MXPA98010167A - Solution of non-electrolytic deposition of copper and method of non-electrolytic deposition of co - Google Patents

Abstract

The present invention relates to: A non-electrolytic copper deposition solution based on a non-electrolytic copper deposition solution comprising a copper ion, a complexing agent, a hydrophophorous acid compound as a reducing agent, and a catalyst metal to initiate a reductive reaction, characterized by further comprising a lithium ion or both a lithium ion and a polyoxyethylene type surfactant, and a method for non-electrolytic copper deposition using the same, as well as a product subjected to said deposition made by that method, the copper electrolytic deposition solution in the present invention allows a uniform and acicular copper film to be deposited on the surface of an object subjected to deposition, and therefore can be used to improve the strength of adhesion between various metals and resins including the joining of a copper sheet to a resin c How it is applied to a resin to a conductive circuit such as in a printed circuit board of mulch layers or in a laminar deposition unit of cob

Description

NON-ELECTROLYTIC DEPOSITION SOLUTION OF COPPER AND NON-ELECTROLYTIC DEPOSITION METHOD OF COPPER TECHNICAL FIELD The present invention relates to a non-electrolytic copper deposition solution and a non-electrolytic copper deposition method using this solution, and more specifically, to a non-electrolytic copper deposition solution and a non-electrolytic copper deposition method , which together can have a uniform and acicular copper film deposited on the surface of an object subjected to deposition, and therefore can be used to improve the bond strength between various metals and resins including the joining of a copper plate to a resin as applied in a conductive circuit such as in a multilayer printed circuit board or in a copper deposition laminar unit; as well as deposition products that can be obtained by said method.

TECHNICAL BACKGROUND A multi-layer printed circuit board is conventionally manufactured by first preparing a copper deposition laminar unit for the inner layer by processing a copper plate on the copper deposition laminar unit to form a printed circuit; then, provide the aforementioned copper sheet with a surface hardening treatment (generally consisting of degreasing, followed by a surface etching procedure as illustrated by treatment with a system of ammonium persulfate, sodium persulfate, cupric chloride, sulfuric acid-hydrogen peroxide and the like, as well as an activation treatment); subsequently accumulating an acicular film of copper oxide or cuprous oxide on top of the sheet by a process such as blackening or browning; and attaching a copper deposition laminar unit for the outer layer or copper sheets in multiple layers with a material impregnated with a thermosetting resin (i.e., a "prepreg") to manufacture a multilayer laminated card having a high adhesion strength. Because electrical continuity must be established in each layer of the multilayer laminated card manufactured in the aforementioned process, deposition is required through holes over holes punched through the card. However, the conventional method has had a disadvantage where the penetration of the acid solution used in the catalyst treatment process for deposition through holes or penetration of the deposition solution in the electroless copper deposition process tends to dissolve the film made of copper oxide or cuprous oxide, thus making a phenomenon called "pink ring" (that is, "bright ring"). On the other hand, there has been an alternate method for manufacturing a multilayer printed circuit board according to which a printed circuit is formed on a laminar copper deposition unit using a copper plate that is pre-processed by surface hardening to eliminate the need for surface hardening as well as the oxide film forming process required in the method described above. This method, however, has disadvantages such as a lower resolution pattern for the resistance of the printed gravel or the resistance of the engraving to ultraviolet exposure, which is associated with the hardness of the surface on the copper plate. In recent years, methods have been developed to correct the aforementioned disadvantages on laminar copper deposition units and to improve adhesion strength by using certain particular types of copper electroless deposition processes (Japanese Patent Application Laid-Open Nos. 15980/1986, 15981/1986, and 41775/1986). The aforementioned methods of electroless copper deposition, however, in practice require formalin as an essential reducing agent and present problems such as (a) abnormal deposition of copper on the substrate resin, (b) unstable deposition bath or (c) an unpleasant odor as well as a potential cancerogenicity.

