TW546670B - Method for electroless deposition and patterning of a metal on a substrate - Google Patents

Abstract

A method for manufacturing a patterned metal layer on a substrate is provided which comprises the step of electrolessly depositing a blanket metal film of a metal onto a substrate, followed by subsequently patterning said metal layer by means of microcontact printing. The deposited metal can be overplated with another metal, which can be microcontact printed to serve as an etch mask.

Description

546670

FIELD OF THE INVENTION The present invention relates to a method for electrodeless deposition and patterning of metal on a substrate. More specifically, the present invention relates to a method in which the process steps of micro-contact printing and electrodeless deposition are combined. Background of the Invention, Known Techniques Drawing metal patterns on a substrate is a generally required and important process in modern technology; it is used in, for example, microelectronics and display manufacturing. This drawing pattern generally requires vacuum deposition of metal on the entire surface of the substrate and selective removal using lithographic etching and etching techniques. Vacuum deposition of metal and photoresist consumption constitute a considerable cost factor in manufacturing metal structures, and limit The pattern can be used to draw the size of the substrate. The technology of electrodeless deposition (hereinafter referred to as ELD) of metal on (insulating) surfaces can provide an alternative method for vacuum deposition of metal on substrates (see, for example, " Electroless Electroless Mining. Basics and Applications ", GO · Mallory, JB Hajdu Editor; American Electroplating Plant and Surface Polishing Association, Orlando, F1, 1990). Electrodeless deposition of metals such as copper, silver, gold, nickel, germanium, and cobalt is a widely used method for making fine metal patterns on printed circuits. Electroless plating is carried out by an autocatalytic redox process, in which the metal cations to be deposited are reduced on the surface of the metal pattern to be formed by a soluble reducing agent, or on the surface of the catalyst used to initiate deposition. This oxidation Reduction is generally made only on the surface where it can be catalyzed. Non-catalytic surfaces are first metalized after being activated with a metal catalyst such as palladium. Selective deposition can selectively deactivate the catalytic substrate to obtain non-reaction through the catalyst. This is achieved by selective activation of the surface. Several methods for making patterned catalysts are known, most of which are based on lithographic etching techniques. Borrow • 6-This paper size applies to China Standard (CNS) A4 (210X297 mm) 546670 A7 B7 V. Description of the invention (2 The size of the pattern produced by metal electrodeless deposition can be as small as 0.1 micron. Micro-contact printing can also provide the use of photolithography etching for metal Alternative method of patterning. Micro-contact printing (hereinafter referred to as pCP) is a technique for forming organic single-layer patterns with lateral dimensions of micrometer and submicrometer. It prints molecules on the substrate by stamping to form a certain type of pattern. Provides experimental simplicity and flexibility. To date, most previous techniques have relied on the remarkable ability of long-chain alkanethiolates to form self-assembled monolayers on, for example, gold or other metals. These patterns can serve as Nano-layer resists to protect the supporting metal from the corrosion of properly formulated etchant or to selectively place fluids on the hydrophilic areas of the printed pattern. Self-assembled single-layer patterns that may be less than 1 micron can be dissolved in Ethanol burning thiol bath is used as "ink" and elastomeric "stamping" is printed on a metal substrate. The stamp is by photolithography or other The technology is made by a master (mold) prepared by electron beam lithography. This stamp surface pattern is disclosed in, for example, EP-B-0 784543.

Hidber et al., "Microcontact Printing of Palladium Colloids: Micron-Specific Patterning of Copper by Electrodeless Deposition of Copper" 'Langmuir, Vol. 12, 1996, pp. 1375-1380, discloses a micro- and sub-micron pattern on the surface This method uses pCP printing colloid, which can be used as a catalyst for selective electrodeless copper deposition. Patterned elastomer made from poly (dimethylsiloxane) (hereinafter PDMS) is stamped for delivery A catalyst (a film stabilized with tetraalkylammonium bromide and dissolved in toluene) onto the surface of the substrate. The electrodeless deposition of copper on the surface of the substrate occurs only where the palladium colloid is printed and transferred to the substrate ^ The metal structure with sub-micron size pattern is formed by electrodeless deposition of this colloid. 、 This paper size is applicable to China National Standard (CNS) A4 specification (210X 297 mm)

