Browse Prior Art Database

Zone Refining of Thin Films in Circuit Processing

IP.com Disclosure Number: IPCOM000099128D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Cronin, JE: AUTHOR [+3]

Abstract

Radiant energy is focused to create a small, high temperature zone in a thin film or thin film to move impurities to preferred locations and/or modify crystal structure. The technique is useful in applications as changing metal crystal size and/or impurities to improve etching selectively adjusting junction doping by impurities to or from the junction via a contacting creating epitaxially grown single crystal lines regions in a thin film.

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Zone Refining of Thin Films in Circuit Processing

       Radiant energy is focused to create a small, high
temperature zone in a thin film or thin film to move impurities to
preferred locations and/or modify crystal structure.  The technique
is useful in applications as changing metal crystal size and/or
impurities to improve etching selectively adjusting junction doping
by impurities to or from the junction via a contacting creating
epitaxially grown single crystal lines regions in a thin film.

      Referring to Fig. 1, radiant energy is focused to form a
temperature zone 10 in a thin film on substrate 12. 10 is moved
across substrate 12 at a rate which permits the zone at a temperature
slightly above the melting of the film.  Since the film material is
quenched when the hot zone is moved forward, crystal is very small
and an alloy such as aluminum-copper found to be very homogeneous.
When an alloy film has zone reflowed in this manner and then etched,
edges of images are observed to be smooth and to accurately photomask
image edges.

      Referring to Fig. 2, a conductive line 20 containing a impurity
is in contact with semiconductor substrate in two places through via
holes in insulator 24.  A beam energy, e.g., from a laser, is focused
to bring a spot in 20 to a temperature near the melting point of line
20 swept toward a region 26 which is to become a junction, source or
drain.  Impurities are moved from conductor by the high temperature
zone to jun...