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US 4,649,261 AGranted
Apparatus for heating semiconductor wafers in order to achieve annealing, silicide formation, reflow of glass passivation layers, etc.
AssigneeTamarack Scientific Co., Inc.
InventorRonald E. Sheets
Life of this patent
Estimating the term…
Abstract
An integrating light pipe, very preferably a kaleidoscope, encloses a source of radiant thermal energy, the light pipe and energy source being so arranged as to achieve efficient and substantially uniform heating of a workpiece in a target plane. The pipe has closed ends so as to heat the workpiece from both sides uniformly and efficiently. The apparatus employs CW lamps, pulsed lamps, and a combination of the two.
Claims49
Heating apparatus, comprising:
- (a) lamp means,
- (b) means to support a workpiece, and
- (c) means to optically couple said lamp means to a workpiece supported on said workpiece-support means, to effect relatively uniform heating of said workpiece, said optical coupling means being a hollow, integrating light pipe that extends at least substantially to said workpiece-support means and that causes the intensity of the light from said lamp means to be relatively uniform across said light pipe at said workpiece, said lamp means being disposed within said light pipe, the aspect ratio in said light pipe being at least 1.
Heating apparatus, comprising:
- (a) a kaleidoscope,
- (b) a source of radiant thermal energy disposed within said kaleidoscope, and
- (c) workpiece-support means disposed in said kaleidoscope and spaced from said radiant source in a direction longitudinal to said kaleidoscope,
- the aspect ratio in said kaleidoscope being at least 1, said kaleidoscope and aspect ratio making substantially uniform the radiation from said radiant source at the region of said workpiece support means,
- whereby a workpiece disposed on said workpiece-support means will be substantially uniformly heated.
2 more elements
Heating apparatus for a semiconductor wafer, said heating apparatus comprising:
- (a) a hollow, integrating light pipe that causes the intensity of light to become relatively uniform across said pipe by reflections and rereflections as the light moves along said pipe,
- (b) wall means to close one end of said light pipe, said wall means having an inwardly-facing reflector means that is diffusely reflective,
- (c) lamp means to create incoherent thermal radiation, said lamp means being disposed within said light pipe, and transmitting radiation in both directions along said pipe,
- (d) means to support a semiconductor wafer in such position as to be struck by radiation transmitted by said lamp means and directed by said light pipe, said support means being spaced sufficiently far from said lamp means, in a direction perpendicular to a cross-section of said light pipe, that a wafer supported by said support means will be relatively uniformly heated by radiation transmitted by said lamp means, reflected by said inwardly-facing diffuse reflector means of said wall means, and integrated by said light pipe, the aspect ratio in said light pipe being at least 1,
- (e) substantially nondiffusing window means disposed between said lamp means and wafer-supported means, and
- (f) means to provide a controlled atmosphere around said wafer, said controlled atmosphere being maintained, by said window means, out of contact with said lamp means.
3 more elements
Apparatus for effecting double-sided and relatively uniform heating of a semiconductor wafer, said apparatus comprising:
- (a) a hollow, integrating light pipe that causes the intensity of light to become relatively uniform across said pipe by reflections and rereflections as the light moves along said pipe,
- (b) means to close one end of said pipe, said closure means incorporating inwardly-facing highly-reflective means over substantially the entire area thereof,
- (c) means to support a semiconductor wafer within said pipe at an intermediate region thereof, said support means being in only small-area contact with said wafer, said support means and the wafer held thereby having such size and such characteristics as to permit a substantial percentage of radiant thermal energy within said pipe to pass along said pipe past said support means and said wafer, the aspect ratio in said light pipe being at least 1, and
- (d) means to supply radiant thermal energy to said pipe at a region farther from said closure means than is said support means,
- whereby a wafer supported by said support means is heated relatively uniformly on both sides,
- one side being heated by radiant thermal energy from said means (d) and directed and integrated by said pipe,
- the other side being heated by radiant thermal energy from said means (d), directed and integrated by said pipe, then passing past said support means and the wafer supported thereby, then reflecting off said closure means, and then being directed and integrated by said pipe back to said other side of said wafer.
4 more elements
Apparatus for effecting double-sided and relatively uniform heating of a semiconductor wafer, said apparatus comprising:
- (a) a hollow, integrating light pipe that operates, by reflections and rereflections, to cause the intensity of light to become substantially uniform across said pipe as the light moves along said pipe,
- (b) means to close one end of said pipe,
- (c) means to close another end of said pipe,
- said closure means (b) and (c) being reflective in an inward direction,
- (d) means to support a semiconductor wafer within said pipe at an intermediate region thereof,
- said support means being in only small area contact with said wafer, said means (d) and the wafer held thereby having such size and such characteristics as to permit a substantial percentage of radiant thermal energy within said pipe to pass along said pipe past said means (d) and said wafer,
- (e) lamp means disposed within said pipe relatively adjacent said closure means (b) and adapted to radiate both toward and away from said closure means (b),
- whereby a wafer supported by said support means (d) is heated relatively uniformly on both sides,
- one side being heated by radiant thermal energy from said means (e) and directed and integrated by said pipe,
- another side being heated by radiant thermal energy from said means (e), directed and integrated by said pipe, then passing past said means (d) and the wafer supported thereby, then reflecting off said closure means (c), and then being directed and integrated by said pipe back to the other side of said wafer, the aspect ratio in said light pipe being at least 1, and
- (f) nondiffusing window means disposed between said wafer-support means (d) and said lamp means (e).
