JPH01500472A - Printed circuit board manufacturing method - Google Patents

Abstract

Printed circuit boards containing thru-holes requiring metallization are manufactured by first applying to the board material an alkaline strippable resist in a predetermined desired pattern, thereafter applying material catalytic to subsequent metallization, thereafter treating the board with an aqueous alkaline solution to remove catalytic material from resist surfaces without adversely affecting the catalyst at non-resist areas, and then metallizing the non-resist areas. The ability to preliminarily apply the resist pattern before catalyst application, metallization, etc., yet prevent metallization of the resist, enables the manufacturing process to proceed straight through the activation, metallization, etc. steps without need for interruption for resist application.

Description

[Detailed description of the invention] Printed circuit board manufacturing method Background of the invention TECHNICAL FIELD This invention relates to the manufacture of printed circuit boards, and more particularly to the manufacture of printed circuit boards. The present invention relates to the production of double-sided and multilayer printed circuit boards with through holes.

Printed circuit manufacturing now uses a flat board with circuit components printed on each side. It is trite to prepare.

Also of increasing importance are insulating substrates and conductive metals (e.g. copper). A so-called multilayer circuit board consisting of an integrated flat laminate, which is completely Structure of one or more parallel inner layers of conductive metal separated by a rimmed substrate, ie, planes exists within the body.

The exposed outer sides of the laminate should have a printed circuit pattern, as with double side panels. The conductive plane itself contains a circuit pattern.

In double-sided and multilayer printed circuit boards, various types of boards with conductive circuit components inside are used. It is necessary to make interconnections between layers or sides. To achieve this , within the plate, electrical interconnection at-requires metallization communicating with the sides and layers. Next, provide a conductive through hole. The main purpose is to provide conductive through holes. The method used is to make non-conductive This is a method of electrolessly depositing metal on the surface.

For manufacturing double-sided or multilayer printed circuit boards with metallized nine through holes. A typical process is shown in a process flow chart, Figure 1, and the individual steps in the process. Figure 2 shows the corresponding structure of the plate in cross-section and with greatly enlarged dimensions. I will explain. In the illustrated process, first, a thin copper foil laminate 12 is applied on both sides. A copper cladding consisting of a non-conductive substrate 10, typically made of epoxy glass resin. Prepare the substrate. Drill a through hole 14 in the laminate with @ and attach it to a non-conductive substrate. Expose the surface of the hole of quality 10. Clean the board and drill the holes. The various materials necessary to completely remove the entire surface of the through-hole and then plate the surface of the through-hole with a conductive metal. Perform the process. That is, generally the sheet metal rack is cleaned, cleaned and adjusted. , and a micro-etching process is performed to remove the activator/catalyst applied to the entire surface of the copper. It is easy to make the catalyst adhere tightly, and the through holes that are opened are generally used to make the catalyst adhere tightly. However, sometimes with glass-filled resin-based plates, , exposed using glass etching to improve the plating suitability of glass fibers frosting the glass fibers. Although not shown in the process diagram, each individual department A cold water rinse is usually used after the process. Next, activator (catalyst) t-1 is exposed After application to the surface, the active agent is promoted as known in the art. next Electroless copper 16 is deposited on the activated surface to metallize the surface of the through hole.

Next, after washing the sheet metal with water and drying it, a plating resist 18 is applied in advance. surface of the holes and conductive circuit components (pads) by applying Additional metal increases are made in areas that clearly define the outline of the object (generally Trezost, by exposing and developing through a mask in the desired pattern, Rurui can alternatively be created by screen printing with a resist l pattern. ), then supply an additional 20 t of copper, for example by fully electroplating. then metal Protect the entire desired area with etching resist and remove the plating resist. Corrosion occurs to the surface of the substrate on areas not protected by etch resist.

There are several known variations of the above process practiced in the art. process of explaining is typically called the “heavy deposition 3 method”. The layer of electroless steel deposited is approximately 80 millionths of an inch to 100 millionths of an inch. That's it. The variation ranges from electroless steel to only about 15 millionths of an inch to 2 millionths of an inch. Deposit to 0 inch ([thin deposition] J) , and then to increase the metal before applying the resist in the desired pattern. Analyzing electrolytic steel strike layers from approximately 100,000ths of an inch to 200 millionths of an inch. Let it come out. “Panel plating is called J. One variation involves depositing a thin layer of copper and then depositing the copper without any subsequent resist application. The electrolytic steel must be plated to a sufficient final thickness, e.g. 1 mil to 1.5 mils. Make it to mil ma・de). In this variation, the resist following the pattern is plated Not only as a person, but also as a naughty lesbian! ! And erotic resort Apply to all areas to be sufficiently increased, such as ha holes, pads, and child figures.

The unprotected copper areas are then etched down to the substrate surface.

Regardless of the individual changes used, the above processes have several processing steps in common. There are things you need to do.

