Fabricating method for silicon structures

Claim 1

A method of fabricating a precision etched, three dimensional device from a silicon wafer, the wafer having a frontside and a backside surface, the device being produced by etching only the frontside surface of the wafer comprising the steps of: (a) depositing an etch resistant masking layer on the frontside and backside surfaces of a clean silicon wafer; (b) depositing a mechanical damage protective layer over the masking layer on both the frontside and backside surfaces of the wafer, (c) placing the backside surface of the wafer, covered by said masking layer and over lying protective layer, on a chuck means suitable for use in applying a photoimagable layer, whereby the protective layer over the masking layer on the wafer backside surface prevents crack-producing damage to said masking layer resulting from mechanical contact with said wafer during said placement of the wafer on said chuck means; (d) applying and patterning a photoimagable layer on the protective layer on the wafer frontside surface to produce a pattern of vias in the photoimagable layer, thereby exposing the protective layer through the vias, while the protective layer on the wafer backside surface prevents damage to the masking layer which could produce cracks in said masking layer, during the application and patterning of the photoimagable layer; (e) sequentially etching the protective layer first and then the masking layer exposed through the vias in the photoimagable layer to produce aligned vias therein exposing the frontside surface of the wafer; (f) stripping the patterned photoimagable layer from the frontside surface of the wafer; and (g) anisotropically etching the wafer in an etch bath, so that the exposed frontside surface of the wafer is etched through the vias in the protective and masking layers to produce the three dimensional device without undesired etching of the backside surface of the wafer through inadvertently produced cracks in the masking layer on the wafer backside surface.

Claim 2

A method of fabricating a precision etched, three dimensional device from a silicon wafer, the wafer having a frontside and a backside surface, the device being produced by etching only the frontside surface of the wafer comprising the steps of: (a) depositing an etch resistant masking layer on the frontside and backside surfaces of a clean silicon wafer; (b) depositing a mechanical damage protective layer over the masking layer on both the frontside and backside surfaces of the wafer, (c) placing the backside surface of the wafer, covered by said masking layer and over lying protective layer, on a chuck means suitable for use in applying a photoimagable layer, whereby the protective layer over the masking layer on the wafer backside surface prevents crack-producing damage to said masking layer resulting from mechanical contact with said wafer during said placement of the wafer on said chuck means; (d) applying and patterning a photoimagable layer on the protective layer on the wafer frontside surface to produce a pattern of vias in the photoimagable layer, thereby exposing the protective layer through the vias, while the protective layer on the wafer backside surface prevents damage to the masking layer which could produce cracks in said masking layer, during the application and patterning of the photoimagable layer; (e) sequentially etching the protective layer first and then the masking layer exposed through the vias in the photoimagable layer to produce aligned vias therein exposing the frontside surface of the wafer; (f) stripping the patterned photoimagable layer from the frontside surface of the wafer; and (g) anisotropically etching the wafer in an etch bath, so that the exposed frontside surface of the wafer is etched through the vias in the protective and masking layers to produce the three dimensional device without undesired etching of the backside surface of the wafer through inadvertently produced cracks in the masking layer on the wafer backside surface.

Claim 8

A method of fabricating a plurality of joined precision etched, three dimensional devices from silicon wafers by etching from only one side of the wafer and then separating the joined devices, comprising the steps of: (a) depositing an etch resistant masking layer on both sides of a clean silicon wafer; (b) depositing a mechanically protective layer over the masking layer on both sides of the wafer, so that the mechanically fragile masking layer is protected from damage during subsequent fabricating steps; (c) placing the wafer with the protective and masking layers on a rotatable vacuum chuck with one side in contact therewith, the protective layer on the side of the wafer contacting the vacuum chuck preventing crack producing damage to masking layer covered thereby during the wafer placement on the vacuum chuck; (d) rotating the vacuum chuck and spin coating a photoresist layer on the side of the wafer's protective layer opposite to the one in contact with the vacuum chuck; (e) patterning the photoresist layer to expose a predetermined pattern on the wafer's protective layer; (f) plasma etching the predetermined pattern of exposed protective layer to remove first the protective layer and then the exposed underlying masking layer to expose the surface of the wafer in said predetermined pattern; (g) stripping the patterned photoresist layer from the wafer; and (h) etching the exposed wafer surface in an anisotropic etchant bath to produce a plurality of three dimensional devices and concurrently etching and removing the protective layer, so that the masking layer is totally exposed and the three dimensional devices are produced by etching only one wafer surface without undesired etching of the other wafer side through cracks caused by damage to the masking layer thereon.