8 more elements
Apparatus for treating semiconductor wafers by means of heat, said apparatus comprising:
- (a) a hollow integrating light pipe that causes the intensity of light, by reflections and rereflections of the light, to become substantially uniform across said pipe as the light moves therealong, said pipe having a diameter sufficiently large to receive a semiconductor wafer therein,
- (b) means to mount a semiconductor wafer generally in a plane perpendicular to the longitudinal axis of said pipe, and
- (c) CW lamp means and pulsed lamp means cooperating with said light pipe to effect combined and substantially uniform isothermal and thermal flux heating of said wafer,
- said wafer and said CW lamp means being disposed within said light pipe,
- the aspect ratio in said light pipe being at least 1.
2 more elements
Apparatus for heating a semiconductor wafer, comprising:
- (a) a kaleidoscope having a diameter at least as large as that of a semiconductor wafer to be heated,
- (b) means to close one end of said kaleidoscope by means of a reflective wall substantially all portions of which are perpendicular to the axis of said kaleidoscope,
- (c) a plurality of lamps disposed in said kaleidoscope relatively adjacent said reflective wall,
- said lamps directing radiant energy both toward and away from said reflective wall, and
- (d) means to mount a semiconductor wafer, having two parallel surfaces, generally in a plane perpendicular to the axis of said kaleidoscope,
- said mounting means being at a location spaced sufficiently far from said lamps, in a direction parallel to said axis, that the radiant energy from said lamps is relatively uniform at one of said surfaces of said wafer,
- said mounting means being a plurality of elongate small-area contact elements adapted to engage said wafer at the ends of said contact elements,
- the aspect ratio in said kaleidoscope being at least 1.
5 more elements
Apparatus for heating semiconductor wafers, comprising:
- (a) an elongate, hollow, integrating light pipe that causes the intensity of light, by reflections and rereflections of the light, to become substantially uniform across said pipe as the light moves therealong,
- (b) means to provide high-power radiant thermal energy in at least one end of said pipe, and
- (c) automatic means to introduce and withdraw large-diameter semiconductor wafers from a region of said pipe spaced substantial distances from both ends thereof, the aspect ratio in said light pipe being at least 1.
Semiconductor wafer-heating apparatus, comprising:
- (a) a kaleidoscope, the cross-sectional shape of the reflective surfaces of said kaleiodoscope being a regular hexagon,
- (b) lamp means provided in said kaleidoscope,
- (c) wafer-support means provided in said kaleidoscope and spaced from said lamp means in a direction perpendicular to a cross section of said kaleidoscope, the amount of said spacing being such that a wafer supported on said means (c) will be relatively uniformly heated, the aspect ratio in said kaleidoscope being at least 1,
- (d) window means disposed between said means (b) and (c) to thus cooperate with the wall means of said kaleidoscope in defining a lamp chamber and a wafer chamber, and
- (e) means to provide a controlled atmosphere in said wafer chamber during operation of said lamp means to heat a wafer.
2 more elements
Semiconductor wafer-heating apparatus, comprising:
- (a) means to define an optical cavity having a substantially nesting cross-sectional shape, said means having sidewalls that have inwardly-facing reflective surfaces, said reflective surfaces being highly reflective,
- (b) lamp means forming a source of radiant heat energy, said lamp means including both CW lamps and pulsed lamps, said lamp means being disposed in said optical cavity, and
- (c) means to support a semiconductor wafer in said cavity in spaced relationship from said lamp means, the direction of said spacing being perpendicular to a cross section of said cavity, said wafer-supporting means being such that when a wafer is supported thereon the radiant energy from said lamp means, and passing through said optical cavity, will strike and heat said wafer, the shape of said optical cavity and the amount of spacing of said semiconductor wafer from said lamp means being such that said wafer is relatively uniformly heated, the aspect ratio in said optical cavity being at least 1.
Apparatus for heating a workpiece, which comprises:
- (a) means to define an optical cavity having highly reflective inwardly-facing surfaces and having a substantially nesting cross-sectional shape,
- (b) incoherent source means of radiant-heat energy disposed in a region of said cavity, and
- (c) means to support a workpiece at a target region in said cavity, the aspect ratio in said cavity being at least 1,
- said inwardly-facing surfaces being so constructed and related to each other and to said source means and said workpiece-support means that:
- (1) much of the incoherent radiant heat energy from said source means will be reflected and re-reflected many times before traveling from said source means to said workpiece, and
- (2) the radiant heat energy from said source that reaches said workpiece will be distributed across said workpiece with a degree of uniformity within plus or minus 2 percent.
3 more elements
Dependencies are inferred from the claim text.