However, in terms of the economics of the actual manufacturing implementation, The number is actually less important than the number of different types of processes. In other words, heavy Through-hole plating by thin deposition or by thin deposition itself requires a number of treatments and water treatment. Although it includes a washing process, the entire process is basically a simple process during manufacturing. It is a wet process that can be performed with From an economic point of view, it is more important to wet-process the board. Take it out from the process, dry it, and use it to create or screen images. Fully applied lean printing, then required to return to wet, plating and etching process There is. The same is true for panel plating, and in this case Electroless and electrolytic treatments are used to increase the total metal etch resist '2 and then return to the wet etching step. of the plant and intermediate drying process. During processing processes that require physically transporting and returning boards between different areas. This can significantly increase manufacturing costs.

Summary of the invention For those who manufacture double-sided and multilayer printed circuit boards with through-holes that require metallization. It is an object of the present invention to provide a method.

Another object of the invention is to provide a manufacturing method of the type described, which This method eliminates the disadvantages mentioned above, which are associated with interruptions in the manufacturing process.

A further unique object of the present invention is that the through-holes requiring metallization are double sided and multi-layered. The purpose of the present invention is to provide a method for manufacturing a layered printed circuit board, in which through-hole The plating resist is applied in the desired predetermined pattern before full metallization. Apply to the surface of the surface.

Yet another object of the present invention is to provide a method for manufacturing the bakashi just described. In this method, the substances used are treated using an aqueous system rather than an organic system. I can do it〇 Achieving these and other objectives in accordance with the present invention is achieved by reducing the necessary speed of metallization. - By providing a method for manufacturing holed, double-sided and multilayer printed circuit boards However, this method uses water-based plating resin that can be stripped with alkaline. Metallize the throughholes into a desired predetermined pattern of MET material Apply it to the surface of the plate before, clearly delineating the areas where you do not want metal growth, and then The surface of the plate, which includes the entire surface of the through hole and the surface of the I/cisist, is covered with a metal receptacle. This surface activation treatment is applied to the surface and then the integrity of the resist is compromised. metallization, and does not passivate the surface desired to be metallized. Conditions effective to render the resist surface selectively inert to subsequent metallization Then, the board is treated with an alkaline aqueous medium, and then the board is treated in this way. gold on these surfaces of the plate, including the through-hole surfaces. Apply the attribution layer.

In accordance with a unique embodiment of the present invention, resist application, full surface activation, and resist Selective passivation of the steel surface followed by metallization can be carried out electrolessly or electrolytically. Through-hole surfaces, including all combinations of plating techniques and processes, as well as other parts of the plate surface such as hole pads and subfigures, cut the metal all over to the desired thickness. can do. After seventh, apply corrosion resistant coat to areas such as holes, pads, child figures etc. Conventional methods are used to apply the coating, followed by corrosion of the metal to the surface of the substrate. Other standard finishing treatments are then applied.

In the method of the present invention, before starting the metallization process, the entire plating resist is prepared in advance. It is applied in a predetermined pattern so that known techniques do not require necessary interruptions. The board is processed through various wet processes such as plating, cleaning, and etching. This means that you will be able to As a result, savings in manufacturing time and costs are achieved. realizable. Further advantages obtained using the present invention are discussed in more detail below. It will become clear during the investigation.

prior art In U.S. Pat. No. 4,537,799, describes a selective electroless metallization process in connection with the production of additive-type printed circuit boards. ing. According to this method, holes are drilled in the insulating substrate to create the desired through holes. , then create a negative resist pattern on the surface of the substrate and coat it with resist. In the unmarked area, outline the desired circuit pattern and remove the resist with an organic solvent. A removable/soluble photoresist or ink. Next, the base and It corrodes the resist surface and increases the adhesion of the catalyst layer and electroless metal layer that will be applied for a long time. so that According to one of the embodiments described, the plate is then soaked in a weak acid (acetic acid, formic acid, zolopic acid). ionic acid) to gently cure the resist surface on the substrate without substantially corroding it. A gentle dissolution or smoothing process is performed to prepare the catalyst for subsequent application to the treated resist. Essentially, it prevents close contact. Then, a catalyst is applied and electroless metal deposition is performed. Then, the areas not covered by resist are metallized. There is another In embodiments, the catalyst is first brought into intimate contact with the corroding substrate and resist; After that, the plate is treated with a weak acid to dissolve all the resist, and the catalyst material is removed from there. and/or render the catalytic species on the resist inactive. Then covered with resost Perform electroless deposition in areas where there is no

A significant disadvantage of the Dolly two-phase process is the lack of solvent removable/dissolvable resists; It is dependent on the treatment substance used to induce attraction.

