EP1256126A1 - Solution decapante et procede - Google Patents

Solution decapante et procede

Info

Publication number
EP1256126A1
EP1256126A1 EP01905084A EP01905084A EP1256126A1 EP 1256126 A1 EP1256126 A1 EP 1256126A1 EP 01905084 A EP01905084 A EP 01905084A EP 01905084 A EP01905084 A EP 01905084A EP 1256126 A1 EP1256126 A1 EP 1256126A1
Authority
EP
European Patent Office
Prior art keywords
etching solution
water
carboxylic acid
etching
solution
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Withdrawn
Application number
EP01905084A
Other languages
German (de)
English (en)
Inventor
George Matamis
Heidi L. Denton
Michael J. Davison
Jeffrey A. Smith
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NXP USA Inc
Original Assignee
Motorola Inc
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 Motorola Inc filed Critical Motorola Inc
Publication of EP1256126A1 publication Critical patent/EP1256126A1/fr
Withdrawn legal-status Critical Current

Links

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
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
    • H01L21/3105—After-treatment
    • H01L21/311—Etching the insulating layers by chemical or physical means
    • H01L21/31105—Etching inorganic layers
    • H01L21/31111—Etching inorganic layers by chemical means
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K13/00—Etching, surface-brightening or pickling compositions
    • C09K13/04—Etching, surface-brightening or pickling compositions containing an inorganic acid
    • C09K13/08—Etching, surface-brightening or pickling compositions containing an inorganic acid containing a fluorine compound

Definitions

  • the present invention relates, in general, to an etching solution and, more particularly, to an etching solution for etching semiconductor and Micro Electro-Mechanical System (MEMS) devices .
  • MEMS Micro Electro-Mechanical System
  • MENS devices such as micro-sensors, micro-actuators and micro-switches
  • micro-machining Etching of a sacrificial dielectric layer, such as silicon dioxide, is an important micro- machining method employed in the fabrication of MEMS devices as well as in the formation of semiconductor devices.
  • the sacrificial oxide is typically provided in a polysilicon structure that may also include silicon nitride and metallization, e.g. aluminum or copper.
  • silicon nitride and metallization e.g. aluminum or copper.
  • etching solution For MENS and other semiconductor devices, a high etch selectivity for oxide relative to metal, for example, is desirable.
  • One prior etching solution is a so-called Buffered Oxide Etch (BOE) solution that contains HF buffered by ammonium fluoride.
  • BOE Buffered Oxide Etch
  • the BOE solution exhibits poor etch selectivity in that this solution severely etches exposed metal, polysilicon, and/or nitride surfaces during the etching of the sacrificial oxide.
  • aluminum metallization is often completely etched before the sacrificial oxide is removed in its entirety.
  • a common use for micro-machining as described above is the formation of a MEMS sensor. Furthermore, it is becoming desirable to form integrated electronics on the same device used to form the MEMS sensor. Thus, when forming a combination MEMS sensor, which requires the etching of a sacrificial oxide, and an integrated circuit, it is critical that the metallization and passivation features of the chip not be detrimentally etched by the sacrificial oxide etching solution.
  • the present invention generally provides an etching solution that is a mixture of anhydrous HF, a carboxylic acid and water.
  • the solution is useful for the etching of oxides used in the fabrication of MEMS devices such as, for example, micro-sensors and micro- machines.
  • An important advantage of the etching solution of the present invention is that it has a high etch selectivity for silicon oxide relative to other materials including metals, nitrides and polysilicon that form the structural components of MEMS and electronic devices.
  • the etching solution of the present invention can remove sacrificial oxides with only relatively minor etching of these other non-oxide materials.
  • the etching solution of the present invention improves the fabrication process of MEMS and electronic devices.
  • the etching solution is described further below in one embodiment of the present invention with an example of its use PhosphoSilicate Glass (PSG) created by chemical vapor deposition.
  • PSG PhosphoSilicate Glass
  • Thermally grown Si0 2 and PSG are two examples of oxide films used as a sacrificial oxide layer in the formation of a micro-machined structure.
  • the sacrificial oxide layer is in contact with portions of the micro-structure prior to sacrificial oxide etching.
  • the etching solution is also generally applicable to the removal of other types of oxides that may be used in MEMS and electronic devices where metals, nitrides and/or polysilicon materials that form the micro- structure or electronic components could be exposed to the etching solution during oxide removal.
  • CMOS Complementary Metal Oxide Semiconductor
  • the carboxylic acid used can be selected generally as any acid having one or more carboxyl groups and more specifically including, for example, oxalic acid, formic acid, lactic acid, tartaric acid, malic acid, succinic acid, citric acid and acetic acid. It has been found that acetic acid, combined with the above identified ingredients, is particularly useful for selectively etching thermally grown Si0 2 and PSG.
  • the mixing ratio of anhydrous HF to carboxylic acid is not considered to be critical, but it has been found that a preferred range is approximately 0.1% anhydrous HF, up to the solubility limit of the particular carboxylic acid.
  • One preferred mixture, which has shown superior experimental results is approximately 10% anhydrous HF relative to the carboxylic acid. Dilution of the solution with respect to the amount of HF, will result in slower etch rates. It should be understood that the mixing ratio of anhydrous HF to carboxylic acid is not a limitation of the present invention.
  • the preferred range of water introduced to one embodiment of the present etching solution is in the range of approximately 0.5% to 5.0% by weight.
  • use of an anhydrous carboxylic acid, e.g., glacial acetic acid, is preferred in order to more precisely control the amount of water in the etching solution.
  • the etching solution is created by injecting anhydrous HF into an aqueous solution of a carboxylic acid, such as glacial acetic acid, having a precisely controlled minimal amount of water.
  • a carboxylic acid such as glacial acetic acid
  • the temperature required for use of the etching solution according to the present invention is not considered to be critical. In general, during etching it is preferred to use a cooler temperature of below approximately 30 degrees Celsius (°C), e.g., in the range of approximately 15°C-30°C. An advantage of such a cooler temperature is a reduction in the evaporative loss of the etching solution. Also, it is preferable that the etching solution is in the liquid phase during etching.
  • the etching solution and device having a sacrificial oxide to be etched be placed in a sealed environment substantially free of non-solution water.
  • a sealed container or etching bath with a closed lid having been purged with an inert gas such as nitrogen can be used. It has been discovered that water absorption from the atmosphere above the controlled minimal water levels of the etching solution undesirably increases the metal etching rate.
  • the etching was performed at 18 °C. and the sample etch rates measured as follows:
  • Etch selectivities of sacrificial oxides relative to metals, polysilicons, and nitrides are derived from the associated etch rates.
  • an etching solution of HF, carboxylic acid, and a minimal controlled amount of water approximately in the ratio of 10:89:1
  • the etch selectivity for thermally grown SiO? relative to aluminum or copper is in the range of approximately 9 to 80; whereas, the etch selectivity for thermally grown Si0 2 relative to polysilicon is in the range of approximately 65 to 320.
  • the etch selectivity for thermally grown Si0 2 relative to silicon nitride is in the range of approximately 9-40.
  • the etch selectivity for PSG relative to aluminum or copper is in the range of approximately 666 to 50,000.
  • the etch selectivity for PSG relative to polysilicon is in the range of approximately 5,000 to 200,000.
  • the etch selectivity for PSG relative to silicon nitride is in the range of approximately 714 to 25,000.
  • the wide range of etch selectivities for PSG is dependent on certain process parameters which include, but are not limited to whether the PSG film is annealed, the phosphorous doping level and the deposition temperature .

