A method for testing a deep ultraviolet LED epitaxial wafer

Abstract

The application discloses a kind of deep ultraviolet LED epitaxial wafer test methods, comprising: using laser device, marking is carried out on the front of the deep ultraviolet LED epitaxial wafer, to expose the N-type structure of the deep ultraviolet LED epitaxial wafer and form N-type exposure point, after N-type exposure point is made N-type contact point;The front of the deep ultraviolet LED epitaxial wafer is pressed in operation, to form a plurality of P-type contact points on the deep ultraviolet LED epitaxial wafer;The deep ultraviolet LED epitaxial wafer is placed on test support, and the position of the test support is adjusted, so that the P-type contact point of the deep ultraviolet LED epitaxial wafer and the data window of integrating sphere under test support are located on the same straight line;The positive and negative poles of power supply table are connected respectively P-type contact point and N-type contact point, and after power-on, the light data is collected by the integrating sphere, and the light data is sent to host computer.The application solves the problem that N-type layer and P-type layer cannot be accurately connected in the prior art.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a testing method for deep ultraviolet LED epitaxial wafers. Background Technology

[0002] The basic epitaxial structure of a deep ultraviolet (DUV) LED epitaxial wafer consists of a sapphire substrate, an ALN ​​bottom layer, an N-type ALGaN electron injection layer, a quantum well layer, and a P-type ALGaN hole injection layer, all stacked with organic compounds. The fabrication process involves using MOCVD technology under specific high-temperature and low-pressure conditions. A group III organic compound is introduced into the MOCVD equipment cavity via a group V hydride as a carrier, and an epitaxial deposition process is performed on the substrate surface to form the DUV LED epitaxial wafer.

[0003] To promptly detect defective deep ultraviolet (DUV) LED epitaxial wafers, it is necessary to inspect the crystal quality of the DUV LED epitaxial wafers to facilitate subsequent process adjustments. Currently, during inspection, the method generally relies on experience to scratch the epitaxial wafer with a diamond cutter, causing the N-type ALGaN electron injection layer to leak out, which damages the epitaxial wafer and is prone to errors, making it impossible to accurately connect the N-type and P-type layers, resulting in inaccurate test data. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a deep ultraviolet LED epitaxial wafer testing method, solving the technical problem that the N-type layer and P-type layer cannot be accurately connected in the prior art.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0006] This invention provides a testing method for deep ultraviolet LED epitaxial wafers, comprising the following steps:

[0007] Using a laser device, markings are made on the front side of the deep ultraviolet LED epitaxial wafer to expose the N-type structure of the deep ultraviolet LED epitaxial wafer and form N-type exposure points. Then, N-type contact points are made on the N-type exposure points.

[0008] An indium pressing operation is performed on the front side of the deep ultraviolet LED epitaxial wafer to form multiple P-type contact points on the deep ultraviolet LED epitaxial wafer;

[0009] The deep ultraviolet LED epitaxial wafer is placed on the test bracket, and the position of the test bracket is adjusted so that the indium point of the deep ultraviolet LED epitaxial wafer is on the same straight line as the data window of the integrating sphere below the test bracket.

[0010] Connect the positive and negative terminals of the power meter to the P-type contact and the N-type contact respectively. After power is applied, collect the light emission data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer through the integrating sphere, and send the light emission data to the host computer.

[0011] In one embodiment, the laser device uses an ultraviolet laser to mark the front side of the deep ultraviolet LED epitaxial wafer.

[0012] In one embodiment, the marking range of the laser device is the front surface area of ​​a 2-inch to 4-inch deep ultraviolet LED epitaxial wafer.

[0013] In one embodiment, the method for creating an N-type contact point on the N-type exposure point specifically comprises:

[0014] An indium pressing operation is performed on the N-type exposed point to create an N-type contact point.

[0015] In one embodiment, the indium pressing operation performed on the front side of the deep ultraviolet LED epitaxial wafer to form a plurality of P-type contact points on the deep ultraviolet LED epitaxial wafer includes:

[0016] A fixed position is determined on the deep ultraviolet LED epitaxial wafer. Indium particles are picked up with tweezers and pressed at the fixed position to make the indium particles stick to the surface of the deep ultraviolet LED epitaxial wafer to form a P-type contact point.