Sawyer U.S. Patent No. 4. 88,351 Specification V also Additional types of printed circuit board manufacturing and selective metallization of this . Negative resist pattern using solvent strippable/dissolvable resist material , fabricated on an insulating substrate9, exposed the entire surface to light, and deposited electroless copper. Apply the catalyst for the resin, apply two strips of resin, and apply the remaining catalyst to the paint. to deposit electroless steel. Alternatively, Registrus) before IJ horn, Flash plating of electroless steel is first deposited on the entire surface including the resist surface, What is left behind after stripping the resist (and the metal flash coating over it)? Further increase electroless copper on the flash pattern. gold in desired area Metallization and (also rl:) complete metallization should be done after stripping the entire resist. The serious disadvantage of the Souki method is that of the above-mentioned U.S. Patent No. 4.53 As discussed in US Pat. No. 7,799, precise control of the desired line width in the metallized region It is impossible to do so.

U.S. Pat. No. 4,574,031 to Dolly Bipha et al. This patent specification uses a photoresist mask on an insulating substrate. in the desired pattern on the surface, covering the entire surface (i.e., the exposed surface of the substrate and the resist). A thin layer of electroless metal is produced by applying a catalyst for electroless metal deposition to both surfaces of the A thin flash is deposited on the entire surface, followed by a mask (and with it a flash over it). [sh]]. Then add additional metal onto the remaining flash, electroless Increase by precipitation. Sawyer's teachings, aqueous alkaline solubility and stripability Although it has been expanded to include photoresists, it is still difficult to use this two-phase photoresist. The method has the same disadvantages as Sawyer, i.e. no resist mask is present. Due to the fact that without additional metal increase 7 lines of desired width in the metallized area It is impossible to precisely control the Moreover, the above-mentioned U.S. patent of Dolly Biphase et al. No. 4,537,799, the Sawyer type method is highly dependent on achieving a specific thickness of the mesh. Most importantly, the If the flash is too thick, the strips of resist can become extremely difficult. and areas on the plate where there should be no metal, where it is unnecessary and preferred. You may end up with scratches from missing metal scales.

U.S. Pat. No. 4,151.313 to Wajima et al. describes a method for manufacturing a printed circuit board. This describes a solid solution of titanium, nickel and antimony oxides. A plating resin made of thermosetting resin is applied to the substrate in a negative pattern, Then, a catalyst is applied to the entire surface of the substrate and resist to cause electroless metal deposition. . The catalyst is then contacted with a solution of ammonium persulfate in hydrochloric acid to Alternatively, it can be removed from the resist surface without acting on the catalyst present on the substrate surface. Then, electroless plating proceeds on the remaining catalyzed substrate surface.

According to this patent specification, the metal oxide in the resist converts the catalyst used. Compounds that can be easily dissolved in inorganic acid solutions. The method of Wazoma et al. A significant drawback is the requirement to use thermosetting resist materials of special composition. However, the method using photoresist cannot be used.

U.S. Patent No. 3,562 of Shipley, Jr., et al. ．． No. 038 relates to selective electroless metallization of substrate surfaces, and It is described as being useful in the manufacture of printed circuit boards. According to this patent specification, the substrate All selectively treated (e.g. mechanically or chemically, roughened) to absorb The colloidal electrolessly deposited catalyst can be selectively preserved in areas that are not treated. Generate an area with Next, apply colloidal catalyst to the entire area and strip the entire substrate. Catalyst from all areas except those with selective retention in contact with the upper solution? Exclusion and then electroless plating the substrate.

The method for metallizing through-holes is described. Contact with the colloidal catalyst, then remove all the catalyst from the entire area above the through hole. contact with stripper solution and then select electroless metal onto the through-hole. to precipitate. In another embodiment described, the circuit board substrate is roughened. The reverse image of the circuit pattern is applied to the substrate, and the substrate is exposed to colloidal contact. Soaked in medium solution, then in stripping solution (copper chloride, hydrochloric acid (67%), water) then dipped in an electroless copper plating solution to clean the inside of the through hole and any rough edges. It is necessary to plate only the exposed substrate surface, and then electroplating. to deposit electrolytic steel on the region-plane of the electroless steel.

In the prior art, in the above method, as a practical matter, electroless metal is still deposited on the resist. It was reported that this resulted in the precipitation of

Brief description of the drawing Figure 1 is a process diagram of the usual method of manufacturing printed circuit boards with through holes. C, Figure 2 shows the through-holes of a printed circuit board at various stages of the process shown in Figure 1. FIGS. 3 and 4 each illustrate an embodiment of the present invention. Therefore, the process flow diagram and the corresponding cross-sectional structure are shown, and FIGS. 5 and 6 illustrate a process system for another embodiment of the invention, respectively. The structure of the system diagram and corresponding cross section is shown.

In each drawing explaining the structure, that is, FIG. 2, FIG. 4, and FIG. Holes and pads that are related to subfigures other than the subfigures in the drawing and are A child drawing that is related to pads and holes other than the pads and holes in the drawing KS. Ru.

