CA1110779A - Fast response temperature sensor - Google Patents
Fast response temperature sensorInfo
- Publication number
- CA1110779A CA1110779A CA317,288A CA317288A CA1110779A CA 1110779 A CA1110779 A CA 1110779A CA 317288 A CA317288 A CA 317288A CA 1110779 A CA1110779 A CA 1110779A
- Authority
- CA
- Canada
- Prior art keywords
- fin
- improvement
- chip
- conductor
- base member
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
- G01K1/08—Protective devices, e.g. casings
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
- G01K1/16—Special arrangements for conducting heat from the object to the sensitive element
- G01K1/18—Special arrangements for conducting heat from the object to the sensitive element for reducing thermal inertia
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/01—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using semiconducting elements having PN junctions
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/22—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor
- G01K7/223—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor characterised by the shape of the resistive element
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C1/00—Details
- H01C1/02—Housing; Enclosing; Embedding; Filling the housing or enclosure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/04—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having negative temperature coefficient
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/02—Arrangements of circuit components or wiring on supporting structure
- H05K7/04—Arrangements of circuit components or wiring on supporting structure on conductive chassis
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Ceramic Engineering (AREA)
- Nonlinear Science (AREA)
- Measuring Temperature Or Quantity Of Heat (AREA)
- Measuring Volume Flow (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A fast response fluid temperature sensor is disclosed which consists of a silicon temperature sensing semiconductor chip mounted on an extremely thin fin having a high surface area to mass ratio. The fin and chip combination are mounted in a frame assembly, with the thermal conductivity of the frame assembly being high and the specific heat being low for maximum heat transfer from the fluid being sensed to the silicon chip.
The chip and fin assembly are illustrated as being open to the free flow of fluid around the assembly, no insulating material being provided between the fluid media being sensed and the fin and chip assembly, and a protective cage is formed around the fin and chip assembly. Suitable connection is made between one electrical terminal of the chip and the fin and between the other electrical terminal of the chip and the external circuitry, with various modified forms of such connections being illustrated.
A fast response fluid temperature sensor is disclosed which consists of a silicon temperature sensing semiconductor chip mounted on an extremely thin fin having a high surface area to mass ratio. The fin and chip combination are mounted in a frame assembly, with the thermal conductivity of the frame assembly being high and the specific heat being low for maximum heat transfer from the fluid being sensed to the silicon chip.
The chip and fin assembly are illustrated as being open to the free flow of fluid around the assembly, no insulating material being provided between the fluid media being sensed and the fin and chip assembly, and a protective cage is formed around the fin and chip assembly. Suitable connection is made between one electrical terminal of the chip and the fin and between the other electrical terminal of the chip and the external circuitry, with various modified forms of such connections being illustrated.
Description
~ ~ ~¢~7 `~`
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates generally to a fluid tempera-ture sensor and more speciflcally t~ a fluid temperature sensor of the semiconductor type having a high sur~ace area to mass ratio ~or the temperature sensing assem~ly thereby provid1n9 an extremely fast acting temperature sensing unit.
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates generally to a fluid tempera-ture sensor and more speciflcally t~ a fluid temperature sensor of the semiconductor type having a high sur~ace area to mass ratio ~or the temperature sensing assem~ly thereby provid1n9 an extremely fast acting temperature sensing unit.
2. Description of the Prior Art ~ ~`
As described above, the present lnvention relatss to a temperature sensor which will provide a fast response device suitable for use in control systems where a rapld t2mperature ..
sensing of a flowin~ fluid media is required. A typical use of -such a temperature sensor would be in conjunction with the air induction system in an automotive engine wherein the air tempera~
ture is utilized in conjunct~on with other en~ine parameters for controlling the fuel in a fuel management syste~. ~
There are devices presently on the market which are ~ ;
similar to that which is to be described, but do not provide the extremely fast temperature response associated wlth the sensor of the present invention. In the temperature sensors presently being manufactured, for example by the Texas Instru-ments Corporation, the temperature sensin~ element is a silicon chip semiconductor which is doped by various impurities to control the resistance of the chip in response to variations in temperature. The silicon semiconductor chips are sized as blocks of approxlmately .015 x .015 x .006 inch dimension, the blocks being bonded to a metal plate on one side and a gold w~re attached to the opposite side of the chip in typical semiconductor manufac- ;
turing fashion. The chip is then bonded to a metallic frame which ~`
- is used as the base of the device, which frame i5 approximately 500 times the rnass of the silicon chip. The entire assembly is then encased in a plastic moldin~ for handling and lnstallation strength.
The metallic frame utilized as the base o~ the device is of a thick cross-sectional area and relatively short in length thereby providing a low surface area to mass ratio. Further, the plastic incapsulant which has been made a strUctural part of the device has a low thermal conductivity compare~ to metal and thus lG impedes the flow of heat to or from the silicon chip. This incap-sulant has been utilized due to the structural design of the assembly.
Co-pending Canadian application 317,292 filed December 4, 1978, commonly assigned, discloses a fast response fluid temperature sensor wherein a semiconductor device ismounted on a relatively flat fin which is open on both sides to the fluid being sensed. In order to facilitate the connection of the silicon chip to the exterior conductors, a pair of fins are proYided, the fins being generally dish-shaped to ensure air flow ~
around the entirety of the assembly. -However, with the air flow flowing around the entire assembly, it is possible that, under certain circumstances, contami~
nants and other foreign material may cause damage to the chip and/or lead attached to the chip. The present invention desrribes a method of overcoming this problem.
As described above, the present lnvention relatss to a temperature sensor which will provide a fast response device suitable for use in control systems where a rapld t2mperature ..
sensing of a flowin~ fluid media is required. A typical use of -such a temperature sensor would be in conjunction with the air induction system in an automotive engine wherein the air tempera~
ture is utilized in conjunct~on with other en~ine parameters for controlling the fuel in a fuel management syste~. ~
There are devices presently on the market which are ~ ;
similar to that which is to be described, but do not provide the extremely fast temperature response associated wlth the sensor of the present invention. In the temperature sensors presently being manufactured, for example by the Texas Instru-ments Corporation, the temperature sensin~ element is a silicon chip semiconductor which is doped by various impurities to control the resistance of the chip in response to variations in temperature. The silicon semiconductor chips are sized as blocks of approxlmately .015 x .015 x .006 inch dimension, the blocks being bonded to a metal plate on one side and a gold w~re attached to the opposite side of the chip in typical semiconductor manufac- ;
turing fashion. The chip is then bonded to a metallic frame which ~`
- is used as the base of the device, which frame i5 approximately 500 times the rnass of the silicon chip. The entire assembly is then encased in a plastic moldin~ for handling and lnstallation strength.
The metallic frame utilized as the base o~ the device is of a thick cross-sectional area and relatively short in length thereby providing a low surface area to mass ratio. Further, the plastic incapsulant which has been made a strUctural part of the device has a low thermal conductivity compare~ to metal and thus lG impedes the flow of heat to or from the silicon chip. This incap-sulant has been utilized due to the structural design of the assembly.
Co-pending Canadian application 317,292 filed December 4, 1978, commonly assigned, discloses a fast response fluid temperature sensor wherein a semiconductor device ismounted on a relatively flat fin which is open on both sides to the fluid being sensed. In order to facilitate the connection of the silicon chip to the exterior conductors, a pair of fins are proYided, the fins being generally dish-shaped to ensure air flow ~
around the entirety of the assembly. -However, with the air flow flowing around the entire assembly, it is possible that, under certain circumstances, contami~
nants and other foreign material may cause damage to the chip and/or lead attached to the chip. The present invention desrribes a method of overcoming this problem.
-3-~.~
SUI~MARY OF THE INVENTlON
It has been found that the dynamic perfor~ance of a sem;conductor type temperature sensor can be max;mized if the rnass of the semiconductor chlp utilized in conjunction with sensors of this type is minimized and is bonded to a metallic fin ha~ing a large area relative to the mass of the fln and semiconductor chip assembly. In a preferre~ embodiment, ~he connection to one terminal of the serniconductor chip is achieved by conductively bondin~ the chip to the metallic fin and providing a second lead to the edge of the fin by various techniques to be ;
described hereinafter.
. ..
The metallic fin should be arranged so that the ~luid flow of the fluid being sensed is parallel to the fin or in maximum heat transfer therewith. As will be shown, the temperature response ; ~-of a thin. constant thickness ~etallic fin emersed in a fluid is , primarily a function of the surface area to mass ratio of the fin. ` ~`
In accordance with the present invention there is provided a bemperature sensor for sensing the temperature of a fluid ccmprising a base ~ember, fin means formed of a thin disc havqng a high surface area to mass ratio mounted in fixed . .:
relationship to the base m~mber whereby the fluid to be sensed may -flow over the fin means, semicc)nductor means moun-ted c~
the fin means having the characteristics of changing resistance with changes in te~perature, a first output conductor connected to the fin means, a second autput conductor electrically in~
sulated from the fin means and cc~nected to the surfaoe of the chip remote from the surface of the chip in electrical CDntaCt with the fin.
cb/t~9, -3a-Tt11JS, for a given material and independent of the size o~f the fin, the temperature response tlme constant approaches ~ero dS the thickness of the fin approaches zero in a theoretical assembly .
For a practical assembly, the dens1ty and specific heat also affect the time constant and both parameters have been found to maximize the time response ~hen these parameters are mininlized. Additionally, when the silicon chip is adcled to the fin, the heat transfer between the fin and S~licon chip beconles important. The thermal contact material between the fin and chip must be of a high conductivity type, as for example gold. Additionally, the heat tlow from the surrounding areas of the fin relative to the area covered by the semiconductor chip nlUS~ t mdxiflli~ed. Accordinyly, the thermal conductivity of the fin becomes important and any material with high hea~ conductivity (such as alurninum) is desirable.