[0017] In one embodiment, the indium particles are indium metal particles ranging from 1µm to 100,000µm.

[0018] In one embodiment, the method for adjusting the position of the test bracket specifically includes:

[0019] Operate the left-right adjustment knob and the up-down adjustment knob on the test bracket in sequence to adjust the position of the test bracket.

[0020] In one embodiment, the step of connecting the positive and negative terminals of the power meter to the P-type contact and the N-type contact respectively, and collecting the emitted light data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer via the integrating sphere after power-on, and sending the emitted light data to the host computer, includes:

[0021] The positive terminal of the power meter is pressed onto the P-type contact point, the negative terminal of the power meter is pressed onto the N-type contact point, and a constant current is applied to the power meter. The light emission data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer is collected by the integrating sphere, and the light emission data is sent to the host computer.

[0022] In one embodiment, the constant current is 1mA-100mA.

[0023] In one embodiment, after connecting the positive and negative terminals of the power meter to the P-type and N-type contacts respectively, and collecting the emitted light data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer via the integrating sphere after power-on, and sending the emitted light data to the host computer, the method further includes:

[0024] The host computer analyzes the emitted light data and outputs the test results.

[0025] Compared with existing technologies, the deep ultraviolet (DUV) LED epitaxial wafer testing method provided by this invention uses a laser device to mark specific symbols or text on the front side of the DUV LED epitaxial wafer, exposing the N-type structure and forming N-type contact points without damaging the DUV LED epitaxial wafer. This avoids damage to the DUV LED epitaxial wafer during testing. Moreover, the marking range is larger than that of using a diamond cutter, ensuring the exposure of the N-type structure and avoiding testing errors. This allows for accurate electrical connection between the N-type and P-type layers, ensuring the accuracy of test data. Furthermore, by adjusting the position of the DUV LED epitaxial wafer, the accuracy of the integrating sphere data acquisition can be further guaranteed. Attached Figure Description

[0026] Figure 1 This is a flowchart of the deep ultraviolet LED epitaxial wafer testing method provided in the embodiments of the present invention;

[0027] Figure 2 This is a schematic diagram illustrating the fabrication of P-type and N-type contact points in the deep ultraviolet LED epitaxial wafer testing method provided in this embodiment of the invention.

[0028] Figure 3 This is a schematic diagram of a test system for implementing a deep ultraviolet LED epitaxial wafer testing method according to an embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Please see Figures 1 to 3 This invention provides a testing method for deep ultraviolet LED epitaxial wafers, which is based on... Figure 3The test system shown is implemented as follows. Specifically, the test system includes a power meter 1, a test bracket 2, an integrating sphere 3, an optical fiber data cable 4, and a host computer (not shown in the figure). The power meter 1 has a positive test pen 11 and a negative test pen 12. The test bracket 2 has an epitaxial wafer placement area 2a for placing a deep ultraviolet LED epitaxial wafer. Specifically, the epitaxial wafer placement area 2a is a groove on the test bracket 2, the size of which is adapted to the deep ultraviolet LED epitaxial wafer. The test bracket 2 has a left-right adjustment knob 21 and an up-down adjustment knob 22. The left-right adjustment knob 21 is used to adjust the left-right position, and the up-down adjustment knob 22 is used to adjust the up-down position. The integrating sphere is located below the epitaxial wafer placement area 2a and is used to collect the light emitted from the back of the deep ultraviolet LED epitaxial wafer during testing. The integrating sphere 3 is connected to the host computer through the optical fiber data cable 4 and is used to feed back the collected data to the host computer through the optical fiber data cable 4. After analysis by the host computer, the test results are output. The host computer is preferably a fiber optic spectrometer.

[0031] Please continue reading. Figure 1 The deep ultraviolet LED epitaxial wafer testing method provided in this embodiment of the invention includes steps S100 to S400.

[0032] S100. Using a laser device, marking is performed on the front side of the deep ultraviolet LED epitaxial wafer to expose the N-type structure of the deep ultraviolet LED epitaxial wafer and form an N-type exposure point. Then, an N-type contact point is created on the N-type exposure point.