Detailed description of the invention In the method of the present invention, before metallizing the surface of the through hole, the resist is applied in advance. Suitable double sided surface with one or more through holes in the desired pattern as specified. , or applied to a multilayer metal-clad circuit board substrate to remove areas that you do not want plated. Define the outline clearly. The resist materials selected are subject to development, solidification, or curing conditions. , under the action of an alkaline aqueous solution, even though it has been catalyzed beforehand. First, it must be able to inactivate the surface against subsequent electroless metal deposition. ◎Furthermore, 1/The cyst material is a metal layer deposited in the next electroplating process. Needless to say, it is necessary to prevent the Must be able to completely strip.

As used herein, "passivation" of a resist surface refers to a metal clad printed circuit board. Depending on the condition of the substrate, apply the resist in the desired pattern on the substrate, and then The entire surface is catalyzed or “activated” to accept the precipitated metal. Process sea urchins non-selectively.

In accordance with the present invention, the substrate thus treated is coated with a catalyst prior to metal deposition. with an alkaline aqueous solution under conditions that allow for selective removal or removal from the surface. In contact with the surface, such a surface is considered to be ``inert'' meaning that metal deposits cannot be deposited on the surface. to be sexualized. This deactivation mechanism is essentially from the resist surface to the contact layer above it. & includes stripping the medium layer. This stripping is done by Regis Strips only the catalyst layer from the resist surface without dissolving the resist itself. can and usually does, and alkaline aqueous solutions Here, the resist surface is softened and the catalyst layer is coated with the solution or the next layer. Wash and strip. However, in the present invention, the catalyst is supported at the bottom. The very thin part of the surface of Resost that is being dissolved is actually dissolved in an alkaline aqueous solution. Therefore, "stripping" of the t1 catalyst layer is included within the scope of the present invention. Which Even in the case of The remaining surface of the resist after treatment with the aqueous solution no longer contains the essential catalytic species. This is because there is none.

With respect to the inherent properties that the resist must maintain, the selection should be made within the limits indicated above. The specific resist to be determined can be selected from a relatively wide variety of resist types. Can be done. Particularly preferred are photosensitive resist materials (photoresists), Within this category, resists may have either negative or positive effects. negative In the active photol/cyst, a photosensitive material that can be developed is applied to the substrate surface. Apply it evenly and then expose through a mask showing the outline of the desired artwork. .

The exposed areas of the resist become “insolubilized” (cross-linked); Dead areas (in patterns such as holes, pads, subfigures, etc.) can be dissolved and removed using a suitable developer. It remains in a form that can be removed and removed. For resists with positive effects, the 11-element region ( pads, holes, child figures, etc.] are converted to a solubilized form and can be dissolved and removed. , while l! The areas that are not exposed to light remain as resist. Photoresist is made by Whether the application is negative or positive, dry film or liquid type. good.

Governed by the requirements pointed out earlier, resist materials are also non-photosensitive! , Sunawa Alternatively, it may be thermosetting or hardening 1N fold. These types of resins The desired pattern is applied to the surface of the board using known screening techniques.

With reference to FIGS. 6 and 4, one particular embodiment of the present invention is shown in which both sides are made of thin metal. The genus begins with an insulating substrate 100 that is coated with <120 (e.g. copper). The insulating substrate is Typical examples include lath reinforced epoxy substrates or polyimide type substrates. but However, any thermosetting resin, thermoplastic resin, or combination thereof that is generally insulating Compounds can also be used in the form of these fibers impregnated, e.g. allyl phthalate , epoxy resin, polyester, polyacrylate, polyester, ABS copolymer Includes combinations, etc. One or more through holes 140 are formed in the board. This is to make a conductive connection between the circuits you are trying to make on each side of the board. Metallization is required.

In the next step of the method of the invention, the resist material 180 is deposited in a desired, predefined manner. Apply it to a plate in the form of a certain pattern to achieve metallization on the plate surface! contour of the area without clearly defined. As I pointed out, the resist is coated with a catalytic species first. Even though it can promote the acceptance of metal precipitates without Under the action of an aqueous potash solution, metal deposits (and It must be possible to activate, but it is not possible to achieve such inertness. It is possible that the resist’l has no disadvantages of corrosion or destruction, or It can be made directly from the board without having to strip it, or without the need for metallization. Catalytic material present in exposed areas of the critical plate shall not be removed and/or deactivated. This is when conditions are favorable. Particularly preferred in this regard are Negative action photosensitive dry film tie that can be stripped with resist (e.g., E.I. du Bon de Nemours) Liston (R15ton) sold by Pont de Nemours & Co. ] 5600 series, especially Liston 6615, Liston 20 also sold by Shubon 0 series photoresistor, sold by Hercules? − Aquamar photoresist, Dynachem H.C. chemHG], and Nichide Alfuo (Nichig.

