CN102711385A

CN102711385A - Method for manufacturing circuit board by addition method

Info

Publication number: CN102711385A
Application number: CN2012102104453A
Authority: CN
Inventors: 黄明安
Original assignee: BEIJING KDS Co Ltd
Current assignee: Beijing Kds Co., Ltd.; Wuhan Kaidisite Technology Co., Ltd.
Priority date: 2012-06-26
Filing date: 2012-06-26
Publication date: 2012-10-03

Abstract

The invention provides a method for manufacturing a circuit board by an addition method. The process is as follows: thinning, drilling; precipitating copper; transferring a dry film image; and conducting electroplating addition, film withdrawing and microetching. By adopting the circuit board manufactured by adopting the method, the line width/interval being smaller than 4mil/4mil can be realized easily, a circuit board with ultra-thick copper can be manufactured, and the quality problems of blocked holes and line breakage can be reduced greatly.

Description

A kind of addition process is made the method for wiring board

Technical field

The invention belongs to the printed wiring board manufacture technology field, what be specifically related to is to adopt addition process to make a kind of method of wiring board.

Background technology

The manufacture method of wiring board generally has only two kinds at present, and semi-additive process and subtractive process are made wiring board.

The method that adopts graphic plating technology to make wiring board is a semi-additive process, and this method is that wiring board is made in the technological process of on substrate Copper Foil basis, carrying out chemical copper, thickening copper facing, dry film figure transfer, the thickening of graphic plating secondary copper facing, zinc-plated lead, move back film, etching, moving back tin.

Adopt dry film to cover hole technology and make the method for wiring board and be a subtractive to method, the method is that wiring board is made in the technological process of on substrate Copper Foil basis, carrying out chemical copper, once plate thick copper, figure transfer, etching, moving back film.

From present process route, the circuit board plant of general day, platform background is selected the subtractive process manufacturing process, and circuit board plant beautiful, the port background is selected the semi-additive process manufacturing process.

The flow process of semi-additive process and subtractive process is simple, technical maturity; But all can there be etching to the substrate Copper Foil; Can cause the lateral erosion of circuit, for superfine circuit and ultra thick Copper Foil, there is intrinsic limit problem in these two kinds of technologies; In general just make very difficulty less than the live width of 4mil and spacing, just be difficult to etching greater than the copper of 4OZ is thick.

Along with the development of wiring board, the heavy current circuit plate demand of the HDI wiring board of superfine circuit and ultra thick Copper Foil increases gradually, and the circuit board technique that exploitation can be made superfine circuit and ultra thick Copper Foil is that everybody expects.

Summary of the invention

It is pile foundation that the process using Copper Foil that addition process is made wiring board is thinned to less than residual and the basic copper base material strong bonded behind the 3um thickness; Adopting this pile foundation mainly is in order to improve the adhesion of addition copper and base material, and also having a purpose is in order to remove the influence of catalyst-palladium residual after the chemical copper to wiring board.

Carry out chemical copper production behind the Copper Foil attenuate, with the deposition last layer very thin substrate of doing the metal addition on insulating material, the copper of chemical copper and attenuate is all very thin, when carrying out the dry film figure transfer, does not carry out little erosion and brush and grinds and carry out direct pad pasting.

Addition is not carried out little erosion before electroplating, and in the process that addition is electroplated, may have the phenomenon of isolated circuit current concentration, in engineering design, will near isolated circuit, increase and rob the electrolytic copper skin.

Substrate copper after addition is electroplated adopts the method for little erosion to remove, and that is to say substrate copper and addition copper integral body are given little erosion.

When adopting galvanoplastic to carry out surface treatment, little erosion of this substrate copper will be carried out after wet film develops.

description of drawings.

Fig. 1 is a structure chart of the present invention, and dash area is expressed as copper in the structure chart.

Fig. 2 is a flow chart of the present invention.

Embodiment

For setting forth practical implementation method of the present invention, the present invention is done further detailed description below in conjunction with accompanying drawing.

Flow process of the present invention is: attenuate → boring → heavy copper → dry film figure transfer → plating addition → move back film → little erosion.

Attenuate: the Copper Foil to copper-clad plate carries out reduction processing; It is thick in 3um to be thinned to copper; The initial thickness of Copper Foil is got over Bao Yuehao; The general copper of 18um that adopts is thick, and the etching speed that adopts during attenuate is for adjusting on the basis of 2 times internal layer 18um Copper Foil etching speed, and is surplus thick less than 3um and to expose base material a little be benchmark with Copper Foil.

