Integrated, microminiature electric-to-fluidic valve and pressure/flow regulator and method of making same

Claim 3

The apparatus of claim 1, wherein said means for heating the material is a resistor element in said container means with conductors available outside said cavity means for allowing passing electrical current through said resistor.

Claim 4

The apparatus of claim 1, wherein said means for heating is a light guide which conducts light energy into said container means.

Claim 5

The apparatus of claim 1, wherein said means for heating is conduction of heat from the ambient into the material trapped in the means for containing.

Claim 7

The apparatus of claim 5, wherein said fluid flow path means is a passageway between said flexible wall and a sealing surface chemically etched into a wafer which is bonded to the wafer in which said container means is etched.

Claim 8

The apparatus of claim 6, wherein said wafer in which said trench is etched is a silicon wafer and wherein said sixth wall is defined by a pyrex wafer on which is formed an etched resistor pattern located on said pyrex wafer such that when said pyrex wafer and said silicon wafer are bonded together, the resistor pattern is located in said trench.

Claim 11

The apparatus of claim 1 wherein said container means is an anisotropically etched trench in a silicon wafer having [100] orientation which is etched far enough through the thickness of the wafer to leave a thin membrane of silicon at the bottom of the trench and further comprising a pyrex wafer hermetically sealed over the mouth of the trench.

Claim 18

The method of claim 13 wherein said step 6 further comprises the steps of: 1) forming a layer of material on said second side of said first wafer before the bonding which is capable of blocking the migration of the metal selected for step 2 below into said semiconductor; 2) forming a layer of metal having a tendancy to diffuse into said semiconductor on top of said migration blocking layer; 3) placing the second side of the first and second wafers together and bringing the structure to a high enough temperature for a long enough time to cause the metal layer to diffuse into the semiconductor far enough to create a bond.

Claim 19

The method of claim 14 wherein step 1 includes the step of forming a layer of oxide, tungsten, titanium, or other diffusion barrier on the second side of a silicon, germanium or galium arsenide or other semi­conductor first wafer and wherein step 2 includes the step of depositing a layer of aluminum on top of said layer of silicon dioxide.

Claim 22

The method of claim 16 wherein said step of encapsulating a fixed volume of material includes the steps of placing the first wafer in a chamber of the material to be encapsulated and anodically bonding a third wafer over a fill hole into the cavity in said first wafer so as to hermetically seal said fill hole.

Claim 23

The method of claim 16 wherein said steps of encapsulating a material in said cavity and providing a means for heating the material in said cavity include the steps of: etching a pattern of resistive conductor on the surface of a third wafer said pattern being small enough to substantially fit in said trench and having metal leads leading away from said conductive pattern to bonding pads located outside the perimeter of said trench; in the presence of vacuum, bonding said third wafer to said first wafer with said conductive pattern facing inward and located substantially within said trench, said bond forming substantially a complete seal except for small leakage paths at the sides of said metal leads leading to said bonding pads; immersing the structure in a chamber containing the liquid to be encapsulated and pressurizing the chamber if necessary to increase the rate of fill of said cavity through said small leaks; after the cavity has been filled to a user defined extent, attaching the bonding pads and metal leads as the cathode in a metal electroplating system including a bath of electroplating solvent and plating a sufficient amount of metal onto the bonding pads and metal leads so as to plug up the small leakage paths and hermetically seal said cavity.

Claim 24

The method of claim 16 wherein the steps of forming said cavity and encapsulating material in said cavity includes the steps of: bonding a third wafer over the opening of the trench to hermetically seal the trench; forming a fill hole in said third wafer to allow fluid access to said trench; filling said cavity with a user defined quantity of the material to be encapsulated through said fill hole; sealing said fill hole.

Claim 25

The method of claim 19 where said fill hole is laser drilled and the filling step includes the step of pressurizing the chamber containing the liquid or gas to be encapsulated.

Claim 26

21 The method of claim 16 wherein the steps of forming said cavity and encapsulating material therein include the steps of anodically bonding a third wafer over the opening of said trench in the presence of the gas, liquid or solid to be encapsulated at a high pressure adequate to control the vapor pressure of the material to be encapsulated and to prevent escape of the material to be encapsulated from the cavity.

Claim 29

The method of claim 22 wherein said trench in said first side has at least one stair step or dis­continuity in the side walls thereof such that the polyimide membrane formed using the walls of the trench as a mold has a fold in it like a bellows fold.

Claim 30

The method of claim 22 or 23, wherein said step of encapsulating comprises the steps of etching a resistor pattern in a layer of conductive material deposited on the surface of a second wafer and anodically bonding the second wafer to said first wafer in the presence of the material to be encapsulated so that the resistor pattern is in the cavity formed by the trench and said second wafer.