Irl one embodiment of the invention the fin i:, fdbiic~ed as a eirculdr, thin metallic disc with a semicon-ductor chip mounted centrally of the edges of the disc. Theo-retically, the fin should be fabricated of a tapering cross-sect~on, the thickest portion of the cross-section being in the area wherein the semiconductor chip is mounted, the fin taperin~ to zero thickness at the periphery. In the practical embodiment of the invelltiorl, the fin is supported at the periphery by various means and the semiconductor chip is electrically bonded on the surface of the chip but not in contact therewith.
It has been found tha-t the assembly which supports the fin r;lust be such that heat flow to or from the support is minimized since this heat flow does not necessarily result from the , . ~ . ,;, . :.. : , :
temperature of the fluld under consideratiun and, therefore, the dynamic performance and the steady state temperature of the semiconductor ehip maybe affected. St~ted otherwise, a difference in temperat~re between the chip and the Fluid media represents an error in the output signal and it ls ~his error which sho~ld be minimized for any given instantan~ous period of time. It is the desiratum of this invention to min~mize the transient time to achieve stabjli~y between the temperature of the chip and the te~perature of the fluid under consideration.
As stated above, one possible source af error in this signal results from heat flow to or from ~he fin support.
Therefore, the fin support shollld be located at a point as remote as possible fro~l the semiconductor chip and in the~;
pre~erred embodiment this support is establlshed at the outer edge of the chip. Therefore, this necessity for a ~echanical attachment prevents the outer edge of the chip from being a theoretical ideal zero thickness. It has been found that if the fin is of sufficient size in area, the radial Flow of heat from the inner to outer or outer to inner port~on of the chip ~0 is essentially zero, and thus the heat flow due to the mechanical support of the fin is minimized.
In this embodlment of th~ invent:Lon, the other ~:
terminal, other than the fin terminal, connected to the chip is formed by providing a thin stripe of insulating material from the outer edge of the fin radially inwardly to the semi-conductor chip, up the side of the semiconductor chip and slightly overlapping the top surface thereof. The lead wire, ribbon or cond~cting film is then fabricated to conform to the , surface of the insulating stripe and extended Dn th~ top surface of the chip beyond the lnsulating stri pe . Fi nally 9 a second thln coat of insulating material ls appll e~ ~o the lead to encase the lead from its end adjacent the bare upper surface ~f the semiconductor chip across the fin to the nuter ed~ of the fin.
The insulating material may be any plastic adhesive which satisfies the adheslve requirements of the fin and has an el ectrical resi stance when in place for at least two orders of magnitude greater than the resistance of the semiconductor chip and is tolerant of the temperature and the environmental conditions of the finished temperature sensor. ~ typical material for automotive applications is the cyanoacrylate class of adhesives such as marketed by the Eastman Corporation as adhesive 910THT.
Since the lead wire and adhesive material described above represent additional undesirable mass, the adhesive insulating stripe should be of minimal thickness and $he wire should he of minimal size to minimize the effect of this additional mass on the dynamic and steady state perf~nance of the sensor assembly.
In selecting suitable fin material the following relation-ship is considered to be of significance in lnvestigating the various characteristics of a material for its merit in conjunçtion with use in connection with the present invention. For maximum theoretical performance, the following relationship exists.
Mt = K where K - thermal conductivity, bo) (Sp.Hp.~ ~= density, and SP.HP, = specific heat ~he most desirable material l5 that which has pro~erties maxl-mizin~ the term Mt. ln a practical applicat;on, other prDperties such as cost fabricabil~ty, envirnnmental tolerance and avall-ability may modify the material selection. In a modified form of the invention it has been found that the heat transfer from the fin to the chip maybe maximized and the apparent mass oF the ;;
assembly minimi~ed by contacting both sides of the chip with an individual fin. Thus, each fin becomes one of the electrical connections to the chip and the transfer of heat to and from the ~
fin, and thus the semiconductor chip, is made most efficient. It ;
is apparent that the fin ~ust be spaced a suFfic;ent distance to prevent interference of the flow of the fluid under consideration ~*tween the fins, which interference would lower the heat transfer between the fins and the fluid. As a modiFied form of the inven-tion, it has been found that the fins could be fabricated of approxl-mately a conical or disc shape with the apex of each disc electri-rally connected to the opposite sides o~ the semiconductor chip.
With both fins attached to a support structure, a ~ery stiff . ~ :
mechanical structure is obtainable. ~
: :~
Electrical connection to the fin or plural fins ~aybe accomplished by providing electrically conducting supports for -the fin or for the conductors in nonconducting supports. The atlacl,l"~nt of ~he leads to the outer peripher maybe made by any suitdble method siJch as soldering, weldin~, conductive adhesives, or hy simple ~lechanical contact. An alternate lead and support approach may be to prbvide integral support ar~s on the basic fin stamping which maybe bent to a suitable shape to provide support and cnrlYerlient electrical connection to the temperature sensing body.
As is readl'ly apparent, the fln or plura'lity of fins maybe formed by die stampin~ methods and suitable radial or clrcumferential ridges maybe provlded in the fins to enhance structural ridig~ty. These fins may additlonally perform the functlon of promoting boundary layer turbulence for better h~at transfer between the fluid under considerat~on and the fin and may also be utilized to provide a protective trough for lead wires and insulation.
In a second em~odiment of th~ venti~n l;he f in ls formed of a do~ed-shaped e'lement wh1~h ~s sealingly ~itted to a multiple plastic member and the semiconductor chip ~s mounted on the inside apex o~ the dome whereby the semiconductor chip and any conductors leading to the chip or the domed fin will be fully enclosed by the domed fin and the plastic molded member. In this way the connections and the semiconductor chip are fully protected from contaminants and mechanical injury due to foreign particles striking either the leads or the semiconductor chip. As will~be :
noted from a further description of the device~ a foamed material may ~e provided within the confined volume of the dome to further protect the semiconductor chip and leads connected therewithO
Accordingly, it is one object of the present invention to provide an improved fluid temperature sensing device.
It is another object of the present invention to provide ~-improved ~emperature sensing device for a fluid having extremely fast dynamic and steady state performance.
It is a further object of the present invention to pro-vide an lmproved fluid temperature sensing device havin~ a high surface area ~o mass ratio to enhance the transfer of heat from a heat transfer deYice to the actual temperature sensin~ element.
It is another obiect of the present invention to provlde an improved fluid temperature sensing device ~hich responds faster than previous known temperature sensing devices by an order of magnitude. -It is still another object of the present invention to provide an improved mountiny assembly for a temperature sensing device wh1ch enhances the response time and steady stata perfor-mance of the temperature sensor assembly.
It is a further object of the present invention to pro- ;
vide improved lead connection techniques for temperature sensing assemblies incorporating assembly conductor chips for the sensin element.
.,~.
: :
-8a- :
' ,,., .. ~... . .. .. ..
l~ is still another object oF the present invention to provide an improved temperature sensing assembly util~zing a semiconductor chip which anhances the transfer of heat from the fluid whose tempera~ure is being considered to the semicon-ductor chip.
It is another object of ~he present inventlan to pro-vide an impro~ed fluld temperature senslng assembly whlch is inexpensive to manufacture, rel~able in operation and easily installed.
Further objects, features and advantages of the present invention will become more readily apparent upon a cons1deration of the following specification when taken in conjunctlDn with the attached drawings, in which:
BRIEF DESCRI~TION OF THE DRAWlNGS
Figure l is a sido view of a preferred form of the fas-t response air temperature sensor incorporating certain features of the present inventiorl;
Figure 2 is a top view of the a~r temperatur0 sensor of Figure 1 and par~içularly illustrating the positioning of the semiconductor chip and the interconnections between ~he output leads and the semiconductor chip and fin;
Figure 3 is a cross-sectional view of the air tempera-ture sensor of Figure 2 taken along lina 3-3 thereof;
Figure 4 is a cross-sectlonal view of the lnterconnec~ion between the output conductor and the semiconduct~r chip of Figure 2 taken along line 4-4 thereof;
Figure 5 is a top view of a modified form o~ ~he fast response temperature sensor of Flgure l;
Figure 6 is a partial cross-sectional view of the modified air temperature sensor of Figure 5 taken along llne 6-6 thereof and particularly ~llustratlng a modlfied positlon for the semiconductor chip and the ~nterconnection w1th the output conductor;
Figure 7 is a cross-secti¢nal view similar to Figure
SUI~MARY OF THE INVENTlON
It has been found that the dynamic perfor~ance of a sem;conductor type temperature sensor can be max;mized if the rnass of the semiconductor chlp utilized in conjunction with sensors of this type is minimized and is bonded to a metallic fin ha~ing a large area relative to the mass of the fln and semiconductor chip assembly. In a preferre~ embodiment, ~he connection to one terminal of the serniconductor chip is achieved by conductively bondin~ the chip to the metallic fin and providing a second lead to the edge of the fin by various techniques to be ;
described hereinafter.
. ..
The metallic fin should be arranged so that the ~luid flow of the fluid being sensed is parallel to the fin or in maximum heat transfer therewith. As will be shown, the temperature response ; ~-of a thin. constant thickness ~etallic fin emersed in a fluid is , primarily a function of the surface area to mass ratio of the fin. ` ~`
In accordance with the present invention there is provided a bemperature sensor for sensing the temperature of a fluid ccmprising a base ~ember, fin means formed of a thin disc havqng a high surface area to mass ratio mounted in fixed . .:
relationship to the base m~mber whereby the fluid to be sensed may -flow over the fin means, semicc)nductor means moun-ted c~
the fin means having the characteristics of changing resistance with changes in te~perature, a first output conductor connected to the fin means, a second autput conductor electrically in~
sulated from the fin means and cc~nected to the surfaoe of the chip remote from the surface of the chip in electrical CDntaCt with the fin.
cb/t~9, -3a-Tt11JS, for a given material and independent of the size o~f the fin, the temperature response tlme constant approaches ~ero dS the thickness of the fin approaches zero in a theoretical assembly .
