JPS60255946A - Novel nickel/indium alloy and use for manufacturing print distributing board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a novel solderable nickel and indium alloy useful in the manufacture of electrical devices.

It also relates to electroplating baths used in the production of this type of alloy. Another aspect of the present invention relates to printed wiring boards in which the nickel/indium alloy of the present invention is used as an etch resist and as a protective coating on copper circuitry. It relates to printed wiring boards and other electrical devices made of alloys.

Still other aspects of the present invention relate to a method for manufacturing a printed wiring board of this type, and a printed wiring board manufactured by this method. Other aspects of the invention will become apparent from the following detailed description and claims.Printed wiring boards are widely used as interconnecting devices by the modern electronics industry.

σ) Prior art manufacturing methods for producing this type of wiring root zone are characterized as subtractive, additive or semi-additive methods.

General techniques for producing printed wiring boards by subtractive methods are well known. Examples of subtractive methods are U.S. Patent Nos. 3,673,680 and 4.135.
, No. 988.

In one variant of the subtractive method, the copper laminate base area (after optional preparation steps, eg cleaning) is coated with a protective photoresist layer. The photoresist layer is then masked with the desired circuit pattern.

An energy source such as an ultraviolet source VCQ light. The photoresist polymerizes in the areas exposed to ultraviolet light and becomes insoluble in the imaging solution. When the unexposed areas of the photoresist are washed away by a developer, the preselected circuit pattern or image g11. The Toki area appears. Standard electroplating techniques then applied over the bare steel which was covered with photoresist in the unexposed areas. Additional copper is deposited using a 60/40 tin/lead alloy etch resist with a thickness of about 10 to about 15 microns, also using standard techniques.
Let me do it. Then, the remaining photoresist 7 is removed.

At this point, the surface of the steel clad laminate is etched using standard etching agents (e.g. alkaline etching agents such as ammonia pouring, and acidic etching agents such as hydrogen sulfide).
? and areas of copper that are protected from the etchant by a protective metal-based etch resist. After etching, the tin/lead alloy covering the copper circuit is reflowed to obtain a bright, homogeneous circuit suitable for soldering. Be able to remove the flux residue after soldering.

Furthermore, drill a hole in the printed circuit and make a hole in this? Be able to give. Drilling is carried out in step σ) at any stage, for example after the first cleaning treatment of the copper laminate. A through-hole where the printed circuit establishes electrical contact between the copper circuit on one side and the copper circuit on the other side? If you want to make a double-sided one with a hole, clean the inside of the drilled hole, and
For example, a palladium/tin catalyst) is then coated with copper or other suitable conductive material and deposited on the inner surface of the hole by electroless plating. In addition, additional conductive material
A layer of conductive material that is electroplated onto the material and is thick enough to carry the required undercurrent? Each component to be applied? When fixing on a printed wiring board using flow soldering (for example, wave soldering using a machine),
Solder? Print a solder mask on the steel circuit where it should not be applied. Instead of electroplating tin/lead alloy over the holes in the copper circuit, selectively apply tin/lead alloy only on the circuit where soldering is to be applied? Can be plated. An alternative to this is to print a different etch resist on the parts of the circuit that are not covered by the tin/lead alloy? This results in alignment and other problems.

In the semi-additive method for manufacturing printed wiring boards, through-holes are used in insulating substrates. 1. The substrate and through-holes are then activated using an activation bath, typically containing noble metal ions.

Next, electroless plating is applied to the upper surface of the substrate and the walls of the formed holes. This is accomplished by immersion in a copper electroless plating solution. Next, a photoresist or screen printable resist is applied to the board formed above with a negative version of the desired circuit pattern, and a blank corresponding to the desired circuit pattern is applied to the photoresist or screen printable resist. I'll let you contribute. Next, a steel layer is electroplated on the upper part of the 8 parts (including the hole) of the kneading. Is it possible to remove this structural material by soaking it in a steel etching agent and coating it with electroless steel? Remove. Alternatively, a second etch resist (eg, silver) is applied to the electroplated side of the substrate.

tin, lead or gold)? Electroplated and electroplated copper surface? Before the removal of the first lugist [temporarily covered, first remove the lugist, and perform steel etching. The steel in the second etch resist layer is formed into a desired circuit on one wiring board.

Plated through holes in printed circuit C% by these known subtractive and semi-additive methods? The manufacture of printed circuits (with printed circuits) is fairly complex and involves a number of different steps, from the edge contact areas of copper circuits to tin/lead alloys. and tin/lead alloys to remove? Energy to encourage reflow? It is also relatively expensive. Furthermore, printed circuits manufactured by these known methods are components of printed circuits? During flow soldering, the tin/lead alloy (which has a low melting point of 190°C) is soldered under the heat of the operation (usually around 26.0°C).
) Under the mask, soldering tends to bleed out, causing short circuits, and the appearance of printed circuits with fixed configuration elements? It is unsatisfactory in that it has the potential to damage OT performance.

Is the present invention an “effective amount” of indium? A new nickel/indium alloy? provide. The alloy of the present invention has many of the drawbacks associated with the prior art for producing printed wiring boards when using common tin/lead solders as etch resists. Remove. For example, the novel nickel/indium alloy of the present invention has a melting point that is significantly higher than the soldering temperature used to solder each component into a final printed circuit board. Thus, the problems of melting or re-Kt mobilization encountered with tin/tin solder resists are eliminated. Furthermore, another advantage of the nickel/indium alloy of the present invention is that it is highly conductive and can be soldered.