Claim 31

The method of claim 22, 23 or 24, wherein said step of encapsulating comprises the steps of etching a resistor pattern in a layer of conductive material deposited on the surface of a second wafer having metal leads extending to bonding pads at some user defined distance from said resistor pattern and bonding the second wafer to said first wafer in a vacuum so that the resistor pattern is in the cavity formed by the trench and said second wafer and said cavity is evacuated and so that a substantial seal except for small leakage paths at the sides of said metal leads, and then immersing the structure in the material to be encapsulated and pressurizing the system until a user defined amount of material has leaked into said cavity, and then connecting the metal leads as the cathode in an electroplating bath and plating a sufficient amount of metal on said metal leads to hermetically seal said cavity by blocking said leakage paths.

Claim 32

The method of claim 22, 23 or 24, wherein the step of encapsulating comprises the steps of forming a cavity by bonding a second wafer over the first wafer so as to hermetically seal said trench and then forming a fill hole in said second wafer to provide fluid access to said cav­ity, filling said cavity through said fill hole and seal­ing said fill hole.

Claim 33

The method of claim 26 wherein said fill hole is formed by laser drilling and wherein the step of filling said cavity comprises the steps of evacuating said cavity and immersing the structure in the material to be encapsulated until the cavity is at least partially full.

Claim 40

The method of claim 30 wherein said step of bonding said first wafer to said second wafer includes the steps of: in the presence of vacuum, bonding said second wafer to said first wafer with said resistor pattern fac­ing inward and located substantially within said trench, said bond forming substantially a complete seal except for small leakage paths at the sides of said metal conductors leading to said bonding pads; immersing the structure in a chamber containing the liquid to be encapsulated and pressurizing the chamber if necessary to increase the rate of fill of said cavity through said small leaks; after the cavity has been filled to a user defined extent, attaching the bonding pads and metal leads as the cathode in a metal electroplating system including a bath of electroplating fluid and plating a sufficient amount of metal onto the bonding pads and metal leads so as to plug up the small leakage paths and hermetically seal said cavity.

Claim 41

A tactile actuator comprised of: means for trapping a material which has changing vapor pressure with changing temperature; and means for allowing a user to change the vapor pressure of the trapped material; and means for converting the changing vapor pressure into movement of movable member.

Claim 42

A tactile actuator comprised of: means for trapping a material which has changing vapor pressure with changing temperature; and means for allowing a user to change the vapor pressure of the trapped material; and means for converting the changing vapor pressure into movement of movable member.

Claim 43

A tactile actuator comprised of: a first substrate;; a semiconductor wafer having a chamber formed therein and attached to said first substrate, and wherein at least one wall of said chamber is a flexible membrane; and means for providing a fluid access channel to said cavity; material in said chamber which has changing vapor pressure with changing temperature; means for changing the temperature of the material trapped in said cavity; and means for plugging said fluid access channel so as to trap said material in said chamber.

Claim 44

A tactile actuator comprised of: a first substrate;; a semiconductor wafer having a chamber formed therein and attached to said first substrate, and wherein at least one wall of said chamber is a flexible membrane; and means for providing a fluid access channel to said cavity; material in said chamber which has changing vapor pressure with changing temperature; means for changing the temperature of the material trapped in said cavity; and means for plugging said fluid access channel so as to trap said material in said chamber.

Claim 45

The apparatus of claim 33 wherein said flexible membrane is polyimide film.

Claim 46

A tactile acuator comprising: a semiconductor wafer having a hole etched therein; a layer of spacer metal attached to at least a portion of the walls of said hole; a polyimide membrane attached to said spacer metal so as to form a pocket having rigidity in the wall at the location of the spacer metal but flexibility in the wall at all other locations; a second wafer attached to said semiconductor wafer so as to seal the mouth of said pocket; means for providing a fluid access channel to said pocket; material in said pocket which has changing vapor pressure with changing temperature; means for plugging said fluid access channel to trap said material in said cavity; means for changing the temperature of the material in the pocket.

Claim 47

A tactile acuator comprising: a semiconductor wafer having a hole etched therein; a layer of spacer metal attached to at least a portion of the walls of said hole; a polyimide membrane attached to said spacer metal so as to form a pocket having rigidity in the wall at the location of the spacer metal but flexibility in the wall at all other locations; a second wafer attached to said semiconductor wafer so as to seal the mouth of said pocket; means for providing a fluid access channel to said pocket; material in said pocket which has changing vapor pressure with changing temperature; means for plugging said fluid access channel to trap said material in said cavity; means for changing the temperature of the material in the pocket.

