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WO2003052364A1 - Procede de production d'une microstructure - Google Patents

Procede de production d'une microstructure Download PDF

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Publication number
WO2003052364A1
WO2003052364A1 PCT/EP2002/014192 EP0214192W WO03052364A1 WO 2003052364 A1 WO2003052364 A1 WO 2003052364A1 EP 0214192 W EP0214192 W EP 0214192W WO 03052364 A1 WO03052364 A1 WO 03052364A1
Authority
WO
WIPO (PCT)
Prior art keywords
spacer
layer
substrate
sacrificial layer
etching
Prior art date
Application number
PCT/EP2002/014192
Other languages
German (de)
English (en)
Inventor
Martin Eickhoff
Stefan Kolb
Reinhard Wittmann
Original Assignee
Infineon Technologies Ag
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Infineon Technologies Ag filed Critical Infineon Technologies Ag
Publication of WO2003052364A1 publication Critical patent/WO2003052364A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00912—Treatments or methods for avoiding stiction of flexible or moving parts of MEMS
    • B81C1/0092—For avoiding stiction during the manufacturing process of the device, e.g. during wet etching
    • B81C1/00944—Maintaining a critical distance between the structures to be released
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/10—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
    • G01J5/20—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/0802—Details

Definitions

  • the present invention relates to the field of manufacturing microstructures, and more particularly to the field of manufacturing microstructures with movable elements.
  • Micromechanical components with one or more elements movable with respect to a substrate are used in many devices.
  • acceleration sensors or rotation rate sensors comprise movable structures, a movable structure serving as a sensor element for detecting mechanical physical quantities, such as an acceleration or an angular velocity. Consequently, the quality and the performance of a method for producing such a movable structure are of decisive importance for the behavior and the accuracy of the measurement of physical quantities in such components.
  • a sacrificial layer which is arranged between a substrate and the layer which is to serve as a movable structure is used to produce a movable structure.
  • the sacrificial layer is partially or completely removed by wet chemical etching in order to form the movable structure, the etching agent used having to have a sufficient lateral etching rate in order to enable the etching of the sacrificial layer.
  • wet chemical etching to remove the sacrificial layer, however, the problem arises that when the etching solution dries, capillary forces occur, which often lead to mechanical contact between the movable one
  • HF gas etching is conventionally used for this purpose, but it has the disadvantage that special devices are required for this, which go beyond the devices used in industrial semiconductor production. Furthermore, performing HF gas etching is complex and difficult to control.
  • a known possibility of fixing the movable structure during the wet chemical etching is to use a so-called "lacquer plug" as described in DE19600399.
  • lacquer is introduced into an opening in the sacrificial layer via an opening in the structure, the lacquer plug thus formed having a small spatial extent.
  • the lacquer plug can then be removed either by a dry chemical method, such as, for example, ashing in an oxygen plasma, or by an organic solvent with supercritical drying.
  • this method has the disadvantage that reliable coating filling and residue-free coating removal are associated with technological difficulties for thick, movable structures.
  • the object of the present invention is to provide an improved method for producing a microstructure with a movable element.
  • the present invention is based on the finding that in the production of a moveable structural layer, an unwanted connection of a substrate and a moveable structural layer can be avoided by using a spacer between the substrate and the moveable structural layer, the material of which is chosen in this way is that the spacer essentially remains during the removal of a sacrificial layer which is arranged between the substrate and the movable structural layer and can be removed in a subsequent dry chemical etching after the removal of the sacrificial layer.
  • An advantage of the present invention is that the manufacture of a movable structural layer can be carried out without special equipment, which goes beyond standard equipment in semiconductor production, and in particular that the spacer can be removed by a dry etching process, in which an adhesive connection of the movable Structure and the substrate does not occur.
  • the movable layer is applied to a first sacrificial layer, which is arranged on a substrate, wherein a second sacrificial layer is further provided on the movable layer, on which a cover layer is provided.
  • the spacer can advantageously be used in this exemplary embodiment. be applied such that it is only connected to the cover layer.
  • the adhesion achieved is sufficient to prevent irreversible adhesion of the movable structure during the removal of the first and second sacrificial layers. The resulting avoidance of a support that is compatible with both the substrate and the