The inventors of the present invention have recently developed a method for forming an acicular and uniform copper shell with excellent adhesion strength using non-electrolytic copper deposition (Japanese Patent Application Laid-lOpen No. 116176/1992). Although this technology allows the manufacture of a laminar copper deposition unit having a high adhesion strength and without the aforementioned disadvantages, the surfactants that can be used in the process are limited and the benefit of the invention has not always been available. Accordingly, it has been necessary to improve the aforementioned technology to present a technology that is able to provide better adhesion strength and is more versatile.

BRIEF DESCRIPTION OF THE INVENTION While honest research efforts were made to improve the technology based on the Japanese Patent Application Laid-Open Patent No. 116176/1992 as described above, the inventors hereby have discovered the unique fact that a lithium ion is extremely effective to facilitate a copper film with a uniform and acicular structure. This and other discoveries, specifically that by having a lithium ion present in the deposition solution without copper electrolysis as prescribed in the aforementioned technology, a uniform and acicular copper film with excellent adhesive strength can be obtained, either alone or with a surfactant of the polyoxyethylene type with the exception of surfactants of the polyoxyethylene type containing acetylene residues used in the said technology have accomplished the invention as set forth hereinafter. Accordingly, an object of the present invention is to provide a non-electrolytic copper deposition solution consisting of a copper ion, a complexing agent, a hypophosphorus acid compound as a reducing agent, and a metal catalyst for initiating the reductive reaction, characterized by additionally consisting of a lithium ion. Another object of the present invention is to provide a non-electrolytic copper deposition solution which is based on a non-electrolytic copper deposition solution consisting of a copper ion, a complexing agent, a hypophosphorus acid compound as an agent reducing agent and a metal catalyst for initiating the reductive reaction, characterized in that it additionally comprises a surfactant of the polyoxyethylene type and a lithium ion. Still another object of the present invention is to provide a method for electroless copper deposition that deposits a uniform and acicular copper film on the surface of a deposition object by using the aforementioned copper electrolytic deposition solution, and also by provide products submitted to deposition using the aforementioned method.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an electron microscope photograph showing the glass structure of a copper film obtained with the copper electrolytic deposition solution of example 1. Figure 2 is an electron microscope photograph showing the structure of crystal of a copper film obtained with the copper electrolytic deposition solution of example 2. Figure 3 is an electron microscope photograph showing the glass structure of a copper film obtained with the non-electrolytic deposition solution of copper of Example 3. Figure 4 is an electron microscope photograph showing the glass structure of a copper film obtained with the copper electrolytic deposition solution of example 10.