Therefore, the alloy of the present invention does not need to be removed from the wiring board after etching and can remain as a permanent component to protect the underlying copper circuitry of the structure.

Furthermore, the new nickel/indium alloy of the present invention exhibits excellent corrosion resistance and contact resistance. Therefore, this alloy could be used as a total or partial replacement for gold in the edge area for printed circuits and other devices.

Another aspect of the invention relates to printed wiring boards of which the novel nickel/indium alloys are a component or are used as etch resists in their construction. Still another aspect of the present invention relates to a method of manufacturing printed wiring boards and other electrical devices by using the novel combination of the present invention. Present invention 0) Furthermore, Tsukuda,
σ) 951 points are 11-1 for a new and unique plating bath for use in the electrodeposition of the novel nickel/indium alloy of the present invention.

The number of steps required by the method and alloy of the present invention.

Plant and equipment necessary to carry out these processesa
V can be saved, resulting in floor space.

Energy and money usage are saved, the appearance is more aesthetically pleasing, and components are soldered by flow soldering (printed circuits that are not damaged by molten metal flowing under the mask). Finally, nickel/indium alloys are suitable for providing touch-sensitive surfaces, such as tantalum type switches, when plated onto printed circuits.

1-10 are a series of fragmentary cross-sectional views corresponding to sequential process steps in the manufacture of printed wiring boards with plated through-holes in accordance with the present invention.

The novel nickel/indium alloy used in the present invention contains 5" effective amount of indium 2. The 1" effective amount of indium used herein is sufficient to make the alloy solderable. This nickel/indium alloy has a melting point t that does not reflow during printed wiring board manufacturing and is resistant to common steel etching agents used during printed wiring board manufacturing.

Generally all or some of these alloy properties are.

This can be achieved when the alloy contains up to about 10% indium by weight of the alloy. In a preferred embodiment of the invention, the alloy contains about 0.1 to about 1 indium based on the weight of the alloy.
In a particularly preferred embodiment, the alloy contains from about 0.5 to about 9 mi% indium, based on the weight of the alloy.
Contains Y. In a fifth of these particularly preferred embodiments of the invention, alloys containing indium are particularly useful as etch resists in the manufacture of printed wiring boards. Alloys containing from about 1 to about 4 percent indium by weight of the alloy are most preferred for the present invention.

The nickel/indium alloy of the present invention can be produced by electrodeposition of the nickel/indium alloy of the present invention from a regular plating bath, preferably onto a conductive metal (e.g. copper), using a conventional electromagnetic process. Barrel' is a useful method of increasing electricity.
) Includes plating methods. “Printed circuit handbook”
(C.F. Coombs, Tr., Matsuf Grow-Hill Book Urn Company, New York, NY)
1979) - Printed Circuit Design, Manufacture, Components and Assembly 7 (G. Leonita, Electrochemical Replication Ltd., Ayr, Scotland (1981) and 1 Electroplating Engineering Handbook''
(Kenneth Graham, Nostrand Reinhold, Inc., New York, NY, 1971), these general electrodeposition methods are well known in the field of electroplating technology and are specifically described here. do not. The novel baths of the present invention are particularly useful because they provide a relatively constant alloying strength over a wide range of operating conditions of pH, 'it, flow density, and temperature. The new bath consists of:

lal at least about 0.5 M nickel cations and at least about 0.001 M indium cations: +
Chloride ions up to about 2.6M bl: pH of the fcl bath
an amount of a buffering substance sufficient to maintain Y below about 5; an effective amount of a chelating agent; and water.

In a preferred embodiment of the invention, the concentration of nickel cations and indium cations in the bath is about 0.5 to about 2.5M, and about 0.001 to about 1M, respectively. In particularly preferred embodiments of the invention, the concentration of nickel cations and indium cations in the bath is from about 0.5 to about 2.0M, and from about 0.009 to about 2.0M, respectively.
It is approximately 0.1M. The most preferred of these particularly preferred embodiments are those in which the concentration of nickel cations and indium cations in the bath is from about 1 to about 2M, and from about 0.015 to about 0.06M, respectively.

The bath of the present invention contains one or more chelating agents that chelate indium cations and other agents. The type of chelating agent used in the practice of this invention can vary widely. For example, useful chelating agents include ferric iron (F
e")y chelating agents. Examples of such chelating agents include Ramunas J, Matekaitis and Arthur E, Martel, "Inorganic Chemistry", 1980.19, 1646-165.
1: Wesley R, Harris and Arthur E, Martel, 'Inorganic Chemistry', 15, 71
5 (1976): and KA, E., Martel and R.
M.

Smith, 1 Critical Stability Constance", )'e(1) VC, and include the following: adipyl, suberyl, cepacil, dodecanedioyl, gluconic acid, saccharic acid, glyceric acid, Bicine, catechol, iminodiacetic acid, nitrilotriacetic acid, ((hydroxyethyl)imino)diacetic acid, cyclohexanediaminetetraacetic acid, diethylenetriaminepentaacetic acid.

Salicyclic acid, chromotropic acid, hydroxamic acid, N,N'-bis(0-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid, ethylene 1,2-bis(O-hydroxy)phenylglycine, N- Hydroxybenzyliminodiacetic acid, N-hydroxyethylethylenediamine-N,N,N'-triJ6 acid, N.N'-ethylenediaminediacetic acid.