Claim 50

The method of claim 36 further comprising the step of forming a resistive heating element on the portion of the face of said second wafer to be within said cavity and forming bonding pads and conductors on the second wafer so that electrical current may be passed through said resistive element when said second wafer is sealed to said semiconductor wafer.

Claim 51

A variable focal length lens comprising: a light transmitting substrate; a means coupled to said substrate for entrapping a material within a cavity having a flexible, light transmitting wall; and a light transmitting material having a vapor pressure which changes with changing temperature entrapped in said cavity.

Claim 52

A variable focal length lens comprising: a light transmitting substrate; a means coupled to said substrate for entrapping a material within a cavity having a flexible, light transmitting wall; and a light transmitting material having a vapor pressure which changes with changing temperature entrapped in said cavity.

Claim 53

The apparatus of claim 38 further compris­ing means for allowing a user to control the temperature of the material entrapped in said cavity.

Claim 54

The apparatus of claim 38 further compris­ing a fiber optic light guide affixed in the light transmission path of light emerging from said flexible wall at such a position that the amount of light that is captured by said fiber optic light guide depends upon the then current shape of the flexible wall.

Claim 59

An apparatus as defined in claim 42 wherein said first wafer is pyrex and said second wafer is silicon and further comprising a second pyrex wafer having a first and second surface, said first surface having an input channel and an output channel etched therein, said input channel and said output channel separated by a valve seat in the form of a wall separating said input channel from said output channel, said first surface being bonded to said second surface of said silicon wafer at substantially all points except a predetermined area surrounding where said diaphragm mates with said valve seat.

Claim 60

The apparatus of claim 43 wherein said input channel and said output channel each have a plural­ity of projecting fingers which are interdigitated and wherein said valve seat takes the form of a serpentine mesa which separates the fingers of the input channel from the output channel fingers.

Claim 61

The apparatus of claim 44 wherein said means for heating is a resistive material deposited on the surface of said first pyrex wafer which seals said trench to form said cavity so as to be included within the perimeter of said cavity such that current may be passed through said resistive material to heat the fluid in the cavity.

Claim 64

The apparatus of claim 45, 46 or 47, wherein said first and second pyrex wafers are anodically bonded to said silicon wafer and wherein the surface of said valve seat which contacts said diaphragm is coated with a material which prevents anodic bonding between said diaphragm and said valve seat.

Claim 65

An integrated pressure regulator compris­ing: a first integrated valve having the construction of claim 48 and having its input port for coupling to a high pressure source; a second integrated valve having the construc­tion of claim 48 and sharing the same silicon wafer and the same pyrex wafers as said first integrated valve and having its input port for coupling to a low pressure ef­fluent sink; an output port for coupling to the output chan­nels of both said first and said second integrated valves; and a pressure sensor coupled to said output port.

Claim 66

An apparatus as defined in claim 49 wherein said pressure sensor comprises a diaphragm formed in the silicon wafer shared by said first and second integrated valves, said diaphragm in fluid communication with said output port and forming an evacuated chamber between said diaphragm and said first pyrex wafer shared by said first and second integrated valves, said evacuated chamber hav­ing a first capacitor plate formed by a conductive coating on at least a portion of the surface of said first pyrex wafer within said cavity and having a second capacitor plate formed by a conductive coating on at least a portion of the surface of said diaphragm.

Claim 67

An integrated pressure regulator compris­ing: a first wafer having first and second surfaces, said second surface having first and second resistor pat­terns formed thereon and having a first conductive film formed thereon; a second wafer bonded to said first wafer and having first and second surfaces, said first surface hav­ing first and second trenches formed therein, said trenches having a depth sufficient to form first and second flexible diaphragms between the bottoms of said trenches and said second surface, and having a third trench formed in said first surface, the bottom of said trench being covered with a second conductive film, and having a fourth trench formed in the second surface op­posite said first surface, said fourth trench formed deep enough that a flexible diaphragm is formed between the bottoms of said third and fourth trenches, said first and second trenches being formed at locations aligned with the locations of said first and second resistor patterns such that said patterns are within the cavities formed between said first and second wafers at the locations of said first and second trenches, said third trench being located such when the first and second wafers are bonded together in a vacuum, an evacuated cavity with said first and second conductive films forming a capacitor with a vacuum dielectric is formed; and a third wafer having first and second surfaces, said first surface being bonded to said second surface of said second wafer at predetermined locations and having a first pair of input and output channels formed in said first surface and separated by a first valve seat in the form of a wall between said input and output channels which said first diaphragm contacts but which is not bonded to said first diaphragm, said first surface also having a second pair of input and output channels separated by a second valve seat in the form of a wall between said input and output channels which said second diaphragm contacts but which is not bonded to said second diaphragm, said second surface having a hole formed therein passing through said third wafer to emerge from said first surface at a location which is fluid communica­tion with said fourth trench.