For a practical assembly, the dens1ty and specific heat also affect the time constant and both parameters have been found to maximize the time response ~hen these parameters are mininlized. Additionally, when the silicon chip is adcled to the fin, the heat transfer between the fin and S~licon chip beconles important. The thermal contact material between the fin and chip must be of a high conductivity type, as for example gold. Additionally, the heat tlow from the surrounding areas of the fin relative to the area covered by the semiconductor chip nlUS~ t mdxiflli~ed. Accordinyly, the thermal conductivity of the fin becomes important and any material with high hea~ conductivity (such as alurninum) is desirable.
Irl one embodiment of the invention the fin i:, fdbiic~ed as a eirculdr, thin metallic disc with a semicon-ductor chip mounted centrally of the edges of the disc. Theo-retically, the fin should be fabricated of a tapering cross-sect~on, the thickest portion of the cross-section being in the area wherein the semiconductor chip is mounted, the fin taperin~ to zero thickness at the periphery. In the practical embodiment of the invelltiorl, the fin is supported at the periphery by various means and the semiconductor chip is electrically bonded on the surface of the chip but not in contact therewith.
It has been found tha-t the assembly which supports the fin r;lust be such that heat flow to or from the support is minimized since this heat flow does not necessarily result from the , . ~ . ,;, . :.. : , :
temperature of the fluld under consideratiun and, therefore, the dynamic performance and the steady state temperature of the semiconductor ehip maybe affected. St~ted otherwise, a difference in temperat~re between the chip and the Fluid media represents an error in the output signal and it ls ~his error which sho~ld be minimized for any given instantan~ous period of time. It is the desiratum of this invention to min~mize the transient time to achieve stabjli~y between the temperature of the chip and the te~perature of the fluid under consideration.
As stated above, one possible source af error in this signal results from heat flow to or from ~he fin support.
Therefore, the fin support shollld be located at a point as remote as possible fro~l the semiconductor chip and in the~;
pre~erred embodiment this support is establlshed at the outer edge of the chip. Therefore, this necessity for a ~echanical attachment prevents the outer edge of the chip from being a theoretical ideal zero thickness. It has been found that if the fin is of sufficient size in area, the radial Flow of heat from the inner to outer or outer to inner port~on of the chip ~0 is essentially zero, and thus the heat flow due to the mechanical support of the fin is minimized.
In this embodlment of th~ invent:Lon, the other ~:
terminal, other than the fin terminal, connected to the chip is formed by providing a thin stripe of insulating material from the outer edge of the fin radially inwardly to the semi-conductor chip, up the side of the semiconductor chip and slightly overlapping the top surface thereof. The lead wire, ribbon or cond~cting film is then fabricated to conform to the , surface of the insulating stripe and extended Dn th~ top surface of the chip beyond the lnsulating stri pe . Fi nally 9 a second thln coat of insulating material ls appll e~ ~o the lead to encase the lead from its end adjacent the bare upper surface ~f the semiconductor chip across the fin to the nuter ed~ of the fin.
The insulating material may be any plastic adhesive which satisfies the adheslve requirements of the fin and has an el ectrical resi stance when in place for at least two orders of magnitude greater than the resistance of the semiconductor chip and is tolerant of the temperature and the environmental conditions of the finished temperature sensor. ~ typical material for automotive applications is the cyanoacrylate class of adhesives such as marketed by the Eastman Corporation as adhesive 910THT.
Since the lead wire and adhesive material described above represent additional undesirable mass, the adhesive insulating stripe should be of minimal thickness and $he wire should he of minimal size to minimize the effect of this additional mass on the dynamic and steady state perf~nance of the sensor assembly.
In selecting suitable fin material the following relation-ship is considered to be of significance in lnvestigating the various characteristics of a material for its merit in conjunçtion with use in connection with the present invention. For maximum theoretical performance, the following relationship exists.
Mt = K where K - thermal conductivity, bo) (Sp.Hp.~ ~= density, and SP.HP, = specific heat ~he most desirable material l5 that which has pro~erties maxl-mizin~ the term Mt. ln a practical applicat;on, other prDperties such as cost fabricabil~ty, envirnnmental tolerance and avall-ability may modify the material selection. In a modified form of the invention it has been found that the heat transfer from the fin to the chip maybe maximized and the apparent mass oF the ;;
assembly minimi~ed by contacting both sides of the chip with an individual fin. Thus, each fin becomes one of the electrical connections to the chip and the transfer of heat to and from the ~
fin, and thus the semiconductor chip, is made most efficient. It ;
is apparent that the fin ~ust be spaced a suFfic;ent distance to prevent interference of the flow of the fluid under consideration ~*tween the fins, which interference would lower the heat transfer between the fins and the fluid. As a modiFied form of the inven-tion, it has been found that the fins could be fabricated of approxl-mately a conical or disc shape with the apex of each disc electri-rally connected to the opposite sides o~ the semiconductor chip.
With both fins attached to a support structure, a ~ery stiff . ~ :
mechanical structure is obtainable. ~
: :~
Electrical connection to the fin or plural fins ~aybe accomplished by providing electrically conducting supports for -the fin or for the conductors in nonconducting supports. The atlacl,l"~nt of ~he leads to the outer peripher maybe made by any suitdble method siJch as soldering, weldin~, conductive adhesives, or hy simple ~lechanical contact. An alternate lead and support approach may be to prbvide integral support ar~s on the basic fin stamping which maybe bent to a suitable shape to provide support and cnrlYerlient electrical connection to the temperature sensing body.
As is readl'ly apparent, the fln or plura'lity of fins maybe formed by die stampin~ methods and suitable radial or clrcumferential ridges maybe provlded in the fins to enhance structural ridig~ty. These fins may additlonally perform the functlon of promoting boundary layer turbulence for better h~at transfer between the fluid under considerat~on and the fin and may also be utilized to provide a protective trough for lead wires and insulation.
In a second em~odiment of th~ venti~n l;he f in ls formed of a do~ed-shaped e'lement wh1~h ~s sealingly ~itted to a multiple plastic member and the semiconductor chip ~s mounted on the inside apex o~ the dome whereby the semiconductor chip and any conductors leading to the chip or the domed fin will be fully enclosed by the domed fin and the plastic molded member. In this way the connections and the semiconductor chip are fully protected from contaminants and mechanical injury due to foreign particles striking either the leads or the semiconductor chip. As will~be :
noted from a further description of the device~ a foamed material may ~e provided within the confined volume of the dome to further protect the semiconductor chip and leads connected therewithO
Accordingly, it is one object of the present invention to provide an improved fluid temperature sensing device.
It is another object of the present invention to provide ~-improved ~emperature sensing device for a fluid having extremely fast dynamic and steady state performance.
It is a further object of the present invention to pro-vide an lmproved fluid temperature sensing device havin~ a high surface area ~o mass ratio to enhance the transfer of heat from a heat transfer deYice to the actual temperature sensin~ element.
It is another obiect of the present invention to provlde an improved fluid temperature sensing device ~hich responds faster than previous known temperature sensing devices by an order of magnitude. -It is still another object of the present invention to provide an improved mountiny assembly for a temperature sensing device wh1ch enhances the response time and steady stata perfor-mance of the temperature sensor assembly.
It is a further object of the present invention to pro- ;
vide improved lead connection techniques for temperature sensing assemblies incorporating assembly conductor chips for the sensin element.
.,~.
: :
-8a- :
' ,,., .. ~... . .. .. ..
l~ is still another object oF the present invention to provide an improved temperature sensing assembly util~zing a semiconductor chip which anhances the transfer of heat from the fluid whose tempera~ure is being considered to the semicon-ductor chip.
It is another object of ~he present inventlan to pro-vide an impro~ed fluld temperature senslng assembly whlch is inexpensive to manufacture, rel~able in operation and easily installed.
Further objects, features and advantages of the present invention will become more readily apparent upon a cons1deration of the following specification when taken in conjunctlDn with the attached drawings, in which:
BRIEF DESCRI~TION OF THE DRAWlNGS
Figure l is a sido view of a preferred form of the fas-t response air temperature sensor incorporating certain features of the present inventiorl;
Figure 2 is a top view of the a~r temperatur0 sensor of Figure 1 and par~içularly illustrating the positioning of the semiconductor chip and the interconnections between ~he output leads and the semiconductor chip and fin;
Figure 3 is a cross-sectional view of the air tempera-ture sensor of Figure 2 taken along lina 3-3 thereof;
Figure 4 is a cross-sectlonal view of the lnterconnec~ion between the output conductor and the semiconduct~r chip of Figure 2 taken along line 4-4 thereof;
Figure 5 is a top view of a modified form o~ ~he fast response temperature sensor of Flgure l;
Figure 6 is a partial cross-sectional view of the modified air temperature sensor of Figure 5 taken along llne 6-6 thereof and particularly ~llustratlng a modlfied positlon for the semiconductor chip and the ~nterconnection w1th the output conductor;
Figure 7 is a cross-secti¢nal view similar to Figure
4 and particularly illustrating th~ intarconnection ~etween the output conductor and the fin, the cross-sectional view taken along line 7-7 of Figure 5;
Figure 8 is a top v1ew of another mod~f1ed form of the fast response air temperature sensor of the present inven-tion, partially broken away; ~ -Figure 9 is a cross-sectional view of the modifled :~
air temperature sensor of Figure 8 taken along line 9-9 thereof;
Figure 10 is another cross-sect~onal view of the modified air temperature sensor of Figure 8 taken along line lO-lO thereof;
Figure 1l is a further modified air temperature sensor utilizing certain other features of the present invention, th1s figure being shown partially in section to illustrate the inter-connection between the dual fins and the support members;
Figure 12 is a cross-sectional view of a further :
modification of the ai~ temperat~re sensor of the present :
invention and particularly illustrating another type of inter-connection between the output conductors and the ~in and semi-conductor chip;
Figure 13 is a cross-sectional view of another modified form of the present invention and partieularly Illustrating a modification of the interconnections between the output conductors and the fin and semiconductor chipi 7'~
Figure 14 is a bottom view of the semiconductor chip, thin and interconnection assembly of Figure 13 taken along l~ne 14-14 thereof;
Figure 15 is an illustration of a further mod~flcation of a method for providiny connections from the output conductor to the semiconductor chip;
Figure 16 is a perspective view oF a modified form of semicond~ctor chip in which the output terminals for the semi-conductor chip are provided on a single face thereof;
Figure 17 is a plan view, partially broken aw~y, of a method of mounting the semiconductor chip ~f Figure 16 on a fin and particularly illustrating the connections between the :~
semiconductor chip and the fin and output conductor; and Figure 18 is a modified form of the invention wherein the temperature responsive element is attached by thick or thin filnl techniques.