N,N-ethylenediaminediacetic acid, N,N-bis(2-
aminoethyl)glycine, N,N'-diglycylethylenediamine-N', N'-tetraacetic acid, N-hydroxyethyliminodiacetic acid, N-(2-hydroxy-5-sulfobenzyl)ethylenediamine-N,N'- Bis(methylenephosphonic) acid, triethylenetetraminehexaacetic acid, tetraethylenepentaminehexaacetic acid, ethylenediamine-,N,N'-diacetate, N・N'-bis(methylenephosphonic) acid, glycine-N,N'-bis (
methylenephosphonic) acid, ethylenediamine-N, N
'-Bis(methylenephosphonic) acid, 1-hydroxycn-1,1-diphosphonic acid, 2-(hydroxybenzyl)
iminobis-(methylenephosphonic) acid, ethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic) acid, and N-(phosphonomethyl)iminodiacetic acid.

Other useful chelating agents for use in the practice of this invention include polycarboxylic acids having one or two (1i5 or more) carboxy functional groups ("carboxylic acids"); Carvone t11 (with a functional group and one or more σ) hydroxy functional groups (
@Hydroxycarboxylic acid”) and carboxylic acids with one or more amino functional groups and one or more carboxy functional groups (maminocarboxylic acid n
)% as well as their salts. Specific examples of this type of material are as follows. Citric acid, malonic acid, tartaric acid, adipic acid, phthalic acid, oxalic acid, glutaric acid, isophthalic acid, maleic acid, fumaric acid, succinic acid, glycolic acid, glyoxylic acid, glutamic acid, glyceric acid,
malic acid, lactic acid, hydroxy dl, mandel ll]
John, arginine, aspartic acid, pyruvate, glutamine, leucine, lysine, threonine, isoleucine, valine and asparagine. Chelating agents can be used individually or combinations of chelating agents can be used. For example, a relatively strong chelating agent, such as ethylenediaminetetraacetic acid, has a variety of σ
)-1 is a relatively weak chelating agent, such as malonic acid,
When used in combination with citric acid, malic acid, tartar, or two or more, it is possible to control the amount of electrically active indium, that is, the amount of indium used in electroplating. reactor.

Preferred chelating agents for use in the practice of this invention are relatively weak chelating agents, such as carboxylic acids such as malonic acid and tartaric acid; hydroxycarboxylic acids such as citric acid and malic acid.

as well as salts of these acids. Hydroxycarboxylic acids and their salts are particularly preferred, citric acid, malic acid and the like are also preferred, and the use of chelating agents is acceptable.
It is important for the soldering of indium alloys and for controlling the amount of indium in the alloy and the dispersion of the amount of indium as a function of the effective flow density. Without wishing to be bound by any theory, it is believed that by properly selecting the chelating agent or combination of 2M1 or higher chelating agents, it is possible to achieve a relatively constant plating over a relatively wide period of operation. Amount of indium? Think of it as possible to control it effectively. Therefore, the use of Q) type of chelating agent provides a means to control the evolution of indium during plating. An "effective amount" of one or more chelating agents is included in the bath. As used herein, an effective chelating agent is an amount effective to control the amount of electroactive indium to any degree. The amount of chelating agent depends on a number of factors. This includes the specific chelating agent used, the desired electroactive indium concentration, the desired indium concentration, current density, and pH in the plating.
Generally, the amount of chelating agent included is at least about 0.001M. In preferred embodiments of the invention, the amount of chelating agent is from about 0.001 to about 2.6M, and in particularly preferred embodiments from about 0.005 to about 2.6M.
It is approximately 1.6M. The most preferred of these particularly preferred embodiments are those in which the amount of chelated All in the bath is from about 0.05 to about 0.25M. The nickel and indium cations can be derived from any source. In a preferred embodiment of the invention, the nickel and indium cations are nickel and/or indium chlorides, nickel or indium Q) carbonates.

Nickel and/or indium salts of sulfamino acids, as well as hydroxycarboxylic acids, carboxylic acids, and aminocarboxylic acids (without mercapto functionality), as well as nickel and/or indium salts of sulfamino acids, which function as chelating agents. and/or derived from indium salts, useful water soluble Q) nickel salts and indium salts
) Specific example C1. Citric acid, acetoacetic acid, glyoxylic acid, pyruvic acid.

Glycolic acid, malonic acid, hydroxamic acid, iminodiacetic acid, salicylic acid, glyceric acid, succinic acid.

Linchoic acid, tartaric acid, hydroxybutyric acid, arginine.

Aspartic acid, asparagine, glutamic acid.

Nickel and indium salts of glycerin, glutamine, leucine, lysine, threonine, isoleucine, valine, etc. In a preferred embodiment of the invention, the nickel and indium salts of sulfamino acids are nickel and indium salts. In a particularly preferred embodiment of the invention, a sulfamic acid σ) nickel salt and an indium salt are used as a source of nickel and as a source of indium.

The concentration of θ) chloride ions in the bath is from 0 to about 2.6M. Chloride ions are not electrodeposited under bath operating conditions.
t-1 or from nickel and/or indium salts. Examples of useful metal salts of this type are sodium chloride, potassium chloride, non-metallic salts such as ammonium chloride, nickel chloride or indium chloride. Chloride ions are preferably derived from indium chloride and/or nickel, with conditioned nickel being a particularly preferred source of chloride ions. In a preferred embodiment of the invention, the concentration of chloride ion in the bath is from about 0.001 to about 2.6M.

In particularly preferred embodiments, the concentration of chloride ions in the bath is from about 0.005 to about 1.6M. Most preferred of these particularly preferred embodiments are those in which the concentration of chloride ion in the bath is from about 0.05 to about 0.25M.