Binding

546670 A7

_ · 23 A1 reveals that there is no electrode on the substrate ⑽ conductive square = Shi Xi uses metal that has been imprinted onto the surface of the substrate for printing substrate and the electrode is deposited by dipping the printing substrate into the electric money bath The substrate is provided with a patterned surface stamp of the catalyst pattern. Therefore, these two references disclose how to combine μ (: ρ and eld. In summary, these methods include: derivatizing the substrate with functionalities that have affinity for ELD catalysts; (ii) using The catalyst solution is imprinted with pDMs ^ printed on the micrometer pattern, (iii) the catalyst is printed on the substrate, and (iv) the ELD metal is printed on the printed catalyst pattern. In short, this strategy can be expressed as " printing and Anal 〇 ". This strategy may vary with the actual printed material, which may print molecules on the substrate to improve the affinity of the catalyst to the substrate. In this change, the printing substrate then needs to be Immerse in the catalyst bath to add the catalyst to the printed area of the substrate. Other changes include coating the ELD's catalyst layer with a uniform coating and printing molecules to deactivate / exist the catalyst on the surface of the substrate. One variation may be to uniformly coat the substrate and the printed molecules with the pre-catalyst layer to the pre-coated substrate to activate the pre-catalyst particles.

Binding However, the 'this " printing and ELD " strategy and its possible changes show some serious shortcomings. First, the chemical that provides adhesion between the ELD catalyst and the glass substrate is easily self-reactive and cannot be easily imprinted onto a "traditional" PDMS stamp, and cannot be transferred uniformly to the substrate. PDMS surface treatment in which PDMS is a hydrophobic elastomer and imparts hydrophilicity to the basin is also necessary in this case. Second, typical ELD catalysts such as Pd / Sn colloids are used as highly-acidic (generally concentrated hydrochloric acid) solutions because these colloids are generally unstable in other types of solutions. These colloids are catalysts for ELD of many metals and are very active. its

Line -8-This paper size applies to China National Standard (CNS) A4 (210X 297 mm) 546670 A7 B7

It is particularly suitable for ELD, but there is a problem with the compatibility of highly acidic inks with printing tools. The HC1 gas spilled from the ink will rot the printing tools and stamped metal back plates' and these vapors also have safety problems. In addition to these disadvantages, no catalyst activator (or deactivator) for printable ELD compatible with stamping has been identified to date. This excludes the use of other methods that achieve the above-mentioned "printing and ELD" to combine ELD and pCP. Furthermore, when trying to use "printing and ELD" inks, the following unresolved problems occur. · How to imprint the stamp? How? Need to make it dry? How to reuse the stamp only in a single imprint? How to clean the ink by self-printing? How to control and prevent the ink from spreading on the substrate during printing? Without variable catalyst activity Uniform imprint stamping on large substrates and ink transfer? And, importantly, how to achieve production volume in a reasonable process to give, printing, and ELD "economically solve the problem of reducing the cost of manufacturing metal substrates on substrates? Achieving good adhesion between electrodeless > cladding metals and their substrates is the most important challenge for ELD. During deposition, during removal of the electroplated substrate from the ELD bath, during the cleaning or drying of this new electroplated metal, or subsequent processing or device manufacturing steps, electrodeless deposited metal will lose its adhesion to the substrate in the electroplating bath. Person. As a result, good adhesion between the deposit and the substrate is often required, and the result of optimizing all the details of the ELD process is to start and post-process the deposited metal from the supplier's substrate for processing in the material. Relieve stress. SUMMARY OF THE INVENTION The purpose of the present month is to provide a method for depositing and patterning metal on electrodes on a substrate, which is a combination of micro-contact printing and electrodeless paper. The paper size is suitable for China (⑽x 297 public love) 546670 A7 ____B7 V. Description of the invention (6) Localized ELD of metal, but instead, the deposited metal may be plated on top of another metal, which can be printed in micro-contact to serve as a silver engraving mask. Generally, the process flow is as follows: 1. Preparing an electrically insulating surface by depositing a catalyst; 2. Depositing a first metal from the solution without an electrode; 3. Preparing a first metal surface for printing, that is, an annealed, gas-forming surface Oxide reduction reaction, oxidation reaction in air, cleaning or deposition of additional metal film through electrodeposition or electrodeless deposition and preparation of a second metal surface for micro-contact printing; 4. Use appropriate inks that can be used as etching barriers in subsequent etching steps ΜOP pattern this surface; and 5. Etch the metal or metal film in a suitable solution. The simplest possible way includes the ELD step of Au, the step of self-assembling monolayers of alkanethiol at 8-11 and the subsequent selective AU2 step. Resolution microcontact printing alkanethiol reduced to 丨 micron on Au substrate is the only application of microcontact printing that is indeed established (see Delamarche et al., J.? 1 ^ 3.〇 ^ 111 .: 6, Volume 1 〇2, 1998, pages 3324-3334). It then appears to be the most appropriate in developing an ELD-based strategy and printing the deposited au with a thiol and patterning it by etching. This method has problems such as cost, poor adhesion of Au to the substrate, and the application sought by Ik, and semiconductor pollution problems (formation of recombination centers (brands) in Shi Xi, and Au atoms seem to diffuse into neighboring Si Layer) but not. Ag can also be used in this application, but the ELD of Ag is difficult to control and typically results in poor adhesion of the film to a smooth insulating substrate. Ag also has semiconductor pollution problems, and -11- this paper size applies to China National Standard (CNS) A4 specifications (210X 297 mm)

