System for measuring PL spectrum of integral surface of C + L wave band wafer

Abstract

The utility model relates to a system for measuring a PL spectrum of a C + L wave band wafer overall plane, and relates to the technical field of semiconductor lasers. Comprising a 980nm pump laser, an optical fiber coupler, a tapering optical fiber, a spectrograph, an electric control two-dimensional translation table, an objective table and a tapering optical fiber clamp. The objective table is used for bearing and fixing a tested wafer and realizing temperature control and heat dissipation of a test environment; the electric control two-dimensional translation stage is fixed with the objective table and drives the objective table to realize the overall displacement of the test wafer; the spectrograph is used for reading the measured light-emitting wavelength and intensity of the test wafer; and the optical fiber coupler is connected with the 980nm pump laser, the tapered optical fiber and the spectrograph, so that the whole optical path structure is connected in series, and the measurement and drawing of the overall plane PL spectrum can be realized. The testing device is simple and low in cost; the testing method is simple and easy to implement, high in accuracy and wide in application range.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor lasers, and particularly relates to a system for measuring the overall surface PL spectrum of C+L band wafers. Background Art

[0002] With the rapid development of optical communication technology, fiber optic communication systems play an increasingly important role in the field of information transmission. The C band (1530nm to 1565nm) and the L band (1565nm to 1625nm) have become important working bands in fiber optic communication due to their superior transmission characteristics. In these bands, optical signals can be effectively transmitted over long distances while maintaining low loss and high signal quality. Therefore, the C band and the L band have become the mainstream choices in modern fiber optic communication systems.

[0003] In order to improve the performance and reliability of communication systems, the research and development of fiber optic communication devices are particularly important. Fiber optic communication devices, such as optical amplifiers, lasers, and photodetectors, are usually made of high-quality semiconductor materials. The performance of these devices depends to a large extent on the quality of the semiconductor materials and the manufacturing process. During the manufacturing process of fiber optic communication devices, the surface characteristics of wafers have a crucial impact on the performance of the devices. Therefore, the testing and analysis of wafer surface characteristics have become an indispensable part of semiconductor manufacturing processes.

[0004] Photoluminescence (PL) spectroscopy, as a non-destructive testing method, is widely used in the research of semiconductor materials and devices. The PL spectroscopy technology excites semiconductor materials with light, causing them to emit light of specific wavelengths, and then measures their spectral characteristics. By analyzing the PL spectrum, information about the energy band structure, impurities, and defects of the material can be obtained, thereby evaluating the quality of the material and the reliability of the process. The PL spectroscopy technology has the advantages of fast testing, high sensitivity, and non-destruction of samples, and is an important tool in semiconductor material research.

[0005] However, existing PL testing systems are expensive and difficult to use widely. The high cost of existing systems limits their popularization and application in small and medium-sized enterprises. For many research institutions and enterprises, purchasing and maintaining a high-performance PL testing system requires a large amount of capital, which to a certain extent hinders the popularization and development of PL spectroscopy technology.

[0006] Therefore, it is of great practical significance and market demand to develop a new testing system that can efficiently and accurately test the surface PL spectrum of C+L band wafers. Content of the Utility Model

[0007] The purpose of the present utility model is to provide a test system for measuring the overall surface PL spectrum of a C+L band wafer with low cost and simple setup, so as to solve the problems existing in the above-mentioned prior art. The test method is simple, suitable for ordinary technicians to operate, and can ensure a certain measurement accuracy.

[0008] To achieve the above object, the present utility model provides a system for measuring the overall surface PL spectrum of a C+L band wafer, including:

[0009] A stage for fixing a temperature control component and an aluminum plate, and the test wafer is mounted on the aluminum plate.

[0010] A 980nm pump laser that emits high-power laser with a wavelength of 980nm and irradiates the test wafer through an optical path structure, causing the test wafer to emit fluorescence.

