Integrated Materials, Incorporated

Robert L Davis

Raanan Y Zehavi

James W Govorko

David B Ackard

James E Boyle

Laurence D Delaney

A method of welding two silicon workpieces () together into one member without the formation of cracks along the weld. A first method passes current () through one or both of the workpieces to heat them to between 600 and 900&#xb0; C. Then an electric, laser, or plasma welder () passes along the seam () between the workpieces to weld them together. A second method passing current () through a plate (), preferably formed of silicon, which either supports the workpieces or is brought into contact with at least one of them, whereby the workpieces are preheated prior to the welding operation.

Two heat sources for welding silicon

A method of fabricating parts of silicon, preferably virgin polysilicon formed by chemical vapor deposition of silane, and assembling them into a complex structure, such as a silicon tower or boat for removably supporting a plurality of silicon wafers during thermal processing. The virgin polysilicon is annealed to above 1025&deg; C. before it is machined into a predetermined shape. After machining, the silicon parts are annealed in an oxygen ambient. The machined parts are then assembled and joined together followed by another anneal of the assembled structure. A preferred embodiment of the tower includes four legs secured on their ends to two bases. A plurality of slots are cut in the legs allowing slidable insertion of the wafers and support for them. The bases may be either virgin poly or monocrystalline silicon and be either integral or composed of multiple parts.

Method of machining silicon

Two silicon workpieces ( ) welded together into one member without the formation of cracks along the weld. It may be formed by a first method in which current ( ) is passed through one or both of the workpieces to heat them to between 600 and 900&deg; C. Then an electric, laser, or plasma welder ( ) passes along the seam ( ) between the workpieces to weld them together. In a second forming method, current ( ) is passed through a plate ( ), preferably formed of silicon, which either supports the workpieces or is brought into contact with at least one of them, whereby the workpieces are preheated prior to the welding operation.

Welded silicon member

A method of fabricating the parts and assembling them into a complex structure, such as a silicon tower or boat for removably supporting a plurality of silicon wafers during thermal processing. A preferred embodiment of the tower includes four legs secured on their ends to two bases. A plurality of slots are cut in the legs allowing slidable insertion of the wafers and support for them. The legs preferably have a rounded wedge shape with a curved front surface of small radius cut with the slots and a back surface that is either flat or curved with a substantially larger radius. Preferably, the legs are machined from virgin polysilicon formed by chemical vapor deposition from silane. The bases may be either virgin poly or monocrystalline silicon and be either integral or composed of multiple parts. Virgin polysilicon is preferably annealed to above 1025&deg; C. before machining. Silicon parts may be joined by applying a spin-on glass between the parts and annealing the assembly. After assembly, the surface of a tower is subjected to sub-surface working.

Method of fabricating silicon structures including fixtures for supporting wafers

A silicon tower or boat for removably supporting a plurality of silicon wafers during thermal processing. A preferred embodiment of the tower includes four legs secured on their ends to two bases. A plurality of slots are cut in the legs allowing slidable insertion of the wafers and support for them. The legs preferably have a rounded wedge shape with a curved front surface of small radius cut with the slots and a back surface that is either flat or curved with a substantially larger radius. Preferably, the legs are machined from virgin polysilicon formed by chemical vapor deposition from silane. The bases may be either virgin poly or monocrystalline silicon and be either integral or composed of multiple parts. Virgin polysilicon is preferably annealed to above 1025&deg; C. before machining. Silicon parts may be joined by applying a spin-on glass between the parts and annealing the assembly. After assembly, the surface of a tower is subjected to sub-surface working.

Silicon fixtures for supporting wafers during thermal processing

A method and apparatus for welding together two silicon workpieces ( ) without the formation of cracks along the weld. In a first embodiment, current ( ) is passed through one or both of the workpieces to heat them to between 600 and 900&deg; C. Then an electric, laser, or plasma welder ( ) passes along the seam ( ) between the workpieces to weld them together. In a second embodiment, current ( ) is passed through a plate ( ), preferably formed of silicon, which either supports the workpieces or is brought into contact with at least one of them, whereby the workpieces are preheated prior to the welding operation.