The plating baths of the present invention are typically less than about 5, preferably about 1.
4 to about 540. Most preferably a p of about 2.5 to about 6.6
HY motsu. The pH of the plating bath can be maintained at the desired pH 1c by using a buffer substance Q).

The type of buffer material used can vary widely depending on the desired pH. Examples include maintaining the preferred pH range by the use of substances such as pH oxide, or by the use of basic substances such as ammonium hydroxide, nickel carbonate, sodium pentahydroxide, triethylamine, triethanolamine, pyridine, sodium carbonate, etc. It can be adjusted by addition. When carboxylic acids, aminocarboxylic acids or hydroxycarboxylic acids or their salts are chelating agents, the use of these Q)
You can also adjust H'a. Invention Q) The particular pI-J used in particularly preferred embodiments will depend on the particular buffer substance used. Even if a hydroxycarboxylic acid such as citric acid is the buffer and chelating agent of choice, the pH range is between about 1.4 and about 4.7.
．． Preferably enough material to maintain the range from about 1.8 to about 6.8? use. Hydroxycarboxylic acid? In particularly preferred embodiments of the invention for use as buffering substances and chelating agents, the pI-1 is from about 2.0 to about 2.8;
Hydroxycarboxylic acid? In the most preferred embodiment of the invention, used as a buffering substance and a chelating agent,
The pH may be from about 2.1 to about 2.7. On the other hand, pH
Boric acid was chosen because experiments have shown that the best results are obtained when boric acid is the buffer material of choice if is maintained in the range of about 1.5 to about 6.5. In preferred embodiments of the invention, the buffering material may have a pH of from about 2.0 to about 6.0, and in particularly preferred embodiments the pH may range from about 2.5 to about 6.0. In the most preferred embodiment of the invention, boric acid is the loose material of choice.

The pH may be from about 2.8 to about 6.0.

In a preferred embodiment of the present invention, a nickel/indium alloy t'Novel nickel/indium alloy and method for its use in the manufacture of printed wiring boards'' is disclosed in pending U.S. Patent Application No. 605.352. (1
(filed April 60, 1984). In preferred baths of the present invention, a combination of chelating agents and buffering agents selected from the group consisting of carboxylic acids, hydroxycarboxylic acids and their salts is used.

In general, preferred baths of this type consist of Q)0 below.

lal at least about 0.9M nickel cations and at least about 0.001M indium cations; lb
l up to about 2.6M chloride ion: Iel selected from the group consisting of carboxylic acids, hydroxycarboxylic acids, and salts thereof; and fd+water.

Particularly useful mating shades for implementing the invention consist of the following:

fal about 0.9 to about 2.0M nickel ion: tbl
About 0.4 to about 2.5M chloride ion; tel about 0.
004 - about 0.05M indium ion: a combination of buffering agents and chelating agents selected from the group consisting of fdl carboxylic acids, hydroxycarbo/acids and their salts (in combination with delicacies or other chelating agents) ) approx. 0.2~
Approximately 1M: as well as tel water.

What other optional ingredients are the baths of the invention commonly used with or contained in plating baths? May be contained. For example, the plating bath of the present invention may contain one or more compounds for reducing surface pitting, such as alkyl sulfonates. Another optional substance that may be included in the bath in the present invention is a dextrose type stabilizer for the indium.

Additionally, other alloy modifiers may be included in the bath, such as saccharin and funarin, which impart an improvement in alloy properties such as the internal stress-induced appearance of the coated alloy.

During the electrodeposition process, the plating bath is normally maintained at a temperature of about 10 to about 80°C. In preferred embodiments of the invention, the electrodeposition temperature is from about 20°C to about 65°C, and in particularly preferred embodiments of the invention, the electrodeposition temperature is from about 65°C to about 65°C. Among the preferred embodiments for W of the present invention, the most preferred are those in which the electrodeposition temperature is about 55 to about 55°C.

The current density in the electrodeposition process can be varied within a wide range. However, in most embodiments of the invention, the i-current density will typically be maintained in the range of about 1 to about 200 mA/cm2. In preferred embodiments of the invention, the current density is from about 5 to about 100 mA/m, and in particularly preferred embodiments from about 10 to about 60 mA/m. The most preferred embodiment of these codes is vL
In embodiments, the current sensitivity is between about 20 and about 40 mA/cIn.

The electrodeposition process is allowed to last for a period of time sufficient to deposit the desired amount of nickel/indium alloy. As will be apparent to those skilled in the art, electrodeposition times will vary widely depending on a number of factors. This includes the desired electrodeposition layer thickness, current density, bath temperature, and
These include, but are not limited to, plating methods and other factors known to those skilled in the art. Typical plating times range from several minutes to several hours or more.

The above nickel/indium alloy is used in the method of the present invention for printed wiring boards,! ! It is particularly useful for electrical circuits, electrical connectors, chip carriers, switches, etc. in electrical devices. For example, the nickel/indium alloy described above can be used as an etch resist in the production of printed wiring boards σ) by subtractive and semi-additive methods. The general technique of creating printed wire roots by subtractive methods is very well known in the art and will not be discussed in detail here.An example of subtractive methods is provided by U.S. Pat.
No. 680 and No. 4,155,988 The present invention is based on (
a) One or more surfaces thl? of a copper clad substrate? coated with a coating of photoresist material: (b) photoresist material χ predetermined circuit design lXIIigI!
(C) masking the photoresist material with energy source VCQ light to mask one or more surfaces of the resist layer sensitive to the etching agent on the intended circuit artist; Presumably, the rest of the surface σ) is a resist layer portion that is resistant to the etching agent? Given: (d) Sensitivity to etching agent σ) Photoresist part? Do you want to remove exposed patterns from bare copper surfaces? Give: tel@
electroplating an etch resist on the plated steel;
(f) Remove the remaining photoresist from the plate to form part of the copper cladding? Exposure: The exposed steel cladding under the photoresist in the Igl step tg+ is then removed by etching, while the copper cladding under the metal-based etch resist is not removed, so that the plate is coated with the metal-based etch resist. Copper circuit? An improvement in the subtractive process for the production of printed wiring boards of the type consisting of having at least about 0.1% by weight of the alloy is provided. nickel/indium alloy Q) Made of metal-based etch resist.

The present invention also provides (31) metal plating or electroless plating on at least one surface of a substrate made of an insulating material; Electrodeposit a metal etch resist on the target circuit pattern; electrodeposit a metal etch resist on the pattern; remove protective material from the metal-plated substrate; Etching metal from all or part of the metal cladding in areas that are not
70) Providing an improvement method in the semi-additive process consisting of a process of providing a plate having a desired metal circuit pattern on at least one surface area 0) Dust, the improvements are: - Approx. It consists of a metallic etch resist of a nickel/indium alloy containing up to 10 parts by weight of indium.

In the above σ) semi-additive method, Jig board?
Usually electroplated with copper metal. But the board? It is also possible to plate with nickel and then apply a nickel/indium alloy to the circuit pattern to be electroplated in step C.

The nickel/indium alloy used in forming the circuit pattern contains from about 0.1 to about 95% by weight of indium based on the total weight of the alloy, preferably about 11k of indium based on the total weight of the alloy.
About 5 to about 20 units of indium? It will contain.

If used as an etch resist, will the above alloy be used for circuits? The etching agent will be deposited to the required thickness for mining. Generally, the thickness of the electrodeposited layer will depend on the etching power of the etching agent and other factors known to those skilled in the art; , 0002546n) 5) Preferred Embodiments In VC, the thickness is at least about 0.2 mil (0,002546n). 000508 cIn), and in particularly preferred embodiments as low as about 0.6 mil (0,000762 crn).

Five particularly preferred embodiments and the most preferred embodiments of koneira provide that the electrodeposited alloy is at least about 0.4 mil (0.4 mil).
0102α).

The following specific examples are provided to describe the invention in more detail.

Example 1 General Processing Standardized commercially available sulfamino acid nickel (Ni(S)
O3NH2)2) Solution (2,55M Nickel Sulfamino Acid) ya - Partially diluted with deionized or distilled water to facilitate dissolution of remaining components of the bath.

Nickel chloride? Boric acid, phosphoric acid, diammonium citrate, or citric acid and diammonium citrate were added together. The pH of the working bath was then adjusted to just above the desired working bath pH by the addition of a mixture of sulfamic acid, nickel carbonate and ammonium hydroxide, sodium hydroxide, potassium hydroxide or hydrochloric acid. I n (S O3NH2)3
) was added as a hydrated salt, followed by trace amounts of a wetting agent (lauryl sulfate), then the bath was made up to a volume of 11 by addition of distilled or deionized water,
It is now available for use. Various plating baths were prepared by the above treatment. Its physical parameters are given in Table I below.
Shown below.

H117> Plating bath? Use various nickel/indium alloys? Substrate VC @ air plated. The equipment used in these experiments consisted of a Hull cell equipped with a heater, a PAR source, a circulating bonder, and a flow meter. Samples were plated on double-plated steel strips and 1 oz. (approximately 28.3 P) steel laminates. A total of 600 coulombs were conducted for each experiment.

These electroplating experiments and the resulting nickel/indium alloy? Evaluate and grade according to below? Established.

1. Appearance of plating - 6 people judged the appearance.

2. Plating composition - X-edge fluorescence? The nickel flea and indium weight were obtained for each plating.

The analysis was performed at three locations on the plating (upper one-sixth, center).

and the lower one-sixth), and the average? I asked for it. Changes in composition are also shown.

6. Suitability for soldering - Contact angle - For this measurement, place the solder ball on the flux-treated surface.

Kuma antennae on the solder and alloy surface after heating? This was done by measuring.

4. Etching resistance - Etching resistance of alloy plating is 6.
It was judged as a pass/fail measurement whether there was an adverse shadow displacement after 10 minutes with a 200 t/l ammonium peroxosulfate solution at 5°C.

The operating parameters of these experiments and the results of the evaluation of the nickel/indium alloys obtained by deposition from the boric acid system are summarized in Table O below. Table 1 shows the results of evaluation of the nickel/indium alloy obtained by deposition.

Table U Boric acid system 1 75 60 Pass 2 25 50 Pass 5 50 45 Pass 4 25 60 Pass 5 2569 Pass 6 75 60 Pass 7 75 50 Pass 8 25 50 Pass 9 75 50 Pass 10 50 45 Pass table lI (continued) Hou Acid-based* bath Suitable for soldering Plating composition Plating A (Ftc
@Angle) *Ni 4Il Appearance 1 16° 98.2
1.8 Gray, matte 2. 17' 98.0 2.0
Gray, matte 6 14° 97.7 2.3 Gray, matte 4 <4 94.2 5.8 Gray, matte 5 4 98
．． 1 1.9 Gray, matte 6 8 97.95 0.0
5 Gray, matte 7 16 98.0 2.0 Gray, N
m8 15 98.9 1.2 Gray, matte 9 17
98.7 1.5 Gray 5 10 15 98.5
1.7 Gray, Matte*The plating was all matte gray, but its appearance varied from burnt black to blackish gray.