[0011] An electronically controlled two-dimensional translation stage fixed to the stage and connected to a computer through an electrical signal, for driving the stage to achieve the overall translation of the test wafer.

[0012] A spectrometer connected to the optical path structure to detect the weak fluorescence emitted by the test wafer after pumping. The spectrometer is also connected to the computer through an electrical signal to realize the real-time storage of signals at various positions of the test wafer.

[0013] Furthermore, it also includes:

[0014] A tapered optical fiber fixed by an optical fiber fixture to achieve the perpendicular incidence of the pump laser on the test wafer, and the tapered optical fiber is also used to collect the fluorescence emitted by the test wafer.

[0015] An optical fiber coupler, which is a one-in-two-out optical fiber splitting structure. Its two output ends are respectively connected to the 980nm pump laser and the spectrometer, and its input end is connected to the tapered optical fiber. The optical fiber coupler plays a role in connecting the entire optical path in series.

[0016] Furthermore, the aluminum plate includes an upper aluminum plate and a lower aluminum plate, which are connected by screws. The test wafer is laid flat in the wafer placement and removal groove opened on the upper aluminum plate.

[0017] Furthermore, the temperature control component includes a TEC cooler and a thermistor. The TEC cooler is clamped between the upper aluminum plate and the lower aluminum plate. A thermistor groove is reserved on the upper aluminum plate, and the thermistor is placed in the thermistor groove. By outputting current according to the preset PID parameters, the overall temperature of the test environment is kept constant.

[0018] Further, first, second, and third calibration points are reserved on the upper aluminum plate to ensure the fixation of the initial placement position of the test wafer.

[0019] Further, four upper threaded holes are reserved at the four corners of the upper aluminum plate, and four lower threaded holes corresponding to the upper threaded holes are reserved on the lower aluminum plate.

[0020] Further, four fixing threaded holes are formed on the lower aluminum plate for connection with the electric control two-dimensional translation stage.

[0021] Further, when the optical fiber coupler is incident from the input end, the light intensity ratio of the two output ends is 1:1. When incident from one output end, the input end can also receive light intensity.

[0022] Further, the optical fiber fixture is fixed on the three-dimensional fine adjustment frame and can find the best initial measurement position.

[0023] The beneficial effects of the present utility model are as follows:

[0024] (1) The test system of the present utility model has significant cost advantages compared with the existing PL test system. Its design is simple, the manufacturing cost is low, the procurement cost is greatly reduced, enabling more scientific research institutions and small and medium-sized enterprises to afford it. This not only expands the application scope of the PL spectrum technology but also provides more cost-effective test means for more researchers. In addition, the system is easy to maintain, reducing the expenses of daily use and long-term maintenance, thus further enhancing the cost performance.

[0025] (2) The test system of the present utility model features high sensitivity and high precision. The high-performance 980nm pump laser and tapered optical fiber ensure the excitation ability for weak fluorescence signals, and the high-precision spectrometer guarantees the accurate detection of weak signals, thereby obtaining detailed and accurate material property information.

[0026] (3) The control program of the test system of the present utility model can be realized by an ordinary computer, with a simple design and easy operation, suitable for ordinary technical personnel. The test method is simple, and users can start operating without complex training. Description of the Drawings

[0027] Figure 1 is the overall structural schematic diagram of the present utility model;

[0028] Figure 2 is the structural schematic diagram of the upper aluminum plate of the present utility model;

[0029] Figure 3 is the structural schematic diagram of the lower aluminum plate of the present utility model;

[0030] Figure 4This is the test PL spectrogram of the present utility model;

[0031] Figure 5 This is the surface PL distribution diagram of the whole present utility model.

[0032] Among them, in the figure:

[0033] 1 - upper aluminum plate; 2 - lower aluminum plate; 101 - wafer placing and taking groove; 102 - thermistor groove; 103 - screw hole; 104 - first calibration point; 105 - second calibration point; 106 - third calibration point; 107 - upper threaded hole; 201 - lower threaded hole; 202 - fixing threaded hole. Specific embodiments

[0034] The technical solutions in the embodiments of the present utility model will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so as to describe the embodiments of this application here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily need to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0036] In this application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe this application and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation or be constructed and operated in a specific orientation.

