Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
  • H01L23/38—Cooling arrangements using the Peltier effect
• • 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
  • G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
  • G01K7/028—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples using microstructures, e.g. made of silicon
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N19/00—Integrated devices, or assemblies of multiple devices, comprising at least one thermoelectric or thermomagnetic element covered by groups H10N10/00 - H10N15/00
• • 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

Definitions

• thermocouples This relates generally to thermocouples and, more particularly, to monolithically integrated thermopiles.
• the reference numeral 100 generally designates a conventional monolithically integrated or "on-chip" thermocouple.
• Thermocouple 100 generally comprises a membrane 102 that includes two different thermally conductive materials 110 and 112 that extend from the silicon substrate 104 (which is typically referred to as a "rim") over a recess 108 formed in silicon substrate 104.
• a temperature differential is created in the membrane 102 between the area over the recess 108 and the "rim" (where the substrate 104 operates as a heat sink).
• Many of the thermocouples 100 can then be arranged into a thermopile so as to be able to ascertain readable and reliable temperature measurements.
• Thermocouple 100 has numerous drawbacks.
• the deep selective etching used to form recess 108 is a non-standard manufacturing step, which can dramatically increase the manufacturing costs.
• the membrane 102 is very fragile, which generally requires special handling and packaging and which generally makes the membrane sensitive to pressure and vibration. Additionally, because of the fragility of the membrane 102, the size of the membrane is mechanically limited.
• thermopile 200 [0004] Turning to FIG. 2, another, alternative thermopile 200 can be seen.
• thermopile 200 generally comprises a first set of materials 202-1, 202-2, 202-3, and 202-4 and a second set of materials 204-1, 204-2, 204-3, and 204-4 arranged in a "serpentine" on a silicon substrate 104. As air (or another fluid) traverses the thermopile, a temperature or thermal gradient is formed across the thermopile 200. While the arrangement of thermopile 200 is more mechanically durable than a thermopile having an array of thermocouples 100, thermopile 200 has very low sensitivity and generally requires a large amount of area, making it prohibitively expensive.
• thermocouples and thermopiles are described in: U.S. Patent No. 3,393,328; U.S. Patent No. 5,059,543; U.S. Patent No. 5,343,064; U.S. Patent No. 6,531,899; U.S. Patent No. 6,565,254; U.S. Patent No. 6,793,389; U.S. Patent No. 6,987,223; U.S. Patent No. 7,042,690; U.S. Patent No. 7,282,712; U.S. Patent No. 7,406,185; U.S. Patent Pre-Grant Publ. No.
• the apparatus comprises a substrate; a thin dielectric layer formed over a first portion of the substrate; a thick dielectric layer formed over a second portion of the substrate; a first conductive layer that extends over at least a portion of each of the thin dielectric layer and the thick dielectric layer, wherein the first conductive layer is made of a first material having a first Seebeck coefficient; a first portion of a second conductive layer that extends over at least a portion of the first conductive layer and the thin dielectric layer, wherein the second layer is made of a second material having a second Seebeck coefficient; a second portion of the second conductive layer that extends over at least a portion of the first conductive layer and the thick dielectric layer; a first conductive via that is formed between the first conductive layer and the first portion of second conductive layers; and a second conductive via that is formed between the first conductive layer and the second portion of the second conductive layer.
• the first conductive layer is formed of polysilicon, and wherein the thin and thick dielectric layers are formed of silicon dioxide, and wherein the second conductive layer is a metallization layer formed of aluminum or copper, and wherein the first and second conductive vias are formed of tungsten or aluminum, and wherein the thin dielectric layer is between about lOnm and about 12nm.
• the thick dielectric layer is a field oxide layer that is between 200nm and about 220nm.
• the apparatus further comprises: a third conductive layer that extends over at least a portion of each of the first and second portions of the second conductive layer; a third conductive via that is formed between the second and third conductive layer, wherein the third conductive via is generally coextensive with the first conductive via; a fourth conductive via that is formed between the second and third conductive layer, wherein the third conductive via is generally coextensive with the second conductive via; an interconnect layer, wherein the interconnect layer has a higher thermal impedance than the third conductive layer; a fifth conductive via that is formed between the third conductive layer and interconnect layer; and a fourth conductive layer that is adapted to receive infrared radiation; a sixth conductive via that is formed between third conductive layer and the fourth conductive layer, wherein the sixth conductive via is generally coextensive with the second via.
• the third and fourth conductive layers is each formed of aluminum or copper, and wherein the third, fourth, fifth, and sixth conductive vias are formed of aluminum or tungsten, and wherein the interconnect layer is formed of titanium nitride.
• the thick dielectric layer is an isolation region that is between about 200nm and about 220nm.