BEST METHOD FOR CARRYING OUT THE INVENTION Although a variety of lithium salts such as lithium hydroxide, lithium carbonate, lithium sulfate, lithium chloride, lithium bromide, lithium fluoride, or lithium hydride can be used as a lithium source to supply a lithium ion to the non-electrolytic copper deposition solution in the present invention, lithium hydroxide and lithium carbonate are preferred from a viewpoint of management, as will be explained later, and due to the fact that there are no other counterions that remain in the solution. It is preferable to provide a lithium ion in a proportion of 0.1 to 200 g / 1, particularly between 1 and 100 g / 1, in equivalents of lithium hydroxide in a non-electrolytic copper deposition solution. Note that the lithium ion mentioned above can be added in the form of lithium hydroxide or lithium carbonate to also serve as a pH adjuster for the non-electrolytic copper deposition solution, in which case sodium hydroxide or hydroxide Potassium can be used together. Meanwhile, for the polyoxyethylene surfactant to be included in the copper electrolytic deposition solution in the present invention, the compounds which may be mentioned include a polyoxyethylene surfactant containing acetylene residues, a polyoxyethylene adduct of a phenylalkyl, a polyoxyethylene adduct of a fatty acid amide, a polyoxyethylene-polyoxypropylene block polymer, a polyoxyethylene-polyoxyethylene ethylenediamine adduct, and a secondary alcohol ethoxylate. Of these, the preferred surfactants include a surfactant of the polyoxyethylene type containing acetylene, a polyoxyethylene adduct of a phenoalkyl, and a polyoxyethylene adduct of a fatty acid amide. For the surfactant of the polyoxyethylene type containing acetylene residue mentioned in the above list of surfactants of the polyoxyethylene type, the illustrative compounds may include those prepared by adding an alkylene oxide such as an ethylene oxide to an alkyleneol such as 2,4, 7,9-tetramethyl-5-decine-4,7-diol or 3,6-dimethyl-4-octine-3,6-diol, wherein the preferred examples can be expressed in formula (I) given below: HO (CH2CH20) ml-> C1- C -C- C i2- (OCH2CH) nl-- OH I I R3 R4 according to which R ^ and R represent alkyl groups, R3 and R4 represent a hydrogen atom or a lower alkyl group, and ml and ni are numbers whose sum is equal to 3.5 to 30. The surfactant of the polyoxyethylene type containing the residue of acetylene expressed in the above formula (I) is the surfactant of the polyoxyethylene type containing acetylene residues as described in Japanese Patent Application Laid-Open No. 116176/1992, including, for example, surfactants sold under registered trademarks such as Surfinol 440, Surfinol 465, or Surfinol 485 (all manufactured by Nisshin Chemical Industries Co., Ltd.), which are available for current application with satisfactory results. For the polyoxyethylene adduct of a phenoalkyl, illustrative compounds include those prepared by adding a alkylene oxide mentioned above to a phenoalkyl such as phenolnonyl or phenoloctyl, wherein preferred examples may be expressed in formula (II) given below: according to which R5 represents an alkyl group and n2 is an integer between 2 and 110 The polyoxyethylene adduct of a phenoalkyl expressed in the above formula (II) includes, for example, surfactants sold under registered trademarks such as Emulgen 985 (manufactured by Kao Corporation), Nonion NS-270 (manufactured by Nippon Oil &Fat Co., Ltd.), Newcol B-10 (manufactured by Nihon Surfactant Co., Ltd.), which are available for current application. For the polyoxyethylene adduct of a fatty acid amide, illustrative compounds include those prepared by adding an alkylene oxide such as that mentioned above to a fatty acid amide such as stearyl amide or oleyl amide, where preferred examples can be expressed in the formula (III) that is given immediately: (CH2CH20) m3 H (CH2CH20) n3 H according to which Rg represents an alkyl group and m3 and n3 are numbers whose sum is equal to 1 to 60. The polyoxyethylene adduct of a fatty acid amide expressed in the above formula (III) includes, for example, surfactants sold under registered trademarks such as Ede HT-60 or Ede 0-15 (both manufactured by Lion Corporation) which are available for current application. Moreover, surfactants of the polyoxyethylene type except those mentioned above may include polyoxyethylene-polyoxyoxypropylene block polymers sold under registered trademarks such as Pluronic P-85 or Pluronic L-44 (both manufactured by ASAHI DENKA KOGYO K.K.); the polyoxyethylene-polyoxypropylene ethylene diamine adducts sold under registered trademarks such as Tetronic TR-704 (manufactured by ASAHI DENKA KOGYO K.L.); the secondary alcohol ethoxylates sold under trademarks such as Adekatol 80-145 (manufactured by ASAHI DENKA KOGYO K.K.); alkylethylene oxide adducts of carboxylic acids sold under registered trademarks such as PO MB-2621S (manufactured by Nikko Chemicals Co., Ltd.), which are available for current application. It is preferable to compose the aforementioned polyoxyethylene surfactant in a solution of electroless copper deposition in the ratio of about 0.001 to 20 g / 1, in particular between 0.01 and 10 g / 1. Additionally, other