Alpho) Sales type (Type) 1038　Fork known as Mw Tresost), and non-photosensitive, screen printable, alkaline strippable type of resist, especially acrylics that harden to a smooth, glossy surface is the base type. Depending on the case, N light/development or curing Afterwards, the resist-coated board is generally washed with water, pickled, washed with water, and treated with a conditioning agent. and rinse again with water. After that, apply a laminar etching agent ( (for example, a dilute solution of hydrogen peroxide/sulfuric acid), rinsed with water, and then Activate with a substance that catalyzes oxidation.

For electroless metallization, surface activation is well known in the art, but generally involves A tin-palladium stage, such as a solution of stannous chloride and palladium chloride in hydrochloric acid. The process consists of creating a palladium catalyst layer on the surface by contacting it with a colloidal solution. death However, activation can be done using a two-step process such as tin/palladium or copper compounds. It can also be done with non-precious metals. After activation, in detail, tin-palladium co When a Lloyd's solution is used for activation, an accelerator solution is generally used to Increases the activity and stability of the catalytic species.

At this stage of the process, sufficient active catalyst is present on the surface of the resist material to - Desired metallization of holes, pads, subfigures and other areas not covered by resist It can be seen that it not only causes the metallization of the resist, but also causes undesired metallization of the resist. . Next, according to the present invention, the resist surface is deactivated, i.e., the resist surface is deactivated. The plate is brought into contact with a dilute alkaline aqueous solution under conditions that remove the catalyst layer from the (e.g. spraying, soaking), but the removal of the catalyst layer requires Sufficient softening of the resist surface, or resist supporting or adhering to a catalyst. either by dissolution of a thin layer of ;-However, at the same time, the resist is corroded. Guaranteed not to be destroyed or completely stripped from the board. and also the catalytic species in close contact with the area requiring metallization. not be removed and/or adversely modified to any substantial degree; This must also be guaranteed.

To achieve these objectives, soluble carbonates, hydroxides, borates, etc. Relatively dilute alkaline solutions, especially salts in the water-soluble sodium or potassium form Use wo. The resist material is completely stripped in an alkaline aqueous medium. The operating conditions for this step, e.g. The basicity, as well as the time and temperature of contact, will cause rapid corrosion on the harsh and resist. or to avoid promoting too aggressively or areas of the board with no resist. It is necessary to ensure that there is no risk of inactivation. Generally, Arca - of the acidic aqueous solution ranges from about 8 to 11.5, preferably from about 8.5 to 11. should be enclosed. The temperature at which the plate is contacted with the solution generally ranges from about 70'F to about 13 The range is preferably from about 90'F to about 110'F. stomach. The contact time should be short enough to ensure that the catalyst layer is removed from the resist. There is also a risk of dissolving too much resist and/or metallization in the areas you want to overlay. The catalyst should be selected without risking the risk of total inactivation.

After washing with water, the board is no longer covered with through-hole surfaces, and resist Metallization of other surfaces is always possible. Metallization method is electroless analysis of metal, generally copper (e.g., layer 160 in FIG. 4) is most typical, and then this analysis Following deposition, similar or dissimilar metals can be deposited additionally by electrolysis. Wear. As an example, the metallization can include electroless copper followed by electrolytic copper.

In either case, this metallization is then followed by a suitable etching resist (e.g. Plating resist is removed by stripping and protected. The unetched areas are etched on the substrate surface 1. Metallization is gold by electrolytic copper Electrolytic methods such as metabolization can be completely deducted.

A resist material that deactivates a predetermined catalyst, regardless of the specific metallization technique. The requirements for will also determine the requirements for the metallization method. . Specifically, to ensure that the resist material does not dissolve during the plating operation. For this purpose, the plating solution must not be strongly alkaline. About electroless plating With this requirement, the well-known strongly alkaline (P) (from 11 to 16) The solution is to use an electroless bath based on luminaldehyde. however , electroless plating baths based on hypophosphite reducing agents can be used effectively. The reason for this is that if the complexing agent is selected appropriately, the range of implementation is low alkalinity and This is because it extends to the low acidity range. For example, a study on suitable electroless steel baths U.S. Pat. No. 4,209,331 to Kukanskis et al. , and No. 4,279,948. Achieving the objectives of the invention The resist selected for this purpose will not dissolve in these baths under the conditions of use. metallization If this is carried out in whole or in part by electrolytic methods, suitable baths such as acidic copper are known.