Table - Current density based on citric acid and/or dipmonium citrate Bath temperature Etching resistance 13 50 20 Pass 14 75 20 Fail.

15 75 20 Pass 169720 Pass 17.7520 Pass 18 60 20 Pass 19 40 20 Fail 20 25 20 Fail 21 10 20 Fail 22 5 20 Fail 24 75 20 Pass 25 75 , 20 *Fail 26 75 20 *Fail Pass 27 50- 20 Fail 28 75 20 *Fail*, failure is due to stress damage in the electrodeposition trap.

Table ■ (continued) 1415° 30' 85.7 14.5 Bright metallic luster 1515°60° 94.2 5B Bright metallic luster 1615°60° 95.2 4.8 Bright metallic luster 17 15'30° 95.7 4.5 Bright metallic luster 1815° 60° 93.1 6.9
Bright metallic luster 19 - - 92.1 7.9
Bright metallic luster 20 - -, 90.3 9.7 Bright metallic luster 21 - - 82,0 18.0 Bright metallic luster 22 - - 80.4 19.6 Bright metallic luster 2415° 20. -60° 99.2
0.8 Bright metallic luster 25 - - 98.3
1.2 Bright metallic luster 26 -, - 98.5 1
．． 5 Bright metallic luster 27 --- Bright metallic luster 28 --- 994 0.6 Bright metallic luster 1°
Product name: AMCO 220- by γMUCO
Synthetic organic acid flux manufactured by 55' and sold by 1IIIi.

2°A rosin-based flux manufactured and published by Amco under the product name Amco 600”0)If1.

EXAMPLE 2 A series of experiments 2 was conducted to determine the effect of PL+ and I flow on the indium composition of alloys soldered from boric acid-based and citric acid-based x-containing baths. Bath set Wt (1t) and operating parameters used with boric acid system? Table IVK below shows.

Tatsu ■ Bath parameters Amount Ial boric acid ・・・・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・・・・・・・
・5511bl sulfamino acid nickel・・・・・・
・・・・・・・・・・・・ 520dtel Nickel Nide・・・・・・・・・・・・・・・・・・・・・
・・・・・・－・・・・・・・・・・・・ 15Pldl Indium Sulfamate・・・・・・・・・・・・・・・・・・
・6? te+sodium lauryl sulfate...
・・・・・・・・・・・・ 0.05y-Igl temperature ・
・・・・・・・・・・・・・・・・・・・・・・・・
...... Bath composition (1 t) and operating parameters 2 used in the experiments regarding the citric acid system at room temperature to 45° C. are shown in Table 2 below.

Table ■ Low High ial citric acid 15.5P 465'fb1. X Lua 7 Minic Acid Nitsuke # 520m1 520m1 [cl
Diammonium citrate 24.77- 74yfd+
Nickel chloride 15y-155'let sulfamino acid indium 6P 6? Tf+sodium lauryl sulfate 0.015' 0.01 (gl temperature 40°C 40°C 6 series 17' using the method of Example 1) p l (and the indium composition of alloy 1 was evaluated by changing the fugitive flow density. The results for the boric acid system are shown in Table 1 below, and the results obtained for the citric acid system are shown in Table VllvC below.

Table ■ Boric acid type 10 6.6 (6, L) 15.915.8) 2.
9 5.220 5.7 3.6 2.5 4. '26
0 3.1 2.7 1.0 2.655 2.5 -
0.8 - 40 2.5 - 1.6 2.1 45 - 1.9 - - 5G 2.1 - 0.8 (2,1/1.7) 60
- 1.6 - - 1. Conductive at ambient temperature.

2. Conductive at 45℃.

Table 4 Citric acid system 65 4.1-1. King 8 12 - Mouth 440-2゜41.8 - 0.7 - 45- - - 1.1 - 0.5 50 2.5 1.9 1.7 -0.555 - -
-o′? 307. -65 1.7 - 1.5
− 0.57υ −−−−0,6− 75,−−1,0−− 801,45,4−−−− )35−−−−0.5− 901.2−− − − − − 95 - - - - 0.6 98 - 1.7 - 1.6 11.6 -* Low enoic acid bathing Example 6 Referring to the drawings, 1m1 to 10 diagrams start from the base material for processing to the final product. Figure 1 shows the sequence of process steps according to a preferred embodiment of the present invention for use of the nickel/indium alloy of the present invention in the production of printed wiring board manufacturing. The final product is a copper circuit.

Plated through-holes and the nickel/indium alloy of the present invention are total or partial gold replacements. It is a double-sided printed wiring board with a contact area that covers both edges.

The starting substrate, shown in FIG. 1, consists of a commercially available laminate 10. The plate 10 may consist of a substrate 12 of a non-conductive material 5, such as a glass fiber reinforced epoxy resin or a thermoplastic material. The substrate 12 has a very thin steel cladding or film 14 and 16 laminated on each opposite side thereof.
6-6, while the substrate has a thickness of approximately 0.157-
Motsu.

A plated through hole is inserted through the laminate plate 10 at a predetermined location (tt) which is a public expense, and then a hole or opening is made.
8 formations. Hole 1B is shown in FIG. 2 and can be formed, for example, by drilling with a tape drill press. Plate 10V supported by aluminum or paper phenolic inlet and outlet materials during drilling operations'f7)
You can also do that.