surfactants than the aforementioned polyoxyethylene surfactant such as a naphthalene-formalin sulfonate condensation product sold under registered trademark such as Demor N (manufactured by Kao Corporation), or a sodium naphthalene sulfonate sold under trademarks. registered as Perex NB-L (manufactured by Kao Corporation) can also be used. Although a copper film having an acicular crystal structure can be obtained in the non-electrolytic deposition of copper according to the present invention by using a lithium ion alone and without the aid of a nonionic surfactant, it is preferable to use a nonionic surfactant, particularly a surfactant of the polyoxyethylene type containing acetylene, for reasons of stability, as well as for the life of the deposition bath. Except for the lithium ion and the polyoxyethylene type surfactant as described above, the copper electrolytic deposition solution in the present invention can be prepared with known materials for a non-electrolytic copper deposition solution using a copper compound. hypophosphorus acid as a reducing agent. For example, a copper ion for electroless copper deposition can be obtained from ordinary copper salts such as copper sulfate, copper chloride, or copper nitrate; and for the complexing agent, any compound that can complex the copper ion mentioned above, such as citric acid, tartaric acid, malic acid, EDTA, Quadrol, or glycine can be used. For the hypophosphorus acid compound as a reducing agent, compounds such as hypophosphorus acid or sodium hypophosphite can be mentioned. As the metallic catalyst for initiating the reductive reaction, metals such as nickel, cobalt, or palladium can be used in the form of inorganic salts. Referring to each ingredient of the copper electrolytic deposition solution in the present invention, if the nickel is used as the metal catalyst to initiate the reductive reaction, it is preferable to have the copper ion concentration of 0.007 to 0.160 mol / 1 and the concentration of nickel ion from 0.001 to 0.023 mol / 1, where the desirable proportion of mol between the copper and nickel ions is approximately 13: 1. It is preferable to use 1 to 10 times the amount of copper ions by mole ratio as a conflexing agent. Also, it is preferable to formulate 0.1 to 1.0 mol / l of a hypophosphorus acid compound as a reducing agent. In case another metal is used as the metal catalyst to initiate the reductive reaction, the amount and ratio given above can be applied although the most suitable amounts can then be determined by experiments. The non-electrolytic copper deposition solution in the present invention, in addition to the ingredients as described above, can be formulated with various other ingredients as appropriate. One such ingredient is a buffering agent to condition the pH of the solution. It should be noted here that one embodiment may be possible where the non-electrolytic copper deposition solution in the present invention is prepared as a concentrated composition for dilution several times or more by a diluent such as water at the time of application. The non-electrolytic copper deposition in the present invention can be performed using the copper electrolytic deposition solution of the present invention prepared as described above, and in accordance with conventional deposition methods. After performing the procedures, it is also preferable to remove the dissolved oxygen in advance from the copper electrolytic deposition solution, and for this purpose, it is preferred to blow the solution with an inert gas such as nitrogen or argon before starting the process of deposition. Also, it is preferable that the temperature of the non-electrolytic copper deposition solution for non-electrolytic copper deposition in the present invention be 40 to 100 ° C, and that the processing time be 5 minutes or more. In addition, for the non-electrolytic deposition of copper in the present invention, although it is preferable to use oscillating agitation to avoid unnecessary oxidation of the solution, an inert gas can also be used to simultaneously perform stirring and deoxidation. Additionally, although the pH used in the non-electrolytic copper deposition is from 11 to 14, for copper electrolytic deposition of the present invention, it is preferable to control the pH within the range of 8 to 10. Electrolytic copper deposition in the present invention, if carried out unless the conventional pH scale, will not produce needle deposition or adhesion strength as desired. In the non-electrolytic deposition of copper to obtain acicular deposition that was initially discovered by the inventors herein, the general tendency was that phosphorus acid as a by-product of reaction accumulates in the deposition bath with repeated use of the solution, and that the acicular structure of the crystal of the deposition film disappears relatively quickly. In comparison, with the non-electrolytic copper deposition solution in the present invention, thanks to the function of the lithium ion, the acicular structure of the produced glass is densely built in itself and is able to last much longer to allow extended use from the bath to the tone of almost four times more than the previous invention.