  • Connected lid is an advantage in that the fact that the shallow depth of the same is considerably facilitated.
  • La-f are schematic cross-sectional representations of an arrangement which undergoes a manufacturing process according to a first exemplary embodiment of the present invention.
  • FIGS. 2a-e are schematic cross-sectional representations of an arrangement which undergoes a manufacturing process according to a second exemplary embodiment of the present invention.
  • Fig. La shows a cross-sectional view of an arrangement before going through a manufacturing process according to the present invention.
  • the arrangement which represents a raw structure for a component, such as a sensor element for detecting an acceleration or an angular velocity, has a substrate 1 made of a semiconductor material, on which a sacrificial layer 2 is applied on one side thereof.
  • a structural layer 3 which is formed, for example, from a polycrystalline silicon material, is applied to the sacrificial layer 2, which preferably consists of an oxide which can be etched by wet chemistry, such as silicon oxide.
  • the structure layer should form the movable structure after going through the manufacturing process.
  • the structural layer has recesses that allow lateral etching of the sacrificial layer 2 to remove enable the same.
  • the structuring of the structure layer 3 is likewise carried out by means of methods and devices which are known from standard semiconductor production and, for example, comprise conventional photolithography.
  • the structural layer 3 comprises recesses in which the material of the structural layer 3 has been removed, so that the sacrificial layer 2 is exposed in these areas.
  • the recesses in the structure layer 3 are formed by means of known methods, such as, for example, photolithography with a subsequent etching process.
  • Fig. Lb shows the arrangement of Fig. La after a first process step.
  • a coherent lacquer layer 4 made of a photoresist is first applied to the structure layer 3.
  • the lacquer layer 4 is removed over a recess of the structure layer 3 by means of known photolithography techniques, so that a channel 5 is formed through the recess in the structure layer 3 and the exposed area of the lacquer layer 4, which in the direction of the substrate 1 through the Sacrificial layer 2 is limited.
  • Fig. Lc shows the arrangement of Fig. La after the execution of a further process step.
  • a recess 6 is formed in the sacrificial layer 2 by an etching process.
  • the etching process can be carried out by etching with an anisotropically etching agent or by etching with an anisotropically etching agent together with an isotropically etching agent, the etching agent in each case being fed via channel 5 to the opera layer 3 and attacking it.
  • the use of a suitable anisotropic etching agent with a sufficient lateral etching rate has the effect that after the etching process, the recess 6 formed beyond the channel 5 formed
  • the recess 6 has a boundary which extends laterally through a surface of the sacrificial layer 2, in the direction toward the substrate 1 through a surface of the substrate 1 and in the direction away from the substrate 1 through a section of the structural layer 3 is delivered.
  • the lacquer layer 4 is then removed, so that the arrangement shown in FIG. 1c is obtained.
  • a spacer 7 is introduced in a deposition process.
  • the spacer material penetrates into the recess 6 and forms a coherent layer along the boundaries of the recess 6 and along lateral surfaces which form the passage to the recess 6 , whereby the spacer layer can be structured in such a way that a spacer layer can be structured so that it only remains in support areas by means of a subsequently applied mask, which consists, for example, of a photoresist layer structured by means of photolithography.
  • the continuous layer that forms the spacer 7 is preferably formed such that it extends partially over a region of the surface of the structural layer 3, as shown in FIG.
  • LPCVD low pressure chemical vapor deposition
  • the use of a nitride layer is advantageous due to the high mechanical stability, as a result of which the thickness and geometry of the spacer 7 can be kept small.
  • the method according to the invention is also suitable for arrangements in which movable structures of small order of magnitude are to be produced.
  • the method of using a nitride layer which is applied by means of an LPCVD method, enables the spacer 7 to be formed even for deep structures with a thick sacrificial layer, since the applied nitride layer has a very good edge coverage, as a result of which good layer adhesion is achieved .
  • a further advantage of using a nitride layer results from the fact that nitride material has a substantially lower etching rate than the material of the sacrificial layer 2 in the case of wet chemical etching.
  • the thickness of the layer of the spacer 7 can be dimensioned such that, in the step of wet chemical etching of the sacrificial layer 2 described below, the spacer 7 is only slightly removed due to the lower etching rate of the nitride material compared to the sacrificial material and remains, so that Nitride layer can maintain a function as an elastic, distance-maintaining connection between the substrate 1 and the structural layer 3 during a subsequent etching process of the sacrificial layer 2.
  • FIG. 1e shows the arrangement after an etching process of the sacrificial layer 2.