After drilling, the laminate 10 is cleaned.

It is desirable to first sensitize the entire laminate and the exposed surfaces of the substrate 12 at the drilled holes 18. This can be done by soaking the plate 10γ in a suitable catalyst, for example tin palladium chloride.

A thin film or layer 19 of copper is then plated onto the plate 10 by conventional electroless plating techniques. Is this an example of a film with a thickness of approximately 0.0O0254onσ? This can be done by electroless steel plating. Layer 19 also covers the surface of hole 18, as shown in FIG.

The target circuit 1ii1+image' on both sides of the board 100 can be applied by any of the conventional methods. Preferably, however, the dry coated photoresist is applied and then developed. After that, the board 10 is first cleaned. This can be done with a sander trap or with a brush equipped with a pumice stone and a pumice stone. Next is board 10? Rinse with deionized or distilled water and dry with TP overcompressed air.

Dry beads coated pattern photoresist layers 20 and 22 are applied to each opposite side of the board 10. An example of a suitable photoresist material is Dupont R15ton 218
R (Registered Trademark (1)). The photoresist layer can be applied by contacting the resist and a root laminator. This may vary depending on the type of laminator used.
It can be carried out at a temperature of ~124°C. The thickness of photoresist layers 20 and 22 is determined by the desired thickness of the plated circuit. Typically, photoresist layers 20 and 22 are slightly thicker than the desired plated circuit thickness, approximately 0.00
It's 0762cm thick and good. For example, the thickness is about 0.0058
In order to obtain a 1-on plating circuit, a photoresist layer 2 is required.
0 and 22 should have a thickness of approximately 0.0[]4'57 cM.

Photoresist layer 20 thus applied or laminated
and 22? Then, the L/cyst layers 20 and 22 are developed one after another through a suitable masking mask.

This will remove the unpolymerized regions 24 that are sensitive to the liquid. The areas on photoresist layers 20 and 22 correspond to the surface of the plated circuit area and holes 18σ). There, photoresist layers 20 and 22 have overlapping regions 26. It is resistant to etching agents and, as shown in FIG.
All other areas of 2? cover. Photoresists 1620 and 22 can be exposed with a light source for about 1 minute in a vacuum of 77.97 kPa (mercury) or greater. After exposure, the pressure is released and the photoresist layers 20 and 22 are allowed to stand at the same temperature for at least 60 minutes. The photoresist layers 20 and 22 can then be photoresisted in a suitable automatic photoresist machine.

FIG. 5 shows the ρ plate 1'0 after the non-polymerized region 24 has been removed. This is, for example, the hole or opening 018 on both sides of the board 1N [1] and the desired circuit group? Discharge can be done by soaking in a suitable liquid (1#).

Next, pattern plating is performed by electrodepositing copper on the plate 10).

This provides the desired thickness of copper on the circuit image and the inner surface of the drilled hole. All this is done in conventional manner. For example pyrophosphate or acid steel treatment?
A minimum steel plating of 0.00254oy+ (Fig. 7) and approximately 0.00381cPn is applied to the surface of the hole 180 using
You can get 62 copper circuits. Circuit plating 32 is contained within the confines of the wall of VC polymerized photoresist 26 as shown in FIG.

After the copper electroplating process, when the electroplating pattern is removed from the plating bath, the plate 104 drag out) (14(d
ragout bath), rinsed with water and anti-stain treatment, for example in IMA 5ACu-56™ for about 1-2 minutes at about 20-25°C.

Rinse with water and dry the exposed copper layers 6o and 6.
2? Then, in a micro-etching acid cleaning bath, about 20 to 2
Wash at 5° C. for about 2 minutes, and rinse the plate in 1° cold water for about 1 minute and in deionized water for about 25 minutes. exposed steel layers 6o and 52Y then a suitable metal etch resist;
A nickel/indium alloy containing from about 0.3% to about 10% by weight of indium based on the total weight of the alloy, preferably from about 1 to 5 coulometric indium based on the total weight of the alloy, as described in Example 1. Law? electroplating using What panel electroplating bath and operating parameters were used? Table 1 below
1yr not shown.

Table vl (at citric acid 0.2M tbl nickel sulfamate/' 1.5M 1cl diammonium citrate 0.4M+dR nickel 0.
063M (el indium sulfamate 0.0089M)
Sodium lauryl sulfate 0.0004Mfgl temperature
45-48℃ [hlpH2,5 (il current density 35 melon2) When taken out from the electroplating bath, the plate was washed in a hot water bath for about 10 seconds, then washed in a boiling water bath for about 1 minute.
Rinse in water and dry. Then apply a 10-ton alkaline solvent stripping agent (e.g. Robertson's®
bertsons) BP-118] for about 10 minutes at about 60-70°C, and a second bath of an alkaline solvent stripping agent for about 5 minutes at about 60-70°C;
The plate is passed through a hot alkaline solvent stripping brush machine at about 50"C to remove the photoresist 26' as shown in FIG.
rRemove. Next, 10 plates of an ammonia-based etching agent [for example, MacDermid
m id ) 9151) Y from the stack of plates 10 etched at about 45° C. and not covered by a nickel/indium etch resist. Remove. Care is taken to keep the etchant within its normal operating limits and avoid over-etching. Over-etching may cause the steel layers 60 and 6 to break to such an extent that the nickel/indium alloy sliver that acts as an etch resist during etching may break and become incorporated into the printed wiring.
The 4 of 2 may be undercut. After etching, rinse the plate 10' in water, dry it, and remove only the edge area. Masking for plating.

