optical fibers 42; the ends of the 5 auxiliary optical fibers 42 are respectively connected with an optical fiber probe 43; 5 test ports 11 corresponding to the 5 optical fiber probes 43 are provided on the bottom plate of the main housing 1. Each auxiliary optical fiber 42 includes 5 incident optical cores 421 and 1 reflection optical core 422; the reflection optical core 422 is located at the center of the auxiliary optical fiber 42; the reflection optical core 422 is connected to the spectrometer 5 through a receiving optical fiber 10; the incident optical cores 421 transmit optical signals to the surface of the sample to be measured, and the optical signals reflected by the sample to be measured are collected by the reflection optical core 422 and transmitted to the spectrometer 5 through the receiving optical fiber 10; in this embodiment, there are 5 spectrometers 5; a HUB hub is also provided in the main housing 1. The spectrometer 5 is connected to the HUB hub, and the HUB hub is connected to an external computer to form an optical signal data analysis module, which analyzes and processes the obtained optical signal data to finally obtain the thin film thickness.

[0036] In this embodiment, the position distribution mode of the 5 optical fiber probes 43 (5 test channels) is as follows: one of them is located at the central position, and the remaining 4 are distributed in a rectangle around the optical fiber probe at the central position. During the test, the 5 optical fiber probes are respectively distributed at the upper left corner, upper right corner, lower left corner, lower right corner and geometric center of the sample to be measured.

[0037] The measurement position adjustment module 6 includes an adjustment disk 64, an adjustment disk driving mechanism, and a plurality of probe fixing members 66 for fixing the optical fiber probes 43. In this embodiment, the number of the probe fixing members 66 is 4, that is, the four optical fiber probes 43 distributed in a rectangular shape are respectively fixed on the probe fixing members 66. Each probe fixing member 66 is movably connected to the adjustment disk 64 through a connecting rod 65; that is, one end of the connecting rod 65 is hinged to the adjustment disk 64, and the other end is hinged to the probe fixing member 66. Each probe fixing member 66 is fixedly connected to a slider 67, and the slider 67 is slidably installed on a slide rail 68 fixed on the bottom plate of the main housing. The adjustment disk driving mechanism drives the adjustment disk 64 to rotate, and the adjustment disk 64 drives the probe fixing member 66 to perform a linear motion in cooperation with the slider 67 and the slide rail 68 to adjust the measurement position. Corresponding to the position adjustment of the optical fiber probe 43, the test port 11 on the bottom plate of the main housing 1 is a long-shaped port.

[0038] Specifically, the adjustment disk driving mechanism includes a rotating shaft 61 and a gear transmission assembly; one end of the rotating shaft 61 passes through the main housing 1 outward, and a knob 611 is provided on the outer end of the extension; the gear transmission assembly includes a driving gear 62 and a driven gear 63. The driving gear 62 is connected to the other end of the rotating shaft 61, and the driving gear 62 is a bevel gear; the driven gear 63 has a connecting shaft portion 633, a bevel gear portion 631 and a spur gear portion 632 fixed on the connecting shaft portion 633. The connecting shaft portion 633 of the driven gear 63 is rotatably installed on the bottom plate of the main housing 1, and the bevel gear portion 631 of the driven gear 63 meshes with the driving gear 62; the adjustment disk 64 is a bearing structure, and a driving tooth is provided on the adjustment disk 64. The spur gear portion 632 of the driven gear 63 meshes with the driving tooth of the adjustment disk 64. Rotating the knob 611 on the rotating shaft 61 from the outside, the rotating shaft 61 drives the driving gear 62 to rotate, thereby driving the driven gear 63 to rotate, further driving the adjustment disk 64 to rotate, and then driving the probe fixing member 66 to linearly move in cooperation with the slider 67 and the slide rail 68 to realize the adjustment of the test position of the optical fiber probe 43.

[0039] A calibration platform 7 is provided on the main housing 1. An incident light hole for the optical signal to pass through is provided on the calibration platform 7. Corresponding to the 5 fiber optic probes 43, 5 incident light holes are provided on the calibration platform 7. 5 reflectors (not shown in the figure) are also installed on the calibration platform 7. Each reflector is respectively located near the incident light hole. The calibration platform 7 can move the reflector onto the optical signal transmission path for light source calibration. The movement of the calibration platform 7 is driven by a drive mechanism installed in the main housing 1. Specifically, a guide rail is installed on the main housing 1, and a moving block is installed on the calibration platform. The calibration platform is slidably installed on the guide rail through the moving block (the guide rail and the moving block are not shown in the figure). The drive mechanism is connected to the calibration platform 7. In this embodiment, the drive mechanism is a cylinder 8, and the cylinder 8 drives the calibration platform 7 to move in cooperation with the guide rail and the moving block.

[0040] Supports are respectively installed on both sides of the main housing of the film thickness measuring instrument. The supports are trapezoidal supports. The film thickness measuring instrument straddles above the battery cell production line through the supports. Specifically, the supports are fixedly connected to the screw hole positions reserved on the base of the battery cell production line, ensuring the overall stability of the actual application of the instrument while ensuring that the incident light perpendicularly irradiates the sample to be measured.

[0041] A cooling fan is also installed on the main housing for dissipating heat from the instrument.

[0042] The present utility model is a thin film thickness measuring instrument with adjustable multi-channel probe positions, which can be used for detecting the thickness of the polysilicon film layer of battery cells. The film thickness measuring instrument straddles above the battery cell production line through the supports, and its external part is connected to an automated power supply. Before testing, adjust the position of the fiber optic probe according to the area to be measured of the battery cell to be tested. The specific operation is as follows: Rotate the knob on the rotating shaft, drive the rotating shaft 61, the gear transmission assembly, the adjustment disc 64 and the connecting rod 65 to move. The moving connecting rod 65 drives the probe fixing member 66 on the slider 67 to translate on the slide rail 68, thereby adjusting the test position of the fiber optic probe 43. After determining the position, trigger the instrument test command through an automated signal. During the test process, first, the internal regulated power supply 2 supplies power to the internal light source 3. The light source is connected to the "one-to-five" transmission optical fiber 4. The light source first irradiates the reflector through the incident light hole of the calibration platform 7 for calibration. After calibration, the software controls the calibration platform 7 to move under the drive of the cylinder 8, moves the reflector away, and the light source can directly irradiate the battery cell on the production line. The light passes through the polysilicon layer of the battery cell and is reflected after irradiating the silicon substrate. The reflected light is received by the reflected light core 422, and the reflected interference light is transmitted to the five internal spectrometers 43 for analysis. Finally, the analysis signal is integrated and transmitted to the external computer through the hub.

[0043] The present utility model applies the principle of optical interference to the measurement of film thickness, and arranges the structural layout of a light source module, a test module, a data analysis module, and a measurement position adjustment module, realizing a simple integrated measurement instrument.

[0044] The unique measurement position adjustment module of the present utility model is based on the principle of mechanical transmission. Through the linkage of a rotating shaft, various gears, and connecting rods, the probe fixing part can be freely translated, realizing controllable adjustment of the position of the optical fiber probe. Therefore, during the test, the measurement area can be selected and adjusted according to actual needs, so as to achieve the purpose of testing battery wafers and other thin film materials of different sizes. When used in cooperation with the polysilicon battery wafer production line, the on-line test can be made more flexible and efficient, and direct testing can be carried out without specific mathematical modeling of the polysilicon layer. The overall test convenience and automation degree are much higher than those of non-contact film thickness test equipment of the same category.

[0045] The optical fiber system of the present utility model is unique, adopting a one-to-five structural design, realizing high-efficiency measurement of multiple channels. The 5 test positions are respectively distributed at the upper left corner, upper right corner, lower left corner, lower right corner, and geometric center of the sample to be measured. Coupled with the flexible adjustable design of the optical fiber probe position, the test area can be selected and adjusted according to actual needs during the test. When applied to the detection of the polysilicon film layer thickness, this measuring instrument is applicable to battery wafers of different sizes, realizing controllable global monitoring of the polysilicon layer of the sample, which is beneficial to quickly monitoring the film layer uniformity after the CVD process section.