  • a protective layer for example made of photoresist, is formed using known techniques in order to protect regions of the structural layer 3 against undesired etching.
  • the etching agent engages through the recesses in the structural layer 3 to the sacrificial layer 2, the sacrificial layer 2 between the structural layer 3 and the substrate 1 being partially or completely removed due to a high lateral etching rate of the etchant.
  • the present invention offers the advantage that etching with a good lateral etching rate can be achieved with a suitable choice of the spacer.
  • the spacer 7 is removed by means of a dry chemical etching process, the arrangement shown in FIG.
  • the etching process can be carried out in systems that are used as standard in semiconductor production.
  • the use of a dry chemical etching process to remove the spacer 7 has the advantages of good controllability and removal of the spacer 7 without leaving residues. It has proven to be an advantage here that the spacer 7 can be formed with a small geometry and thickness, whereby a simple and residue-free removal of the same is additionally facilitated by means of a dry chemical etching process.
  • a structural layer 3 movable with respect to the substrate 1 can be used, for example, as a detection element in an acceleration sensor or a rotation rate sensor, the movable structure layer 3 serving as a sensitive element for detecting physical quantities.
  • the spacer 7 is introduced in such a way that it is connected to a cover 10 and a structural layer 3.
  • FIG. 2a shows a raw structure of the second exemplary embodiment.
  • a first sacrificial layer 8 is formed on a substrate 1, on which in turn a structural layer 3 is formed, which is to form the movable structure.
  • the structural layer 3 has recesses in order to enable lateral etching.
  • a second sacrificial layer 9 is formed on the structure layer 3 and in the recesses thereof. Furthermore, a cover 10 is formed on the second sacrificial layer 9, which has recesses to enable lateral etching, which are preferably formed above the recesses in the structural layer 3, as shown in FIG. 2a.
  • the first sacrificial layer 8 and the second sacrificial layer 9 have a material that can be etched by wet chemistry, such as silicon oxide.
  • the first 8 and second 9 sacrificial layers are used in this exemplary embodiment in order to keep the movable structure which is formed from the structure layer 3 movable with respect to the substrate 1 and the cover 10.
  • FIG. 2b shows the structure of FIG. 2a after a first etching process has been carried out to form a recess 6, in which the spacer 7 is introduced in a subsequent step.
  • the recess 6 is formed by etching with an anisotropically etching agent or with an anisotropically etching agent together with an isoptrop-etching agent.
  • the etchant is ne recess 11 in the cover 10 to the second sacrificial layer 9 is supplied.
  • the use of the anisotropic etching agent causes the recess 6 in the second sacrificial layer 9 to extend laterally beyond the recess 11 of the cover 10.
  • a photoresist is applied to the cover 10 and into the recesses thereof prior to the etching process, the area in which the recess 6 is to be formed being defined by suitable structuring by means of, for example, photolithography.
  • the depth of the etching is regulated via the etching time.
  • the spacer 7 is introduced by means of a deposition process and preferably by a CVD process, with reference to FIG. 2c. Since the recess 6 is only formed in the second sacrificial layer 9, the spacer 7 is formed as a coherent layer which extends along the boundary surfaces of the recess 6 and on an area of the cover 10.
  • the spacer 7 is applied in such a way that a coherent layer is first applied along the boundary surfaces of the recess 6, on the cover 10 and in recesses thereof. As has already been described in the first exemplary embodiment, the spacer 7 is then limited to the desired area by means of a photolithography and an etching step.
  • the first 8 and second 9 sacrificial layers are removed by wet-chemical anisotropic etching in accordance with the first exemplary embodiment.
  • the first 8 and second 9 sacrificial layers are preferably removed in one process step.
  • the spacer 7 prevents the structural layer 3 from coming into contact with the substrate 1 or the cover 10 during the etching step.
  • the spacer since the spacer is anchored to the cover 10 and not to the substrate 1 after the etching of the first 8 and second 9 sacrificial layer, in order to provide support for the structural layer 3, it is necessary to include the material for the spacer 7 to select a large adhesiveness in order to withstand the weight of the structural layer 3 and the cohesive forces generated during the etching.
  • nitrite which has a high anchoring ability, is advantageously used for this purpose.
  • the method according to the second exemplary embodiment enables the first sacrificial layer by limiting the spacer 7 to the depth of the structural layer 3
  • the movable structure 3 is freely movable with respect to the substrate 1 and the cover 10, the latter being connected at one edge to the substrate 1 and the cover 10 via remnants of the sacrificial layers 8 and 9.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Micromachines (AREA)
  • Pressure Sensors (AREA)