The edge electrical contact 66 is connected to the l/
A450 and 62 can be obtained by plating up to the required thickness with nickel/indium alloy by a general electroplating method or as described in the present inventor's application.
US Pat. No. 605 entitled "Novel Nickel/Indium Alloys Used in the Fabrication of Electrical Point Areas of Electrical Devices"
, No. 435 (filed April 50, 1984) VC preferably contains about 5 to about 20% by weight based on the total weight of the alloy - two layers of nickel/indium alloy 60 and 52 VC Plated to a thickness of 9 and edge contacts 56? Alternatively, the edge electrical contacts 66 are first formed on the gills 1) FIe point area σ) copper W160 and 52
This can also be accomplished by increasing the thickness of layers 60 and 62 of edge electrical contact area 66 by plating with a nickel/indium alloy as described above and then plating with gold.

Money in the edge of a printed circuit with a twist point? You can save money by not using it at all or by eating less of it.

The final IF wire plate with plated through holes is shown in FIG. This can function similarly to printed wiring boards manufactured by conventional methods.

For example, in flow soldering, it is possible to apply a solder mask and fix the component base.

[Brief explanation of drawings]

Figures lA1-10 are a series of fragments corresponding to a sequential process technique in the manufacture of printed wiring boards having through holes' in which gold is wholly or partially replaced by a nickel/indium alloy containing an effective amount of indium. FIG. 10: Laminate: 12: Substrate/board: 14.16: Steel film: 18: Hole: 19: Copper film: 20
・22: Photoresist layer: 24: Non-polymerized region (photoresist layer): 26: Mated region (photoresist layer):
60, 62: Steel plating; 66: Edge electric contact clock Applicant: Allied Corporation (5 others) FIG, 6 FIG, 7 FIG, 8 IG, 10 Continued from page 1 ■ Int, CI, ' Identification symbol Internal HO5K 3106 6 Priority claim 6198 Cape March 268 [phase] United States (US)
@71849

Claims (1)

[Scope of Claims] fil A novel nickel/fil consisting of an effective amount of indium
Indium alloy. f21 fal at least about 0.5M nickel cations and less (both 0.001M indium cations; +bl up to about 2.6M chloride ions: Icl consisting of boric acid, hydroxycarboxylic acids and salts of these hydroxycarboxylic acids) a buffer substance selected from the group approximately 0.2
A novel nickel/indium alloy electrodeposition aqueous bath having a pH of about 5 or less, comprising: 5-1.6 M: as well as TDL water. +31 fat at least about 0.5 M nickel cations and at least o,ooi·M indium cations: +bl about 2.6 M chloride ions at 1:t
a buffering substance sufficient to maintain the pH of the EL bath at a value of about 5 or less: an effective amount of one or more chelating agents;
and let water, a novel nickel/indium alloy electrodeposition aqueous bath having a pH of about 5 or less. (4) The buffer substance is about 0.4-0.7M boric acid. A bath according to claim 2. (5) The chelating agent is selected from the group consisting of carboxylic acids, hydroxycarboxylic acids, and salts thereof. 7. The linen according to claim 6, wherein the chelating agent acts as a buffer substance. (6) The chelating agent is a hydroxycarboxylic acid or a salt thereof. A bath according to claim 5. f71 fat at least about 0.5 M nickel cations and at least 0.001 M indium cations; tbl up to about 2.6 M chloride ions: an amount of buffering material sufficient to maintain the pH of the fcl bath below about 5. an alloy consisting essentially of indium and nickel produced by an electric field from a plating bath having an OpH of less than 5; an effective amount of chelating agent or more; and tel water. (8) When the aqueous plating bath is ial about 0.9-2M nickel cations; lbl about 0.04-2.5M chloride ions; let about 0.0
04-0.05 M indium sulfamate; about 0.25-1.6 M chelate from the group consisting of tdl hydroxycarboxylic acids, dicarboxylic acids and aminocarboxylic acids and their salts 1 or 2 drops An alloy according to claim 1iKZ, wherein the chelating agent acts as a buffer substance; and let water. 191 One or more surfaces of a 1al metal clad substrate? Coating with a film of photoresist: masking the photoresist with a predetermined circuit design image; exposing the photoresist to an energy source; A target circuit on one or more surfaces - providing a portion of the resist layer sensitive to the etching agent on the surface and a portion of the resist layer resistant to the etching agent on the remainder of the surface?
Provide; remove the photoresist portions sensitive to the +dl etchant and attach the desired circuit to the surface of the metal cladding - IJI! Give: Let the desired circuit image area metal etch resist plating: Remove the remaining tf+ photoresist from the board to reveal some of the metal cladding: and remove the exposed metal cladding from the board. Q) Indium is coated with a metal etch resist and provides an improvement of up to about 10% by weight based on the total weight of the alloy. The solder-containing material consists of a metal-based etch resist composed of a possible nickel/indium alloy. A method for manufacturing printed wiring roots from metal clad substrates. θOfat electroless metal plating on at least one surface of the substrate made of an insulating material; fbl applying a protective material to a part of the metal plating to give a desired circuit pattern to the metal plating surface; lcl purpose circuit butter yFC, metal plating Electroplating; (dl Electroplating a metal-based etch resist on the target circuit diagram 1; let removing the protective material from the metal-plated substrate:
and gold x from the metal clad part covered with lf+ protective material.
a nickel/indium alloy having an indium content of at least about 0.1 t% by weight of the alloy; 5. An improved method for manufacturing printed wiring boards comprising metal-based etch resists.