Figure l9is a perspective view of a preferred form of fast response fluid temperature sensor incorporating the features : of the present invention; :-Figure 20is a cross-sectional view of the improved fluid temperature sensor of Figurel9 taken along line 2-2 thereof and particularly illustrating the interconnections between the external ~-conductors and the semiconductor chip and domed fin; ~;~
Fiyure 21is a cross-sectional view of a mod~fied form of the improved fluid tenlperature sensor of Figure 19and particu~
larly illustrating a modifica~ion of the manner in which the con-ductors are led through a molded plast~c memher;
Figure 22is a cross sectional view of a further modifiecl form of the temperature sensor of the present invention and illus-trating an alternative method of interconnecting the external con-ductors to the semiconductor chip and the doomed fin; and Figure 23is a cross-sectional view of a further modified form of the temperature sensor illustrating applying the temperature responsive element with thick film techniques.
D_TAlLED DESCRIPTION ~F THE I VENTI~N
Referring now to the drawings, and part1cular~y Figure l thereof, there is illustrated a side view of a preferred form of temperature sensor 20 incorporating the features of the present invention. The sensor 20 includes three portions, a c~nnectDr ; .
22, the sensor assembly 24 and a pair of interconnecting wires 26 -~
which provlde a connection between the sensor ~4 and the connector `
22. The connector 22 is of the tYpe typically utili~ed in the automotive industry which includes a housing 28, within which are formed the plug and socket members utilized to mate with the corresponding socket and plug members, respectively, in the wiring harness of the automobile. Suitable interlocking means 30 is provided to lock the houslna 28 to the corresponding member in the wiring harness to preclude the two members from being uninten-tionally disassembled.
7~
The temperature sensor assembly includes a brass or other suitable metal f~ttin~ 34 which is adapted to be threaded into an aperture in the intake manifold of an automobile and suitably tightened by means of a hexagonal head port~on 36 as is common in the automotive art~ The temperature sensor assembly 24 further includes a molded element 38 which ~s adapted to mount a fin 40 at one end thereof and r~gidly fix the fin 40 relative to the brass f~tting 34 as we will fully explain hereinafter. The conductors 26 are molded within the interior of the plast~c element 3B and, as will be seen herein-after, the conductors are led up through the center of a pair of mounting arms 42, 44. The entire assembly including arms 42, 44 and the fin 40 are protected by a wire cage 46 which lnclude a pair of formed domed wires which are welded at their apex and the opposite ends thereof are inserted 1nto apertures fcrlned in the brass fitting 34 and soldered into place. ~hus, the tempera-ture sensing fin 40, and the semiconductor chip to be described hereinafter, are protected from foreign elements which may be injurious to the fin and semiconductor chip shuuld these latter elements be struck by the foreign elements.
Referring now to Figure 2, wh~ch is a top view of the temperature sensor assembly 24 of Figure 1, there is illustrated the particular referred method of mounting the semiconductor chip on the fin 40 and also the method in which the connect~ons are made to the conductors 26 froln the fin 40 and a semiconductor chip4~. 5pecifically, the fin 40 has mounted thereon a nonconductin~
ceramic chip S0 by any suitable method described above, for example by conductive adhesive, etc. As is seen from Fi~ure 2, the chip 50 is mounted a sli~ht distance away from the mountinq arm 44 to ~13-7'7~
permit a conductor 52 cenkered in the mountlng arm 44 to be 'led up through an aperture formed in the fin 40. The conductor 52 is then lapped over the top of the fin 40 and attached to the non-conducting chip 50 as will be more fully explained in coniunction with the description of Figure 4 a conductor 539 in the form of a gold wire~ connects the conductor 52 w~th the semiconductor chip 48. Similarly, a conductor 54 which i5 molded into the center of mounting arm 42 is led up through a second aperture for~ed ~n the fin 40 and folded over into engagement with the top surface of the fin 40. The conductor 54 is then suitably attached to fin 40 by soldering or conductive adhesives.
Flgure 3 illustrates various features of the assembly nnt illustrated in great detall in Figur~s 1 and 2. For example, the conductors 26 are molded within the member 38 and suitable connectors 58, 60 are provided to connect the interconductors of conductors 26 to the conductors 52, 54. As is seen from Figure 3, the conductors 54 are molded within the mountlng arms 44, 42 respectively and folded over at the tops thereof to form the , connections described in con,iunction with Figure 2, The material forming support elements 42, 44 is of the thermal plastic type whereby heat is applied to the upper ends of the members 42, 44 and the upper ends are melted over to form a firm at~achment to the fin 40. As is seen from the left end of the drawing, the bottom of brass fastener 24 is swaged over at 62 to firmly hold the molded member 38 within the brass element 36.
Referring to Figure 4, there is illustrated one me$had of interconnecting the conductor 52 with the semiconductor chip 48. Also illustrated is the heated portion of the upper end of mounting arm 44 whicn is melted to form the attachment between arm 44 and the ~in 40.
As is seen froln Figure 4/ the conductor 52 ls led through an aperture 64 formed in the fin 40 and fo'lded over to f'orm a loop and a flat portion 66, flat portion being cont~guous ~ith the upper surface of the chip 60. The portion 66 is then s~ita~ly attached to the nonconducting chip 50 by any suitable method, as for example, by using a conductive adhesive forming a mechanical bond and electrical contact between conductor 66 and chip 50. As will be seen from the description of Figures 12 to 17, other methods of attaching the conductors may be utilized or keeping within the spirit of the invention.
Referring now to Figure 5, there is illustrated a modified form of the air temperature sensor of the Present invention which includes substantially the same base element described above bearing reference numerals 34 and 36 and the same protective cage wires 46. The modified form as best illustrated ~n Figure 6,' :', includes a plastic element 70, into which is molded into the conductors 26, the connectc~rs 58, 60 and a pair of conductors 72, 7~. The conductors 74 is led up through a mounting arm 76 integrally for~ed as a part of the plastic member 70 and folded over for attachment to a fin element 78 as will be more fully described in conjunction with the descriptlon of Figure 7. : ,;
As is seen from Figure 6, the fin 78 is formed with a dished portion 80 into which is placed a semiconductor chip 82.
lhe semiconductor chip 82 is suitably electrically ccn~ected to, the conductor 72 by any suitable method as for example that describing in conjunction with Figure 4 and to be described in conjunction with Figures 12-15. The dished portion 80 of the fin 78 pro~ides -~' protection for the chip 82 and enhances the uniform heating of the chip 82 by the fin member 78.
r~ f Referring to Figure 7, it is seen that an aperture 86 is formed in the fin 78, ~hrQugh which is passed a thin upper portion of the mountin~ arm 76 and the conductor 74. The f1n 76 is heated ~nd melted to form a head ~o securely fasten the ~in 78 to the mounting arm 76. The conductor 74 i~s fDlded oVcr to be placed in close contact with tha fin 78 and is considerably attached thereto, for example by soldering or through the use of adhesives.
Referring now to Figure 8, there is illustrated another modified form of the assembly of the present invention. Partlcu- :
larly, a base element 86 is provlded which maybe similar to that described in conjunetion with the description of base element 24.
~lithin the base element is mounted a plastlc support member 8~
which is molded with a base member 90 and a plurality of pairs of arms 92 including an outer arm 94 and an inner arm 96. As is best seen in Figure 8, the pairs of support arms 94, 96 are adapted to rigidly support a generally square fin ele~ent 981 there bein~
four pairs of arms 92, 10~, 102 and 10~.
As is best seen in Fiyures 9 and 10, there is molded ?0 between the inner and outer arms of each pair of arms 92, 102 a generally U-shaped conducti~e element 106, the conductive element being formed with a cross rnember 108 and a pair of arms 110, 112.
It will be noted from Figure 9 that the arms llQ, 112 are generally tapered from the cross member 1~8 to the ~uter end of the arms 110, 112. It is to be noted that the U-shaped member 106 is only provided between pairs of support arms 92 and 102. Prior to attaching the disc 98, an aperture 114 is drilled into the assembly to separate the arm or the conductive member 112 from the conductive member llO for purpose to be seen from a further 3U explanation of the assembly.
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s7~7Q~
The molded base member 90 h~s embedded therein a pair of conductors 120, 122 whlch are electr~cally connected to the conductive arms 110. 112 respectively by any suitable means, as for example by solderin~. After assembly of the disc 98 into place, the ends 124, 126 are heated and folded o~er to form a rigid attachment of the disc 98 between ~he arms 94, g63 ~he pair of arms 102 is illustrated ln Figure 9, and also between the pairs of arms 100 and pairs of arms lD4 as seen in Figure 8. As best seen in Figures 8 and 9J the disc 98 is provided with a centrally located semiconductor chip 130 mounted ;
on the bottom thereof, with a suitable conductor 132 interconnect- ~ r ing the semiconductor chip 130 with the cond~ctive element 112.
This connection to the semiconductor chip 130 could be by any suitable means as for example that illustrated in Figure 4, 12, 13, 14, and 15. 0-F course, suitable insulating material must be provided between the conductor 132 and the disc 98 to ensure that i ~;
the conductor 132 is insulated from the disc 98. The disc 98 is 1:
caused to overlap the upper end of the conductive arm 110 to 1~
ensure an electrical connection to the conductlve arm 110. Thus, ¦~ ;
the electrical circuit illustrated in Figure ~ is from conductor 120, through conductor 110. through disc 98, chip 130, conduct;or 132, conductor 112, to conductor 122.