[0046] The optical fibers and spectrometers of the present utility model are connected one by one in a 5-5 form, and a hub is used to summarize digital information to a data analysis computer. This data test, analysis, and processing process has convenience and high efficiency.

[0047] While realizing the connection between the instrument and the production line, the present utility model is equipped with a light source calibration module (calibration platform and reflector) by itself, realizing high automation of the instrument.

[0048] For those skilled in the art, it is obvious that the present utility model is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present utility model. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present utility model is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present utility model.

[0049] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A multi-channel film thickness measuring instrument with adjustable measuring position, characterized in that: It comprises a main housing; a voltage-stabilized power supply, a light source, a transmission optical fiber, a spectrometer and a measurement position adjustment module are installed in the main housing; The light source is connected to the transmission optical fiber; the transmission optical fiber includes a main optical fiber and a plurality of auxiliary optical fibers, one end of the main optical fiber is connected to the light source, and the other end is connected to the auxiliary optical fiber, each auxiliary optical fiber includes an incident optical core and a reflection optical core, the incident optical core transmits the optical signal to the surface of the sample to be measured, and the optical signal reflected by the sample to be measured is collected by the reflection optical core and transmitted to the spectrometer; A fiber optic probe is connected to the tail end of each secondary optical fiber. The measurement position adjustment module includes an adjustment disk, an adjustment disk driving mechanism, and a plurality of probe fixings for fixing the fiber optic probes. Each probe fixing is movably connected to the adjustment disk via a connecting rod. The adjustment disk driving mechanism drives the adjustment disk to rotate, and the adjustment disk drives the probe fixing to move via the connecting rod to adjust the measurement position.

2. The multi-channel film thickness measuring instrument with adjustable measuring position according to claim 1, characterized in that: The number of the auxiliary optical fibers is 5, and each auxiliary optical fiber includes 6 incident optical cores and 1 reflection optical core, and the reflection optical core is located at the center of the auxiliary optical fiber.

3. The multi-channel film thickness measuring instrument with adjustable measuring position according to claim 2, characterized in that: Corresponding to the number of the secondary optical fibers, the number of the optical fiber probes is 5; among the 5 optical fiber probes, one is located at the center position, and the remaining 4 are distributed in a rectangular shape around the optical fiber probe at the center position.

4. The multi-channel film thickness measuring instrument with adjustable measuring position according to claim 3, characterized in that: Four optical fiber probes distributed in a rectangular shape are fixed on the probe fixing member.

5. The multi-channel film thickness measuring instrument with adjustable measuring position according to claim 1, characterized in that: The adjusting disk driving mechanism comprises a rotating shaft and a gear transmission assembly, wherein the rotating shaft passes through the main housing, the gear transmission assembly is connected to the rotating shaft, and the gear transmission assembly is drivingly connected to the adjusting disk.

6. The multi-channel film thickness measuring instrument with adjustable measuring position according to claim 5, characterized in that: The gear transmission assembly includes a driving gear and a driven gear, the driving gear is connected to the rotating shaft, and the driving gear is also drivingly connected to the driven gear, the adjustment disk is a bearing structure, the adjustment disk is provided with driving teeth, and the driven gear is drivingly connected to the driving teeth of the adjustment disk.

7. The multi-channel film thickness measuring instrument with adjustable measuring position according to claim 1, characterized in that: The probe fixing piece is fixedly connected to the sliding block, and the sliding block is slidably connected to the sliding rail.

8. The multi-channel film thickness measuring instrument with adjustable measuring position according to claim 1, characterized in that: The main shell is provided with a calibration platform, and the calibration platform is provided with an incident light hole for the optical signal to pass through; the calibration platform is also provided with a reflector; the calibration platform can move the reflector to place the reflector on the optical signal transmission path to perform light source calibration.

9. The multi-channel film thickness measuring instrument with adjustable measuring position according to claim 1, characterized in that: A solid-state relay is also installed in the main housing.

10. The multi-channel film thickness measuring instrument with adjustable measuring position according to claim 1, characterized in that: The film thickness measuring instrument is placed across the production line involving film thickness detection through a bracket for online detection.

Images