Method for making a microstructure by surface micromachining

A method for making a surface micromachined microstructure, comprising the steps of:

• forming a first sacrificial layer over a first substrate, wherein said first substrate comprises an upper surface that extends in a lateral dimension;
• forming a first intermediate layer on said first sacrificial layer and after said forming a first sacrificial layer step;
• forming a plurality of first strips from said first intermediate layer that extend in said lateral dimension, wherein each said first strip comprises a pair of vertically extending sidewalls, wherein said forming a plurality of first strips step is executed after said forming a first intermediate layer step;
• forming a second sacrificial layer on said first sacrificial layer and at least alongside and in interfacing relation with each said sidewall of each of said plurality of first strips, wherein said forming a second sacrificial layer step is executed after said forming a plurality of first strips step;
• forming a first structural layer over said second sacrificial layer after said forming a second sacrificial layer step, wherein said first structural layer extends in said lateral dimension and comprises a first perimeter that defines a lateral extent of said first structural layer, wherein said plurality of first strips extend underneath said first structural layer in said lateral dimension such that said first structural layer overlies said plurality of first strips, wherein at least one end of at least one of said plurality of first strips is at a location in said lateral dimension that at least generally corresponds with a location in said lateral dimension of a corresponding portion of said first perimeter;
• and
• removing said first and second sacrificial layers after said forming a first structural layer step, wherein said removing step comprises etching said first and second sacrificial layers, and wherein said etching step comprises forming a conduit that extends along each said sidewall of each of said plurality of first strips, wherein each said conduit is hollow, embedded, has a closed perimeter that is defined at least in part by said second sacrificial layer, and extends in said lateral dimension.

A method for making a surface micromachined microstructure, comprising the steps of:

• forming a first sacrificial layer over a first substrate, wherein said first substrate comprises an upper surface that extends in a lateral dimension wherein said forming a first sacrificial layer step comprises forming a plurality of low density regions within said first sacrificial layer that extend in said lateral dimension;
• forming a first structural layer over said first sacrificial layer and after said forming a first sacrificial layer step, wherein said first structural layer extends in said lateral dimension and comprises a first perimeter that defines a lateral extent of said first structural layer, wherein said plurality of low density regions each extend in said lateral dimension underneath said first structural layer such that said first structural layer overlies said plurality of low density regions, wherein at least one end of at least one low density region is at a location in said lateral dimension that at least generally corresponds with a location in said lateral dimension of a corresponding portion of said first perimeter;
• and
• removing said first sacrificial layer, wherein said removing step comprises etching said first sacrificial layer using a first etchant, and wherein said etching step comprises etching said plurality of low density regions with said first etchant to define a plurality of conduits that are hollow, embedded, have a closed perimeter that is defined at least in part by said first sacrificial layer, and that extend in said lateral dimension under said first structural layer such that said first structural layer overlies said plurality of conduits, and thereafter retaining said first etchant within said plurality of conduits to etch a remainder of said first sacrificial layer.

A method for making a surface micromachined microstructure, comprising the steps of:

• forming a first sacrificial layer over a first substrate, wherein said first substrate comprises an upper surface that extends in a lateral dimension;
• forming a first structural layer over said first sacrificial layer, wherein said first structural layer extends in said lateral dimension and comprises a first perimeter that defines a lateral extent of said first structural layer;
• and
• removing said first sacrificial layer, wherein said removing step comprises using a first etchant to define at least one etch release conduit that is hollow, embedded, has a closed perimeter that is defined at least in part by said first sacrificial layer, and that extends in said lateral dimension, and thereafter using a second etchant that is different from said first etchant to remove said first sacrificial layer by allowing said second etchant to flow within said at least one etch release conduit, wherein said at least one etch release conduit extends in said lateral dimension underneath said first structural layer such that said first structural layer overlies said at least one etch release conduit.

A method for making a surface micromachined microstructure, comprising the steps of:

• forming a first sacrificial layer over a first substrate, wherein a lateral dimension is at least generally parallel with an upper surface of said first substrate;
• forming a plurality of discrete and at least generally laterally extending hollow conduits that are defined at least in part by said first sacrificial layer;
• forming a first structural layer over said first sacrificial layer;
• and
• forming a first intermediate layer between said first sacrificial layer and said first structural layer, whereby said first intermediate layer is disposed at least somewhere between said first sacrificial layer and said first structural layer;
• patterning said first intermediate layer into a plurality of at least generally laterally disposed and axially extending strips that are disposed in at least substantially parallel and equally spaced relation, wherein a maximum spacing between adjacent pairs of said plurality of strips is about 1.5 microns, and wherein a minimum thickness of each of said plurality of strips is about 1.5 microns;
• forming said first sacrificial layer over said first intermediate layer, wherein said forming said first sacrificial layer step fails to fill an entirety of said spacing between said adjacent pairs of said plurality of strips and which thereby defines said plurality of conduits;
• and
• removing said first sacrificial layer, wherein said removing step comprises flowing an etchant within at least some of said plurality of conduits.

A method for making a surface micromachined microstructure, comprising the steps of:

• forming a first sacrificial layer over a first substrate;
• forming a first intermediate layer on said first sacrificial layer;
• forming a plurality of first strips from said first intermediate layer that are disposed on and extend at least generally laterally relative to said first sacrificial layer;
• forming a second sacrificial layer on said first sacrificial layer and at least alongside each of said plurality of first strips;
• forming a first structural layer over said second sacrificial layer;
• and
• removing said first and second sacrificial layers, wherein said removing step comprises etching said first and second sacrificial layers, and wherein said etching step comprises etching said second sacrificial layer at a greater rate within each portion of said second sacrificial layer which interfaces with any portion of said first strips in comparison to portions of said second sacrificial layer which are free from contact with any portion of any of said plurality of first strips, wherein said first strips are structural and remain after execution of said removing step;
• planarizing an upper surface of said second sacrificial layer;
• etching through said second sacrificial layer to each of said plurality of first strips to define a first interconnect aperture assembly in said second sacrificial layer, wherein said forming a first structural layer step is executed after said etching through said second sacrificial layer step to expose each of said plurality of first strips, and wherein said forming a first structural layer step comprises depositing structural material both within said first interconnect aperture assembly and on top of said second sacrificial layer.

A method for making a surface micromachined microstructure, comprising the steps of:

• forming a first sacrificial layer over a first substrate, wherein said forming a first sacrificial layer step comprises forming a plurality of at least generally laterally extending low density regions within said first sacrificial layer;
• forming a first structural layer over said first sacrificial layer;
• removing said first sacrificial layer, wherein said removing step comprises etching said first sacrificial layer, and wherein said etching step comprises etching said first sacrificial layer at a greater rate within each of said plurality of low density regions than outside said plurality of low density regions;
• forming a second sacrificial layer over said first substrate;
• patterning said second sacrificial layer to define a plurality of at least generally laterally extending apertures, wherein each said aperture comprises first and second aperture sidewalls that are disposed in spaced relation, wherein said forming a first sacrificial layer step is executed after said patterning step such that at least a portion of said first sacrificial layer is disposed within each of said plurality of apertures, and wherein said plurality of low density regions exist along said first and second sidewalls.