Claim 9

A method of fabricating a plurality of joined precision etched, three dimensional devices from silicon wafers by etching from only one side of the wafer and then separating the joined devices, comprising the steps of: (a) depositing an etch resistant masking layer on both sides of a clean silicon wafer; (b) depositing a mechanically protective layer over the masking layer on both sides of the wafer, so that the mechanically fragile masking layer is protected from damage during subsequent fabricating steps; (c) placing the wafer with the protective and masking layers on a rotatable vacuum chuck with one side in contact therewith, the protective layer on the side of the wafer contacting the vacuum chuck preventing crack producing damage to masking layer covered thereby during the wafer placement on the vacuum chuck; (d) rotating the vacuum chuck and spin coating a photoresist layer on the side of the wafer's protective layer opposite to the one in contact with the vacuum chuck; (e) patterning the photoresist layer to expose a predetermined pattern on the wafer's protective layer; (f) plasma etching the predetermined pattern of exposed protective layer to remove first the protective layer and then the exposed underlying masking layer to expose the surface of the wafer in said predetermined pattern; (g) stripping the patterned photoresist layer from the wafer; and (h) etching the exposed wafer surface in an anisotropic etchant bath to produce a plurality of three dimensional devices and concurrently etching and removing the protective layer, so that the masking layer is totally exposed and the three dimensional devices are produced by etching only one wafer surface without undesired etching of the other wafer side through cracks caused by damage to the masking layer thereon.

Claim 13

A method of fabricating a plurality of joined precision etched, three dimensional devices from silicon wafers by etching from only one side of the wafer and then separating the joined devices, comprising the steps of: (a) depositing an etch resistant masking layer on both sides of a clean silicon wafer; (b) depositing a mechanically protective layer over the masking layer on both sides of the wafer, so that the mechanically fragile masking layer is protected from damage during subsequent fabricating steps; (c) placing the wafer with the protective and masking layers on a rotatable vacuum chuck with one side in contact therewith; (d) rotating the vacuum chuck and spin coating a first photoresist layer on the side of the wafer's protective layer opposite to the one in contact with the vacuum chuck; (e) removing the protective layer on the wafer surface opposite the one with the first photoresist layer; (f) stripping the first photoresist layer; (g) placing the wafer on a rotatable vacuum chuck with the side having the protective layer being in contact therewith, so that the protective layer prevents crack-producing damage to the masking layer covered thereby; (h) rotating the vacuum chuck and spin coating a second photoresist layer on the masking layer; (i) patterning the second photoresist layer to expose a predetermined pattern on the wafer's masking layer while the masking layer on the opposite side of the wafer is being concurrently protected by the protective layer from crack-producing mechanical damage; (j) plasma etching the predetermined pattern of exposed masking layer to expose the surface of the wafer in said predetermined pattern; (k) stripping the patterned second photoresist layer from the wafer; and (l) etching the wafer surface exposed in an anisotropic etchant bath to produce a plurality of joined three dimensional devices and concurrently etching and removing the protective layer on the opposite side of the wafer, so that the masking layer is totally exposed and the three dimensional devices are produced by etching only one wafer surface without undesired etching of the other wafer side through cracks in the masking layer thereon caused by mechanical damage thereto.

Claim 14

A method of fabricating a plurality of joined precision etched, three dimensional devices from silicon wafers by etching from only one side of the wafer and then separating the joined devices, comprising the steps of: (a) depositing an etch resistant masking layer on both sides of a clean silicon wafer; (b) depositing a mechanically protective layer over the masking layer on both sides of the wafer, so that the mechanically fragile masking layer is protected from damage during subsequent fabricating steps; (c) placing the wafer with the protective and masking layers on a rotatable vacuum chuck with one side in contact therewith; (d) rotating the vacuum chuck and spin coating a first photoresist layer on the side of the wafer's protective layer opposite to the one in contact with the vacuum chuck; (e) removing the protective layer on the wafer surface opposite the one with the first photoresist layer; (f) stripping the first photoresist layer; (g) placing the wafer on a rotatable vacuum chuck with the side having the protective layer being in contact therewith, so that the protective layer prevents crack-producing damage to the masking layer covered thereby; (h) rotating the vacuum chuck and spin coating a second photoresist layer on the masking layer; (i) patterning the second photoresist layer to expose a predetermined pattern on the wafer's masking layer while the masking layer on the opposite side of the wafer is being concurrently protected by the protective layer from crack-producing mechanical damage; (j) plasma etching the predetermined pattern of exposed masking layer to expose the surface of the wafer in said predetermined pattern; (k) stripping the patterned second photoresist layer from the wafer; and (l) etching the wafer surface exposed in an anisotropic etchant bath to produce a plurality of joined three dimensional devices and concurrently etching and removing the protective layer on the opposite side of the wafer, so that the masking layer is totally exposed and the three dimensional devices are produced by etching only one wafer surface without undesired etching of the other wafer side through cracks in the masking layer thereon caused by mechanical damage thereto.