Figure 10 illustrates a method of connecting the disc 98 to the conductive member 110 whereby the conductive member 110 is provided with a 90-degree bend at the end thereof to be placed in electrical contact with the disc 98. As described above, the upper end of arm 94 is heated and folded over at end 136 to ensure a tight connection between the conductive member 110 and the disc I ~
98. i :
Referrin~ now to Figure 11, it is Illustrated a further modification of the fast response ~r temperatur~
sensor of the present in~ention. ln this modlfied verslon, a pair of fins 140, 142 are provided, the fins 140, 142 being generally dished shaped with the apex of each dish faclng the other apex of the other dish. Sandwiched between the two fins 140, 142 is a semiconductor chip 144 similar to that described I ;
in coniunction with the prevlous flgures. As ~as ~he case previously, the discs 140, 142 are suitAbly fastened to a thermal plastic member 146, the thermal plastlc member 146 having a pair of arms 14~, 150 into which are molded a pa~r of con- ', ductors 152, 154. As is seen from Figure 11~ the conductor 152 is folded over and suitably soldered to the upper face of fin 142 and conductor 154 exits from the support arm 150 short of the end thereof and is directed toward the f;n 140 and suitably soldered thereto. The upper ends of arms 148, 160 are heated and folded over to provide a rigid attachment for the upper fin 142. While only two arms 1489 150 have been shown, it is to be understood that molded Plement 146 maybe provlded with four arms of an identical configuration two arms 148, 150 with the exception that no conductors will be molded wlthin two of the arms. As was described in the earlv part of the specification, the confinuration of Fi~ure 11 provides a slrnple method of electrically connectiny f~ns 1-~0, 142 to the semiconductor chip 144. Also, the confi~uration of figure 11 does not require the delicate attachment of a conductive lead to the semiconductor chip as was prevlously described.
Fiyures 12-15 illustrate various other methods of attdching leads to the serniconductor chip, particularly Figure 12 illustrates the attachment of a fine gold ~ire 160 from a 1, I
conductor 162 molded in a support member 164. the wire being attached at the other end thereof to a semiconductor chip 166, The chip 166 is attached ~o a fin member 168 as was described above. The electrical connection between the fin 168 and a second conductor 170 ls pro~lded by folding over the end of conductor 170 and positioning it in face-to-face relation with the fin 168.
Figure 13 is a similar conf~guration to that described in conjunction wlth Fi9ure 12 with respect to the mountin~ of the fin 168 and its interconnection with the conductor 170. However, a conductor 172 is provided which is molded into the other arm of support element l64 and folded over at the end thereof to prov~de an open face for electrical attachment to another conductor. Again, the chip 166 is provided hut is connected to the conductor 172 .
through a conductor 176. ~he conductor 176 is insulated from the .
fin 168 by means of insulatin~ material 178 sandwlched between the ~ ;
fin 168 and the conductor 176. A bridge is provided between the conductor 176 and the chip 166 by means of a flap conductor 180 a~
is best illustrated in Figure 14.
Figure 15 illustrates a rather slmple connection between a chip 182 and a conductor 184. Taking for example an attachment .
to the disc 168, a suitable layer of insulatin~ material 186 is provided and the conductor 184 is attached to the insulating material lB6. The conductor 186 could be the conductor illustrated as conductor 172 in Fi~ure 13. The insulating ma~erial 186 could be built up tQ the level of the lower face of chip 132 and the conductor 184 would merely pass across the insulatin~ material 186 and the chip 182 in a straight line rather than the loop illustrated in Figure 15.
1, Figure 16 and 1~ illustrate a modifled form of semi-conductor chip wherein the chip is provlded with both output terminals on a single -Face thereof. For exanlple, a chip 188 may have a pair of terminal pro~jections 190, 192 formed thereon, which projections are utili~ed -to form the terminals for con-nection to the disc and external conductor associated with the chip. Figure 17 ill IIS trates this particular connection wherein a disc 194 is provided with a strip of insulating material 196 and a conductor 198. lhe chip 1~8 is then positioned as shown wherein the projection 192 is an electrical contact with the fin 194 and the projection 190 is in contact with the strip conductor 198. The strip conductor can then be connecte~ to the chip associated support arms illustrated in Figures 3, 9 or 11.
~igure 18 illustra~es the invention as applied by thick film techniques. While thick film application is described, it is to be understood that thin filnl techniques apply equally as well.
Referring to the drawin~, the fin 40 forms the substrate on ~hich the various layers are deposited by the screening process. In carrying out the process, an insulating strip 200 is deposited on the fin 40 with an aperture 202 formed in the strip 200 hy either blocking the area of the aperture 202 with an emulsion or by etching the ared of the aperture from the strip 200. A semiconductor portion 204 is then deposited in the aperture 202 in contact with the fin 40.
Finall~y a strip conductor 2~6 is deposited on the portion 204 and on strip 200, and within the confines thereof, to form the conductive strip corresponding to strip 19~ in Figure 17, or conductor 53 in Figure 2. In the thin film counterpart~ the various layers are sputtered or evaporated with the necessary masking or etching to fornl the desired shapes.
$ ~
A preferred form of the above described temperature sensor included a brass disc having a thickness of between 3 and 4 mils and a diameter of approximately 7/16 inch, and the response time of the sensor is approximately one second for one hundred declrees change in temp~rature. The above dimensions provide a f'in which is sufficiently stiff while maintaining the high surface area to mass ratio required to give the desired fast response time.
Referring to Figurel9, there is illustrated a fluid temperature sensor 208 which is extremely fa~t and highly stable in its response which includes a bdse member 210,a sensing assembly 212,a protective cage 214for the sensing assembly 212,and a pair of external conductors 216~lhictl are utilized to inlerconnect the dome and semiconductor chip i;o external circuitry. The base element 210 includes a threaded portion218 which Is adapted to be threaded, for examp1e, into the air intake of an ~nternal combustion engine or other device through which fl~id is flowiny and the temperature of that fluid is to be sensed. As is common in devices of this type, the bas~ member210incllldes a h~xa(1onal portion220which is u~ilized to tighten the sensor into position.
The sensing assembly 212includes a domed fill224which~
as can be seen from Figure 20,is utili~ed to conduct heat to and away from a semiconductor chip while protecting the chip, and associated connecting conductors, from contaminants and other foreign material The dome memDer 224,which is extremely thin to reduce its mdss-to-area ratio as e~plained in the aforementioned applications, is protected by means of the cage214which includes a pair of U-shaped wires 226,228positioned at 90, one relative to the other, and inserted into apertures formed in the ~ase member 210and suitably attached therein~
Referring now to Figure 20,there is also illustrated a cross-section of the air temperature sensor of Figure 19 to illustrate the interior portion of the temperature sensing el~nent 212. As is seen from this drawing, the external conductor 216, which include a pair of conductive members230,232 are molded in a plastic member234, which plastic member is rigldly seated within the base member 210. In order to ensure that the molded member 234 is rigidly positioned within the base member210, a lip 236 is swaged over the bottom of the molded element234 to securely position the molded member234 within the cavity formed by th~ base member 210.
The conductor 230is, in the embodiment shown in Figure 20, turned at 90 at portion 238and mechanically contacts the ;nner surface of the domed member 224to effect an electrical connection between the conductor230and the fin 224. On the other hand, conduc-tor 232is led straight through the molded member234 to a position above the top of the molded member 234but within the confines of the fin224. A connection ls made between the top of conductor 232 and a semiconductor chip240 by means of a fine gold wire242 ha~lng a diàmeter of approximately .002 ;nches.
Thus~ as is seen from Figure 20,the chip 240, gold wir~
242, andthe interior pnrtion of the domed fin224 are protected from any contaminants or foreign material which may flow past the domed fin224. As stated above, the interior of the domed fin 224 may be provided with foamed material to further mechanically protect the semiconductor chip240 and the gold wire 242.
Referring now to Figure 21,there is illustrated a modified form of connections whereby the conductors230, 232 are embedded in a modif~ed molded plastic member 246. The plastlc member 246~s modified by providing cutaway portions at surfaces 248an~ 250 to provide access to the top Df conductors 230, 232 which are now positioned outside of the confines of a domed fin 252.
The connections between the conductor230and the Fln 252 is provided by a gold wire 254having a diameter of approxlmately .002 inches, the gold wire being suitably fastened to the domed fin 252. As was the case with ~igure 20,a semiconductor chip 258 is mounted within the fin 252 and at the apex thereof, and the con-ductor232is interconnected therewith by a second gold wire 260.
The bonding of the semiconductor258 to the domed fin2s2 may be by ;~
any suitable methods, as for example, by gold bonding techniques.
The domed fin 252is press-fitted onto the upper end of the plastic molded member 246and fixed thereto.
Referring now to Figllre 22,there is illustrated a further modification of the invention disclo,ure wherein the dorned element 252is again provided with a semiconductor chip 258. However, a molded member264 is shown as being modified from that previously described except that the domed fin 252is again press-fitted onto the plastic molded memben264 and suitably attached thereto. In the case of Figure 22,the conductor230is provided at its upper end thereof with a flexible whisker-type lead 266which is in wiping contact with the domed fin 252thereby providinq electrical connec-tion thereto. On the other hand, the conductor 232is provided with a slightly longer flexible whisker-type lead 268which is in wiping contact with the semiconductor chip 258.
