GB2327146A - Thermal insulation of integrated circuit components - Google Patents
Thermal insulation of integrated circuit components Download PDFInfo
- Publication number
- GB2327146A GB2327146A GB9714573A GB9714573A GB2327146A GB 2327146 A GB2327146 A GB 2327146A GB 9714573 A GB9714573 A GB 9714573A GB 9714573 A GB9714573 A GB 9714573A GB 2327146 A GB2327146 A GB 2327146A
- Authority
- GB
- United Kingdom
- Prior art keywords
- integrated circuit
- component
- trench
- components
- thermal insulation
- 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.)
- Withdrawn
Links
- 238000009413 insulation Methods 0.000 title claims abstract description 18
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 34
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 17
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 17
- 238000010438 heat treatment Methods 0.000 claims abstract description 10
- 229910052581 Si3N4 Inorganic materials 0.000 claims abstract description 6
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 9
- 239000011810 insulating material Substances 0.000 claims description 3
- 229910021420 polycrystalline silicon Inorganic materials 0.000 abstract description 3
- 229920005591 polysilicon Polymers 0.000 abstract description 3
- 239000000203 mixture Substances 0.000 abstract description 2
- 238000002955 isolation Methods 0.000 description 6
- 229910052710 silicon Inorganic materials 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 230000004888 barrier function Effects 0.000 description 2
- 239000012212 insulator Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012850 fabricated material Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000010561 standard procedure Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
- H01L21/76—Making of isolation regions between components
- H01L21/762—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers
- H01L21/7624—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers using semiconductor on insulator [SOI] technology
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers
- H01L27/0203—Particular design considerations for integrated circuits
- H01L27/0248—Particular design considerations for integrated circuits for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Semiconductor Integrated Circuits (AREA)
- Element Separation (AREA)
Abstract
Trench structures 24, 26 are used to surround, or partially surround, component(s) of an integrated circuit to provide thermal insulation for the component(s). The isolated component(s) may be a transistor or more than one matched components, i.e. bipolar transistors 20, 22. The thermally isolated region may include heating resistors 30-36 and a temperature sensor 28. The trenches 24, 26 may be filled with silicon dioxide, silicon nitride or a mixture of polysilicon and silicon dioxide, and may also include voids.
Description
INTEGRATED CIRCUITS
This invention relates to integrated circuits, and in particular to the structures thereof, and to methods of fabrication thereof.
DESCRIPTION OF RELATED ART
It is well known that many of the components of common integrated circuits have parameters which are temperature dependent in some way. For example, the resistivity of a resistor may vary with temperature, as may the base-emitter voltage of a bipolar transistor.
For this reason, there are many standard techniques which may be used, in integrated circuit design, in order to achieve some degree of control of the temperature of a component. For example, when the performance of a circuit depends on the accurate matching of two or more similar components, the circuit layout may be designed in an attempt to keep those components at the same temperature. For example, the components may be placed equally far from a heat source in the integrated circuit.
However, these known design techniques, while useful, cannot completely insulate temperaturesensitive components from heat sources.
At the same time, it is known that integrated circuit components may be electrically isolated from one another by means of trench structures, surrounding the components, which contain silicon dioxide. US
Patent No. 5,410,176 shows an example of an isolation structure of this type.
SUMMARY OF THE INVENTION
The present invention relates to an integrated circuit structure which allows a temperature-sensitive component, or group of components, to be maintained at a desired temperature, thermally insulated from unwanted heat sources in the device.
The thermal insulation is provided by trench structures, which have some similarities to the trench structures used previously to provide electrical isolation, as well as by a horizontal layer of thermally insulating material, for example silicon dioxide.
In order to provide thermal insulation, the trench structures do not necessarily need to surround the components entirely. A useful degree of thermal insulation may be provided by a trench structure which only partly surrounds the component, although such a structure would not provide useful electrical isolation.
Moreover, the trench structure may include two or more trenches separating the temperature-sensitive component or components, although there would be no need to provide more than one trench in order to achieve electrical isolation.
Further aspects of the invention provide integrated circuit structures in which one or more components are provided within a thermally insulating trench structure, together with a heating device, for example a resistor to which a variable current may be supplied, in order to maintain the components within the insulating structure at a desired temperature.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic view of a part of an integrated circuit in accordance with the invention.