Abstract

L'invention concerne un procédé permettant de produire une microstructure comprenant un substrat (1) et une structure pouvant être déplacée par rapport à ce substrat (1). Selon ce procédé, sur une structure brute comprenant le substrat (1), une couche sacrificielle (2) disposée sur ce substrat (1) et une couche structurelle (3), la couche sacrificielle (2) étant située entre la couche structurelle (3) et le substrat (1), un élément d'espacement (7) est placé entre la couche structurelle (3) et le substrat (1). Le matériau de l'élément d'espacement (7) est différent du matériau de la couche sacrificielle (2) et il peut être gravé à sec. Une fois l'élément d'espacement (7) mis en place, la couche sacrificielle (2) est éliminée de telle sorte qu'il reste une partie de l'élément d'espacement (7), puis ce dernier est éliminé par un procédé de gravure à sec.
PCT/EP2002/014192 2001-12-17 2002-12-12 Procede de production d'une microstructure WO2003052364A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10161953.7 2001-12-17
DE2001161953 DE10161953A1 (de) 2001-12-17 2001-12-17 Verfahren zum Herstellen einer Mikrostruktur

Publications (1)

Publication Number Publication Date
WO2003052364A1 true WO2003052364A1 (fr) 2003-06-26

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Application Number Title Priority Date Filing Date
PCT/EP2002/014192 WO2003052364A1 (fr) 2001-12-17 2002-12-12 Procede de production d'une microstructure

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DE (1) DE10161953A1 (fr)
WO (1) WO2003052364A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011028384A1 (fr) * 2009-08-27 2011-03-10 International Business Machines Corporation Commutateurs de circuits intégrés: structure de conception et procédé de fabrication

Citations (4)

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Publication number Priority date Publication date Assignee Title
WO1993021536A1 (fr) * 1992-04-22 1993-10-28 Analog Devices, Inc. Procede de fabrication de microstructures
US5258097A (en) * 1992-11-12 1993-11-02 Ford Motor Company Dry-release method for sacrificial layer microstructure fabrication
DE19536228A1 (de) * 1995-09-28 1997-04-03 Siemens Ag Mikroelektronischer, integrierter Sensor und Verfahren zur Herstellung des Sensors
DE19600399C1 (de) * 1996-01-08 1997-08-21 Siemens Ag Herstellverfahren für ein mikromechanisches Bauteil mit einer beweglichen Struktur

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19536250A1 (de) * 1995-09-28 1997-04-03 Siemens Ag Mikroelektronischer, integrierter Sensor und Verfahren zur Herstellung des Sensors

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
WO1993021536A1 (fr) * 1992-04-22 1993-10-28 Analog Devices, Inc. Procede de fabrication de microstructures
US5258097A (en) * 1992-11-12 1993-11-02 Ford Motor Company Dry-release method for sacrificial layer microstructure fabrication
DE19536228A1 (de) * 1995-09-28 1997-04-03 Siemens Ag Mikroelektronischer, integrierter Sensor und Verfahren zur Herstellung des Sensors
DE19600399C1 (de) * 1996-01-08 1997-08-21 Siemens Ag Herstellverfahren für ein mikromechanisches Bauteil mit einer beweglichen Struktur

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HIRANO T ET AL: "Dry releasing of electroplated rotational and overhanging structures", PROCEEDINGS OF THE WORKSHOP ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS) FORT LAUDERDALE, FEB. 7 - 10, 1993, NEW YORK, IEEE, US, vol. WORKSHOP 6, 7 February 1993 (1993-02-07), pages 278 - 283, XP010111027, ISBN: 0-7803-0957-X *
MASTRANGELO C H ET AL: "A dry-release method based on polymer columns for microstructure fabrication", PROCEEDINGS OF THE WORKSHOP ON MICRO ELECTRO MECHANICAL SYSTEMS (MEMS) FORT LAUDERDALE, FEB. 7 - 10, 1993, NEW YORK, IEEE, US, vol. WORKSHOP 6, 7 February 1993 (1993-02-07), pages 77 - 81, XP010111065, ISBN: 0-7803-0957-X *
MESCHER M J ET AL: "A dry etch fabrication process for microelectromechanical devices using silicon nitride sacrificial layers", ADVANCES IN ELECTRONIC PACKAGING 1997. PROCEEDINGS OF THE PACIFIC RIM/ASME INTERNATIONAL INTERSOCIETY ELECTRONIC AND PHOTONIC PACKAGING CONFERENCE. INTERPACK '97, PROCEEDINGS OF INTERPACK '97, KOHALA COAST, HI, USA, 15-19 JUNE 1997, 1997, New York, NY, USA, ASME, USA, pages 435 - 438 vol.1, XP002240569, ISBN: 0-7918-1559-5 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011028384A1 (fr) * 2009-08-27 2011-03-10 International Business Machines Corporation Commutateurs de circuits intégrés: structure de conception et procédé de fabrication
GB2485714A (en) * 2009-08-27 2012-05-23 Ibm Integrated circuit switches, design structure and methods of fabricating the same
CN102471048A (zh) * 2009-08-27 2012-05-23 国际商业机器公司 集成电路切换器、设计结构及其制造方法
US8569091B2 (en) 2009-08-27 2013-10-29 International Business Machines Corporation Integrated circuit switches, design structure and methods of fabricating the same
GB2485714B (en) * 2009-08-27 2014-05-14 Ibm Integrated circuit switches, design structure and methods of fabricating the same
US9284185B2 (en) 2009-08-27 2016-03-15 Globalfoundries Inc. Integrated circuit switches, design structure and methods of fabricating the same

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Publication number Publication date
DE10161953A1 (de) 2003-06-26

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