As pointed out earlier, the method of the present invention allows the resist to be soluble in alkaline water under specific conditions. In liquid, various types of resins can be used, provided they maintain the necessary properties for catalyst deactivation. This can be done using Zost. In Figures 5 and 6, the photosensitivity of positive action An embodiment of the present invention for use on a resist surface will be described. As in the previous embodiment In the metal foil-clad base w 100.120 with the through hole 140, this In this case, apply a photoresist photosensitive material 180 that has a positive effect, and this - exposed through a light mask with a predetermined pattern, then developed and exposed. If the exposed areas are removed by melting, the surface of the plate will be exposed in areas that do not need to be metallized. Some resist remains. The board is then subjected to various cleaning, conditioning, and etching procedures as described above. Perform tucking and activation/promotion treatment. The catalytic species on the resost surface is already sufficiently active. It has been found that metallization occurs during plating (although this is undesirable). Karu. As before, the properties of the resist are prepared using a dilute alkaline solution. Catalytic species can be removed. Since it contains a positive resist surface, the resist Simply rub the entire plate for just enough time to break down and solubilize the outer surface. Inactivation can also be effected by exposure to ultraviolet light. Then this The process can be followed by a cleaning step to remove any affected thin sections. . As shown in Figure 5, the two-branch method can be combined, that is, the plate is simply Exposure to ultraviolet light and then contacting the plate with an alkaline aqueous solution is generally preferred. stomach. This treatment is followed by metallization, as discussed above.

The above embodiment illustrates the metallization of through holes in a double-sided printed circuit board. However, it will be clear that exactly the same method can be used for multilayer boards.

As is well known in the industry, through-holes made by drilling holes in a multilayer board are plated. In this method, drilling generally removes the exposed inner layer of the metal without leaving any resin contaminated by the process. A cleaning process is required to remove dirt from the surface. Typical techniques for removing dirt include: Chemical methods (e.g. chromic acid, concentrated sulfuric acid), mechanical methods (e.g. water vapor fluoride) drilling, secondary drilling) or other methods (e.g. plasma etching). inclusion, followed by other special treatments, followed by activated species and metallization. The through-hole surface can be adjusted to make it possible. for example, Kukanskis, “Improved Smear Remov” al) J, CIRCUITS MA NUFACTURING), June 1983, pages 576-574 page, and general application U.S. Pat. No. 4,597,988.

Regarding the present invention, such stain removal treatment is performed before applying the resist to the surface of the substrate. Or you can do it later.

Particularly useful in the method of the present invention is the use of "pro-oxidants" such as Kukanskis et al. ng　Accelerator　J　J　(April 22, 1986, publication fee paid Pending Patent Application No. 712,981, entitled Pending General Application No. 712,981. The activation/promotion described in this document is also included as reference material in this specification. The specification describes a one-step catalyst activation method using a palladium/tin sol followed by acid The acceleration is carried out with an alkaline solution containing a oxidizing agent; Hypophosphorous acid reduction, such as those used in Particularly effective in conjunction with electrolytic plating. These preferred accelerating solution properties, viz. Because of their alkalinity and aqueous nature, in the context of the process of the invention, resist Deactivates the surface and at the same time promotes absorption of the catalyst onto the surface of the plate without resist. Solutions such as advancing means can be used. However, alkalinity and metallization by electroless deposition due to different operating temperature requirements. If the resist surface is to be promoted and deactivated in separate steps (in either order), ) is generally and preferably.

Although the embodiments described typically use copper metallization, special As long as the selected resost can be precipitated under conditions that do not dissolve it, other Any metal can be used.

The present invention will be described in detail with respect to the manufacture of printed circuit boards, in order to illustrate the advantages of the method of the present invention. This is because it is in this field that the most obvious and most important is Which, The resist is applied according to the pattern before the plating method even begins. The method of the present invention, which allows for significant improvements over conventional methods, is due to the metallization process and etching process. ting, etc., without the need for interruption to perform the necessary resorst application. This is because it can be compared with other methods that can be applied to the same purpose. Therefore, the method of the present invention clearly defines the outline with delicate lines and uses a photosensitive resist material. and the hazards and disposal issues associated with the use of organic solvents to dissolve resist materials. problems can be avoided. Double-sided, or multilayer requiring through-hole metallization Although highly advantageous with respect to the manufacture of printed circuit boards of the type, the present invention substrate in a predetermined pattern that requires improved detail or economy. It can be applied to any method in which a surface needs to be metallized.

The method of the invention is further illustrated in the Examples below.

Example 1 The glass-reinforced epoxy substrate is laminated with copper foil, and through-holes can be drilled into it. Then, wash it and remove the baffle. Next, dry the plate with a photosensitive negative film. Liston CR15toΩ) 3615-11' coating of mu/cyst.

After exposing the desired pattern through a mask, the resist is exposed to sodium carbonate. Count in a 10fi/11 solution, wash with water, and follow the processing cycle below (as appropriate). 1. Wash at 110'F for 2 minutes with acidic detergent (Matsukuderumi). 2. Adjust at room temperature for 2 minutes. contact with a 1.5% (volume) aqueous solution of agent (Matsudermid 9420), 6. Microetching solution (MacDermid G4) (MacDelMid G4) for 1 minute at room temperature. Contact with Mido 60 F15 volume % il sulfate), 4.9Q? for 3 minutes, activator solution - Macdermid tivate〕1Q　, 1.5 capacity section, Matsuku Dermid 9008.50 capacity section and 5 volumes of thihydrochloric acid are contacted with the remainder, 5. 1001C'5 minutes, charcoal esu)! Jium 10.9//, dimethylamine Contact with an aqueous solution of borane (reducing agent) 0.5 g/l, --ii, s, Remove the catalyst layer from the surface and inactivate it. This can be seen by the absence of blue (resist color) in the contact solution). 6. At 130”F to 140”F, add an oxidant (sodium bicarbonate) for 2 to 5 minutes. Sodium hypochlorite aqueous solution with pi-18,5~p) (9,0) ) and Z　An electroless copper bath that contains no formaldehyde and is reduced with hypophosphorous acid. , Matsucdermid 249-T, p) (in -9, 130"F' for 2 minutes without electricity) Copper plating is performed, Acid immersion in 8.5 volumes of sulfuric acid, 9 Electroplating in an acidic copper plating bath.