Figure 2 is a schematic cross section through the part of the integrated circuit shown in Figure 1.
Figure 3 is a larger scale view of a part of the cross section shown in Figure 2.
Figure 4 is a schematic illustration of a further integrated circuit in accordance with the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Figure 1 is a schematic view of a part of an integrated circuit, which includes a particular heat source 2. For example, the heat source may be a high current device such as a power transistor.
Also located within the integrated circuit is a region 4, which may for example contain one or more temperature-sensitive components, which may, for example, be a resistor, with the performance of the circuit depending on the precise value of the resistor.
If there are more than one temperature-sensitive component, the thermally insulating structure can keep them at the same temperature so that they are matched.
This may be so that a parameter value of each of the components has the same value, or so that a parameter value has the same value, or so that a parameter value of each of the components remains in a constant ratio, for example.
In order to maintain the region 4 at a relatively constant temperature, irrespective of the amount of heat being generated by the source 2, the region 4 is surrounded by a pair of trenches 6, 8, which provide thermal insulation. Thus, these trenches restrict the lateral flow of heat, and prevent the temperature within the region 4 being unduly affected by the heat source 2. Two trenches are shown, but any number may be provided. Moreover, the trench or trenches need not entirely surround the region 4 (a trench may include gaps or holes), provided that the thermal resistance of the trench structure (including any discontinuities) is sufficiently high. For example, the trench structure may have a thermal conductance of less than about l1yW.K-1 per micron of perimeter, for example 7yW.K-l per micron.
Figure 2 is a cross-sectional representation of the integrated circuit, showing the trenches 6, 8 surrounding the region 4. In the example shown in
Figure 2, the integrated circuit includes a horizontal silicon dioxide layer 10, with an active layer 12 above it, and the trenches 6, 8 are formed in that active layer. The silicon dioxide in the horizontal layer 10 acts as an insulator to restrict the vertical movement of heat within the integrated circuit, and the trenches 6, 8 similarly act to prevent lateral heat flow into or out of the region 4.
Figure 3 is a larger scale cross-sectional view of one of the trenches 6, formed within an active layer 12 of silicon, above a horizontal layer 10 of silicon dioxide.
As an example, the active layer 12 of silicon may have a depth of 5.sum, and the trench 14 may have a width of approximately 1.8m at the upper surface of the silicon, and a width of approximately lym at the bottom, where it is in contact with the horizontal layer 10. The bottom of the trench 6 may however be separated from the horizontal layer 10 if desired. The walls 14 of the trench are formed of silicon dioxide, while the rest of the trench 16 is filled with undoped polysilicon. The walls 14 may have a thickness in the region of 350nm, for example.
Silicon dioxide has a thermal resistance which is greater than that of silicon by a factor of approximately 100, which means that placing a trench around a component has the same insulating effect as moving it away from a heat source by a distance which is 100 times the thickness of silicon dioxide in the trench.
In addition, the thermal insulation can be improved by increasing the thickness of silicon dioxide in the trench structure. Because of the time taken to grow silicon dioxide during fabrication, this might most easily be achieved by using a larger number of trenches, rather than by using a single thicker trench.
Figure 4 shows a part of a further integrated circuit in accordance with the invention. The circuit includes a pair of bipolar transistors 20, 22, the base-emitter junctions of which should be maintained at, for example, 1000C, in order to optimise circuit performance. The transistors 20, 22 are therefore placed within a thermally insulating trench structure made up of trenches 24, 26, and a temperature sensor 28 is located adjacent to them. Also located within the insulating structure are a number of heating resistors 30, 32, 34, 36. The temperature sensor 28, and heating resistors 30, 32, 34, 36 are connected to circuitry (not shown) for controlling the current through the resistors in response to the sensed temperature.
The temperature sensor 28 is therefore able to detect the temperature within the insulating structure, and current can be supplied to the heating resistors 30, 32, 34, 36, in order to ensure that the temperature is maintained at the desired level. The insulating structure ensures that the temperature within it remains relatively constant over time, and over the whole of the area within the structure.
