Thick film circuit printing composite screen printing plate production process

Modern screen printing technology has experienced more than 100 years of development and has been widely used in the electronics industry, ceramic decals, textile printing and dyeing, packaging and printing industries. However, the real rapid development of screen printing technology is still a matter of recent years. This is mainly due to the continuous improvement in the quality of screen printing and the development of electronic high-tech fields, which has accelerated the invention of printing materials, printing inks and plate making technologies. And innovation, composite screen is to overcome the shortage of nylon screen and stainless steel screen developed a new type of screen. The following describes the features, application technologies and technical specifications of composite screens.

Composite screen features

During the development of the chip-type electronic components, the project team used a screen plate made of stainless steel mesh and polyester mesh. During the course of use, the resilience of the stainless steel wire mesh was found to be poor, while the polyester wire mesh was repetitive. The problem of poor sex, these issues affect the production efficiency and product qualification rate. In order to solve the above problems, a screen production problem was tackled. The research group cooperated with the screen professional manufacturers to prepare a new type of nylon-stainless steel composite screen with nylon mesh at the edges and stainless steel mesh at the middle.

The composite screen has both the high resilience of the nylon screen screen and the excellent print quality of the stainless steel screen screen, which overcomes the problems of poor resilience of the stainless steel screen, excessive stress, and plastic deformation. Under the same printing process and working environment conditions, the composite screen screen has the characteristics of high overlay accuracy and clear graphics, and can print high-precision lines and graphics. In the production and application of laminated electronic components, it has been found that using composite screen screen printing internal electrode patterns under the same process conditions can effectively improve the product qualification rate and create good economic benefits.

Composite screen production requirements and print quality

A micrograph of a composite screen printing pattern prepared by the research group in cooperation with a domestic screen printing company solves the problem of lack of resilience in the screen printing process using this screen, but it is found that the printed lines have serious sawtooth phenomenon and the line size accuracy Not enough, there is generally a deviation of 20-40 um. Another problem is that the same negative film is used to make the screen with poor repeatability and affect the production.

In response to this phenomenon, the research team and screen production companies conducted in-depth analysis. First of all, the use of electron microscopy analysis of the printed silver paste, the silver paste particles have a good sphericity, viscosity adjustment can not eliminate this phenomenon, that causes the above problems There are the following aspects:
1. Production environment is not controlled by temperature and humidity, resulting in poor consistency of products produced at different times;

2. The film is not kept at constant temperature and humidity, there may be deformation phenomenon 3. There is a problem with the quality of the exposure machine, there are more serious reflection phenomenon, resulting in pattern exposure distortion;

4. Not flushed after exposure.

These problems were not solved in many screen-making small businesses due to capital investment. Therefore, the research team produced composite screens in a wholly foreign-owned enterprise with a 10,000-grade purification plant. The company was in the middle of the screen. 400 mesh a stainless steel screen, through sanding to improve the surface roughness of stainless steel wire mesh, thereby improving the bond strength between the photosensitive rubber and stainless steel; the use of non-reflective exposure machine, so that the image has a good fidelity, line accuracy Can be controlled in ± 5um; through the photosensitive surface treatment, it has to maintain the solvent characteristics, thereby reducing friction and improve ink permeability, screen life of more than 100,000 times. It is a photomicrograph of a high-quality composite screen printing pattern. The lines are straight and there is no obvious sawtooth phenomenon. The diamond pattern has four corners and the deviation of the line accuracy is +3um. The company's purification plant maintains constant temperature and humidity, and has a professional constant temperature and humidity film storage box, so that the screen production is not limited by the weather conditions, to ensure consistent working conditions, so as to ensure that the quality of the screen produced by different batches is stable, ensure the product Pass rate.

Conclusion

With the advancement of science and technology, the printing accuracy requirements in the electronic field have been gradually increased. Currently, the requirements for screen printing line width have been changed from 100um to 50um. To ensure the quality and pass rate of products, it is bound to print with the purpose of screen printing. Materials, printing inks and plate making technologies, and printing equipments put forward higher requirements. Composite screens are bound to be widely used in electronic high-tech fields. At present, the printing pastes, screens, sensitized adhesives, plate-making equipment and printing equipment required for high-quality printing in China all rely on imports. This is a very unfavorable condition for the development of high-precision printing in China. Currently, large foreign printing companies are involved Electronic high-tech enterprises enter China together and serve the corresponding domestic and foreign-funded enterprises. Their technology and quality have impacted domestic enterprises. At the same time, there is no corresponding discipline and professional research and development of screen printing technology in China. The development is very unfavorable. I hope that all walks of life can pay attention to this situation, increase hardware and scientific research investment, start improving the quality of screen printing from both hardware and software, and serve the electronics industry that is taking off in China.

Source: Chinese and foreign business network businessmen