• the apparatus further comprises an absorption layer that extends over the second portion of the second conductive layer.
• the apparatus further comprises a buried layer formed in the substrate below the first portion of the second conductive layer.
• the absorption layer is formed of polyamide.
• the first conductive layer is formed of polysilicon doped with a material of a first conduction type, and wherein the thin and thick dielectric layers are formed of silicon dioxide, and wherein the second conductive layer is formed of polysilicon doped with a material of a second conduction type.
• an apparatus comprises a plurality of thermocouples that are coupled to one another in an array to form a thermopile, wherein each thermocouple includes: a thin dielectric layer; a thick dielectric layer; a first conductive layer that extends over at least a portion of each of the thin dielectric layer and the thick dielectric layer, wherein the first conductive layer is made of a first material having a first Seebeck coefficient; a first portion of a second conductive layer that extends over at least a portion of the first conductive layer and the thin dielectric layer, wherein the second layer is made of a second material having a second Seebeck coefficient; a second portion of the second conductive layer that extends over at least a portion of the first conductive layer and the thick dielectric layer; a first conductive via that is formed between the first conductive layer and the first portion of second conductive layers; and a second conductive via that is formed between the first conductive layer and the second portion of the second portion of the second
• each thermocouple further comprises: a third conductive layer that extends over at least a portion of each of the first and second portions of the second conductive layer; a third conductive via that is formed between the second and third conductive layer, wherein the third conductive via is generally coextensive with the first conductive via; a fourth conductive via that is formed between the second and third conductive layer, wherein the third conductive via is generally coextensive with the second conductive via; an interconnect layer, wherein the interconnect layer has a higher thermal impedance than the third conductive layer; a fifth conductive via that is formed between the third conductive layer and interconnect layer; a fourth conductive layer that is adapted to receive infrared radiation; a sixth conductive via that is formed between third conductive layer and the fourth conductive layer, wherein the sixth conductive via is generally coextensive with the second via; and a seventh conductive via that is formed between the second conductive layer and the third conductive
• the apparatus further comprises: an amplifier that is coupled to the thermopile; an analog-to-digital converter (ADC) that is coupled to the amplifier; a digital linearization engine that is coupled to the ADC; and an interface that is coupled to the digital linearization engine.
• ADC analog-to-digital converter
• the ADC is a sigma- delta ADC.
• the interface is an
• a method of manufacturing a thermocouple comprises forming a thick dielectric layer and a thin dielectric layer over a substrate; forming a first conductive layer that extends over at least a portion of each of the thick and thin dielectric layers, wherein the first conductive layer has a first Seebeck coefficient; forming an oxide layer over the first conductive layer; etching the oxide layer to form a first aperture that is generally coextensive with at least a portion of the first conductive layer and the thin dielectric layer and to form a second aperture that is generally coextensive with at least a portion of the first conductive layer and the thick dielectric layer; filling the first and second apertures to form first and second conductive vias; forming a second conductive layer over the oxide layer, wherein the second conductive layer has a second Seebeck coefficient; and etching the second conductive layer to form first and second portions of the second conductive layer that are substantially electrically isolated from one another.
• the metallization layer further comprises a first metallization layer
• the oxide layer further comprises a first oxide layer
• the method further comprises: forming a second oxide layer over the first metallization layer; forming an interconnect layer over the second oxide layer; forming a third oxide layer over the interconnect layer; etching the second and third oxide layers to form: a third aperture that is generally coextensive with the first conductive via; a fourth aperture that is generally coextensive with the second conductive via; a fifth aperture that is generally coextensive with at least a portion of the interconnect layer; and a sixth aperture that is generally coextensive with at least a portion of the interconnect layer; filling the third, fourth, fifth, and sixth apertures to form third, fourth, fifth, and sixth conductive vias; forming a second metallization layer over the third oxide layer; and etching the second metallization layer so that fourth and fifth conductive vias are electrical
• the oxide layer further comprises a first oxide layer, and wherein the first and second portions of the metallization layer are electrically connected to first and second adjacent thermocouples, and wherein the method further comprises: forming a buried layer in the substrate underneath the first conductive via; forming a second oxide layer over the metallization layer; and forming an absorption layer over the second via.
• FIG. 1 is an example of a conventional thermocouple