Figure ~3illustrates the invention as applied by thick film techniques, although lt is to be understood thin film techniques apply equally as well. Referring to Figure 23, fin2s2forms the substrate on which the various layers are deposited by the screening process. In carrying out the process, an insulating strip 270j 5 deposited on the fin 252with an aperture 272formed in the strip270 by either blocking the area of the aperture 272with an emulsion or by etching the area of the aperture from the strip. A semiconductor portion274 is then deposited in the aperture272in contact with the fin252. Finally a strip conductor276is de,uosited on the semiconductor274and on strip 270, maintaining the conductor 276, within the confines ~ -thereof, to form the conductive strip corresponding to the conductor 242 or 260. III the thin film counterpart, the various layers are sputtered or evaporated with the masking or etching desired to form the stIapes needed.
Having described a preferred embodiment of the inven~
- tion and several modi1~ications thereof, it will be understood that the examples given are employed in a descriptive sense only ;~
and not for purposes of limitation. Other embodiment and vari-ations will be obvious to those skilled in the art and be Inade without deploying from the spirit and scope of my invention which is li~ited only by the appended claims.
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Figure 8 is a top v1ew of another mod~f1ed form of the fast response air temperature sensor of the present inven-tion, partially broken away; ~ -Figure 9 is a cross-sectional view of the modifled :~
air temperature sensor of Figure 8 taken along line 9-9 thereof;
Figure 10 is another cross-sect~onal view of the modified air temperature sensor of Figure 8 taken along line lO-lO thereof;
Figure 1l is a further modified air temperature sensor utilizing certain other features of the present invention, th1s figure being shown partially in section to illustrate the inter-connection between the dual fins and the support members;
Figure 12 is a cross-sectional view of a further :
modification of the ai~ temperat~re sensor of the present :
invention and particularly illustrating another type of inter-connection between the output conductors and the ~in and semi-conductor chip;
Figure 13 is a cross-sectional view of another modified form of the present invention and partieularly Illustrating a modification of the interconnections between the output conductors and the fin and semiconductor chipi 7'~
Figure 14 is a bottom view of the semiconductor chip, thin and interconnection assembly of Figure 13 taken along l~ne 14-14 thereof;
Figure 15 is an illustration of a further mod~flcation of a method for providiny connections from the output conductor to the semiconductor chip;
Figure 16 is a perspective view oF a modified form of semicond~ctor chip in which the output terminals for the semi-conductor chip are provided on a single face thereof;
Figure 17 is a plan view, partially broken aw~y, of a method of mounting the semiconductor chip ~f Figure 16 on a fin and particularly illustrating the connections between the :~
semiconductor chip and the fin and output conductor; and Figure 18 is a modified form of the invention wherein the temperature responsive element is attached by thick or thin filnl techniques.
Figure l9is a perspective view of a preferred form of fast response fluid temperature sensor incorporating the features : of the present invention; :-Figure 20is a cross-sectional view of the improved fluid temperature sensor of Figurel9 taken along line 2-2 thereof and particularly illustrating the interconnections between the external ~-conductors and the semiconductor chip and domed fin; ~;~
Fiyure 21is a cross-sectional view of a mod~fied form of the improved fluid tenlperature sensor of Figure 19and particu~
larly illustrating a modifica~ion of the manner in which the con-ductors are led through a molded plast~c memher;
Figure 22is a cross sectional view of a further modifiecl form of the temperature sensor of the present invention and illus-trating an alternative method of interconnecting the external con-ductors to the semiconductor chip and the doomed fin; and Figure 23is a cross-sectional view of a further modified form of the temperature sensor illustrating applying the temperature responsive element with thick film techniques.
D_TAlLED DESCRIPTION ~F THE I VENTI~N
Referring now to the drawings, and part1cular~y Figure l thereof, there is illustrated a side view of a preferred form of temperature sensor 20 incorporating the features of the present invention. The sensor 20 includes three portions, a c~nnectDr ; .
22, the sensor assembly 24 and a pair of interconnecting wires 26 -~
which provlde a connection between the sensor ~4 and the connector `
22. The connector 22 is of the tYpe typically utili~ed in the automotive industry which includes a housing 28, within which are formed the plug and socket members utilized to mate with the corresponding socket and plug members, respectively, in the wiring harness of the automobile. Suitable interlocking means 30 is provided to lock the houslna 28 to the corresponding member in the wiring harness to preclude the two members from being uninten-tionally disassembled.
7~
The temperature sensor assembly includes a brass or other suitable metal f~ttin~ 34 which is adapted to be threaded into an aperture in the intake manifold of an automobile and suitably tightened by means of a hexagonal head port~on 36 as is common in the automotive art~ The temperature sensor assembly 24 further includes a molded element 38 which ~s adapted to mount a fin 40 at one end thereof and r~gidly fix the fin 40 relative to the brass f~tting 34 as we will fully explain hereinafter. The conductors 26 are molded within the interior of the plast~c element 3B and, as will be seen herein-after, the conductors are led up through the center of a pair of mounting arms 42, 44. The entire assembly including arms 42, 44 and the fin 40 are protected by a wire cage 46 which lnclude a pair of formed domed wires which are welded at their apex and the opposite ends thereof are inserted 1nto apertures fcrlned in the brass fitting 34 and soldered into place. ~hus, the tempera-ture sensing fin 40, and the semiconductor chip to be described hereinafter, are protected from foreign elements which may be injurious to the fin and semiconductor chip shuuld these latter elements be struck by the foreign elements.
Referring now to Figure 2, wh~ch is a top view of the temperature sensor assembly 24 of Figure 1, there is illustrated the particular referred method of mounting the semiconductor chip on the fin 40 and also the method in which the connect~ons are made to the conductors 26 froln the fin 40 and a semiconductor chip4~. 5pecifically, the fin 40 has mounted thereon a nonconductin~
ceramic chip S0 by any suitable method described above, for example by conductive adhesive, etc. As is seen from Fi~ure 2, the chip 50 is mounted a sli~ht distance away from the mountinq arm 44 to ~13-7'7~
permit a conductor 52 cenkered in the mountlng arm 44 to be 'led up through an aperture formed in the fin 40. The conductor 52 is then lapped over the top of the fin 40 and attached to the non-conducting chip 50 as will be more fully explained in coniunction with the description of Figure 4 a conductor 539 in the form of a gold wire~ connects the conductor 52 w~th the semiconductor chip 48. Similarly, a conductor 54 which i5 molded into the center of mounting arm 42 is led up through a second aperture for~ed ~n the fin 40 and folded over into engagement with the top surface of the fin 40. The conductor 54 is then suitably attached to fin 40 by soldering or conductive adhesives.
Flgure 3 illustrates various features of the assembly nnt illustrated in great detall in Figur~s 1 and 2. For example, the conductors 26 are molded within the member 38 and suitable connectors 58, 60 are provided to connect the interconductors of conductors 26 to the conductors 52, 54. As is seen from Figure 3, the conductors 54 are molded within the mountlng arms 44, 42 respectively and folded over at the tops thereof to form the , connections described in con,iunction with Figure 2, The material forming support elements 42, 44 is of the thermal plastic type whereby heat is applied to the upper ends of the members 42, 44 and the upper ends are melted over to form a firm at~achment to the fin 40. As is seen from the left end of the drawing, the bottom of brass fastener 24 is swaged over at 62 to firmly hold the molded member 38 within the brass element 36.
Referring to Figure 4, there is illustrated one me$had of interconnecting the conductor 52 with the semiconductor chip 48. Also illustrated is the heated portion of the upper end of mounting arm 44 whicn is melted to form the attachment between arm 44 and the ~in 40.
As is seen froln Figure 4/ the conductor 52 ls led through an aperture 64 formed in the fin 40 and fo'lded over to f'orm a loop and a flat portion 66, flat portion being cont~guous ~ith the upper surface of the chip 60. The portion 66 is then s~ita~ly attached to the nonconducting chip 50 by any suitable method, as for example, by using a conductive adhesive forming a mechanical bond and electrical contact between conductor 66 and chip 50. As will be seen from the description of Figures 12 to 17, other methods of attaching the conductors may be utilized or keeping within the spirit of the invention.
Referring now to Figure 5, there is illustrated a modified form of the air temperature sensor of the Present invention which includes substantially the same base element described above bearing reference numerals 34 and 36 and the same protective cage wires 46. The modified form as best illustrated ~n Figure 6,' :', includes a plastic element 70, into which is molded into the conductors 26, the connectc~rs 58, 60 and a pair of conductors 72, 7~. The conductors 74 is led up through a mounting arm 76 integrally for~ed as a part of the plastic member 70 and folded over for attachment to a fin element 78 as will be more fully described in conjunction with the descriptlon of Figure 7. : ,;
As is seen from Figure 6, the fin 78 is formed with a dished portion 80 into which is placed a semiconductor chip 82.
lhe semiconductor chip 82 is suitably electrically ccn~ected to, the conductor 72 by any suitable method as for example that describing in conjunction with Figure 4 and to be described in conjunction with Figures 12-15. The dished portion 80 of the fin 78 pro~ides -~' protection for the chip 82 and enhances the uniform heating of the chip 82 by the fin member 78.
r~ f Referring to Figure 7, it is seen that an aperture 86 is formed in the fin 78, ~hrQugh which is passed a thin upper portion of the mountin~ arm 76 and the conductor 74. The f1n 76 is heated ~nd melted to form a head ~o securely fasten the ~in 78 to the mounting arm 76. The conductor 74 i~s fDlded oVcr to be placed in close contact with tha fin 78 and is considerably attached thereto, for example by soldering or through the use of adhesives.
Referring now to Figure 8, there is illustrated another modified form of the assembly of the present invention. Partlcu- :
larly, a base element 86 is provlded which maybe similar to that described in conjunetion with the description of base element 24.
~lithin the base element is mounted a plastlc support member 8~
which is molded with a base member 90 and a plurality of pairs of arms 92 including an outer arm 94 and an inner arm 96. As is best seen in Figure 8, the pairs of support arms 94, 96 are adapted to rigidly support a generally square fin ele~ent 981 there bein~
four pairs of arms 92, 10~, 102 and 10~.
As is best seen in Fiyures 9 and 10, there is molded ?0 between the inner and outer arms of each pair of arms 92, 102 a generally U-shaped conducti~e element 106, the conductive element being formed with a cross rnember 108 and a pair of arms 110, 112.
