Why use film technology?
Compared with three-dimensional bulk materials, the film can generally be regarded as a two-dimensional form of matter because of its relatively small thickness and size. The thick film is made by rolling and other production methods. The thick film does not need a substrate and can be made independently, usually with a thickness of 10~25μm. Thin films are formed by the accumulation of the constituents of the film, and the film can only be attached to the substrate, usually with a thickness of about 1μm.
The main functions of the film are divided into three types: electrical connection, component loading, and surface modification.
1. Electrical connection. The circuit board and film are integrated with the substrate, and the components are mounted on the substrate to connect with the conductor terminals;
2. Component mounting. Chips mounted on the packaging substrate require welding pads, while components mounted on the substrate rely on conductor terminals, of which the welding pads and conductor terminals are both important parts of the film circuit;
3. Surface modification. Through the use of films, materials can be modified in certain properties, such as increasing the material’s wear resistance, corrosion resistance, high-temperature resistance, etc.
What is thin-film circuit?
Thin film circuit means that the components and wires of the entire circuit are made of films with a thickness less than 100nm. Through several common thin film processes such as thermal oxidation, chemical vapor deposition (CVD), physical vapor deposition (PVD), and epitaxial growth, the steps are prepared with good coverage, good adhesion, good filling in a large aspect ratio, complete structure, and thickness uniform, low-stress film.
What is thick-film circuit?
Thick film circuit refers to integrated circuits formed by using array film technology (screen printing, sintering and electroplating, etc.) on the substrate to make a passive network and assemble discrete semiconductor devices, monolithic integrated circuits or micro components. A film having a thickness of several micrometers to several tens of micrometers is generally considered to be a thick film. There are five types of pastes for making thick films: conductor, resistor, dielectric, insulation and encapsulation. Thick-film integrated circuits are simple in process, low in cost, and capable of high power, but there are certain restrictions on the types and numerical ranges of components it makes.
What is the difference between thin-film circuit vs thick-film circuit?
1. Difference in film thickness
The film thickness of thick film circuits is generally greater than 10μm, and the film thickness of thin films is less than 10μm, mostly less than 1μm;
2. Difference in the manufacturing process
Thick-film circuits generally use screen printing technology. The most advanced material substrates use ceramics as substrates (alumina ceramics are more commonly used). Thin-film circuits use vacuum evaporation, magnetron sputtering and other processes.
3. Different applications
The advantages of thick-film circuits are reliable performance, flexible design, small investment, and low cost, and are mostly used in high-voltage, high-current, and high-power occasions; thin-film circuits are mostly used in high-precision, high-integration product fields, and are resistant to high temperatures, corrosion resistance, high insulation, ceramic substrates are usually used as base materials to process thin film ceramic circuit boards, which are popular.