The embodiment illustrated in Figure 4 has two matched components within the trench structure. It will be appreciated that any desired number of matched components may be located within an appropriate trench structure.
It should be noted that there are significant differences between the trench structures described and illustrated herein, and those known from the prior art, used for electrical isolation. For example, to achieve electrical isolation, it is necessary for a component to be completely isolated from other components. Thus, for example, a vertical barrier would need to be completely continuous, and extend all the way down to a horizontal insulating layer within the device.
By contrast, in order to achieve a good level of thermal insulation, the barrier may not need to be entirely continuous, and may not need to extend all the way down to the horizontal layer, or all the way up to the upper surface of the device.
Moreover, the use of two or more trenches would provide additional thermal insulation.
As described above, the insulating material which is used is silicon dioxide, although any readily fabricated material may be used, an example of which is silicon nitride. Furthermore, the trench structure may include voids, which are of course excellent insulators, but also provide stress relief within the structure. Finally, any convenient material may be used to fill the trenches. For example, the trenches may be filled with a mixture of silicon dioxide and polysilicon, and may also possibly include silicon nitride.
There is thus provided a structure which can provide thermal insulation within an integrated circuit, allowing the temperatures of thermally sensitive components to be controlled, either in absolute terms, or relative to the temperatures of other components, with which they need to be matched.
Claims (23)
1. An integrated circuit, including a trench structure to provide thermal insulation of a component within the structure, the structure comprising a plurality of trenches.
2. An integrated circuit as claimed in claim 1, wherein the component within the structure is a transistor.
3. An integrated circuit as claimed in claim 1, wherein the component within the structure is a pair of matched components.
4. An integrated circuit as claimed in claim 1, 2 or 3, wherein the trench structure includes silicon dioxide.
5. An integrated circuit as claimed in one of claims 1 to 4, wherein the trench structure includes silicon nitride.
6. An integrated circuit, including a trench structure to provide thermal insulation of components within the structure, the structure comprising at least one trench, the or each trench not entirely enclosing the components within the structure.
7. An integrated circuit as claimed in claim 6, wherein the component within the structure is a transistor.
8. An integrated circuit as claimed in claim 6, wherein the component within the structure is a pair of matched components.
9. An integrated circuit as claimed in claim 6, 7 or 8, wherein the trench structure includes silicon dioxide.
10. An integrated circuit as claimed in one of claims 6 to 9, wherein the trench structure includes silicon nitride.
11. An integrated circuit, comprising a pair of matched components, the pair of matched components being surrounded by a trench of insulating material to provide thermal insulation thereof from other components of the circuit.
12. An integrated circuit as claimed in claim 11, wherein the trench structure includes silicon dioxide.
13. An integrated circuit as claimed in one of claims 11 and 12, wherein the trench structure includes silicon nitride.
14. An integrated circuit, including a trench structure to provide thermal insulation of a component within the structure, and a temperature sensor and a controllable heating means located within the structure.
15. An integrated circuit as claimed in claim 14, wherein the component within the structure is a transistor.
16. An integrated circuit as claimed in claim 14, wherein the component within the structure is a pair of matched components.
17. An integrated circuit as claimed in claim 14, 15 or 16, wherein the controllable heating means includes at least one resistor or transistor, connected to a controllable current or voltage source.
18. An integrated circuit, including a trench structure to provide thermal insulation of components within the structure, the structure having a thermal conductance of less than about llyW.K-1 per micron of perimeter.
19. A method of providing thermal insulation of a component in an integrated circuit, the method comprising locating the component within a thermally insulating trench structure.
20. A method of providing thermal insulation of a pair of matched components in an integrated circuit, the method comprising locating the components together within a thermally insulating trench structure.
21. A method of maintaining a component of an integrated circuit at a desired temperature, the method comprising locating the component within a thermally insulating trench structure, together with a temperature sensor and a controllable heating means, and controlling the heating means such that the temperature of the component becomes equal to the desired temperature.
22. A method as claimed in claim 21, wherein the controllable heating means includes at least one resistor or transistor, connected to a controllable current or voltage source.
