An all-glass passivated diode and a method for producing the same

Abstract

This invention provides a method for producing all-glass passivated diodes, comprising the following steps: (I) Preparation: (a) Chip preparation; (b) Raw material preparation; (c) Software preparation: Presetting laser parameters and raw material parameters, using computer-aided design (CAD) technology with computer modeling software to complete the preset information for laser sintering according to different diode design requirements, and transmitting the preset information to the semiconductor laser; (II) Uniform powder spreading; (III) Laser sintering; (IV) Recycling; (V) Removal of adhesive residue. The all-glass passivated diode production method of this invention uses laser forming technology to prepare the glass seal of the diode PN junction, precisely controls the diode glass sintering, completes the full seal of the diode PN junction in a single step, and eliminates potential sources of failure. This invention also provides an all-glass passivated diode produced using the aforementioned all-glass passivated diode production method.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic packaging technology, and in particular to an all-glass passivated diode and its manufacturing method. Background Technology

[0002] Currently, most semiconductor diodes use passivated glass to protect the exposed PN junction surface of the diode chip. The most superior method is Glass Passivated Pellet (GPP), which involves glass sealing and sintering the glass on the exposed PN junction surface of the half-cut diode wafer to complete the protection of the half-cut chip. However, the GPP method also has several drawbacks and does not achieve optimal performance. Specifically, because the diode chip has a half-cut shape with an open P-side, the chamfer angle of its PN junction surface is negative. Therefore, the glass sealing and sintering process using the GPP method cannot easily achieve complete passivation glass protection. These drawbacks lead to problems such as easy aging and breakdown of the diode chip at high temperatures, forming potential sources of diode failure. Summary of the Invention

[0003] To address the aforementioned technical problems, the present invention aims to provide a method for manufacturing all-glass passivated diodes. This method utilizes laser forming technology to prepare the glass encapsulation of the diode PN junction. By controlling the operating parameters of the laser beam and the raw material parameters of the passivation glass powder and curing agent, the deposition amount, glass powder placement position, and thickness of the glass coating on the PN junction are controlled, achieving complete glass encapsulation of the diode PN junction in a single step, thus achieving optimal glass passivation performance. The present invention also provides an all-glass passivated diode manufactured using the aforementioned method.

[0004] The technical solution adopted in this invention is:

[0005] A method for manufacturing an all-glass passivated diode includes the following steps:

[0006] (I) Preparatory work

[0007] (a) Chip preparation: According to the requirements, the diode is processed to form a diode chip semi-finished product with trenches on the P side and exposed PN junction surface, and the individual chip is in a half-cut state.

[0008] (b) Raw material preparation: According to the requirements, the passivation glass powder and the curing agent are mixed evenly in proportion to obtain the mixed powder of diode packaging material, and then the mixed powder is injected into the powder nozzle matched with the semiconductor laser;

[0009] (c) Software preparation: Preset laser parameters and raw material parameters. Using computer modeling software and computer-aided design (CAD) technology, complete the preset information for laser sintering according to different diode design requirements, and transmit the preset information to the semiconductor laser. The preset information includes: the placement position of the passivation glass powder is the exposed position of the diode chip, and the CAD path for laser sintering is the position of the diode PN junction.

[0010] (ii) Uniform powder spreading: The computer modeling software controls the powder nozzle according to the preset information, controls the amount and position of powder coating deposition, and uniformly sprays the encapsulation material around the diode PN junction to achieve full coverage of the encapsulation material of the diode PN junction;

[0011] (III) Laser sintering: The semiconductor laser controls the laser beam to selectively scan the packaging material powder layer laid at the PN junction of the diode according to the two-dimensional CAD path set in the preset information. The scanned packaging material powder is sintered together at the PN junction due to the high temperature of the laser focus, thereby generating a glass-encapsulated thin layer at the PN junction of the diode. The packaging material in the unscanned area remains in its original loose powder state.

[0012] Second sintering: After the first laser sintering is completed, the semiconductor laser proceeds to the next step according to the preset number of sintering cycles. If the preset number of sintering cycles is completed, the laser laser will control the powder nozzle to spray the encapsulation material powder evenly around the diode PN junction again, and then start the laser sintering of a new layer. This process is repeated until all layers are sintered according to the preset information, thereby generating a protective passivation glass sheet of a predetermined thickness around the PN junction, which fully covers the diode PN junction and completes the encapsulation forming process.

[0013] (iv) Recycling: Remove and recycle the unsintered encapsulation material powder from the diode to obtain a sealed diode chip;

[0014] (V) Remove adhesive residue: The diodes that have completed the encapsulation molding process are heated to remove adhesive residue, and the glass encapsulation of the diode PN junction is completed to obtain a fully glass passivated diode component that meets the requirements.

[0015] The method for producing an all-glass passivated diode according to the present invention, wherein the chip preparation in step (a) specifically involves: cutting the original semiconductor chip to an appropriate size according to the diode design dimensions, and removing defects such as microcracks, roughness, and poor alignment on the cut surface by acid etching to make the PN junction smooth, thus preparing a PN-type diffused silicon semiconductor wafer, and oxidizing the silicon semiconductor wafer, then coating the wafer with photoresist, and removing the photoresist from the edges of each chip by development and cleaning, and selectively chemically etching the areas not coated with photoresist to form a diode chip semi-finished product with trenches on the P-side, exposed PN junction surface, and individual chips in a half-cut state.

[0016] The method for producing all-glass passivated diodes according to the present invention, wherein the curing agent in step (b) is high-impact polystyrene adhesive, and the mass ratio of the passivation glass powder to the curing agent is 98wt% and 2wt%, respectively.

[0017] The method for producing an all-glass passivated diode according to the present invention, wherein in step (c), the thickness of the glass powder is 20 μm.

[0018] The method for producing all-glass passivated diodes according to the present invention includes a powder sprayer in step (iii) with a nozzle diameter of 2 μm, a single spray layer thickness of 10 μm, and a powder spraying positioning accuracy of 2 μm.

[0019] The method for producing an all-glass passivated diode according to the present invention includes a laser power of 3000W, an X and Y axis resolution of 2μm, and a Z axis resolution of 10μm in step (iii).

[0020] The method for producing an all-glass passivated diode according to the present invention, wherein the heating and debinding process in step (v) specifically involves using high temperature to remove the curing agent in the glass slurry, so that the passivated glass is reassembled and tightly bonded to the periphery of the diode PN junction.

[0021] All-glass passivated diodes produced using the all-glass passivated diode manufacturing method described in this invention.

[0022] Beneficial effects of this invention:

[0023] The all-glass passivated diode manufacturing method described in this invention employs laser forming technology to prepare the glass seal of the diode PN junction, precisely controlling the diode glass sintering and completing the complete sealing of the diode PN junction in a single step, without any potential sources of failure. Compared with other technologies, diodes with PN junction glass seals prepared by laser forming technology have advantages such as better product performance, faster manufacturing speed, and greater safety and reliability. It can solve the technical problems that traditional technologies have been unable to overcome, such as the easy aging and breakdown of diodes at high temperatures, and can achieve optimal performance in the glass passivation of the diode. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the main equipment location structure in the all-glass passivated diode manufacturing method described in this invention;

[0025] Figure 2 This is a process flow diagram of the all-glass passivated diode manufacturing method described in this invention;

[0026] In the diagram, 1-diode; 2-powder nozzle; 3-semiconductor laser; 4-laser beam; 5-passivated glass; 6-workstage; 7-scanning mirror.

[0027] The present invention will be further described below with reference to specific embodiments and accompanying drawings. Detailed Implementation

[0028] Example 1

[0029] like Figure 1 and Figure 2 As shown, a method for producing an all-glass passivated diode uses diode passivation glass powder and high-impact polystyrene adhesive as raw materials. A semiconductor laser 3 is selected as the laser source for glass encapsulation. Using computer modeling software on the semiconductor laser 3, a preset file is read to control laser parameters (laser power, X / Y axis resolution, Z axis resolution, number of scans) and the parameters of the passivation glass powder and curing agent. This allows for rapid, flexible, and accurate completion of passivation glass encapsulation and selective laser sintering, thereby controlling the deposition amount, glass powder placement position, and thickness of the glass coating. The method completes the processing and forming of the passivation glass powder in the diode PN junction, including the following steps:

[0030] (I) Preparatory work

[0031] (a) Chip preparation: According to the requirements, the original semiconductor chip is cut to the appropriate size according to the design size of diode 1, and the micro-cracks, roughness, poor alignment and other defects on the cut surface are removed by acid etching to make the PN junction present a smooth state, and the silicon semiconductor wafer with PN diffusion is prepared. The silicon semiconductor wafer is oxidized and then coated with photoresist. The photoresist on the edge of each chip is removed by development and cleaning. Selective local chemical etching is performed on the area without photoresist to form a diode chip semi-finished product with trenches on the P side, exposed PN junction surface, and individual chips in half-cut shape.

[0032] (b) Raw material preparation: According to the requirements, the passivation glass powder and the curing agent are mixed evenly in proportion to obtain the mixed powder of diode packaging material, and then the mixed powder is injected into the powder nozzle 2 of the semiconductor laser 3; the curing agent is high-impact polystyrene adhesive, and the mass ratio of the passivation glass powder to the curing agent is 98wt% and 2wt%, respectively.

[0033] (c) Software preparation: Laser parameters and raw material parameters are preset. Using computer modeling software and computer-aided design (CAD) technology, the preset information for laser sintering is completed according to the design requirements of different diodes 1, and the preset information is transmitted to the semiconductor laser 3. The preset information includes: the passivation glass powder is laid at the exposed position of the diode chip, the glass powder thickness is 20μm, and the CAD path for laser sintering is the position of the diode PN junction (diode PN junction surface).

[0034] (ii) Uniform powder spreading: The computer modeling software controls the powder nozzle 2 according to the preset information, controls the deposition amount and deposition position of the powder coating, and uniformly sprays the encapsulation material (a mixture of passivation glass powder and curing agent) around the diode PN junction to achieve full coverage of the encapsulation material of the diode PN junction. The nozzle diameter of the powder nozzle 2 is 2μm, the layer thickness of a single spray is 10μm, and the positioning accuracy of the powder spray is 2μm.

[0035] (III) Laser Sintering: The semiconductor laser 3 controls the laser beam 4 to selectively scan the packaging material powder layer laid at the diode PN junction position according to the two-dimensional CAD path set in the preset information. The scanning mirror 7 scans the laser beam 4 emitted by the semiconductor laser 3 along the X and Y axes respectively, thereby achieving the deflection of the laser beam 4, so that the laser focusing point with a certain power density is on the marking material (glass powder), and moves as required according to the settings. The reflection angle of the scanning mirror 7 can be controlled by computer software; wherein: the laser power is 3000W, the X and Y axis resolution is 2μm, and the Z axis (layer thickness) resolution is 10μm; the scanning packaging material powder is sintered together at the PN junction position due to the high temperature of the laser focus, thereby generating a thin glass encapsulation layer at the diode PN junction position, while the packaging material in the unscanned area remains in its original loose powder state;

[0036] Second sintering: After the first laser sintering is completed, the semiconductor laser 3 proceeds to the next step according to the preset number of sintering cycles. If the preset number of sintering cycles is completed, the process continues. If not, the powder nozzle 2 is controlled to spray the encapsulation material powder evenly around the diode PN junction again, and then the laser sintering of a new layer begins. This process is repeated until all layers are sintered according to the preset information, thereby generating a thin film of encapsulation passivation glass 5 with a predetermined thickness around the PN junction, fully covering the diode PN junction and completing the encapsulation forming process. In this embodiment, the thickness of the layer sprayed by the powder nozzle in a single pass is 10μm. Generally, two sintering cycles are sufficient to complete the sintering of the encapsulation material powder layer with a preset thickness of 20μm.

[0037] (iv) Recycling: Remove and recycle the unsintered encapsulation material powder from diode 1 to obtain a sealed diode chip;

[0038] (V) Removal of adhesive residue: The diode 1 that has completed the encapsulation molding process is subjected to heat removal of adhesive residue. The high temperature is used to remove the curing agent in the glass paste, so that the passivation glass 5 is reassembled and tightly bonded to the periphery of the diode PN junction, thus completing the glass encapsulation of the diode P / N junction and obtaining a fully glass passivated diode component that meets the requirements.

[0039] The all-glass passivated diode produced by the all-glass passivated diode manufacturing method described in this embodiment has the following effects:

[0040] 1. Higher PN junction operating temperature: The higher the PN junction operating temperature, the higher the operating temperature of the diode can adapt to the higher temperature operating environment. The maximum operating temperature of the diode PN junction is 150℃ when glass encapsulation is performed by GPP method; the maximum operating temperature of the diode PN junction is 180℃ when laser selective sintering is used in this invention.

[0041] 2. Lower high-temperature leakage current: The higher the leakage current, the easier it is for the tube to heat up and for the diode to burn out, indicating poor quality. With GPP glass encapsulation, the high-temperature leakage current of the diode is 50μA-100μA (at an ambient temperature of 150℃). This invention uses laser selective sintering, and the high-temperature leakage current of the diode is 10μA (at an ambient temperature of 150℃).

[0042] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for manufacturing an all-glass passivated diode, characterized in that: Includes the following steps: (I) Preparatory work: (a) Chip preparation: According to the requirements, the diode (1) is processed to form a diode chip semi-finished product with trenches on the P side, exposed PN junction surface, and a single chip in a half-cut state. (b) Raw material preparation: According to the requirements, the passivation glass powder and the curing agent are mixed evenly in proportion to obtain the mixed powder of diode packaging material, and then the mixed powder is injected into the powder nozzle (2) of the semiconductor laser (3); (c) Software preparation: Laser parameters and raw material parameters are preset. Computer-aided design technology (CAD) is used to complete the preset information of laser sintering according to the design requirements of different diodes (1) and transmit the preset information to the semiconductor laser (3). The preset information includes: the position of the passivation glass powder is the exposed position of the diode chip, and the CAD path of laser sintering is the position of the diode PN junction. (ii) Uniform powder spreading: The computer modeling software controls the powder nozzle (2) according to the preset information, controls the amount and position of powder coating deposition, and uniformly sprays the encapsulation material around the diode PN junction to achieve full coverage of the encapsulation material of the diode PN junction; (III) Laser sintering: The semiconductor laser (3) controls the laser beam (4) to selectively scan the packaging material powder layer laid at the diode PN junction position according to the two-dimensional CAD path set in the preset information. The scanned packaging material powder is sintered together at the PN junction position due to the high temperature of the laser focus, thereby generating a glass-encapsulated thin layer at the diode PN junction position. The packaging material in the unscanned area remains in its original loose powder state. Second sintering: After the first laser sintering is completed, the semiconductor laser (3) will proceed to the next step if the preset number of sinterings is completed. If not, the powder nozzle (2) will be controlled to spray the encapsulation material powder evenly around the diode PN junction again, and then start the laser sintering of a new layer. This process is repeated until all layers are sintered according to the preset information, thereby generating a protective passivation glass (5) sheet with a predetermined thickness around the PN junction, which fully covers the diode PN junction and completes the protective forming process. (iv) Recycling: Remove and recycle the unsintered encapsulation material powder from the diode (1) to obtain a sealed diode chip; (V) Remove adhesive residue: The diode (1) that has completed the sealing molding process is heated to remove adhesive residue, and the glass sealing of the diode PN junction is completed to obtain a fully glass passivated diode component that meets the requirements. The chip preparation in step (a) is as follows: according to the requirements, the original semiconductor chip is cut into appropriate sizes according to the design size of diode (1), and the micro-cracks, roughness, poor alignment and other defects of the cut surface are removed by acid etching, so that the PN junction is in a smooth state, and the PN type diffused silicon semiconductor wafer is prepared. The silicon semiconductor wafer is oxidized and then coated with photoresist. The photoresist on the edge of each chip is removed by development and cleaning. The area without photoresist is selectively chemically etched to form a diode chip semi-finished product with trenches on the P side, exposed PN junction surface, and individual chips in a half-cut state. The curing agent mentioned in step (b) is high-impact polystyrene adhesive, and the mass ratio of the passivating glass powder to the curing agent is 98 wt% and 2 wt%, respectively; The powder nozzle (2) mentioned in step (iii) has a nozzle diameter of 2μm, a single spray layer thickness of 10μm, and a powder spray positioning accuracy of 2μm; Step (c) The thickness of the glass powder layer is 20 μm; In step (iii), the laser power is 3000W, the X and Y axis resolution is 2μm, and the Z axis resolution is 10μm.

2. The method for producing an all-glass passivated diode according to claim 1, characterized in that: The heating and debinding process described in step (5) specifically involves using high temperature to remove the curing agent from the glass slurry, so that the passivated glass (5) can be reassembled and tightly bonded to the periphery of the diode PN junction.

3. The all-glass passivated diode produced by the all-glass passivated diode manufacturing method according to any one of claims 1 and 2.

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