[0037] Moreover, in addition to being able to represent the orientation or positional relationship, some of the above-mentioned terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0038] In addition, the terms "installed", "set up", "equipped with", "connected", "linked", "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there is internal communication between two devices, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0039] The present utility model aims to provide a new PL test system that can cover the C-band and L-band, has the characteristics of high sensitivity and high precision, and also has the advantages of high cost-effectiveness and easy maintenance, so as to provide strong technical support for the research and development and production of optical fiber communication devices.

[0040] The research and development of this new test system will significantly improve the test ability and efficiency of optical fiber communication devices, reduce the test cost, and promote the further development and application of optical communication technology. Through a comprehensive analysis of the PL spectra on the surface of C+L-band wafers, the characteristics of semiconductor materials can be better understood, the manufacturing process of devices can be optimized, the performance and reliability of devices can be improved, and a solid foundation can be laid for the upgrade and innovation of optical fiber communication systems.

[0041] As Figure 1 shown, the present utility model provides a system for measuring the overall surface PL spectrum of a C+L-band wafer, including:

[0042] A stage for fixing a temperature control component and an aluminum plate, on which a test wafer is installed, and the stage is used to control the temperature of the test environment and drive the overall displacement of the test wafer to achieve surface PL spectrum scanning test;

[0043] An electrically controlled two-dimensional translation stage, which is fixed to the stage and connected to a computer through an electrical signal, and performs a stepping movement according to the control signal fed by the computer and the set XY-direction step size, drives the stage to achieve the overall translation of the test wafer, and saves the position information of the test wafer in the computer in real time;

[0044] A tapered optical fiber fixed by an optical fiber fixture to enable the pump laser to be perpendicularly incident on the test wafer, and the tapered optical fiber is also used to collect the fluorescence emitted by the test wafer;

[0045] A spectrometer connected to the tapered optical fiber through an optical path structure to detect the weak fluorescence emitted by the test wafer after being pumped, and the spectrometer is also connected to the computer through an electrical signal to achieve the real-time saving of signals at each position of the test wafer;

[0046] A 980nm pump laser, which emits high-power laser with a wavelength of 980nm and irradiates the test wafer through an optical path structure to cause the test wafer to emit fluorescence.

[0047] An optical fiber coupler, which is a one-in-two-out optical fiber splitting structure. Its two output ends are respectively connected to the 980nm pump laser and the spectrometer, and its input end is connected to the tapered optical fiber. The optical fiber coupler plays a role in connecting the entire optical path in series.

[0048] The computer described in the embodiment of the present utility model can be regarded as a signal processing device. It communicates with the electronically controlled two-dimensional translation stage and the spectrometer through electrical connections. The signal connection methods can include wired connections or wireless connections, etc. On the one hand, this computer controls the movement of the electronically controlled two-dimensional translation stage to achieve automated detection (the specific control method will be described in detail later); on the other hand, it receives electrical signals from the spectrometer to obtain light intensity and wavelength signals, and based on these signals, it realizes the PL spectrum detection of the entire surface of the test wafer.