Inspect the plate at various stages during this process to ensure that no metal plating has occurred on the resist surface. It was shown that there was no corrosion of the resost, and that no corrosion of the resost was observed. In detail, resist the edges of the child figure or pattern that clearly defines the contours of the pad. evidenced by wrinkles or shrinkage). Copper coating on through holes The rate was excellent.

In certain variations of the above process, steps 5 and 6 can be interchanged and The reducing agent in the solution in step 5 can be omitted.

Example 2 The method of Example 1 was repeated on four plates through the first four steps (sample A to sample A). up to the price). The sample was then processed in the following steps: 5. Sodium carbonate 10g/l and dimethylamine borane 0.59/l, p Sample A was brought into contact with an aqueous solution of H-11,5, and the contact time and temperature were as follows. 5 minutes, 88 yen Sample B 5 minutes, 100°F Sample 0 5 minutes, 120°F' Sample D 2 minutes, 1203F 6. Acid soak with 5-thiosulfuric acid at room temperature, and 7. rR copper electroplating bath, Maxsp. Electroplated with Ku [: MaCuSpec] 9239 (Matsuku Dermid Co., Ltd.) Ru.

All plate samples showed good copper coverage in the through-holes and were consistent with all treatments. , does not significantly (if at all) remove catalyst from unresisted surfaces. It was shown that there is no such thing. Sample A showed no resist corrosion, but resist Some plating occurs on the surfaces, indicating that these surfaces are not sufficiently passivated. Ta. Sample C clearly showed corrosion of the resist.

In sample B and sample sample, there was no corrosion of the resist, and there was metal plating on the resist surface. There is no negative effect on resist adhesion, and the desired inactivation can be achieved. demonstrated the ability to draw detailed outlines, and the ability to draw detailed outlines. Example 6 The procedure of Example 2 was repeated with 6 plates (Sample A1 Sample B1 Sample C). Example 2 At the end of step 5 shown in step 5, the sample was mixed with 10 g/l of borax and 1 liter of dimethylamine borax. 0.5El/1. , -19.5 was brought into contact with the aqueous solution as follows: Sample E 5 minutes, 100'F Sample F 2 minutes, 120'F Sample 0 5 minutes, 120°F The through-hole copper coverage of all samples was good. Every sample has a resist surface. There was no metal plating.

In samples E and F, it was clear that there was no corrosion of the resist, but in sample G There was very slight corrosion on the resist.

Example 4 The procedure of Example 2 was repeated with three plates (sample H1, sample J), but in step 5. Sample H using pH 8.3' and the following contact times and temperatures: 5 minutes, 100″F’ Sample processing: 2 minutes, 120°F Sample 3 5 minutes, 120°F The copper coverage in the through-holes was good in all samples, but in sample H and sample machining, showed metal plating on the resist surface. In sample J, corrosion of resost and resos There was no plating on the surface. As indicated, the foregoing description describes the invention, shows that the invention can be practiced, and that it is possible to carry out the invention. The best known method for Neither the particular course of description nor the materials or conditions should be construed as limiting the invention. do not have.

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Claims (23)