23. Use of a trench structure surrounding a component of an integrated circuit, in order to provide thermal insulation thereof.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9714573A GB2327146A (en) | 1997-07-10 | 1997-07-10 | Thermal insulation of integrated circuit components |
| PCT/EP1998/004214 WO1999003147A1 (en) | 1997-07-10 | 1998-07-07 | Thermally insulated integrated circuits |
| AU88582/98A AU8858298A (en) | 1997-07-10 | 1998-07-07 | Thermally insulated integrated circuits |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9714573A GB2327146A (en) | 1997-07-10 | 1997-07-10 | Thermal insulation of integrated circuit components |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9714573D0 GB9714573D0 (en) | 1997-09-17 |
| GB2327146A true GB2327146A (en) | 1999-01-13 |
Family
ID=10815670
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9714573A Withdrawn GB2327146A (en) | 1997-07-10 | 1997-07-10 | Thermal insulation of integrated circuit components |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU8858298A (en) |
| GB (1) | GB2327146A (en) |
| WO (1) | WO1999003147A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004001798A2 (en) * | 2002-06-25 | 2003-12-31 | Advanced Micro Devices, Inc. | A silicon-on-insulator device with strained device film and method for making the same with partial replacement of isolation oxide |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0008903A1 (en) * | 1978-08-25 | 1980-03-19 | Fujitsu Limited | Semiconductor integrated circuit device |
| WO1986007192A1 (en) * | 1985-05-21 | 1986-12-04 | Stemme Nils Goeran | Integrated semiconductor circuit and method for producing it, and use of such a circuit for providing a flow meter |
| WO1991013463A1 (en) * | 1990-02-27 | 1991-09-05 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Process for producing an insulated monocrystalline silicon island |
| GB2290165A (en) * | 1994-06-08 | 1995-12-13 | Hyundai Electronics Ind | Trench isolation |
| US5577309A (en) * | 1995-03-01 | 1996-11-26 | Texas Instruments Incorporated | Method for forming electrical contact to the optical coating of an infrared detector |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56137661A (en) * | 1980-03-31 | 1981-10-27 | Toshiba Corp | Semiconductor device |
| JPS60160646A (en) * | 1984-02-01 | 1985-08-22 | Hitachi Ltd | Manufacture of soi type semiconductor device |
| JPH07273282A (en) * | 1994-03-30 | 1995-10-20 | Rohm Co Ltd | Semiconductor device |
| JPH08222700A (en) * | 1995-02-16 | 1996-08-30 | Nissan Motor Co Ltd | Semiconductor device |
-
1997
- 1997-07-10 GB GB9714573A patent/GB2327146A/en not_active Withdrawn
-
1998
- 1998-07-07 WO PCT/EP1998/004214 patent/WO1999003147A1/en active Application Filing
- 1998-07-07 AU AU88582/98A patent/AU8858298A/en not_active Abandoned
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0008903A1 (en) * | 1978-08-25 | 1980-03-19 | Fujitsu Limited | Semiconductor integrated circuit device |
| WO1986007192A1 (en) * | 1985-05-21 | 1986-12-04 | Stemme Nils Goeran | Integrated semiconductor circuit and method for producing it, and use of such a circuit for providing a flow meter |
| WO1991013463A1 (en) * | 1990-02-27 | 1991-09-05 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Process for producing an insulated monocrystalline silicon island |
| GB2290165A (en) * | 1994-06-08 | 1995-12-13 | Hyundai Electronics Ind | Trench isolation |
| US5577309A (en) * | 1995-03-01 | 1996-11-26 | Texas Instruments Incorporated | Method for forming electrical contact to the optical coating of an infrared detector |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004001798A2 (en) * | 2002-06-25 | 2003-12-31 | Advanced Micro Devices, Inc. | A silicon-on-insulator device with strained device film and method for making the same with partial replacement of isolation oxide |
| WO2004001798A3 (en) * | 2002-06-25 | 2004-07-29 | Advanced Micro Devices Inc | A silicon-on-insulator device with strained device film and method for making the same with partial replacement of isolation oxide |
| CN1333454C (en) * | 2002-06-25 | 2007-08-22 | 先进微装置公司 | A silicon-on-insulator device with strain film and method for forming strain film |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9714573D0 (en) | 1997-09-17 |
| AU8858298A (en) | 1999-02-08 |
| WO1999003147A1 (en) | 1999-01-21 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |