CN1469939A - A method for wet etching - Google Patents

A method for wet etching Download PDF

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Publication number
CN1469939A
CN1469939A CNA018176453A CN01817645A CN1469939A CN 1469939 A CN1469939 A CN 1469939A CN A018176453 A CNA018176453 A CN A018176453A CN 01817645 A CN01817645 A CN 01817645A CN 1469939 A CN1469939 A CN 1469939A
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CN
China
Prior art keywords
etching
substrate
protective layer
deactivation matter
agent
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Granted
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CNA018176453A
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Chinese (zh)
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CN1243849C (en
Inventor
比加尼・比加纳森
比加尼·比加纳森
德森
佩·比德森
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Obducat AB
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Obducat AB
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Priority claimed from SE0003345A external-priority patent/SE517275C2/en
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Publication of CN1469939A publication Critical patent/CN1469939A/en
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Publication of CN1243849C publication Critical patent/CN1243849C/en
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    • 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
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
    • H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
    • H05K3/067—Etchants
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/02—Local etching
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C25F3/02—Etching
    • C25F3/14—Etching locally

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Electrochemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • ing And Chemical Polishing (AREA)
  • Weting (AREA)

Abstract

In etching, an etchant (4) for etching of a substrate (1) is applied in a given pattern. Before etching, a resist layer (2) is applied to the substrate (1) in said pattern to define at least one exposed portion (3) of the substrate (1). In order to minimize under etching, a passivating substance is arranged, before etching, on the substrate (1) to also define said pattern, i.e. at the periphery of the exposed portion (3). The passivating substance is such as to form, during etching, an etch-protecting compound at the periphery.

Description

Wet etching method
Technical field
The present invention relates generally to that etch substrate produces minor structure therein.More specifically, the present invention relates to a kind of method of anisotropic material dissolving etching.
Background technology
Can in substrate, produce micron and nanostructure by the selected part that etches away substrate surface.These part contacts of substrate surface can be with the etching agent of etching mode and baseplate material reaction.Usually, substrate was coated with one deck and etching agent sluggish or nonreactive at all etching protecting materials (resist) before etching.The etching protective layer is made in the multi-stage process of being everlasting, and multi-stage process comprises that wherein the etching protecting materials is coated in the lip-deep coating step of whole base plate, and the step of exposing that wherein produces the exposed portions serve figure in being coated to the etching protecting materials of substrate.Can and develop subsequently by the etching protecting materials (photo-resist) that applies via mask irradiation expose its irradiation or not illuminated portion finish and expose step.
During the etching technics, dissolving and/or machinery are removed baseplate material in the part of exposing.The material dissolves etching method can be divided into wet and dried technology.In wet stock dissolving etching method, use liquid etchant.In the wet chemical etching, etching agent and baseplate material spontaneous reaction are in the electrochemistry wet etching, when applying voltage etching agent transmission electric current, in the surface etch agent generation electrochemical reaction of baseplate material.
In the wet etching method; equally in some dry etching methods; for example in the plasma etching; plan only also is easy to take place in around the exposed portions serve in the material dissolves surface reaction that takes place on the exposed portions serve of substrate; also under the etching protective layer, take place, produce so-called end eclipse (underetching) thus.This end eclipse has limited and has produced narrow and the deep structure possibility of mutual compact arranged bus for example.Though the cycle of etching technics increases the degree of depth that causes etching structure and increases, also cause the trend of end eclipse to increase simultaneously.
Even in this case because dry etching produces less end eclipse and preferred dry etching method, but it is fast not as wet etching.
In US 5 962 346, US 5 176 792, US 5 837 616 and JP 3 082 120, provided the example of dry etching.Thus, when at full speed carrying out etching, because the ability of the higher etching speed of wet etching, and preferred wet etching.This mainly be since during the wet etching etching agent towards substrate transmit and material delivery leave substrate in liquid than fast in plasma body.
US-A-4,877,480 disclose the method for removing the material etch substrate by laser.For cooling base between radiation era, substrate be immersed in can etching and can illuminated activated liquid in.During the etching technics, the material dissolves etching effect of liquid is assisted the etching effect of removing of laser.Allegedly can the etching structure littler than routine.
US-A-5,279,702 disclose the technology of wet chemical etch substrate.The substrate that is coated with the resist layer of composition is immersed in the etching agent of spontaneous etching.This etching agent contains the deactivation matter that spontaneously forms etching protection compound on the exposed portions serve of substrate, and these parts are not reacted with etching agent thus.By perpendicular to the surface irradiation substrate, in the direction of irradiation, remove etching protection compound, so that in the exposed portions serve of substrate, carry out etching.Yet etching protection compound has stoped around exposed portions serve proceeds etching, protects not exposure by synergetic etching protective layer.During etching technics, the blocking layer is formed on the sidewall of etching structure thus, makes the end eclipse minimum thus.
The limitation of above technology is must shine whole base plate so that can carry out etching during whole etching technics.In a lot of situations, be difficult to provide this irradiation.
Summary of the invention
Given this, an object of the present invention is to provide improving one's methods of a kind of wet etching, eliminated the shortcoming of above prior art.
Conspicuous these and other objects can obtain by the method that limits in the independent claim 1 from the following describes.Preferred embodiment limits in the dependent claims.
Method of the present invention is based on following understanding: the deactivation matter that forms etching protection compound during the etching is arranged near rather than the top of the part that will be etched away.Deactivation matter is arranged on ceiling substrate and makes the figure that will be etched in the substrate thus.In substrate surface during the etching structure, deactivation matter forms the etching protection compound that defines the above figure of substrate, thereby the blocking layer of etching protection compound automatically is formed on the sidewall of structure and has prevented end eclipse.Compared with prior art significantly having simplified etching, is owing to prevent that the protective layer of end eclipse automatically is positioned at needed position, just with the position of the part direct neighbor that will be etched away, does not need irradiation or similarly measure.Thus, can realize easily that etching minor structure and end eclipse are little.
The method according to this invention is applicable to chemistry and electrochemistry wet etching, and both combinations.
According to the present invention, be positioned at the composition reaction of substrate surface during the active substance of deactivation matter and the etching, form etching protection compound.This composition can be contained in the etching agent or for example form the etching of substrate by apply ion from substrate.In two kinds of situations, can guarantee that the etching protection compound that forms has defined the figure that will be etched on the substrate.
The etching protective layer is being coated on the substrate before the etching usually.Be coated in the preferred described figure ceiling substrate make at least one substrate exposed portions serve the etching protective layer and be arranged on deactivation matter around the exposed portions serve so that etching protection compound only be formed on described around.According to preferred embodiment, by deactivation matter being incorporated in the etching protecting materials, the etching protecting materials will be coated to substrate and form the etching protective layer.This means in the etching protective layer deactivation matter when forming figure automatically be positioned at the substrate exposed portions serve around.During the etching technics, deactivation matter, perhaps its active substance leaks out the etching protective layer and form etching protection compound around the exposed portions serve of substrate.
Preferably, the etching protective layer is essentially organic materials.
According to another preferred embodiment, before the etching protective layer formed on the substrate, the releasing layer of one deck at least that contains deactivation matter was coated to substrate.Releasing layer has the component and the thickness of the partial concn that produces deactivation matter or its active substance needs around exposed portions serve.
Preferably, releasing layer is made up of organic materials basically.Favourable part is the good adhesion of etching protective layer and organic layer.
Make etching protection compound according to the present invention by ionic reaction.Be owing to need not to be a kind of etching agent but can freely select with the composition of the active substance reaction of deactivation matter and therefore can in wide region, select ion according to the major advantage of the inventive method to obtain the fact of good etching protective layer.
Thus, deactivation matter preferably be contained in the organic materials, in the etching protective layer or in the releasing layer.
Description of drawings
Introduce the present invention and advantage thereof in more detail below with reference to schematic figures by the preferred embodiment shown in the example.
Fig. 1-3 is the sectional view of substrate, shows the lithographic method according to the first embodiment of the present invention, and
Fig. 4 is the sectional view of substrate, shows lithographic method according to a second embodiment of the present invention.
Embodiment
Introduce the first embodiment of the present invention below with reference to Fig. 1-3.
Fig. 1 shows the part of the substrate 1 that will be etched.In first step, be coated to substrate surface as the etching protecting materials of photo-resist and form etching protective layer 2.Etching protective layer 2 is used to protect following substrate 1 not to be subjected to etching.In step of exposure subsequently, remove the selected part of etching protective layer 2 in known manner, so that in given figure, expose substrate 1, as can be seen from Figure 2.The exposed portions serve like this 3 of substrate 1 is reacted with etching agent 4 in etch step subsequently then, as shown in Figure 3.
In the etch step according to Fig. 3, etching agent 4 applies with the form of electrolytic solution, electrochemistry and/or etch substrate 1 chemically.In electrochemical etching, electrolytic solution 4 generally includes can not be with the mode of etching and neutral salt or the acid or the alkali of substrate 1 reaction.Electrolytic solution 4 also contains self can be with the chemical oxidation composition of etching mode and substrate 1 reaction.In chemical etching, electrolytic solution 4 contains this chemical oxidation composition of high level.
At the embodiment that illustrates, the deactivation matter (not shown) is contained in the etching protective layer 2.This deactivation matter is forming etching protection compound on substrate 1 during the etch step.During the etch step, deactivation matter or its active substance stay etching protective layer 2, represent as the arrow A among Fig. 3, so that use and be positioned near the substrate 1 composition and form and be difficult to dissolving or insoluble etching protection compound.This compound is positioned at also forming of exposed portions serve 3 on every side and stops the local blocking layer 5 of continuing etching.Blocking layer 5 comprises the individual layer of at least one the etching protection compound that contacts with substrate 1 physics.During the etch step, take place on the structure side wall 6 that in substrate, forms blocking layer 5 gradually with spontaneous synthetic.The synthetic of blocking layer 5 carries out in self-regulating process basically.If etching agent 4 has also dissolved the substrate 1 below the etching protective layer 2, etching protective layer 2 surface that is exposed to etching agent 4 also increases so, deactivation matter or its active substance will be increased to stay etching protective layer 2 and with the degree of above-mentioned composition reaction.Subsequently, the formation of etching protection compound also increases.
For example be contained in the amount of the deactivation matter in the etching protecting materials, the perhaps thickness of etching protective layer 2, the degree of the blocking effect around can the exposed portions serve 3 of control basal plate 1 by change.Also can advantageously limit the amount that is contained in the deactivation matter in the etching protecting materials, so that for example expose and step is exposed in development by the method for routine.
In the example that illustrates, substrate 1 is made of metal, and is generally Cu, Cr, Ag, Au, Ni or alloy.In the example that illustrates, deactivation matter can by organic etching protecting materials for example the etching protective layer 2 that forms of photo-resist make.This deactivation matter was generally and contained just like I this moment -, F -, Cl -, Br -, S 2-, SCN -, CN -, SO 4 2-, C 2O 4 2-, PO 4 3-, CO 3 2-Or CrO 4 2-Deng the ionic compound of inorganic anion, and can mix with organic etching protecting materials.The example of this deactivation matter is ion pair reagent (ion pairing reagents), for example tetrabutylammonium iodide.In addition, deactivation matter can be a compound, and for example thioacetamide otherwise changes suitable negatively charged ion into.Suitably select deactivation matter so that it or it active substance its negatively charged ion and near the composition reaction that is positioned at the substrate 1 for example, form the compound that is difficult to dissolve and be positioned on the substrate 1.This composition can be the positively charged ion that discharges from metal substrate 1 during the etching, or natural or be contained in positively charged ion in the etching agent 4 as additive-package.Latter event uses given deactivation matter when allowing the dissimilar baseplate material of etching, because deactivation matter needn't form etching protection compound with the baseplate material cooperation.
For example, can make by the substrate 1 of etching copper or copper alloy.In addition, can make as the passivation of active substance by containing iodide, for example tetrabutylammonium iodide.During the etch step, iodide ion leave etching protective layer 2 and with etching during the cupric ion reaction that discharges from substrate, form the sidewall that cupric iodide (CuI) prevented etching structure and continue etching.In addition, can make as active substance by chlorion, stay the silver ions reaction in etching protective layer 2 and the etching agent 4 and form silver chloride (AgCl) be deposited in substrate 1 exposed portions serve around.
Below only for the example of indefiniteness of the present invention is described.Should be appreciated that for each given baseplate material deactivation matter can have many different combinations with the composition that causes forming suitable etching protection compound.In addition, replace negatively charged ion, from the positively charged ion of deactivation matter as active substance and by be positioned near the substrate composition reaction and form and be difficult to the dissolved compound.Also can use other compound outside the deionization compound, if these compounds can dissolve in the etching protecting materials, for example can be directly or by the active substance composite base plate place organic compound of negatively charged ion or cation constituent for example.
Fig. 4 shows another embodiment of the present invention.In the present embodiment, one deck or the more releasing layers 7 that at first contains deactivation matter is applied to substrate 1.Releasing layer 7 is preferably very thin and directly be coated to substrate 1.The thickness that has now found that about 50-1000nm can obtain satisfied result.Yet, also can use other thickness.Subsequently; the etching protecting materials that does not preferably have deactivation matter is coated to the etching protective layer 2 on the releasing layer 7, therefore the selected part of removing etching protective layer 2 and releasing layer 7 in known manner in exposing step; so that substrate 1 exposes given figure, as shown in Figure 4.
Similar with first embodiment according to Fig. 1-3, deactivation matter or its active substance will stay releasing layer 7 partly and form etching protection blocking layer 5 around the exposed portions serve 3 of substrate 1.Because releasing layer 7 can be provided with the deactivation matter of optional thickness and optional amount, the release of deactivation matter or its active substance may be controlled to the value of optimization around exposed portions serve 3.Except the advantage according to the method for first embodiment, present embodiment allows further to prevent end eclipse.In addition, owing to do not need to be dissolved in the etching protective layer, so present embodiment has bigger degree of freedom in the selection of deactivation matter.
According to the deactivation matter in the releasing layer 7 with select the selection of concentration, before etch step, may need the extra step of exposing, plasma etching for example is so that expose substrate 1 fully according to the figure that limits.Should be appreciated that to the invention is not restricted to specifying of above preferred embodiment, can in the scope of incidental claim bundle, revise.
Should be noted in the discussion above that to the invention is not restricted to above-mentioned specific descriptions, but can make amendment within the scope of the claims existing preferred implementation.
The effective constituent of deactivation matter can be positively charged ion.This moment, appropriate ingredients was a negatively charged ion.