EXAMPLES In the following descriptions, a more detailed explanation of this invention will be presented based on numerous examples. However, the present invention is not restricted in any way to those described in the examples.

EXAMPLE 1 Preparation of non-electrolytic copper deposition solution A copper electrolytic deposition solution is prepared based on the composition given below and according to the conventional method: Composition Copper sulfate (pentahydrate) 8.0 g / 1 Citric acid (monohydrate) 11.0 g / 1 Hypophosphorus acid 50% aq ... 31.0 ml / 1 Boric acid 31.0 g / 1 Nickel sulfate (hexahydrate) 0.6 g / 1 Surfinol 465 0.1 g / 1 Lithium hydroxide (monohydrate) 28.8 g / 1 (pH) 9.0 Using the electroless copper deposition solution mentioned above, the electroless copper deposition was tested on a copper deposition laminar unit (a 35 μm copper plate base) built on top of a copper Epoxy resin substrate, at 70 ° C, with oscillation shake applied at a speed of 80 cm / min. The result was examined with an electron microscope to confirm the formation of uniform and acicular crystals as shown in Figure 1.

EXAMPLE 2 Preparation of Electroless Copper Deposition Solution 121 Based on the non-electrolytic copper deposition bath of Example 1, a non-electrolytic copper deposition solution was prepared in exactly the same manner except that Surfinol 465 was changed to Emulgen 985. Using this non-electrolytic copper deposition solution, A non-electrolytic copper deposition was provided on a copper deposition laminar unit built on top of an ethoxy resin substrate with exactly the same conditions as in Example 1. The result was examined with the electron microscope to confirm an uniform and acicular deposition as shown in figure 2.

EXAMPLE 3 Preparation of copper electrolytic deposition solution lll Based on the non-electrolytic copper deposition bath of Example 1, a non-electrolytic copper deposition solution was prepared in exactly the same manner except that Surfinol 465 was changed to Esomide HT-60. Using this non-electrolytic copper deposition solution, the electroless copper deposition was provided on a copper deposition sheet built on top of an epoxy resin substrate with exactly the same conditions as in Example 1. The result was examined with the electron microscope to confirm a uniform and acicular deposition as shown in figure 3.

EXAMPLE 4 Preparation of copper electrolytic deposition solution 111 Based on the non-electrolytic copper deposition bath of Example 1, a non-electrolytic copper deposition solution was prepared in exactly the same manner except that Surfinol 465 was changed to Pluronic P-85.

EXAMPLE 5 Preparation of Electroless Copper Deposition Solution 151 Based on the non-electrolytic copper deposition bath of Example 1, a non-electrolytic copper deposition solution was prepared in exactly the same manner except that Surfinol 465 was changed to Tetronic TR-704. EXAMPLE 6 Preparation of copper electrolytic deposition solution (6): Based on the electroless copper deposition bath of Example 1, a non-electrolytic copper deposition solution was prepared in exactly the same manner except that Surfinol 465 was changed to Adekatol 80-145. EXAMPLE 7 Preparation of copper electrolytic deposition solution (7): Based on the copper electroless plating bath of Example 1, a copper electrolytic deposition solution was prepared in exactly the same manner except that Surfinol 465 was changed to AKYPO MB-2621S. Example 8 Preparation of copper electrolytic deposition solution (7): Based on the copper electroless plating bath of example 1, a non-electrolytic copper deposition solution was prepared in exactly the same way except that Surfinol 465 was changed to Demor N. Example 9 Preparation of copper electrolytic deposition solution (7): Based on the electroless copper deposition bath of Example 1, a non-electrolytic copper deposition solution was prepared in exactly the same manner except that Surfinol 465 was changed to Perex NB-L. Example 10 Preparation of copper electrolytic deposition solution (10): A solution of copper electroless deposition was prepared based on the composition given below and according to the conventional method: (Composition) Copper sulfate (pentahydrates) 8.0 g / 1 Citric acid (monohydrate) 11.0 g / 1 Hypophosphorus acid 50% aq. 31.0 ml / 1 Boric acid 31.0 g / 1 Nickel sulphate (hexahydrate) 0.6 g / 1 Lithium hydroxide (monohydrate) 28.8 g / 1 (pH) 9.0 Using the copper electrolytic deposition solution mentioned above, a non-electrolytic deposition of copper was provided on a copper deposition laminar unit (a copper plate base of 35 μm) built on top of an epoxy resin substrate for 10 minutes at 70 ° C, with oscillation agitation applied at a speed of 80 cm / min. As a result, a copper deposition of 1.55 μm was observed. A subsequent observation on the copper film with an electron microscope confirmed the formation of uniform and needle-like crystals as shown in Figure 4.