• FIG. 2 is an example of a conventional thermopile
• FIG. 3A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention
• FIG. 3B is a elevation view of the process step along section line A-A;
• FIG. 4A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 4B is a elevation view of the process step along section line B-B;
• FIG. 5A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention
• FIG. 5B is a elevation view of the process step along section line C-C;
• FIG. 6A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 6B is a elevation view of the process step along section line D-D;
• FIG. 7A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 7B is a elevation view of the process step along section line E-E;
• FIG. 8A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 8B is a elevation view of the process step along section line F-F;
• FIG. 9A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 9B is a elevation view of the process step along section line G-G;
• FIG. 10A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 10B is a elevation view of the process step along section line H-H;
• FIG. 11A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 1 IB is a elevation view of the process step along section line I-I;
• FIG. 12A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 12B is a elevation view of the process step along section line J-J;
• FIG. 13A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 13B is a elevation view of the process step along section line K-K;
• FIG. 14A is a plan view of an example of a process step for forming thermocouple in accordance with an example embodiment of the invention.
• FIG. 14B is a elevation view of the process step along section line L-L;
• FIG. 15 is an example of an integrate circuit (IC) that employs the thermocoupl show in process steps of FIGS. 3A to 14B.
• thermocouple 300-1 the process for forming a thermocouple 300-1 (as shown
• FIG. 10B is illustrated.
• a thin dielectric layer 304 and a thick dielectric layer or field oxide layer 302 are formed over the substrate 104.
• these layers 302 and 304 are formed of silicon dioxide and are grown on the substrate 104 through one or more conventional oxidation process steps.
• the thin oxide layer 304 can be between about lOnm and about 12nm thick, while the field oxide layer 302 can be between about 200nm and about 220nm thick.
• substrate 104 can be formed of silicon, but substrate 104 may also be made of several other suitable materials.
• a conductive layer Following the formation of the dielectric layers 302 and 304, a conductive layer
• this conductive layer 306-1 is formed over dielectric layers 302, as seen in FIGS. 4A and 4B.
• this conductive layer 306-1 is formed of polysilicon, which has a Seebeck coefficient of about 40 ⁇ / ⁇ and which is one of the thermally conductive materials used to form the thermocouple 300-1.
• a layer of polysilicon is generally formed over layers 302 and 304, which is then patterned an etched to form the shape seen in the plan view of FIG. 4A.
• the conductive layer 306-1 can also be doped with either a P-type material (such as boron, indium, or aluminum) or N-type material (such as phosphorous, arsenic, and antimony).
• conductive contacts are formed with the conductive layer 306-1.
• a dielectric layer (typically silicon dioxide) 308-1 is formed over the conductive layer 306-1 and is patterned and etched (forming apertures that are each generally or partially coextensive with the conductive layer 306-1 and one of the layers 304 or 302. These apertures are then filled with a conductive material (i.e., tungsten or aluminum) to form vias 310-1 and 312-1.
• a conductive material i.e., tungsten or aluminum
• the metallization layer 314-1 is formed of a material having a similar or approximately the same Seebeck coefficient as the conductive material used for vias 310-1 and 312-1. For example, if tungsten or aluminum (which, respectively, have Seebeck coefficients of 7.5 ⁇ / ⁇ and 3.5 ⁇ / ⁇ ), aluminum or copper (6.5 ⁇ / ⁇ ) would have similar or approximately Seebeck coefficients.
• This metallization layer 314-1 (once in place) can be patterned and etched to form two separate portions or "pads" that are electrically isolated from one another. Additionally, each of these "pads" is in electrical contact with one of the vias 310-1 and 312-1.
• conductive layer 314-1 can also be formed of polysilicon doped with either a P-type material (such as boron, indium, or aluminum) or N-type material (such as phosphorous, arsenic, and antimony).
• a P-type material such as boron, indium, or aluminum
• N-type material such as phosphorous, arsenic, and antimony.
• conductive layer 306-1 has the opposite doping of conductive layer 314-1.
• a dielectric layer i.e., portion of dielectric layer 316-1
• an interconnect layer is formed (i.e., deposited and etched).
• the remainder of the dielectric layer 316-1 is formed.
• apertures are formed and filled with a conductive material (i.e., aluminum or tungsten) to form vias 320, 322, 324, and 326.
• the interconnect layer 318 (which operates as a connective layer between adjacent thermocouples, such as thermocouple 300-1) is formed of a material that has good electrical conductivity, with a higher thermal impedance than the materials used for metallization layers 314-1 and 328.
• interconnect layer 318 can be formed of titanium nitride.
• a second metallization layer 328 (as shown in FIGS. 8 A and 8B) is deposited, patterned, and etched. As with the first metallization layer 314-1, there are several portions or "pads" in metallization layer 328 that are generally electrically isolated from one another. In particular, metallization layer 328 electrically connects vias 322 and 324 together, electrically connects via 326 to one adjacent cell or thermocouple (i.e., thermocouple 300-1), and electrically connects via 320 to another adjacent cell or thermocouple (i.e., thermocouple 300-1). Additionally, as shown in FIG. 8B, vias 322 and 320 can be generally coextensive or can be generally aligned with vias 310-1 and 312-1, respectively.
