Thick film circuit printing composite screen printing plate production

introduction

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

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

Figure 2 is a photomicrograph of a composite screen printing pattern prepared by the research group in cooperation with a domestic screen printing company. The screen version solves the problem of insufficient elasticity in the screen printing process, but it is found that the printed lines have serious sawtooth phenomenon. The dimensional accuracy of the lines is not sufficient, and there is usually a deviation of 20 to 40 μm. Another problem is that the reproducibility of the screen plate made of the same film is poor, which affects 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 does not use constant temperature and humidity storage, there may be deformation;

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 α-stainless steel wire mesh is used to increase the surface roughness of the stainless steel wire mesh by sanding, thereby improving the bond strength between the photosensitive resist and the stainless steel; using a non-reflective exposure machine, the image has a good fidelity, line accuracy It can be controlled within ±5 μm. It can maintain the solvent characteristics through the surface treatment of photosensitive adhesive, thus reducing the friction and increasing the ink permeability. The screen life is over 100,000 times. Figure 3 is a photomicrograph of a high-quality composite screen printing pattern. The lines are straight, with no obvious jaggies. The diamond pattern has four corners and the line accuracy is +3 μm. 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.

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 transitioned from 100 μm to 50 μm. To ensure product quality and pass rate, it is bound to print materials related to screen printing. , printing ink and plate making technology and printing equipment put forward higher requirements, composite screen version will 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.