32) Hitachi Competed against NEC with LTP Transistors
Hitachi’s engineering team who promoted industrialization of LTP transistors
(From left to right: Tokuyama, Tomono and Shotaro Shibata)
NEC's acquisition of the exclusive license of planar patent
in Japan, incurred bitterness to NEC among other Japanese semiconductor manufacturers,
as confessed by NEC's Hiroe Osafune in the book titled "Semiconductor
Development in Japan," co-authored by Nishizawa and Ouchi. It created
several controversies in the industry.
Especially Hitachi strongly stood against NEC, and Masami Tomono, who was
Vice General Manger of Hitachi Musashi Works at that time, complained to me,
"NEC claims us to pay 5% re-license fee with additional 0.5% on top of
the percent which NEC pays to Fairchild. We can’t accept such unreasonable
request. Instead of accepting such request, we will develop our own technology."
With such background, Hitachi developed their own technology of LTP transistor.
LTP is an abbreviation of Low Temperature Passivation. This process is to
make a thin lead layer on top of silicon dioxide, then to heat in oxygen atmosphere
in order to make part of the silicon dioxide surface into lead glass, intending
to stabilize the device surface. This technology was invented by Takashi Tokuyama
of Hitachi Central Research Laboratory. The transistor utilizing this technology
has advantages of low noise and high moisture resistance, which accelerated
the adoption of plastic molding of the packages.
Photo is Hitachi's engineering team who promoted industrialization of LTP
transistors.
(From left: Tokuyama, Tomono and Shotaro Shibata)
(By courtesy of Tokuyama)