[0033] In this embodiment, since the front side of the deep ultraviolet LED epitaxial wafer does not emit light, markings are made on the front side of the deep ultraviolet LED epitaxial wafer, and light emission data is collected from the back side during testing. This embodiment of the invention uses a laser device to mark symbols or text on the front side of the deep ultraviolet LED epitaxial wafer, exposing the N-type structure and forming N-type contact points without damaging the deep ultraviolet LED epitaxial wafer. Compared to the diamond-cutting method, this method covers a larger area and is more accurate. Furthermore, it avoids damaging the deep ultraviolet LED epitaxial wafer.

[0034] S200, an indium pressing operation is performed on the front side of the deep ultraviolet LED epitaxial wafer to form multiple P-type contact points on the deep ultraviolet LED epitaxial wafer.

[0035] In this embodiment, to perform light emission testing on the LED epitaxial wafer, at least two contact points need to be fabricated: an N-type contact point and a P-type contact point. The light emission testing of the deep ultraviolet LED epitaxial wafer is achieved by energizing the N-type and P-type contact points. The purpose of the indium pressing operation is to fabricate electrodes for subsequent energizing testing.

[0036] S300. Place the deep ultraviolet LED epitaxial wafer on the test bracket and adjust the position of the test bracket so that the P-type contact point of the deep ultraviolet LED epitaxial wafer is on the same straight line as the integrating sphere data window below the test bracket.

[0037] In this embodiment, in order to obtain more accurate test data, the deep ultraviolet LED epitaxial wafer is placed on the test bracket, specifically in the groove of the test bracket. The wafer can be adjusted up and down and left and right so that the P-type contact point of the deep ultraviolet LED epitaxial wafer is on the same straight line as the data window of the integrating sphere below the test bracket, making the data collected by the integrating sphere more accurate and avoiding test errors.

[0038] S400. Connect the positive and negative terminals of the power meter to the P-type contact point and the N-type contact point respectively. After power is applied, collect the light emission data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer through the integrating sphere, and send the light emission data to the host computer.

[0039] In this embodiment, during testing, since the P-type contact point and the N-type contact point form two electrodes, the positive and negative terminals of the power meter are connected to the two electrodes respectively, thereby forming a test circuit between the N-type structure and the P-type structure of the deep ultraviolet LED epitaxial wafer. This allows the light-emitting layer of the deep ultraviolet LED epitaxial wafer to emit light, which is then emitted from the sapphire substrate surface of the deep ultraviolet LED epitaxial wafer and enters the data window of the integrating sphere. The integrating sphere collects the emitted light data, which is then transmitted to the host computer via an optical fiber data line, and the host computer obtains the test results.

[0040] This invention employs a laser device to engrave specific symbols or text on the front side of a deep ultraviolet (DUV) LED epitaxial wafer. This exposes the N-type structure without damaging the DUV LED epitaxial wafer, forming N-type contact points. This avoids damage to the DUV LED epitaxial wafer during testing. Furthermore, compared to scratching with a diamond tool, the engraving covers a larger area, ensuring the N-type structure is exposed and preventing testing errors. This allows for accurate electrical connection between the N-type and P-type layers, guaranteeing the accuracy of test data. Additionally, adjusting the position of the DUV LED epitaxial wafer further ensures the accuracy of data acquisition from the integrating sphere.

[0041] In one embodiment, in step S100, the laser device uses an ultraviolet laser to mark the front side of the deep ultraviolet LED epitaxial wafer.

[0042] For example, the laser device is an ultraviolet laser marking machine, which marks text or patterns on the front side of a deep ultraviolet LED epitaxial wafer, such as... Figure 2As shown, the text symbols below the small dots are formed by ultraviolet laser marking. After marking is completed, N-type contact points are made on the text.

[0043] Among them, ultraviolet lasers have better beam quality and smaller focused spot, which can achieve more precise marking. In addition, ultraviolet lasers have a small heat-affected zone and do not produce thermal effects. Therefore, they will not damage the deep ultraviolet LED epitaxial wafers. Moreover, the marking speed is fast and the efficiency is high.

[0044] In one embodiment, the marking range of the laser device is the front surface area of ​​a 2-inch to 4-inch deep ultraviolet LED epitaxial wafer.

[0045] In this embodiment, the marking area of ​​the laser device can cover the entire front side of the deep ultraviolet LED epitaxial wafer, thereby avoiding errors and ensuring that the N-type structure of the deep ultraviolet LED epitaxial wafer can be exposed. Moreover, this invention can mark deep ultraviolet LED epitaxial wafers ranging from 2 inches to 4 inches, enabling the testing of even smaller deep ultraviolet LED epitaxial wafers.