[0049] Appendix Figure 2 And Figure 3 As shown in the figure, the aluminum plate includes an upper aluminum plate 1 and a lower aluminum plate 2. The upper aluminum plate 1 and the lower aluminum plate 2 are connected by screws. The test wafer is laid flat in the wafer placement and extraction groove 101 opened on the upper aluminum plate 1, so as to facilitate the placement and extraction of the test wafer without causing unnecessary damage to it. The temperature control component includes a TEC cooler and a thermistor. A TEC cooler is clamped between the upper aluminum plate 1 and the lower aluminum plate 2. A thermistor groove 102 is reserved on the upper aluminum plate 1, and the thermistor is placed in the thermistor groove. By outputting current through pre-set PID parameters, the overall temperature of the test environment is kept constant. The thermistor groove 102 is mechanically fixed by a pressing piece to ensure the stability of long-term operation. Screw holes 103 are provided on both sides of the pressing piece. First calibration points 104, second calibration points 105, and third calibration points 106 are also reserved on the upper aluminum plate 1 to ensure the fixation of the initial placement position of the test wafer. Four upper threaded holes 107 are reserved at the four corners of the upper aluminum plate 1, and four lower threaded holes 201 corresponding to the upper threaded holes 107 are reserved on the lower aluminum plate 2. Four fixed threaded holes 202 are opened on the lower aluminum plate 2 for connecting to the electronically controlled two-dimensional translation stage. The entire stage can realize multiple functions such as facilitating the placement and extraction of the test wafer, controlling the temperature stability of the long-term test environment, and connecting to the electronically controlled two-dimensional translation stage.

[0050] To further optimize the technical solution, when the optical fiber coupler is incident from the input end, the light intensity ratio of the two output ends is 1:1. When incident from one output end, the input end can also receive relatively strong light intensity.

[0051] Further optimize the technical solution. The optical fiber fixture is fixed on a three-dimensional fine adjustment frame and can find the best initial measurement position. Therefore, the initial position of the optical fiber taper can be finely adjusted to achieve the best pumping effect.

[0052] Further optimize the technical solution. The operating temperature of the pump laser is 25°C, the injection current is 300 mA, the output power of the pump source is 237 mW, the output power measured after passing through the fiber coupler is 115 mW, and the core diameter of the tapered fiber is 5 μm. Therefore, a sufficiently high pump power density can be obtained to achieve full excitation of the test wafer.

[0053] Further optimize the technical solution. The temperature of the TEC cooler is controlled by predetermined PID parameters to keep the test environment temperature at 25°C. In particular, the temperature of the test environment can be changed to simulate the performance changes of the test wafer under different environments.

[0054] The working principle of the present utility model is as follows:

[0055] Place the test wafer on the aluminum plate capable of realizing temperature control and heat dissipation functions according to the reserved positioning mark points. The aluminum plate is mechanically connected to the electric control two-dimensional translation stage;

[0056] At the start of the test, the 980 nm pump laser first emits laser light with a wavelength of 980 nm. The laser light enters the tapered fiber after passing through the fiber coupler and is vertically incident on the surface of the test wafer. The test wafer emits fluorescence due to electron transition after receiving the pump light. The fluorescence is collected by the tapered fiber and enters the input end of the fiber coupler, and is output from the other output end of the tapered fiber to the spectrometer for measurement. The spectrometer converts the light intensity signal at a certain point into an electrical signal and feeds it back to the computer;

[0057] Both the spectrometer and the electric control two-dimensional translation stage are electrically connected to the computer. When the spectrometer completes a reading, the electric control two-dimensional translation stage moves by a preset step size. After the movement is completed, the spectrometer reads again, and finally realizes the surface photoluminescence spectrum scanning of the entire test wafer, and automatically draws the surface PL distribution and detailed spectral diagrams of each point, etc. Figure 4 Recording the single-point pl measurement data at each point in the same graph can clearly show whether there is an obvious error in the measurement at a certain point during the overall measurement. Figure 5 That is, the pl peak data at each point obtained by measurement and fitting are plotted on a two-dimensional plane according to the spatial position to increase the visibility of the results.

[0058] Furthermore, by changing the scanning step distance and the number of cycles, the overall surface photoluminescence spectrum test of test wafers of any size can be realized, and the test fineness can be changed according to requirements.