It will be noted from Figure 9 that the arms llQ, 112 are generally tapered from the cross member 1~8 to the ~uter end of the arms 110, 112. It is to be noted that the U-shaped member 106 is only provided between pairs of support arms 92 and 102. Prior to attaching the disc 98, an aperture 114 is drilled into the assembly to separate the arm or the conductive member 112 from the conductive member llO for purpose to be seen from a further 3U explanation of the assembly.
.
s7~7Q~
The molded base member 90 h~s embedded therein a pair of conductors 120, 122 whlch are electr~cally connected to the conductive arms 110. 112 respectively by any suitable means, as for example by solderin~. After assembly of the disc 98 into place, the ends 124, 126 are heated and folded o~er to form a rigid attachment of the disc 98 between ~he arms 94, g63 ~he pair of arms 102 is illustrated ln Figure 9, and also between the pairs of arms 100 and pairs of arms lD4 as seen in Figure 8. As best seen in Figures 8 and 9J the disc 98 is provided with a centrally located semiconductor chip 130 mounted ;
on the bottom thereof, with a suitable conductor 132 interconnect- ~ r ing the semiconductor chip 130 with the cond~ctive element 112.
This connection to the semiconductor chip 130 could be by any suitable means as for example that illustrated in Figure 4, 12, 13, 14, and 15. 0-F course, suitable insulating material must be provided between the conductor 132 and the disc 98 to ensure that i ~;
the conductor 132 is insulated from the disc 98. The disc 98 is 1:
caused to overlap the upper end of the conductive arm 110 to 1~
ensure an electrical connection to the conductlve arm 110. Thus, ¦~ ;
the electrical circuit illustrated in Figure ~ is from conductor 120, through conductor 110. through disc 98, chip 130, conduct;or 132, conductor 112, to conductor 122.
Figure 10 illustrates a method of connecting the disc 98 to the conductive member 110 whereby the conductive member 110 is provided with a 90-degree bend at the end thereof to be placed in electrical contact with the disc 98. As described above, the upper end of arm 94 is heated and folded over at end 136 to ensure a tight connection between the conductive member 110 and the disc I ~
98. i :
Referrin~ now to Figure 11, it is Illustrated a further modification of the fast response ~r temperatur~
sensor of the present in~ention. ln this modlfied verslon, a pair of fins 140, 142 are provided, the fins 140, 142 being generally dished shaped with the apex of each dish faclng the other apex of the other dish. Sandwiched between the two fins 140, 142 is a semiconductor chip 144 similar to that described I ;
in coniunction with the prevlous flgures. As ~as ~he case previously, the discs 140, 142 are suitAbly fastened to a thermal plastic member 146, the thermal plastlc member 146 having a pair of arms 14~, 150 into which are molded a pa~r of con- ', ductors 152, 154. As is seen from Figure 11~ the conductor 152 is folded over and suitably soldered to the upper face of fin 142 and conductor 154 exits from the support arm 150 short of the end thereof and is directed toward the f;n 140 and suitably soldered thereto. The upper ends of arms 148, 160 are heated and folded over to provide a rigid attachment for the upper fin 142. While only two arms 1489 150 have been shown, it is to be understood that molded Plement 146 maybe provlded with four arms of an identical configuration two arms 148, 150 with the exception that no conductors will be molded wlthin two of the arms. As was described in the earlv part of the specification, the confinuration of Fi~ure 11 provides a slrnple method of electrically connectiny f~ns 1-~0, 142 to the semiconductor chip 144. Also, the confi~uration of figure 11 does not require the delicate attachment of a conductive lead to the semiconductor chip as was prevlously described.
Fiyures 12-15 illustrate various other methods of attdching leads to the serniconductor chip, particularly Figure 12 illustrates the attachment of a fine gold ~ire 160 from a 1, I
conductor 162 molded in a support member 164. the wire being attached at the other end thereof to a semiconductor chip 166, The chip 166 is attached ~o a fin member 168 as was described above. The electrical connection between the fin 168 and a second conductor 170 ls pro~lded by folding over the end of conductor 170 and positioning it in face-to-face relation with the fin 168.
Figure 13 is a similar conf~guration to that described in conjunction wlth Fi9ure 12 with respect to the mountin~ of the fin 168 and its interconnection with the conductor 170. However, a conductor 172 is provided which is molded into the other arm of support element l64 and folded over at the end thereof to prov~de an open face for electrical attachment to another conductor. Again, the chip 166 is provided hut is connected to the conductor 172 .
through a conductor 176. ~he conductor 176 is insulated from the .
fin 168 by means of insulatin~ material 178 sandwlched between the ~ ;
fin 168 and the conductor 176. A bridge is provided between the conductor 176 and the chip 166 by means of a flap conductor 180 a~
is best illustrated in Figure 14.
Figure 15 illustrates a rather slmple connection between a chip 182 and a conductor 184. Taking for example an attachment .
to the disc 168, a suitable layer of insulatin~ material 186 is provided and the conductor 184 is attached to the insulating material lB6. The conductor 186 could be the conductor illustrated as conductor 172 in Fi~ure 13. The insulating ma~erial 186 could be built up tQ the level of the lower face of chip 132 and the conductor 184 would merely pass across the insulatin~ material 186 and the chip 182 in a straight line rather than the loop illustrated in Figure 15.
1, Figure 16 and 1~ illustrate a modifled form of semi-conductor chip wherein the chip is provlded with both output terminals on a single -Face thereof. For exanlple, a chip 188 may have a pair of terminal pro~jections 190, 192 formed thereon, which projections are utili~ed -to form the terminals for con-nection to the disc and external conductor associated with the chip. Figure 17 ill IIS trates this particular connection wherein a disc 194 is provided with a strip of insulating material 196 and a conductor 198. lhe chip 1~8 is then positioned as shown wherein the projection 192 is an electrical contact with the fin 194 and the projection 190 is in contact with the strip conductor 198. The strip conductor can then be connecte~ to the chip associated support arms illustrated in Figures 3, 9 or 11.
~igure 18 illustra~es the invention as applied by thick film techniques. While thick film application is described, it is to be understood that thin filnl techniques apply equally as well.
Referring to the drawin~, the fin 40 forms the substrate on ~hich the various layers are deposited by the screening process. In carrying out the process, an insulating strip 200 is deposited on the fin 40 with an aperture 202 formed in the strip 200 hy either blocking the area of the aperture 202 with an emulsion or by etching the ared of the aperture from the strip 200. A semiconductor portion 204 is then deposited in the aperture 202 in contact with the fin 40.
Finall~y a strip conductor 2~6 is deposited on the portion 204 and on strip 200, and within the confines thereof, to form the conductive strip corresponding to strip 19~ in Figure 17, or conductor 53 in Figure 2. In the thin film counterpart~ the various layers are sputtered or evaporated with the necessary masking or etching to fornl the desired shapes.
$ ~
A preferred form of the above described temperature sensor included a brass disc having a thickness of between 3 and 4 mils and a diameter of approximately 7/16 inch, and the response time of the sensor is approximately one second for one hundred declrees change in temp~rature. The above dimensions provide a f'in which is sufficiently stiff while maintaining the high surface area to mass ratio required to give the desired fast response time.
Referring to Figurel9, there is illustrated a fluid temperature sensor 208 which is extremely fa~t and highly stable in its response which includes a bdse member 210,a sensing assembly 212,a protective cage 214for the sensing assembly 212,and a pair of external conductors 216~lhictl are utilized to inlerconnect the dome and semiconductor chip i;o external circuitry. The base element 210 includes a threaded portion218 which Is adapted to be threaded, for examp1e, into the air intake of an ~nternal combustion engine or other device through which fl~id is flowiny and the temperature of that fluid is to be sensed. As is common in devices of this type, the bas~ member210incllldes a h~xa(1onal portion220which is u~ilized to tighten the sensor into position.
The sensing assembly 212includes a domed fill224which~
as can be seen from Figure 20,is utili~ed to conduct heat to and away from a semiconductor chip while protecting the chip, and associated connecting conductors, from contaminants and other foreign material The dome memDer 224,which is extremely thin to reduce its mdss-to-area ratio as e~plained in the aforementioned applications, is protected by means of the cage214which includes a pair of U-shaped wires 226,228positioned at 90, one relative to the other, and inserted into apertures formed in the ~ase member 210and suitably attached therein~
Referring now to Figure 20,there is also illustrated a cross-section of the air temperature sensor of Figure 19 to illustrate the interior portion of the temperature sensing el~nent 212. As is seen from this drawing, the external conductor 216, which include a pair of conductive members230,232 are molded in a plastic member234, which plastic member is rigldly seated within the base member 210. In order to ensure that the molded member 234 is rigidly positioned within the base member210, a lip 236 is swaged over the bottom of the molded element234 to securely position the molded member234 within the cavity formed by th~ base member 210.
The conductor 230is, in the embodiment shown in Figure 20, turned at 90 at portion 238and mechanically contacts the ;nner surface of the domed member 224to effect an electrical connection between the conductor230and the fin 224. On the other hand, conduc-tor 232is led straight through the molded member234 to a position above the top of the molded member 234but within the confines of the fin224. A connection ls made between the top of conductor 232 and a semiconductor chip240 by means of a fine gold wire242 ha~lng a diàmeter of approximately .002 ;nches.
Thus~ as is seen from Figure 20,the chip 240, gold wir~
242, andthe interior pnrtion of the domed fin224 are protected from any contaminants or foreign material which may flow past the domed fin224. As stated above, the interior of the domed fin 224 may be provided with foamed material to further mechanically protect the semiconductor chip240 and the gold wire 242.
Referring now to Figure 21,there is illustrated a modified form of connections whereby the conductors230, 232 are embedded in a modif~ed molded plastic member 246. The plastlc member 246~s modified by providing cutaway portions at surfaces 248an~ 250 to provide access to the top Df conductors 230, 232 which are now positioned outside of the confines of a domed fin 252.