Claim 68

An integrated pressure regulator compris­ing: a first wafer having first and second surfaces, said second surface having first and second resistor pat­terns formed thereon and having a first conductive film formed thereon; a second wafer bonded to said first wafer and having first and second surfaces, said first surface hav­ing first and second trenches formed therein, said trenches having a depth sufficient to form first and second flexible diaphragms between the bottoms of said trenches and said second surface, and having a third trench formed in said first surface, the bottom of said trench being covered with a second conductive film, and having a fourth trench formed in the second surface op­posite said first surface, said fourth trench formed deep enough that a flexible diaphragm is formed between the bottoms of said third and fourth trenches, said first and second trenches being formed at locations aligned with the locations of said first and second resistor patterns such that said patterns are within the cavities formed between said first and second wafers at the locations of said first and second trenches, said third trench being located such when the first and second wafers are bonded together in a vacuum, an evacuated cavity with said first and second conductive films forming a capacitor with a vacuum dielectric is formed; and a third wafer having first and second surfaces, said first surface being bonded to said second surface of said second wafer at predetermined locations and having a first pair of input and output channels formed in said first surface and separated by a first valve seat in the form of a wall between said input and output channels which said first diaphragm contacts but which is not bonded to said first diaphragm, said first surface also having a second pair of input and output channels separated by a second valve seat in the form of a wall between said input and output channels which said second diaphragm contacts but which is not bonded to said second diaphragm, said second surface having a hole formed therein passing through said third wafer to emerge from said first surface at a location which is fluid communica­tion with said fourth trench.

Claim 69

An integrated flow regulator comprising: an integrated valve having the construction of the valve of claim 48 and having first, second and third wafers bonded together; a flow channel in fluid communication with said output channel of said integrated valve formed between said pyrex wafers of said integrated valve; and first, second and third electrically isolated electrically resistive patterns formed on a surface of one of said pyrex wafers at least two of which resistive pat­terns change resistance with changes in temperature, said first, second and third resistive patterns arranged such that heat from power dissipated in one of the patterns must travel upstream in said flow channel to reach one of the resistive patterns that changes resistance with temperature and must travel downstream to reach the other resistive pattern that changes resistance with temperature.

Claim 70

An integrated flow regulator comprising: a first wafer having first and second surfaces, said second surface having a first resistive pattern formed thereon at a first location; a second wafer having first and second surfaces, said first surface having a trench formed therein having a depth sufficient to form a flexible diaphragm between the bottom of said trench and said second surface, said first surface being bonded to said first wafer so that said trench forms a sealed cavity which contains said first resistor pattern; a third wafer having first and second surfaces, said first surface having an input channel and an output channel formed therein and having a valve seat in the form of a wall separating said input channel from said output channel, said valve seat formed in a location such that said diaphragm contacts said valve seat to control the flow from said input channel to said output channel, said first surface being bonded to said second wafer at pre­determined points not including the point of contact between said valve seat and said diaphragm, said output channel being located so as to be in fluid communication with a flow channel formed between said first and second wafers; and resistor means formed in said flow channel for supplying heat to the material in said flow channel when current is passed through said resistor; first and second temperature sensing means formed in said flow channel such that heat diffusing through any material in said flow channel must diffuse in a direction which is upstream if the material is moving to reach said first temperature sensor, and must diffuse in a direction which is downstream if the material in the flow channel is moving to reach said second temperature sensor.

Claim 71

An integrated flow regulator comprising: a first wafer having first and second surfaces, said second surface having a first resistive pattern formed thereon at a first location; a second wafer having first and second surfaces, said first surface having a trench formed therein having a depth sufficient to form a flexible diaphragm between the bottom of said trench and said second surface, said first surface being bonded to said first wafer so that said trench forms a sealed cavity which contains said first resistor pattern; a third wafer having first and second surfaces, said first surface having an input channel and an output channel formed therein and having a valve seat in the form of a wall separating said input channel from said output channel, said valve seat formed in a location such that said diaphragm contacts said valve seat to control the flow from said input channel to said output channel, said first surface being bonded to said second wafer at pre­determined points not including the point of contact between said valve seat and said diaphragm, said output channel being located so as to be in fluid communication with a flow channel formed between said first and second wafers; and resistor means formed in said flow channel for supplying heat to the material in said flow channel when current is passed through said resistor; first and second temperature sensing means formed in said flow channel such that heat diffusing through any material in said flow channel must diffuse in a direction which is upstream if the material is moving to reach said first temperature sensor, and must diffuse in a direction which is downstream if the material in the flow channel is moving to reach said second temperature sensor.