Maskless deposition technology targets passive embedded components

摘要

Presently, microelectronic fabrication is dominated by thick film and thin film technologies. Thick film techniques typically use a screen print process to produce features down to about 100 microns wide. Thin film techniques employ masks and photoresists to produce sub-micron features, and are costly and complex. In contrast, Optomec Inc. has developed a process for producing features in the mesoscale range, i.e., from 1 to 100 microns, which avoids many of these issues. This process can deposit electronic materials onto low-temperature, planar and non-planar substrates, without the use of masks or photoresistive deposits. Simpler and less expensive than thin-film techniques, this technology can deposit 25-micron lines of inorganic (and organic) materials onto polymer, glass, silicon, and alumina and other ceramic substrates. The process, Maskless Mesoscale Materials Deposition (M3D), deposits aerosolized particles as small as 20 nanometers in diameter using aerodynamic focusing. The particle beam may be focused down to a 25-micron diameter. Approximately one billion particles per second can be deposited, with accuracies on the order of 25 microns. After the deposition process is completed, the material is decomposed or densified to produce the desired electrical and mechanical properties. Typical thick film techniques deposit materials that must be fired well above 400°C, limiting the process to high-temperature substrates. However, the M3D process is capable of depositing materials onto low-temperature substrates, and then using thermal or laser processing to obtain the desired properties by virtue of the initial precursor chemistry or localized laser heating. Specifically, the M3D process can deposit electronic materials onto low-cost polymer substrates that cannot withstand high-temperature oven fires. The M3D tool will allow manufacturers to integrate many active and passive components into one compact, lightweight, and conformal electronic system. Surface-mount resistors, capacitors, and inductors occupy most of the surface of a typical PWB. The M3D technology can embed these components into the board. By embedding components and reducing interconnect pitch and line widths, a reduction in area of approximately 70 percent may be obtained for today's standard PWB. As a specific example, this capability will allow PWB designers to populate boards with the components required by next-generation wireless devices. Additionally, the M3D process can precisely deposit metal onto non-planar surfaces for flex circuit manufacturing applications. Other applications include bond-pad redistribution, rework and repair of electronic circuitry, custom deposition for under-bump metallization, and custom bump fabrication for flip-chip interconnects.