Boring: to processings of holing of the plate behind the attenuate copper, attenuate prevents that in boring be for fear of etching away multiple-plate internal layer, the attenuate again if double sided board then can be holed earlier before.

Heavy copper: the plate after attenuate and the boring is carried out electroless copper plating handle, with the chemical copper of deposition last layer electric action on the hole wall of insulating material.

The dry film figure transfer: the plate to behind the heavy copper carries out pad pasting, exposure, development, forms the negative circuit, and the copper foil layer behind the heavy copper is very thin, can not carry out little erosion and polish-brush and handle.

Electroplate addition: the position addition there not being dry film to cover is electroplated, and forms the positive circuit, and is better for the uniformity that makes plating, in engineering design, just needs to increase the auxiliary electrolytic copper skin of robbing.

For superfine circuit, as long as the resolution of dry film can reach below the 2mil, it is thick in build (build is generally 40um) just can to make copper, and width comes out less than the circuit of 2mil.

For the making of ultra thick copper, through the method for dry film figure transfer → plating addition repeatedly, it is above to make the copper thick 4OZ of surpassing, and does not have the thick copper coin of side etching quantity to come out basically.

Move back film: return and cover used dry film.

Little erosion: all copper layers of plate face are carried out whole little erosion, form required circuit, in order to reduce the influence of chemical copper catalyst-palladium, micro-corrosion liquid uses the acidic etching liquid that contains chloride ion.

Surface treatment is galvanoplastic when carrying out surface treatment, and little erosion will be placed on wet film and carry out after developing.

The wiring board that adopts the present invention to make not only can be less than live width/spacing of 4mil/4mil easily, but also can make the wiring board of ultra thick copper.

The subtractive process flow process is simple, but the Copper Foil that etching is removed is more, and the loss of copper is bigger; Side etching quantity is very big, can not make the wiring board of superfine circuit and ultra thick Copper Foil.

The obstructed problem of via hole that takes place when subtractive process is produced is more, and this is all can cause etching solution to get in the hole because skew takes place for boring and contraposition, and the present invention can significantly reduce the generation of the obstructed problem of via hole because the skew of position, hole can not cause hole copper to be etched.

Subtractive process is very high to the environmental requirement in figure transfer workshop, and the rubbish during exposure can cause broken string, can't repair; The rubbish of addition process exposure can cause short circuit, can be at an easy rate to the circuit place under repair.

Relative semi-additive process, the present invention does not use corrosion resistant metals such as tin lead, on the cost He on the environment bigger advantage is being arranged all.

Claims

1. flow process of the present invention is: attenuate → boring → heavy copper → dry film figure transfer → plating addition → move back film → little erosion.

2. attenuate in the claim 1: the Copper Foil to copper-clad plate carries out reduction processing; The initial thickness of Copper Foil is got over Bao Yuehao; The general copper of 18um that adopts is thick; The etching speed that adopts during attenuate is for adjusting on the basis of 2 times internal layer 18um Copper Foil etching speed, and is surplus thick less than 3um and to expose base material a little be benchmark with Copper Foil.

3. the boring of claim 1: to the processing of holing of the plate behind the attenuate copper, attenuate prevents that be for fear of etching away multiple-plate internal layer, the attenuate again if double sided board then can be holed earlier before boring.

4. the dry film figure transfer of claim 1: the plate to behind the heavy copper carries out pad pasting, exposure, development, forms the negative circuit, and the copper foil layer behind the heavy copper is very thin, can not carry out the processing of little erosion and polish-brush.

5. the plating addition of claim 1: the position addition there not being dry film to cover is electroplated, and forms the positive circuit, and is better for the uniformity that makes plating, in engineering design, just needs to increase the auxiliary electrolytic copper skin of robbing.

Claim 1 for superfine circuit, as long as the resolution of dry film can reach below the 2mil, it is thick in build (build is generally 40um) just can to make copper, width comes out less than the circuit of 2mil.

7. the making for ultra thick copper of claim 1, through the method for dry film figure transfer → plating addition repeatedly, it is above to make the copper thick 4OZ of surpassing, and does not have the thick copper coin of side etching quantity to come out basically.

8. little erosion of claim 1: all copper layers of plate face are carried out whole little erosion, form required circuit, in order to reduce the influence of chemical copper catalyst-palladium, micro-corrosion liquid uses the acidic etching liquid that contains chloride ion.

9. Flow process according to right 1The wiring board of making not only can be less than live width/spacing of 4mil/4mil easily, but also can make the wiring board of ultra thick copper.