Claims (9)

1. the wet etching method of a substrate (1); wherein applying etching agent (4) is used for by given pattern etching substrate (1); be characterised in that deactivation matter is arranged on substrate (1) and goes up to limit described figure; and deactivation matter forms the etching protection compound that limits the above figure of substrate (1) during being etching; wherein deactivation matter comprise with etching during be contained in the active substance of the composition reaction in the etching agent (4); form etching protection compound; wherein etching agent (4) is a solution; wherein active substance comprises and is dissolved in the etching agent (4) and forms the ion of compound with described composition, and this compound is difficult to dissolving at least in solution.
2. according to the method for claim 1; wherein go up coating etching protective layer (2) by described figure at substrate (1) before the etching; to limit at least one exposed portions serve (3) of substrate (1); and wherein deactivation matter be arranged on exposed portions serve (3) around so that only form etching protection compound during the etching around described.
3. according to the method for claim 2, at least one contains the releasing layer (7) of deactivation matter wherein to go up coating at substrate (1), preferably directly be coated on the surface of wanting etching, and wherein etching protective layer (2) is coated at least one releasing layer (7).
4. according to the method for claim 3, wherein releasing layer consists essentially of organic materials.
5. according to the method for claim 3 or 4, wherein apply etching agent (4) before, described figure is formed in the etching protective layer (2) and in described at least one releasing layer (7).
6. according to the method for claim 2, wherein deactivation matter is incorporated in the etching protecting materials, and the etching protecting materials is coated in substrate (1) and goes up formation etching protective layer (2) then.
7. according to the method for claim 6, wherein apply etching agent (4) before, in etching protective layer (2), forming described figure.
8. according to any one method among the claim 2-7, wherein etching protective layer (2) consists essentially of organic materials.
9. according to any one method in the above claim, wherein preferred by from substrate (1) thus the release ion forms described composition when substrate (1) etching.
CN 01817645 2000-09-20 2001-09-20 A method for wet etching Expired - Fee Related CN1243849C (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US23418400P 2000-09-20 2000-09-20
SE0003345A SE517275C2 (en) 2000-09-20 2000-09-20 Wet etching of substrate involves arranging on the substrate a passivating substance comprising active substance reacting with component contained in etchant to form etch protecting compound
SE00033456 2000-09-20
US60/234,184 2000-09-20

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CN1469939A true CN1469939A (en) 2004-01-21
CN1243849C CN1243849C (en) 2006-03-01

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1262883C (en) 2000-07-17 2006-07-05 得克萨斯州大学系统董事会 Method and system of automatic fluid dispensing for imprint lithography processes
US8850980B2 (en) 2006-04-03 2014-10-07 Canon Nanotechnologies, Inc. Tessellated patterns in imprint lithography

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5279702A (en) * 1992-09-30 1994-01-18 Texas Instruments Incorporated Anisotropic liquid phase photochemical copper etch
EP1060299A1 (en) * 1998-03-05 2000-12-20 Obducat AB Method of etching

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CN1243849C (en) 2006-03-01
WO2002024977A1 (en) 2002-03-28

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Granted publication date: 20060301

Termination date: 20110920