[0059] The test system of the present utility model has significant cost advantages compared with the existing PL test systems. Its design is simple and the manufacturing cost is low, greatly reducing the procurement cost, enabling more scientific research institutions and small and medium-sized enterprises to afford it. This not only expands the application scope of the PL spectrum technology but also provides more researchers with affordable test means. In addition, the system is easy to maintain, reducing the expenses for daily use and long-term maintenance, thus further enhancing the cost performance. The test system of the present utility model features high sensitivity and high precision. The high-performance 980nm pump laser and tapered fiber ensure the excitation ability for weak fluorescence signals, and the high-precision spectrometer guarantees the accurate detection of weak signals, thereby obtaining detailed and accurate material property information. The control program of the test system of the present utility model can be implemented by an ordinary computer, with a simple design and easy operation, suitable for ordinary technicians. The test method is simple, and users can start operating without complex training.

[0060] The above description is only a preferred embodiment of the present utility model, and does not impose any limitation on the technical scope of the present utility model. Therefore, any minor modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims

1. A system for measuring the overall surface PL spectrum of a C+L band wafer, characterized in that Comprising: A stage for fixing a temperature control component and an aluminum plate, on which a test wafer is mounted; A 980nm pump laser that emits high-power laser with a wavelength of 980nm and irradiates the test wafer through an optical path structure to cause the test wafer to emit fluorescence; An electronically controlled two-dimensional translation stage fixed to the stage, connected to a computer through an electrical signal, and used to drive the stage to achieve the overall translation of the test wafer; A spectrometer connected to the optical path structure to detect the weak fluorescence emitted by the test wafer after pumping. The spectrometer is also connected to the computer through an electrical signal to achieve real-time storage of signals at various positions of the test wafer; 2. The system for measuring the overall surface PL spectrum of a C+L band wafer as described in claim 1, wherein It further comprises: A tapered fiber fixed by a fiber fixture to enable the pump laser to be perpendicularly incident on the test wafer. Moreover, the tapered fiber is also used to collect the fluorescence emitted by the test wafer; An optical fiber coupler with a one-in-two-out optical fiber splitting structure, whose two output ends are respectively connected to the 980nm pump laser and the spectrometer, and whose input end is connected to the tapered fiber. The optical fiber coupler plays a role in connecting the entire optical path in series; 3. A system for measuring the overall surface PL spectrum of a C+L band wafer as described in claim 1 or 2, characterized in that, The aluminum plate includes an upper aluminum plate and a lower aluminum plate, which are connected by screws. The test wafer is laid flat in the wafer placement and retrieval groove opened on the upper aluminum plate; 4. A system for measuring the overall surface PL spectrum of a C+L band wafer as described in claim 3, characterized in that, The temperature control component includes a TEC cooler and a thermistor. The TEC cooler is clamped between the upper aluminum plate and the lower aluminum plate. A thermistor groove is reserved on the upper aluminum plate, and the thermistor is placed in the thermistor groove. By outputting current according to pre-set PID parameters, the overall temperature of the test environment is kept constant; 5. The system for measuring the overall surface PL spectrum of a C+L band wafer as described in claim 3, wherein The upper aluminum plate also reserves a first calibration point, a second calibration point, and a third calibration point to ensure the fixation of the initial placement position of the test wafer; 6. The system for measuring the overall surface PL spectrum of a C+L band wafer as described in claim 3, characterized in that, Four upper threaded holes are reserved at the four corners of the upper aluminum plate, and four lower threaded holes corresponding to the upper threaded holes are reserved on the lower aluminum plate; 7. The system for measuring the overall surface PL spectrum of a C+L band wafer as described in claim 3, characterized in that, Four fixed threaded holes are opened on the lower aluminum plate for connection with the electronically controlled two-dimensional translation stage; 8. A system for measuring the overall surface PL spectrum of a C+L band wafer as described in claim 2, characterized in that, When the optical fiber coupler is incident from the input end, the light intensity ratio of the two output ends is 1:

1. When incident from one output end, the input end can also receive the light intensity; 9. The system for measuring the overall surface PL spectrum of a C+L band wafer as described in claim 2, wherein The fiber fixture is fixed on a three-dimensional fine adjustment frame and can find the best initial measurement position.

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