Susumu Hoshinouchi

Electron beam direct writing technology for printed wiring board

An electron-beam lithography system has been developed which can write electric circuit patterns directly on printed wiring boards from computer-aided design data without making the master and working film masks which are necessary for conventional photolithography. The electron beam is focused to 34 mu m in diameter at an accelerating voltage of 60 kV. The sensitivity of an electrodeposited photoresist to electron-beam exposure is investigated. It is shown that the photoresist is very sensitive to the electron beam and has a threshold dosage of 0.2 mu C/cm/sup 2/. The spatial contours of equienergy density deposited by the electron beam in a 20- mu m-thick resist-copper substrate configuration have been calculated with a Monte Carlo computer method. The geometry of the resist patterns is determined according to the contour line corresponding to about 6*10/sup 18/ eV/cm/sup 3/. It has been confirmed that fine patterns with linewidths less than 100 mu m can be obtained and that this technology is efficient for meeting the constantly growing demand for greater density and shorter turnaround.<<ETX>>

Large area electron beam direct imaging technology for printed wiring boards

An electron beam direct imaging system that can image electric circuit patterns directly on printed wiring boards (PWBs) from computer-aided design (CAD) data without using film masks has been developed. The system realizes beam deflection over a large field of 100 mm*100 mm. The deflection field can be imaged in less than 1 s with an accuracy of better than +or-30 mu m. The maximum deflection speed is 254 m/s, and the beam diameter in full width at half maximum is 40 mu m. This technology can use the same kinds of resists as those for conventional photolithography. It was shown that fine patterns with line widths less than 100 mu m can be imaged for PWBs 340 mm*400 mm in size by stitching deflection fields.<<ETX>>