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • General Chemical & Material Sciences (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Weting (AREA)
  • ing And Chemical Polishing (AREA)
  • Micromachines (AREA)
  • Pressure Sensors (AREA)

Abstract

L'invention concerne une solution décapante de fluorure d'hydrogène (HF), d'acide carboxylique et d'eau possédant une forte sélectivité de décapage pour l'oxyde de silicium par rapport au métal, au polysilicium et au nitrure. La solution décapante se forme en injectant du HF anhydre dans un acide carboxylique ayant un quantité minimale d'eau calculée avec précision. La solution décapante est utile dans la fabrication de dispositifs à systèmes mécaniques microélectriques (MEMS), ainsi que dans la fabrication de dispositifs MEMS associés à des composants électroniques intégrés sur la même puce.
EP01905084A 2000-02-04 2001-01-26 Solution decapante et procede Withdrawn EP1256126A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US49786400A 2000-02-04 2000-02-04
US497864 2000-02-04
PCT/US2001/002569 WO2001057921A1 (fr) 2000-02-04 2001-01-26 Solution décapante et procédé

Publications (1)

Publication Number Publication Date
EP1256126A1 true EP1256126A1 (fr) 2002-11-13

Family

ID=23978615

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01905084A Withdrawn EP1256126A1 (fr) 2000-02-04 2001-01-26 Solution decapante et procede

Country Status (5)

Country Link
EP (1) EP1256126A1 (fr)
JP (1) JP2003536242A (fr)
KR (1) KR20020075907A (fr)
AU (1) AU2001233002A1 (fr)
WO (1) WO2001057921A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI282814B (en) * 2002-09-13 2007-06-21 Daikin Ind Ltd Etchant and etching method
KR100626382B1 (ko) 2004-08-03 2006-09-20 삼성전자주식회사 식각 용액 및 이를 이용한 자기 기억 소자의 형성 방법
JP4828451B2 (ja) * 2006-03-27 2011-11-30 東京エレクトロン株式会社 基板処理方法、半導体装置の製造方法および基板処理装置
WO2007140193A1 (fr) * 2006-05-25 2007-12-06 Honeywell International Inc. Agents d'attaque chimique sélectifs du carbure de tantale, procédés de production et utilisations de ceux-ci

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4395304A (en) * 1982-05-11 1983-07-26 Rca Corporation Selective etching of phosphosilicate glass
US5824601A (en) * 1997-06-30 1998-10-20 Motorola, Inc. Carboxylic acid etching solution and method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0157921A1 *

Also Published As

Publication number Publication date
JP2003536242A (ja) 2003-12-02
KR20020075907A (ko) 2002-10-07
WO2001057921A1 (fr) 2001-08-09
AU2001233002A1 (en) 2001-08-14

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