[0046] In one embodiment, the method for creating an N-type contact point on the N-type exposure point in step S100 specifically includes:

[0047] An indium pressing operation is performed on the N-type exposed point to create an N-type contact point.

[0048] In this embodiment, to fabricate the electrode, an indium pressing operation needs to be performed on the N-type exposed points. Specifically, after marking, indium particles are pressed onto the marked text to form the N-type electrode. Figure 2 The N-type contact points shown are for subsequent power-on testing.

[0049] In one embodiment, step S200 specifically includes:

[0050] A fixed position is determined on the deep ultraviolet LED epitaxial wafer. Indium particles are picked up with tweezers and pressed at the fixed position to make the indium particles stick to the surface of the deep ultraviolet LED epitaxial wafer to form a P-type contact point.

[0051] In this embodiment, in order to fabricate the P-type electrode, tin, gold, and indium particles are first used to fix the position on the front side of the deep ultraviolet LED epitaxial wafer. The indium particles are then picked up with tweezers, placed in the fixed position, and pressed to firmly adhere the indium particles to the surface of the deep ultraviolet LED epitaxial wafer, thereby forming a P-type contact point. The application range of this point is the front side area of ​​the 2-inch to 4-inch deep ultraviolet LED epitaxial wafer.

[0052] Preferably, the indium particles are high-purity indium metal particles ranging from 1µm to 100,000µm.

[0053] In one embodiment, the method for adjusting the position of the test bracket in step S300 specifically includes:

[0054] Operate the left-right adjustment knob and the up-down adjustment knob on the test bracket in sequence to adjust the position of the test bracket.

[0055] In this embodiment, in order to ensure the accuracy of data collection during testing, the position of the test stand needs to be adjusted. The test stand is equipped with left-right adjustment knobs and up-down adjustment knobs. Therefore, the test stand can be adjusted to the required position by operating the left-right adjustment knobs and the up-down adjustment knobs in sequence.

[0056] In one embodiment, step S400 specifically includes:

[0057] The positive terminal of the power meter is pressed onto the P-type contact point, the negative terminal of the power meter is pressed onto the N-type contact point, and a constant current is applied to the power meter. The light emission data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer is collected by the integrating sphere, and the light emission data is sent to the host computer.

[0058] In this embodiment, a constant current is applied to the P and N junctions of the LED epitaxial wafer, causing it to emit light through the sapphire surface of the deep ultraviolet LED epitaxial wafer. The light is then received by the integrating sphere on the back of the deep ultraviolet LED epitaxial wafer and transmitted to the host computer via an optical fiber data line.

[0059] Preferably, the constant current is 1mA-100mA.

[0060] In one embodiment, step S400 is followed by:

[0061] The host computer analyzes the emitted light data and outputs the test results.

[0062] In this embodiment, since the integrating sphere collects light output data, which cannot be directly output, a fiber optic spectrometer is needed to analyze the collected test data before it can be finally converted into digital data for direct output.

[0063] To better understand this invention, the following is combined with... Figures 1 to 3 The testing method for deep ultraviolet LED epitaxial wafers of the present invention is described in detail below:

[0064] Step 1: Use an ultraviolet laser to mark the text on the front side of the deep ultraviolet LED epitaxial wafer using a laser device, and then press indium particles onto the marked text to form N-type contact points;

[0065] Step 2: Press indium particles onto the front side of the deep ultraviolet LED epitaxial wafer to form P-type contact points on the front side of the deep ultraviolet LED epitaxial wafer;

[0066] Step 3: Place the deep ultraviolet LED epitaxial wafer on the test bracket, and adjust the up and down adjustment knobs and the left and right adjustment knobs so that the P-type contact point is directly above the small hole in the middle of the integrating sphere;

[0067] Step 4: Apply a current of 1mA-100mA to the power meter, and press the positive and negative test pens of the power meter onto the P-type and N-type contact points respectively, and collect the light emission data from the back of the deep ultraviolet LED epitaxial wafer through the integrating sphere.

[0068] Step 5: The host computer receives the output optical data through the fiber optic data cable, processes the output optical data, and outputs the test results.

[0069] In summary, the deep ultraviolet (DUV) LED epitaxial wafer testing method provided by this invention uses a laser device to mark specific symbols or text on the front side of the DUV LED epitaxial wafer, exposing the N-type structure and forming N-type contact points without damaging the DUV LED epitaxial wafer. This avoids damage to the DUV LED epitaxial wafer during testing. Moreover, compared to scratching with a diamond cutter, the marking covers a larger area, ensuring the exposure of the N-type structure and avoiding testing errors. This allows for accurate electrical connection between the N-type and P-type layers, ensuring the accuracy of the test data. Furthermore, by adjusting the position of the DUV LED epitaxial wafer, the accuracy of the integrating sphere data acquisition can be further guaranteed.

[0070] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for testing deep ultraviolet LED epitaxial wafers, characterized in that, Includes the following steps: Using a laser device, markings are made on the front side of the deep ultraviolet LED epitaxial wafer to expose the N-type structure of the deep ultraviolet LED epitaxial wafer and form N-type exposure points. Then, N-type contact points are made on the N-type exposure points. An indium pressing operation is performed on the front side of the deep ultraviolet LED epitaxial wafer to form multiple P-type contact points on the deep ultraviolet LED epitaxial wafer; The deep ultraviolet LED epitaxial wafer is placed on the test bracket, and the position of the test bracket is adjusted so that the P-type contact point of the deep ultraviolet LED epitaxial wafer is on the same straight line as the integrating sphere data window below the test bracket. Connect the positive and negative terminals of the power meter to the P-type contact and the N-type contact respectively. After power is applied, collect the light emission data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer through the integrating sphere, and send the light emission data to the host computer.

2. The deep ultraviolet LED epitaxial wafer testing method according to claim 1, characterized in that, The laser device uses an ultraviolet laser to mark the front side of the deep ultraviolet LED epitaxial wafer.

3. The deep ultraviolet LED epitaxial wafer testing method according to claim 1, characterized in that, The marking range of the laser device is the front area of ​​the deep ultraviolet LED epitaxial wafer, which is 2 inches to 4 inches in diameter.

4. The deep ultraviolet LED epitaxial wafer testing method according to claim 1, characterized in that, The method for creating an N-type contact point on the N-type exposure point is as follows: An indium pressing operation is performed on the N-type exposed point to create an N-type contact point.

5. The deep ultraviolet LED epitaxial wafer testing method according to claim 1, characterized in that, The indium pressing operation is performed on the front side of the deep ultraviolet LED epitaxial wafer to form multiple P-type contact points on the deep ultraviolet LED epitaxial wafer, including: A fixed position is determined on the deep ultraviolet LED epitaxial wafer. Indium particles are picked up with tweezers and pressed at the fixed position to make the indium particles stick to the surface of the deep ultraviolet LED epitaxial wafer to form a P-type contact point.

6. The deep ultraviolet LED epitaxial wafer testing method according to claim 5, characterized in that, The indium particles are indium metal particles ranging from 1µm to 100,000µm.

7. The deep ultraviolet LED epitaxial wafer testing method according to claim 1, characterized in that, The method for adjusting the position of the test bracket is as follows: Operate the left-right adjustment knob and the up-down adjustment knob on the test bracket in sequence to adjust the position of the test bracket.

8. The deep ultraviolet LED epitaxial wafer testing method according to claim 1, characterized in that, The process of connecting the positive and negative terminals of the power meter to the P-type and N-type contact points respectively, and collecting the emitted light data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer via the integrating sphere after power-on, and sending the emitted light data to the host computer includes: The positive terminal of the power meter is pressed onto the P-type contact point, the negative terminal of the power meter is pressed onto the N-type contact point, and a constant current is applied to the power meter. The light emission data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer is collected by the integrating sphere, and the light emission data is sent to the host computer.

9. The deep ultraviolet LED epitaxial wafer testing method according to claim 8, characterized in that, The constant current is 1mA-100mA.

10. The deep ultraviolet LED epitaxial wafer testing method according to claim 1, characterized in that, After connecting the positive and negative terminals of the power meter to the P-type and N-type contact points respectively, and collecting the emitted light data emitted through the sapphire substrate on the back of the deep ultraviolet LED epitaxial wafer via the integrating sphere after power-on, and sending the emitted light data to the host computer, the method further includes: The host computer analyzes the emitted light data and outputs the test results.

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