Method for welding silicon workpieces

A method of fabricating support members for wafer processing fixtures and the produce are disclosed. In the first step of the method, an elongate support member basic form is provided. The basic form has a substantially wedge-shaped cross-section and angular comers. A plurality of wafer-retaining slots are cut along one side of the support member basic form. The support member basic form can include a front surface and a rear surface, with at least one angular comer occurring on each of the surfaces. The comers have a larger radius on the rear than in the front. Attachment structures on terminal ends can be fixed to bases. The elongate support member basic form can be fabricated from an inert crystalline material, such as polycrystalline silicon or monocrystalline silicon.

Silicon support members for wafer processing fixtures

A method and apparatus for welding together two silicon workpieces (,) without the formation of cracks along the weld. In a first embodiment, current (,) is passed through one or both of the workpieces to heat them to between 600 and 900&deg; C. Then an electric or plasma welder (,) passes along the seam (,) between the workpieces to weld them together. In a second embodiment, current (,) is passed through a silicon plate (,) which either supports the workpieces or is brought into contact with at least one of them, whereby the workpieces are preheated prior to the welding operation.

Crack free welding of silicon

A method for fabricating elongate structural members from a unitary blank of crystalline material is provided. The blank has a predetermined length, width, and depth. A first substantially planar cut is made in the blank, the cut extending substantially along the entire length of the blank and substantially less than the entire width of the blank. At east one additional cut is made in the blank, the at least one additional cut extending in the same plane as the first cut, to cut the blank into two pieces. The step of making at least one additional cut can include making a plurality of additional cuts, in one embodiment at least three additional cuts. The cuts can be made using a rotary saw with a blade having diamond-coated cutting surfaces. The saw can be operated with the blade rotating at between 50 rpm and 50,000 rpm, preferably at approximately 4,000 rpm. The blank of crystalline material can be provided as a unitary blank of silicon material. The method of the present invention can be practiced using monocrystalline silicon material or polyaystalline silicon material. In an embodiment, the blank can be provided as a generally cylindrical blank. The step of making a first substantially planar cut and the step of making at least one additional cut can be repeated on each of the two pieces to make four pieces from the original cylinder, and subsequently repeated to yield eight pieces from the original cylinder, each of the eight pieces having a substantially wedge-shaped cross-section.

Method and apparatus for fabricating elongate crystalline members

A method of fabricating support members for wafer processing fixtures is disclosed. In the first step of the method, an elongate support member basic form is provided. The basic form has a substantially wedge-shaped cross-section and angular edges. Next, the edges of the support member basic form are machined to replace the angular edges with substantially arcuate edges. A plurality of wafer-retaining slots are cut along one side of the support member basic form. The support member basic form can include a front surface and a rear surface, with at least one angular edge occurring on each of the surfaces. The step of machining the edges of the support member basic form can be performed as machining the edges on the respective surfaces to radii of between 0.25&Prime; and 5.25&Prime;. In an embodiment, the at least one angular edge occurring on the rear surface can be machined to a radius of approximately 1.5&Prime;, and the at least one angular edge occurring on the front surface can be machined to a radius of approximately 0.35&Prime;. At least one attachment structure can be provided on at least one terminal end of the support member basic form. In an embodiment, the attachment structure can be provided as a pair of cylindrical pegs, each of which extends from a respective terminal end of the support member basic form. The elongate support member basic form can be fabricated from an inert crystalline material, such as polycrystalline silicon or monocrystalline silicon. A support member for wafer processing fixtures is also disclosed. The support member can include an elongate body portion having a pair of opposite terminal ends, an arcuate front surface with a first radius of curvature, and an arcuate rear surface with a second radius of curvature. The first radius of curvature can be substantially smaller than the second radius of curvature. A plurality of mutually parallel wafer-retaining slots are formed in the front surface of the body portion.

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Belmont, CA, United States of America

Robert L Davis