Comparative Example 1 Preparation of copper electrolyte non-electrolyte deposition (1): Based on the copper electroless plating bath of Example 1, a copper electroless plating solution was prepared in exactly the same way except that hydroxide was changed from lithium to sodium hydroxide. The amount of sodium hydroxide required to adjust the pH to 9.0 was 26.9 g / 1 (0.67 mol / 1).

Comparative Example 2 Preparation of comparative solution of copper electroless deposition (2): A non-electrolytic copper deposition solution was prepared based on the composition given below and according to the conventional method: (Composition) Copper sulfate ( pentahydrate) 8.0 g / 1 Citric acid (dihydrate) 15.6 g / 1 Hypophosphorus acid (monohydrate) 29.0 g / 1 Boric acid 31.0 g / 1 Nickel sulfate (hexahydrate) 0.6 g / 1 Sodium hydroxide 19.0 g / 1 (pH) 9.0 Test Examples To examine the performance of the copper electrolytic deposition solutions of Examples 1 to 10 and the comparative copper electrolytic deposition solutions obtained in Comparative Examples 1 and 2, test pieces were prepared using laminate units of copper deposition (copper plate base of 35 μm) built on epoxy resin substrates according to the conditions as described above, and where the thickness of the deposition film, the appearance of the deposition, and the thickness of the deposition film were evaluated. Coating resistance of multilayer laminated cards after non-electrolytic copper deposition by pressure bonding of each test piece using pre-impregnation. Note that the previous electroless copper deposition was provided by immersion in a bath with a pH of 9.0 for 10 minutes at 70 ° C, with oscillation shaking applied at a speed of 80 cm / min. The test results are summarized in table 1. (Conditions of preparation of the test pieces) Sample 1 Electroless copper deposition was carried out immediately after the preparation of a fresh electroless copper deposition bath according to example 1.

Sample 2 Based on the non-electrolytic copper deposition bath according to example 1, copper electrolytic deposition was performed using the deposition bath which has been used for approximately one shift (*) while it was analyzed and refilled again the spent portions of copper sulfate, hypophosphorus acid, nickel sulfate, and pH (this is lithium hydroxide). The amount of the phosphorus acid compound (this is reaction by-product) accumulated in the electroless copper deposition bath as analyzed in this step was 0.12 mol / 1.

Sample 3 Based on the non-electrolytic copper deposition bath according to Example 1, the electroless copper deposition was performed using the deposition bath which has been used for approximately 4 turns (*) while it was analyzed and refilled. new spent portions of copper sulfate, hypophosphorus acid, nickel sulfate, and pH (this is lithium hydroxide). The amount of the phosphorus acid compound (this is reaction by-product) accumulated in the electroless copper deposition bath as analyzed in this step was 0.46 mol / 1.

Sample 4 Electroless copper deposition was carried out immediately after the preparation of a fresh electroless copper deposition bath according to example 2.