Binding 546670 A7 B7 V. Description of the invention

Ag is prone to electrical movement and corrosion. Cu can also be printed with alkanethiol and has an etch selectivity and a high selectivity to the etchant in consideration of the oxides present on the metal surface. As for Au and Ag, the adhesion of the Cu film plated on a smooth insulating surface is limited. Therefore, another method is proposed, that is, the ELD of the first metal is next deposited and printed. Since a single ELD metal (such as Au, Ag, Cu) does not provide the required properties such as good adhesion and compatibility with pCP, multilayer metallization and printing processes may be better. For example, electrodeless deposited films of Ni, Co, or Pd (or their alloys) can be used as the first and second metal layers such as Cu, Ag, or Au (ELD or electroplating). They can be used for printing and as etching barriers. In particular, Qinhezhou alloys (NiB, NiP, NiWP, NiReP, etc.) are excellent candidates for elD on smooth insulating substrates. Several kinds of recording baths are commercially available 'which can generate good electrical conductivity Ni. In the present invention, glass processing and manufacturing processes are usually developed to improve the adhesion on the glass of electrodeless Ni deposited. Cu is convenient for electroplating, cheap, compatible with Ni when electroplated, and it can be a good substrate for micro-contact printed alkanethiols. The high conductivity of NiB and Cu helps to maintain a uniform current density on large samples during electroplating ', which is to obtain a plating mask with uniform thickness. The printed Cu is selectively etched as a mask for the underlying Ni. This Cu mask can be easily removed at the end of the process if needed. The typical process of the ELD and printing process of the present invention is as follows: 1. An organic layer having an affinity for ELD catalyst is grafted on the glass substrate from the solution. … 2 · Deposit a uniform catalyst particle layer on the treated glass from the solution and perform contact -12- This paper size is applicable to China National Standard (CNS) A4 (210X297 mm)

Installation line 5. Description of the invention (8) 3. The substrate is immersed in the ELD bath to deposit the required metal. 4. The substrate is preferably mounted on the cathode frame and immersed in the mask of the sacrificial electrode of electrochemical power. The golden eyebrows where the frame touches all its edges: the current is distributed to the layer and the substrate is avoided: the layer is damaged (scratched). Development & Device Metals 5. Mask selection by micro-contact printing resist. _Bioprotection (Self-combination single layer 6. The mask and the electrodeless metal are then selectively removed. 7. The mask is finally removed entirely. Then, the method of the present invention is provided. This is also mentioned as an example And the present invention is not limited to the substrate, metallurgy, etching bath, chemicals, etc. described herein, but other substrates and materials can be used, and glass substrates (Coming # 1737) are well known in the art. At room temperature under N · (2 · aminoethylbumonaminopropyltrimethoxysilane (hereinafter referred to as EDA-Si, obtained from Gelest # SIA0591.0, 0.250 ml in 120 ml ethanol and 20 ml water) Soak for 3 minutes. During this step, the EDA is adhered to the glass. The glass is then removed from the graft bath and washed with water and dried. The glass substrate is baked on a 150 ° C hot plate or in an oven for 1 〇 Minutes. This produces a uniformly thin graft layer on some pd / colloidally compatible glass. The treated glass is cooled or used immediately after cooling. The glass substrate is then immersed in an acidic Pd / SiT solution (from Fidelity, File # 1018 '50% dilution with concentrated HC1) for 30 seconds to form ELD on the grafted glass -13- This paper size applies to Chinese National Standard (CNS) A4 (210 X 297 mm) 546670

Uniform Pd / Sn catalyst particle layer. Then "Pd / Sn glass substrate was washed and immersed in " accelerator " solution (extracted from Fidelity, file # 1019, diluted 10% in Chinese) with deionized water, followed by deionized water. Cleaning and cleaning ^ The activated glass substrate was placed on a 80 C hot plate. It has been mentioned that this activation or heating step is not necessary in some cases where eld can fully function with the non-activated catalyst. Now, the pre-heated glass substrate is immersed in NiB (Shipley, NipQsit㊣468, according to Jianjian, pH adjusted to 7.2 with ammonia), without electroplating bath at 60 ° C, but without stirring, but with about 20-30 nanometer NiB was deposited at a rate of meters per minute. ELD NiB film thickness can be controlled by deposition rate and immersion time.

After Ik, a thin (about 50 to 400 nm) NiB film was placed on a 150 C hot plate for 10 minutes, which improved the Ni deposition and the adhesion between the glass substrates. After this step, a Cu thin film (50 nm) was electroplated on the NiB deposits using a copper pyrophosphate bath: 1.1 g of CuS04 · 5h20, 30 g of N ~ ρ207 and 200 mg of NaHJO4 in 120 ml Deionized water. This bath was ^^ [about 9 and used at 30c> c. The natural oxide of Ni, which is typically present on NiB deposited without electrodes, is etched and washed with deionized water by immersing the NiB-coated sample in a 0.3 M HC1 solution before plating. Removal of Νί〇χ is not extremely needed but provides good adhesion between the offender and others. Cu voltameter model 263A (sold by EG & G) was used for cu plating at a fixed voltage of -0.7 to -1.00 (relative to Ag / AgCl reference electrode), and a titanium grid (30 cm2, Large-area samples require larger electrodes) as opposite electrodes. The tracking current during plating shows the rate of Cu deposition and its thickness (0 · 15 cm · 2 for cu of 50 nm). -14- This paper size is applicable to China National Standard (CNS) A4 (210X297 mm)

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546670 Five A7 B7, invention description (1G)

The Cu-covered substrate was immersed in a 0.1 M HC1 solution for 10 seconds to remove copper oxide from the surface, washed with deionized water and dried before printing to ensure that a uniform and dense protective monolayer was formed during the printing step. Now, micropatterned stamps made by PDMS (Sylgard® 184 from Dow Corning) are first eicosanethiol (ECT, provided by Robinson Brothers, Inc., document # SV109 / 4) on a 0.2 mM solution of ethanol Ink, dried and used to print electroplated copper for 20 seconds, which forms a single layer in the contact area. Unprinted Cu is etched at room temperature in a 0.025 M KCN solution (in deionized water, buffered at pH 12) with appropriate agitation (etch rate is about 50 nm Cu per minute). No etching of NiB deposits was observed during this step. Subsequently, NiB was etched in 1 M H2S04 for 20 minutes at room temperature with moderate agitation (the etch rate is 5-10 nm NiB per minute, and this etch rate also varies depending on the geometry of the pattern). If the Cu mask is still protected by the thiol monolayer, the selectivity of this etch is extremely high; the thiol monolayer on the Cu is only subsequently removed for this reason. The sample was now immersed in KOH and 10% H202 aqueous solution (pH 14) for 20 minutes to remove all organic layers (the ECT single layer on copper and the EDA grafted layer on glass). The Pd / Sn catalyst existing on the etched place of NiB on the glass can also be etched by etching down Sn, EDA graft and trace glass during this step. The electroplated Cu is uniformly etched at this step, but the rate is extremely low. This step is important if the areas left between the NiBs need to be fully transparent or some Pd / Sn left in these areas can block some light or induce some current between adjacent and adjacent NiB structures. Electrical insulation. All remaining Cu was then etched in KCN's 0.02ΓM aqueous solution (buffered at pH 12) for 2 minutes. -15- This paper size applies to China National Standard (CNS) A4 (210X 297mm)

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Claims (1)

