Mask technology is an important process used to make printed circuit boards (PCBs). It forms a circuit pattern by coating a photosensitive adhesive film on top of the copper layer, and then using light and chemical corrosion methods to partially remove the unwanted copper layer. Here's how mask technology has evolved:
1.Early handmade: In the early stages of PCB fabrication, mask technology was done by hand. Workers use knives and adhesive film to cut and paste by hand, which is time-consuming and error-prone.
2.Photo-plate-making technology: In the 50s of the 20th century, the introduction of photo-plate-making technology made it possible to automate mask technology. This technique uses a camera to project a circuit pattern onto a photosensitive adhesive film, which is then chemically etched to remove unwanted copper layers.
3.Direct light painting technology: In the 70s of the 20th century, the emergence of direct light painting technology further improved the accuracy and efficiency of mask technology. This technique uses a laser or electron beam to draw a circuit pattern directly on the photosensitive film, avoiding the intermediate steps of photo plate making.
4.Lithography technology: In the 80s of the 20th century, the application of lithography technology made mask technology more accurate and reliable. Lithography uses photoresist and lithography machines to transfer circuit patterns to copper layers through light and chemical processing.
5.Digital mask technology: In recent years, with the development of computer technology, digital mask technology has gradually become the mainstream. This technique uses computer-aided design (CAD) software to create a circuit pattern and transfer the pattern to a photosensitive film through direct photographic or photolithography.
In general, the development of mask technology has gone through a process from manual production to automation, precision and digitization. The continuous improvement and innovation of these technologies has made PCB manufacturing more efficient, precise, and reliable.