Sample 5 Electroless copper deposition was carried out immediately after the preparation of a fresh bath of electroless copper deposition according to example 3.

Sample 6 Electroless copper deposition was carried out immediately after the preparation of a fresh electroless copper deposition bath according to example 4.

Sample 7 Electroless copper deposition was carried out immediately after the preparation of a fresh bath of electroless copper deposition according to example 5.

Sample 8 Electroless copper deposition was carried out immediately after the preparation of a fresh electroless copper deposition bath according to example 6.

Sample 9 Electroless copper deposition was carried out immediately after the preparation of a fresh electroless copper deposition bath according to example 7.

Sample 10 Electroless copper deposition was carried out immediately after the preparation of a fresh electroless copper deposition bath according to example 8.

Sample 11 Electroless copper deposition was carried out immediately after the preparation of a fresh electroless copper deposition bath according to example-9.

Sample 12 Electroless copper deposition was carried out immediately after the preparation of a fresh bath of electroless copper deposition according to example 10.

Sample 13 Electroless copper deposition was carried out immediately after the preparation of a fresh electroless copper deposition bath according to comparative example 1.

Sample 14 Based on the non-electrolytic copper deposition bath according to comparative example 1, the electroless copper deposition was performed using the deposition bath which has been used for approximately one turn (*) while it was analyzed and refilled again the spent portions of copper sulfate, hypophosphorus acid, nickel sulfate and pH (this is lithium hydroxide). The amount of phosphorus acid compound (this is reaction byproduct) accumulated in the electroless copper deposition bath as analyzed in this step was 0.11 mol / 1.

Sample 15 Based on the non-electrolytic copper deposition bath according to comparative example 1, the electroless copper deposition was performed using the deposition bath which has been used for approximately one shift (*) while it was analyzed and refilled again the spent portions of copper sulfate, hypophosphorus acid, nickel sulfate and pH (this is lithium hydroxide). The amount of phosphorus acid compound (this is reaction byproduct) accumulated in the electroless copper deposition bath as analyzed in this step was 0.49 mol / 1.

Sample 16 Electroless copper deposition was carried out immediately after the preparation of a fresh bath of electroless copper deposition according to comparative example 2. (*): a "turn" refers to a condition wherein the ingredients In a fresh prepared deposition bath they have all been spent and replaced. Specifically, "one shift" is the point at which an amount of copper sulphate equivalent to be used in the original bath was re-used again, and "four shifts" also means that the cumulative reacompletion is four times that used in the original bathroom.

RESULTS TABLE 1 The above results clearly indicate that the samples using the copper electrolytic deposition solution in the present invention (ie, samples number 1, 4 through 12) demonstrate sufficient depositions of metal that are acicular in shape and that They have excellent adhesion strength. It is also obvious that the above performance is well supported after repeated use (samples 2 and 3) to indicate utility in industrial applications. In contrast, in the comparative non-electrolytic copper deposition solutions, although a certain degree of performance exists in the beginning (sample 13), such yields tend to be degraded with repeated use (samples 14 and 15), suggesting a disadvantage in the current industrial application.

INDUSTRIAL APPLICABILITY The copper film obtained through the non-electrolytic copper deposition in the present invention has a uniform and acicular structure that provides excellent adhesion to the prepreg resin. In addition, because the coating is made of metallic copper as opposed to copper oxide or cuprous oxide, which are products of conventional methods, there is hardly any occurrence of a "pink ring" (or "bright halo") in the process of deposition through holes. Accordingly, the non-electrolytic copper deposition solution and the method for a non-electrolytic copper deposition of the present invention can be advantageously used in the manufacture of various electronic parts such as multi-layer printed circuit boards for industrial use. , multi-layer substrates for accumulation systems, flexible substrates, IC packages, or input / output terminals; as well as for objects such as improving the bonding of metal to resin in the manufacture of other industrial products such as electromagnetic covers or molds.