The connections between the conductor230and the Fln 252 is provided by a gold wire 254having a diameter of approxlmately .002 inches, the gold wire being suitably fastened to the domed fin 252. As was the case with ~igure 20,a semiconductor chip 258 is mounted within the fin 252 and at the apex thereof, and the con-ductor232is interconnected therewith by a second gold wire 260.
The bonding of the semiconductor258 to the domed fin2s2 may be by ;~
any suitable methods, as for example, by gold bonding techniques.
The domed fin 252is press-fitted onto the upper end of the plastic molded member 246and fixed thereto.
Referring now to Figllre 22,there is illustrated a further modification of the invention disclo,ure wherein the dorned element 252is again provided with a semiconductor chip 258. However, a molded member264 is shown as being modified from that previously described except that the domed fin 252is again press-fitted onto the plastic molded memben264 and suitably attached thereto. In the case of Figure 22,the conductor230is provided at its upper end thereof with a flexible whisker-type lead 266which is in wiping contact with the domed fin 252thereby providinq electrical connec-tion thereto. On the other hand, the conductor 232is provided with a slightly longer flexible whisker-type lead 268which is in wiping contact with the semiconductor chip 258.
Figure ~3illustrates the invention as applied by thick film techniques, although lt is to be understood thin film techniques apply equally as well. Referring to Figure 23, fin2s2forms the substrate on which the various layers are deposited by the screening process. In carrying out the process, an insulating strip 270j 5 deposited on the fin 252with an aperture 272formed in the strip270 by either blocking the area of the aperture 272with an emulsion or by etching the area of the aperture from the strip. A semiconductor portion274 is then deposited in the aperture272in contact with the fin252. Finally a strip conductor276is de,uosited on the semiconductor274and on strip 270, maintaining the conductor 276, within the confines ~ -thereof, to form the conductive strip corresponding to the conductor 242 or 260. III the thin film counterpart, the various layers are sputtered or evaporated with the masking or etching desired to form the stIapes needed.
Having described a preferred embodiment of the inven~
- tion and several modi1~ications thereof, it will be understood that the examples given are employed in a descriptive sense only ;~
and not for purposes of limitation. Other embodiment and vari-ations will be obvious to those skilled in the art and be Inade without deploying from the spirit and scope of my invention which is li~ited only by the appended claims.
-- 2~ --
Claims (26)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:
1. A temperature sensor for sensing the temperature of a fluid comprising a base member, fin means formed of a thin disc having a high surface area to mass ratio mounted in fixed relation-ship to said base member whereby said fluid to be sensed may flow over said fin means, semiconductor means mounted on said fin means having the characteristics of changing resistance with changes in temperature, a first output conductor connected to said fin means, a second output conductor electrically insulated from said fin means and connected to the surface of said chip remote from the sur-face of said chip in electrical contact with said fin.
2. A temperature sensor for sensing the temperature of a fluid comprising a base member having at least first and second support arms thereon, fin means formed of a thin disc having a high surface area to mass ratio fixedly mounted on said first and second support arms whereby said fluid to be sensed may flow over the top and bottom surface of said fin means, semiconductor means mounted on said fin means having the characteristic of changing resistance with changes in temperature, a first output conductor connected to said fin means, a second output conductor electrically insulated from said fin means and connected to the surface of said chip remote from the surface of said chip in electrical contact with said fin.
3. The sensor of Claim 2 wherein said first and second conductors are molded in said base member, said first conductor being molded in said first support arm and said second conductor being molded in said second support arm.
4. The improvement of Claim 3 further including a relatively open cage means fixingly mounted in surrounding relation with said fin means and said semiconductor chip.
5. The improvement of Claim 4 wherein said cage means is formed of a pluralistic wire having a generally U-shaped, said wires being joined at the apex of said U-shape.
6. The improvement of Claim 5 wherein said temperature sensor further Includes a connector element having a threaded portion far attaching said temperature sensor to a member through which the fluid to be sensed is flowing, said cage assembly being fixingly attached to said connector to enclose at least a portion of said base member said fin means and said semiconductor means.
7. The improvement of Claim 6 wherein said connector member is generally angular shaped, said base member being re-ceived within the interior of said connector, said connector having a portion thereof swaged to retain said base member within the confines of said connector.
8. The improvement of Claim 7 wherein said fins means is formed with an aperture therein and said first conductor is led through said aperture from said first support arm, said first conductor being bent over into engagement with the surface of said fin means and electrically connected therewith.
9. The improvement of Claim 8 wherein said cage means is a pair of wires disposed at 90° one relative to the other.
10. The improvement of Claim 2 wherein said base member includes third and fourth support arms, said first and third support arms cooperating to attach to an edge portion of fin means and said second and said fourth support arms cooperating to attach to another portion of said fin means and conductive means supported between said first and third support arms and said second and fourth support arms.
11. The improvement of Claim 10 wherein said first and second conductor means are formed as thin conductive sheets.
12. The improvement of Claim 11 wherein an edge of said first conductor overlaps a surface portion of said fin means to make electrical connection therewith.
13. The improvement of Claim 12 wherein said base member includes fifth and sixth and seventh and eighth support arms, said fifth and seventh and said sixth and eighth support arms cooperating to attach to additional portions of said fin means to fixedly support said fin means.
14. The improvement of Claim 2 further including insulating means between said second conductor and said fin means.
15. The improvement of Claim 14 wherein said insulating means, semiconductor means and second output conductor are deposited on said fin means by thick film techniques.
16. The improvement of Claim 14 wherein said insulating means, semiconductor means and second output conductor are deposited on said fin means by thin film techniques.
17. A temperature sensor for sensing the temperature of a fluid comprising a base member, fin means formed of a thin disc having a high surface area to mass ratio fixedly mounted on said base member, said fin means being in the shape of a dome and positioned in sealing engagement with said base member whereby said fluid to be sensed may flow only over the outer surface of said fin means, semiconductor means mounted on an interior surface of said fin means having the characteristic of changing resistance with changes in temperature, a first output conductor connected to said fin means, a second output conductor electrically insulated from said fin means and connected to the surface of said semiconductor means remote from the surface of said semiconductor means in electrical contact with said fin means.
18. The sensor of Claim 17 wherein said first and second conductors are at least partially molded in said base member.
19. The improvement of Claim 18further including a relatively open cage means fixingly mounted in surrounding relation with said fin means and said semiconductor means.
20. The improvement of Claim 19wherein said cage means is formed of a plurality of wires having a generally U-shaped, said wires being joined at the apex of said U-shape.
21. The improvement of Claim 20 wherein said temperature sensor further includes a connector element having a threaded portion for attaching said temperature sensor to a member through which the fluid to be sensed is flowing, said cage assembly being fixingly attached to said connector to enclose at least a portion of said base member said fin means and said semiconductor means.
22. The improvement of Claim 21 wherein said connector member is generally circular shaped, said base member being received within the interior of said connector, said connector having a portion thereof swaged to retain said base member within the confines of said connector.
23. The improvement of Claim 22 wherein said fin means is formed with an aperture therein and said first conductor is led through said base member and being bent over into engagement with the surface of said fin means and electrically connected therewith.
24. The improvement of Claim 17 wherein said semiconductor means is deposited on said fin means by thick film techniques.
25. The improvement of Claim 17 wherein said semiconductor means is deposited on said fin means by thin film techniques.
26. The improvement of Claim17 wherein said second conductor is a whisker element in resilient engagement with said semiconductor means.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US857,558 | 1977-12-05 | ||
| US857,557 | 1977-12-05 | ||
| US05/857,557 US4142170A (en) | 1977-12-05 | 1977-12-05 | High response temperature sensor |
| US05/857,558 US4174512A (en) | 1977-12-05 | 1977-12-05 | Fast response temperature sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1110779A true CA1110779A (en) | 1981-10-13 |
Family
ID=27127413
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA317,288A Expired CA1110779A (en) | 1977-12-05 | 1978-12-04 | Fast response temperature sensor |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1110779A (en) |
| ES (1) | ES475731A1 (en) |
| FR (1) | FR2422944A1 (en) |
| GB (1) | GB2033655A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2505494A1 (en) * | 1981-05-07 | 1982-11-12 | Sdecc | IMPROVEMENTS ON TEMPERATURE SENSORS |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB488838A (en) * | 1937-08-26 | 1938-07-14 | Gen Motors Corp | Electrical temperature-responsive units |
| US2818482A (en) * | 1953-04-21 | 1957-12-31 | Victory Engineering Corp | High speed clinical thermometers |
| CH355625A (en) * | 1958-01-31 | 1961-07-15 | Landis & Gyr Ag | Temperature sensor with temperature-sensitive electrical element |
| FR1462680A (en) * | 1965-12-31 | 1966-04-15 | Amp Inc | Temperature sensing device used as a rapid thermometer |
| US3592059A (en) * | 1969-06-27 | 1971-07-13 | Computer Diode Corp | Temperature measuring apparatus |
| DE2142729A1 (en) * | 1971-08-26 | 1973-03-08 | Bbc Brown Boveri & Cie | ARRANGEMENT OF A THERMISTOR IN A TEMPERATURE MEASURING ELEMENT |
| US4065760A (en) * | 1977-03-04 | 1977-12-27 | Fea Devices, Inc. | Liquid level sensor |
| JPS53147784U (en) * | 1977-04-25 | 1978-11-21 |
-
1978
- 1978-12-04 CA CA317,288A patent/CA1110779A/en not_active Expired
- 1978-12-05 ES ES475731A patent/ES475731A1/en not_active Expired
- 1978-12-05 GB GB7847224A patent/GB2033655A/en not_active Withdrawn
- 1978-12-05 FR FR7834206A patent/FR2422944A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| ES475731A1 (en) | 1979-11-01 |
| FR2422944A1 (en) | 1979-11-09 |
| GB2033655A (en) | 1980-05-21 |
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |