US 4,966,646 AGranted

Method of making an integrated, microminiature electric-to-fluidic valve

AssigneeThe Board of Trustees of the Leland Stanford University

InventorMark Zdeblick

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Abstract

A method of making an integrated, microminiature, electric-to-fluidic valve. The method comprises, in one embodiment, anisotropically etching a cavity in a silicon wafer to form a thin membrane at the bottom of a trench. Then a second wafer is etched to form an exit path surrounded by a valve seat positioned such that when these two wafers are sandwiched together, the valve seat lies under the membrane. An input passageway joining a manifold cavity formed around the valve seat is then etched in the surface of the second wafer which will mate with the diaphragm side of the first wafer. The two wafers are then bonded together after suitable alignment. A third pyrex wafer is then coated with a resistor material which will be over the cavity in the first wafer when the first and third wafers are bonded together. Conductive leads and wire attach pads are also formed. Finally, a fill hole is etched into the third wafer over the position of the cavity such that the cavity can be filled. The first and third wafers are then bonded together to complete the valve.

Claims17

Dependent claims

A method for manufacturing an apparatus comprising the steps of:

(1) etching a membrane cavity trench using masking material in a first semiconductor wafer having first and second sides with a depth such that a flexible diaphragm is left which is defined by the bottom of the trench and said second side;
(2) etching a nozzle trench in a first side of a second semiconductor wafer having first and second sides using masking material;
(3) making with masking material a sealing surface portion of the second side of said second wafer and etching said second surface back so that when said masking material is removed, said sealing surface projects as a mesa from said second side, said sealing surface being shaped and located so as to have an etched back depression therein located within the perimeter of said nozzle trench as said perimeter is projected onto said second side of said second wafer;
(4) masking a manifold trench portion of said second side of said second wafer without removing said sealing surface masking material and etching said second side of said second wafer back sufficiently to form a manifold trench in said second side around said sealing surface, said etch also being deep enough to etch said second side of said second wafer so as to form a fluid communication path from said depression to said nozzle trench so as to create a nozzle aperture in said sealing surface;
(5) removing all masking material from said second side of said second wafer;
(6) bonding said second side of said second wafer to said second side of said first wafer so that said sealing surface and nozzle aperture are located such if said flexible diaphragm is flexed toward said second wafer far enough, said flexible diaphragm would come to rest on said sealing surface and cut off flow of any material flowing through said nozzle aperture;
(7) filling said membrane cavity trench with a material which has a changing vapor pressure with changing temperature and hermetically sealing said material in said membrane cavity.

4 more elements

A method of forming an apparatus comprising the steps of:

(1) forming a trench in a first wafer said trench having, at least one flexible wall;
(2) forming a fluid passageway in a second wafer with a sealing surface forming a part of the fluid passageway boundary;
(3) bonding said first and said second wafers together so that said sealing surface and said flexible wall and the walls of said fluid passageway define a portion of said fluid passageway which has a variable cross sectional area which depends upon the position of said flexible wall;
(4) forming a cavity by sealing the opening in said trench as part thereof and encapsulating a fixed volume of a material which changes its vapor pressure with changing temperature in said cavity;
and
(5) providing a means for allowing the material trapped in said cavity to be heated above or cooled below the ambient temperature.

3 more elements

A method of forming an apparatus comprising the steps of:

etching a trench in a first side of a first wafer;
depositing a spacer layer in said trench;
depositing a layer of polyimide over said spacer layer;
etching away the polyimide lying on the surface of the wafer outside the perimeter of the trench;
etching a trench in a second side of said first safer which is parallel to said first side, said etching of the trench in said second side to continue until the trench exposes at least a portion of said spacer layer;
etching away at least some of said spacer layer to form a polyimide membrane;
encapsulating a fixed volume of material which has a changing vapor pressure with changing temperature in a cavity comprising said trench in said first side having a top placed over said trench and bonded to said first wafer.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/263,117Filed 26 Oct 1988 · division
Priority: 24 Sep 1986
Granted: 30 Oct 1990
Term ends: Not estimatedThe source records don’t support an estimate.

Classification19 codes

F16K 99/0001
Subject matter not provided for in other groups of this subclass: microvalves
F15C 3/04
Circuit elements having moving parts: using diaphragms
F15C 5/00
Manufacture of fluid circuit elements
F16K 99/0015
Constructional types of microvalves; Details of the cutting-off member: diaphragm or membrane valves