Claims (12)

NOVELTY OF THE INVENTION CLAIMS

1. - A non-electolytic copper deposition solution to obtain a uniform and acicular copper film which is based on a non-electrolytic copper deposition solution consisting of a copper ion, a complexing agent, a hypophosphorus acid compound as a reducing agent, and a metal catalyst for initiating a reductive reaction, characterized by additionally consisting of a lithium ion.

2. - A non-electolytic copper deposition solution to obtain a uniform and acicular copper film which is based on a non-electrolytic copper deposition solution consisting of a copper ion, a complex forming agent, a copper compound hypophosphorus acid as a reducing agent; and a metal catalyst for initiating a reduction reaction, characterized in that it additionally comprises a polyoxyethylene surfactant and a lithium ion.

3. The copper electrolytic deposition solution according to claim 2, further characterized in that said polyoxyethylene surfactant is a surfactant of the polyoxyethylene type containing acetylene residue, a polyoxyethylene adduct of an alkyl phenol or an adduct. polyoxyethylene of an amide fatty acid.

4. The copper electrolytic deposition solution according to claim 2, further characterized in that said polyoxyethylene surfactant is a surfactant of the polyoxyethylene type containing acetylene residue which can be represented by the formula (I) given below: R 1 R 2 HO (CH 2 CH 20) m 1 - CI-C-C-CI- (OCH 2 CH 2) n α ~ - OH R 3 R 4 according to which R 2 and R 2 represent alkyl groups, R 2 and R 4 represent a hydrogen atom or a lower alkyl group, and ml and ni are numbers whose sum is equal to 3.5 to 30.

5. The copper electrolytic deposition solution according to claim 2, further characterized in that said polyoxyethylene surfactant is an adduct. polyoxyethylene of an alkyl phenol which can be represented by the formula (II) given below: according to which R 5 represents an alkyl group and n 2 is an integer between 2 and 110.

6. The copper electroless plating solution according to claim 2, further characterized in that said polyoxyethylene type surfactant is a polyoxyethylene adduct. of a fatty acid amide which can be represented by the formula (III) given below: (CH2CH20) m3 H R6- C- N \ O \ (CH2CH20) n3 H according to which Rg represents an alkyl group and m3 and n3 are numbers whose sum is equal to 1 to 60. 7.- The copper electrolytic deposition solution in accordance with any of claims 1 to 6, further characterized in that the source of a lithium ion is either lithium hydroxide or a lithium carbonate. 8. The copper electrolytic deposition solution according to any of claims 1 to 7, further characterized in that the hydrogen exponent of the solution (pH) is between 8 and 10. 9. - A method for non-electrolytic deposition consisting of immersing an object for deposition in a non-electrolytic copper deposition solution consisting of a copper ion, a complexing agent, a hypophosphorus acid compound, a metal catalyst to initiate a reductive reaction, and a lithium ion, thus depositing a uniform and acicular copper film on the object. 10. A method for non-electrolytic deposition consisting of immersing an object for deposition in a non-electrolytic copper deposition solution consisting of a copper ion, a complex forming agent, a hypophosphorus acid compound, a metal catalyst for initiating a reductive reaction, a polyoxyethylene surfactant, and a lithium ion, thereby depositing a uniform and acicular copper film on the object. 11.- A deposition product from which the surface is covered with a uniform and acicular copper film that is obtained by immersing the product in a non-electrolytic copper deposition solution consisting of a copper ion, a complexing agent, a hypophosphorus acid compound, a metal catalyst for initiating a reductive reaction, and a lithium ion. 12. - A deposition product from which the surface is coated with a uniform and acicular copper film which is obtained by immersing the product in a non-electrolytic copper deposition solution consisting of a copper ion, a complexing agent, a hypophosphorus acid compound, a metal catalyst for initiating a reductive reaction, a polyoxyethylene surfactant, and a lithium ion.