APPLICATION OF ELECTRON-BEAM MACHINING TECHNIQUES TO SEMICONDUCTORS

A silicon film 200 Angstrom units thick was machined by an electron-beam-activated machining process to a resolution of 1000 Angstrom units by using commercial electron-optical and highvacuum apparatus. This process uses an electron beam to produce a chemically resistant layer of silica on the surface of silicon. The unprotected silicon is removed by a molecular beametching process in a high-vacuum chamber, thus forming a pattern of silicon that conforms to the shape of the electron beam. A design was completed for a scanning electron microscope which should give a resolution of greater than 200 Angstrom units. The electrostatic lens system is being constructed of metallized ceramic, so that high mechanical stability can be obtained through repeated ultrahigh-vacuum bake-out cycles. Electron gun parts and lens elements were constructed and tested in operation, and found to agree with the design values, although the entire lens system has not been tested as a unit. Upon successful completion of the electronoptical system and accessory equipment, it is expected that this method of micromachining of semiconductors can be applied to the fabrication of useful microelectronic semiconductor devices. Author