[Claims] 1. One or more through-holes requiring metallization and surface areas where metallization is not desired. In the manufacturing of printed circuit boards, which has a wide range of a) A flat circuit containing a metal clad insulating substrate and having one or more through holes. preparing the roadplate material, b) a layer capable of being stripped in an alkaline aqueous medium; Metallic coating is applied to the surface of the plate material in a predetermined pattern. clearly delineate the surface area where you do not want c) remaining exposed areas of the plate material, through-hole surfaces, and resist surfaces; applying a catalytic species capable of promoting metallization on the region and surface; d) reducing the Both the resist surface and the resist surface are treated with a material effective to render the resist surface inert to metallization. e) contacting the plate material with an alkaline deactivating aqueous solution under conditions of area, and the surface of the plate that includes the through-hole surface that is not protected by resist. immersed in a metal-containing solution under conditions effective to metallize the f) then applying additional metal to the metallized areas and surfaces not protected by the resist; increase coating, A method of manufacturing a printed circuit board, characterized by a process. 2. Metalized areas, and even more layers of additional metal on surfaces not protected by resist The increase of the claimed invention comprises applying an electrolytically deposited metal to said area and surface. The method described in Scope No. 1. 3. Claims wherein the photosensitive resist is an alkaline strippable resist. The method described in Section 2. 4. Resists that can be stripped with alkaline are negative photoresists, as claimed. The method described in Scope No. 3. 5. Resists that can be stripped with alkali are negative dry film photoresists. A method according to claim 4. 6. Resists that can be stripped with alkali are screen-printed non-photosensitive resists. The method according to claim 2. 7. The flat circuit board material is attached to the insulating substrate cradle on the upper and lower surfaces of the copper foil. 3. The method of claim 2, comprising: 8. The flat circuit board material comprises an insulating substrate and a conductive metal layer. The method described in section. 9. the metal-containing solution of step (e) is a metal precipitation solution having a pH of less than about 10; The method according to claim 2. 10. Claim 9, wherein the metal-containing solution in step (e) is an electroless metal deposition solution. The method described in section. 11. Claim 9, wherein the metal-containing solution in step (e) is an electrolytic metal deposition solution. Method described. 12. Application of catalyst species to remaining exposed areas of plate material, through-holes, and resist surfaces the agent is applied to the surface and area, and then the surface and area is exposed to the catalytic material. A method according to claim 2, comprising a separate step of contacting with an accelerator that . 13. Claim 1, wherein the accelerator includes an alkaline aqueous solution containing an oxidizing agent. The method described in Section 2. 14. The alkaline inert aqueous solution has a pH ranging from about 8.0 to about 11.5. The method according to claim 2. 15. The alkaline inert aqueous solution consists of hydroxides, carbonates, and borates. The method according to claim 14, wherein the method is an aqueous solution of an alkaline substance selected from the group . 16. A resist that can be stripped with alkali is a positive photoresist and Prior to contacting in step (a), the plate material is briefly exposed to ultraviolet light to create a positive photoresist. 3. The method of claim 2, wherein a small portion of the surface area of the strike is dissolved. 17. One or more through-holes requiring metallization and surface areas where metallization is not desired. In the manufacturing of printed circuit boards, which has a wide range of a) A flat circuit board consisting of a copper foil clad insulating substrate with one or more through holes. prepare the substance and b) remove the resin from which it can be stripped in an alkaline aqueous medium; is applied in a predetermined pattern to the surface of the plate material to metallize it. Clearly delineate the surface areas where you do not want to to precisely define the width of the surface area of the plate to be metallized. has at least sufficient vertical thickness above the plate surface; c) remaining exposed areas of the plate material, through-hole surfaces, and resist surfaces; applying on the area and surface a catalytic species capable of promoting copper precipitation; d) removing at least the catalyst species that are in close contact with the resist surface; contact with an alkaline deactivating aqueous solution under conditions effective to remove the gold. Maintaining the integrity of the resist to precisely define the area to be attributed; Moreover, it promotes copper precipitation on the surface and in areas not covered by resist. maintain sufficient active catalytic species to under conditions effective to metallize the area of the plate containing the through-hole surfaces with copper. , immersion in a copper deposition solution without substantially degrading the quality of the resist. Ku, Katsu f) Then apply an additional electrolytic metal coating to the metallized area and protect it. Increase on the surface that is not, A method of manufacturing a printed circuit board characterized by a process. 18. The pH of the alkaline inactivated aqueous solution ranges from about 8.0 to about 11.5. 18. The method of claim 17, wherein the method is: 19. Contacting the plate material with the alkaline inert aqueous solution at temperatures ranging from about 70°F to about 130°C 19. The method of claim 18, wherein the method is carried out at a solution temperature of up to °F. 20. The alkaline deactivation solution contains alkali metal hydroxides, carbonates, and hydroxides. Claim 19 which is an aqueous solution of a water-soluble salt selected from the group consisting of borates. Method described. 21. The circuit board material consists of one or more copper inner layer planes separated by a plane of insulating material, and an outer Claim 1, which is a multilayer board consisting of a cladding with a copper foil on the side finishing side. The method described in Section 7. 22. Claim 21: The through-hole is cleaned before metallization. The method described in. 23. In a method of applying a pattern to a metal foil clad insulating substrate surface, the pattern is The turn consists of a metallized region and a non-metalized region, and the substrate is treated with an aqueous alkali. Applying a strippable resist in a predetermined pattern, Clearly delineate the surface areas that do not need to be metallized, then coat the entire substrate with metallization. contact with a substance that catalyzes oxidation, and then resists the substrate against metal plating. contact with an alkaline aqueous solution under conditions effective to render the surface area of the spray inert. and without having any harmful effect on the catalyst material in areas without resist. , the substrate is then contacted with a metal-containing solution to remove the resist-covered substrate. A pattern on a metal foil clad insulation surface characterized by full metallization of the area. How to apply.