546670 ^ λ pp "Patent No. 1_90_Please file g Chinese paper storm patent scope replacement (May 1992) C8 VI. Patent scope-'" A method for manufacturing a patterned metal layer on a substrate, The method includes the following steps: a) pre-adjusting the substrate by grafting an organic layer on the substrate; b) depositing a catalyst layer on the pre-adjusted substrate; Depositing a metal layer on the layer; d) depositing a sacrificial mask on the metal layer; e) depositing a patterned etch protection layer on the sacrificial mask using micro-contact printing; f) in the patterned #etched protective layer free area Etching the sacrificial mask by etching: and g) Etching the electrodeless metal layer in an area not containing the sacrificial layer. 2. If the method according to item 1 of the scope of patent application is characterized in that it is also included in step 骡b) the subsequent step of activating the catalyst layer deposited without electrodes. 3. If the method of the first scope of the patent application is applied, it is characterized by including etching the rest of the sacrificial layer. 4. If the second scope of the patent application is applied Zhi Fang>, which is characterized by including the last name The rest of the sacrificial layer. 5. The method according to any one of claims 1 to 4, which is characterized in that it further comprises a step of engraving the grafted organic layer and the catalyst layer. ... 6 · 如The method according to any one of claims 1 to 4, wherein the organic layer is characterized by N- (2-aminoethyl) -3-aminopropyl = and, ϋΤΛΛ, —Τ milk-based sand The method 'is characterized in that the substrate is immersed in the catalyst-containing particles, and the step of accumulating the catalyst layer as described in any of claims 1 to 4 of the patent application range is performed by the 7.46 In solution. 8. The method according to item 7 of the patent, characterized in that the catalyst particles include Pd / Sn 〇 9. The method in item 2 of the patent, characterized in that the activation step is performed by applying a salty substrate Immersion is performed in an accelerator solution. The L application is called the tenth method of the patent, which is characterized in that the accelerator solution includes HBF40 u ·, and the method in any one of the first to fourth patent applications, which is characterized in that the sacrificial mask includes copper. 12 ^ Apply the method of item 丨 丨 characteristic, which is characterized in 4 the sacrificial mask plating method depositor. W applies for patent scope! The method to any item in the collar is characterized in that the etch protective layer is coated by printing a self-assembled monolayer (SAM) of twenty-thiol mercaptan using a micro-patterned stamping method. η For example, please refer to the method of item 13, characterized in that the micro-patterned stamp is a poly (dimethylsiloxane) (PDMS) stamp. = Any method of item W in the scope of patent application, which is characterized in that the step of etching the sacrifice mask is performed by & KCN / oxygen-based bath performer = any item in the scope of patent application ... The method is characterized in that the step of etching away the metal layer is performed by a HjO4 solution. 17.2 The method according to item 3 or 4 of the patent, characterized in that the step of removing the rest of the layer is performed by KCN. 18 · If the method of the scope of patent application No. 5 is used, the characteristic silk engraving removes the organic sound -2-6. The scope of patent application = the touch of the "" is to discuss the scope of the patent application with the aqueous mixture at H The method according to any one of the items, characterized in that the group is selected from the group consisting of a glass oxide surface, 2 made of Si, and the like. It is characterized in that the electrodeless deposited metal layer is a group selected from the group consisting of Ni, NiB, Nip, Niwp, co, CoWP 'CoP, Pd, etc. 21. A method as claimed in claim 20 of the patent scope, which It is characterized in that the metal layer including the alloy of Ni and B is deposited on the catalyst layer. 22. The method according to any one of claims! To 4 in the patent application scope, characterized in that the first subordinate layer is selected from Groups of Au, Cu and Ag. 23. The method according to any one of claims 1 to 4, characterized in that the micropatterned stamp is imprinted with an alkanethiol. 24. If applying for a patent The method of the scope item 23 is characterized in that the alkanethiol is eicosanethiol. 25. Any one of the items 1 to 4 of the scope of the patent application The method is characterized in that the etching of the sacrificial mask is performed by an etchant that is selective to the mask. 26. The method of any one of items 1 to 4 of the patent scope of claim 4, characterized in that The metal layer is an etcher using any etching chemical that is selective to the sacrificial mask. 27. The method of any one of claims! To 4 in the scope of patent application, characterized in that the sacrificial mask is plated using a cathode frame 28. If applying the method of the 27th patent scope, it is characterized in that the frame contacts the gold 8 8 8 8 AB c D t 4 546670 6. The scope of patent application belongs to all edges of the layer. This paper standard applies to Chinese national standards (CNS) A4 size (210 X 297 mm)