• an additional via 330 and third metallization layer 334 are formed (which is shown in FIGS. 9A through 10B).
• via 330 is formed of a conductive material (i.e., tungsten or aluminum) that is deposited in an aperture in dielectric layer 332 (i.e., silicon dioxide).
• the third metallization layer 334 is then formed over the cell so as to conduct heat to the "hot junction.”
• an absorber 336 can be formed over the metallization layer 334; typically, this absorber 336 can be formed of polyamide or any other suitable infrared or heat absorber.
• cell or thermocouple 300-1 is able to use the Peltier- Seebeck effect to generate a voltage.
• Heat or infrared radiation is applied to the metallization layer 334, which is transferred through metallization layers 328 and 314-1 and vias 330, 322, and 310-1 to conductive layer 306-1.
• the thick dielectric layer 302 (which is a field oxide layer) is a less thermally conductive than thin oxide layer 304 due to their relative thicknesses, a "hot” junction is formed at junction between via 310-1 and conductive layer 306-1, and a "cold” junction is formed at the junction between the conductive layer 306-1 and via 312-1.
• a voltage is generated when infrared radiation or heat is applied to metallization or conductive layer 334.
• polymers and/or buried layers can be used for infrared absorption.
• FIGS. 11A to 13B a structure that is similar to the structure of FIGS. 6A and 6B is formed. Some differences are: (1) that dielectric layer 302 is replaced with an isolation region 402 (i.e., shallow trench isolation or deep trench isolation) with oxide layer 406 extending over the isolation region 402; (2) that a buried layer 404 (which is generally comprised of an implanted or diffused dopant and is generally coextensive with or generally aligned with via 312-2) is provided in the substrate 104; and (3) that the "pads" or portions of metallization layer 314-2 are electrically connected to adjacent cells.
• isolation region 402 i.e., shallow trench isolation or deep trench isolation
• oxide layer 406 extending over the isolation region 402
• a buried layer 404 which is generally comprised of an implanted or diffused dopant and is generally coextensive with or generally aligned with via 312-2
• an absorption layer 408 (which is generally formed of polyamide) is formed on the dielectric layer 316-2 so as to be generally coextensive with via 310-2.
• the buried layer is heavily doped with either a P-type material (such as boron, indium, or aluminum) or N-type material (such as phosphorous, arsenic, and antimony).
• thermocouple 300-2 allows for absorption from both the top and bottom. Both the buried layer 404 and the absorption layer 408 operate to "trap" infrared radiation. Regardless of the direction of the radiation, heat is trapped on the "hot” junction (junction between via 310-2 and conductive layer 603-2) and is dissipated into the substrate 104 on the "cold” junction (junction between via 312-2 and conductive layer 306-2). Therefore, similar to thermocouple 300-1, thermocouple 300-2 generates a voltage when infrared radiation is received.
• thermocouples 300-1 and/or 300-2 can be seen.
• thermocouples 300-1 and/or 300-2 are formed as part of an integrated circuit (IC).
• Cells or thermocouples 300-1 and/300-2 (which are each about 7.5 ⁇ ) are arranged in an array to form thermopile 502.
• thermopile 502 includes tens of thousands of cells or thermocouples 300-1 and 300-2.
• the thermopile 502 is coupled to an amplifier 504, and an amplified signal is provided to analog-to-digital converter (ADC) 506.
• ADC 506 is a sigma-delta ADC that receives a local temperature LT from temperature sensor 508 and a reference voltage REF from reference voltage generator 510.
• the digital representation of the amplified signal is linearized by the digital linearization engine 512 and provided to interface 514 (which is generally SMBus compatible).
• thermocouples 300-1 and/or 300-2 are fully compatible with the standard semiconductor manufacturing processes. There are no extra processing steps, and the cost per wafer is equal to the base cost per wafer for the used process. There are no restrictions on the thermopile 502 size. The desired sensitivity and signal to noise ratio can be achieved by scaling up the thermopile 502.
• Thermocouples 300-1 and/or 300-2 have mechanical robustness that is generally equal to the robustness of the silicon chip itself. Thermocouples 300-1 and/or 300-2 are also not sensitive to pressure and/or vibrations or to chemical and/or ion contamination.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Photometry And Measurement Of Optical Pulse Characteristics (AREA)
• Measuring Temperature Or Quantity Of Heat (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=44708663

Family Applications (1)

Country Status (4)

Families Citing this family (9)

Citations (4)

Family Cites Families (19)

• 2010
  • 2010-03-30 US US12/750,408 patent/US8304851B2/en active Active
  • 2010-12-23 CN CN2010800659377A patent/CN102823005A/zh active Pending
  • 2010-12-23 WO PCT/US2010/062055 patent/WO2011126530A1/en not_active Ceased
  • 2010-12-23 JP JP2013502561A patent/JP6038771B2/ja active Active
  • 2010-12-23 CN CN201710055694.2A patent/CN107068635B/zh active Active
• 2012
  • 2012-10-18 US US13/654,591 patent/US8802476B2/en active Active

Patent Citations (4)

Also Published As

Similar Documents

Legal Events