CN-115440623-B - Laser sintering device and sintering method

Abstract

The invention provides a laser sintering device and a laser sintering method. The laser sintering device comprises a laser, a temperature sensor, a pressure sensor base, a moving platform, a light-transmitting plate and a weight load. According to the laser sintering device and the sintering method, the sintering temperature is regulated in real time, so that damage to the chip and the substrate caused by overhigh sintering temperature is avoided, and meanwhile, the integral mechanical strength and the fatigue resistance reliability of the sintered body are improved.

Inventors

• CHEN HAIXUE
• LIU PAN
• ZHANG GUOQI

Assignees

• 复旦大学
• 复旦大学
• 复旦大学义乌研究院
• 复旦大学义乌研究院

Dates

Publication Date

20260421

Application Date

20220704

Priority Date

20220704

Claims (10)

1. 1. A laser sintering device, comprising The base is used for placing the substrate attached with the chip; The light source is used for sintering the chip; The temperature sensor is used for monitoring a temperature signal of a chip sintering area in the sintering process and transmitting the temperature signal to an external computer, and the light source is used for adjusting the sintering light intensity and the sintering time according to the detection result of the temperature sensor; the light-transmitting plate is arranged on a light path of the light source sintering and used for buffering thermal shock of the light source and placing weight loads, and the weight loads are arranged at four corners above the light-transmitting plate and used for adjusting pressure in the sintering process; and the pressure sensor is arranged in the base and is used for monitoring the pressure of the chip sintering area in the sintering process.
2. 2. The apparatus of claim 1, further comprising And the motion platform is arranged below the base and is used for realizing the plane and up-and-down displacement of the base plate in the sintering process.
3. 3. The device of claim 1, wherein the light source is a laser and is selected from one of a Nd: YAG laser and a Nd: YVO4 laser.
4. 4. The apparatus of claim 3, wherein the laser has a power range of 10W-200W, a scanning speed of 0.01m/s-5m/s, a spot diameter of 10 μm-100 μm, a pulse width of 50fs-200ns, a pulse frequency of 40 kHz-300kHz, and a wavelength of one of 355nm, 532nm, 970nm, and 1064 nm.
5. 5. The device of claim 1, wherein the temperature sensor is a non-contact infrared temperature sensor.
6. 6. The device of claim 1, wherein the base is ceramic and the light-transmitting plate is glass.
7. 7. A laser sintering method using the laser sintering apparatus according to claim 1, comprising the steps of: providing a substrate, wherein the surface of the substrate is attached with a chip through slurry; placing the substrate on a base; Irradiating the surface of a chip, and sintering the chip area; monitoring the sintering temperature and the sintering pressure of the chip sintering area, and adjusting the pressure by increasing or decreasing the weight or the number of the weight load; adjusting the power of a light source to stabilize the sintering temperature of a chip sintering area; And cooling to obtain the packaged device.
8. 8. The method of claim 7, wherein the paste is a nano silver paste comprising silver nanoparticles and an organic solvent, the silver nanoparticles having a particle size of 10nm to 300nm and a spherical or quasi-spherical shape, and the substrate is a polymeric substrate comprising at least one of polyethylene terephthalate, polyethylene naphthalate, polydimethylsiloxane, or polyimide.
9. 9. The method of claim 7, further comprising preheating the slurry at 532K for 60s prior to the step of sintering the chip region.
10. 10. The method of claim 7, wherein when sintering a plurality of chips attached to a same substrate, the substrate is displaced by a moving stage, and each chip is sintered one by one.

Description

Laser sintering device and sintering method Technical Field The invention relates to the field of semiconductor packaging, in particular to a laser sintering device and a sintering method. Background With the development of electronic products toward high power, high density and high integration, higher requirements are being placed on connection materials in power devices. The nano silver paste has the advantages of low sintering temperature, high heat conductivity, high-temperature environment application and the like due to the nano size effect, is more suitable for high-temperature high-power and high-power density packaging, and gradually replaces tin-lead solder to become a preferred interconnection material for high-temperature application of high-power electronic devices. At present, the nano silver paste interconnection of the large-area chip is mainly realized by adopting a hot-pressing sintering mode, external pressure and a complex temperature curve are required to be applied, an inert gas atmosphere is sometimes required, the sintering process is complex, the sintering time is long, the efficiency is low, and the requirement on automatic production equipment is high. In addition, long-time sintering not only easily causes serious growth of nano silver particles and reduces the performance of a sintered joint, but also can influence the mechanical and electrical properties of electronic components. Therefore, development of a rapid sintering method of nano silver paste for chip interconnection is receiving increasing attention. The prior art adopts a laser low-temperature sintering method, can provide a rapid and high-energy sintering process, has a simple sintering process, and can realize automatic sintering by controlling irradiation time and laser power parameters. Because the laser sintering has the characteristics of non-contact heating and smaller laser spot diameter, the precise selective sintering can be realized, and the thermal shock to surrounding materials, especially sensitive components, can be avoided. The flexible mixed electrons are manufactured by combining the flexible substrate and laser sintering, so that the manufacturing efficiency can be greatly improved, and the prepared flexible device has good flexibility and repeated bending performance and has wide application prospects in various fields such as wearable electronics, electronic skin, implantable electronics, soft robots and the like. However, the laser rapid sintering at low temperature generates a large amount of heat in a short time to rapidly raise the sintering temperature, and the excessively high sintering temperature is liable to ablate the flexible substrate, which is also unfavorable for forming a pure silver sintered body with low porosity and high conductivity. Too low a sintering temperature may result in low mechanical strength of the sintered flexible substrate and chip part areas, ultimately affecting the fatigue reliability of the sintered joint. Disclosure of Invention The invention aims to solve the technical problem that the packaging quality is affected by the fact that the laser sintering temperature is too high or too low, and provides a laser sintering device and a sintering method. In order to solve the problems, the invention provides a laser sintering device which comprises a base, a light source, a temperature sensor and a light-transmitting plate, wherein the base is used for placing a substrate attached with a chip, the light source is used for sintering the chip, the temperature sensor is used for monitoring a temperature signal of a chip sintering area in the sintering process and transmitting the temperature signal to an external computer, the light source is used for adjusting the sintering light intensity and the sintering time according to the detection result of the temperature sensor, and the light-transmitting plate is arranged on a light path sintered by the light source and used for buffering the thermal shock of the light source and placing weight load. The invention provides a laser sintering method which is characterized by comprising the steps of providing a substrate, attaching a chip on the surface of the substrate through slurry, placing the substrate on a pressure sensor base, irradiating the surface of the chip to sinter the chip area, monitoring the sintering temperature, the sintering pressure and the sintering time of the chip sintering area, adjusting the power of a laser to enable the sintering temperature of the chip sintering area to be stable, and cooling to obtain a packaged device. According to the laser sintering device and the sintering method, the sintering temperature is regulated in real time, so that damage to the chip and the substrate caused by overhigh sintering temperature is avoided, and meanwhile, the integral mechanical strength and the fatigue resistance reliability of the sintered body are improved. The rapid sintering of the slurry in the chi