CN102404942A

CN102404942A - Method of manufacturing thick copper foil PCB (Printed Circuit Board)

Info

Publication number: CN102404942A
Application number: CN2010102757624A
Authority: CN
Inventors: 田先平
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-09-08
Filing date: 2010-09-08
Publication date: 2012-04-04
Also published as: WO2012031522A1

Abstract

The invention discloses a method of manufacturing a thick copper foil PCB (Printed Circuit Board) and relates to a manufacturing technology of a PCB. The technical problem that thicker copper foil degree leads to bigger influence caused by obviously thinning surface of a copper foil circuit due to large lateral erosion amount in the etching process is solved. The method comprises the following steps of: 1) producing an anti-corrosion layer on a front surface of a copper foil according to a designed circuit diagram and applying the anti-corrosion layer on the back surface of the copper foil for protection; 2) etching the copper foil and stopping the etching when the depth of an etching area of the front surface is larger than 1/3 and is smaller than 2/3 the thickness of the copper foil; 3) removing the anti-corrosion layers on the front surface and the back surface of the copper foil and adhering the front surface to an insulating medium in a pressing manner; 4) forming an another anti-corrosion layer on the back surface of the copper foil again, wherein the anti-corrosion layer on the back surface of the copper foil is a mirror image of the circuit diagram on the front surface of the copper foil; and 5) etching the copper foil again and stopping the etching when the etching area of the back surface and the etching area of the front surface are etched to penetrate each other. The etching thickness of the copper foil can be increased by one time under the condition that the etching amount is reduced by 50% or the same lateral etching amount is required.

Description

A kind of method of making thick Copper Foil PCB

Technical field

The present invention relates to the manufacturing technology of printed circuit board (pcb), particularly realize a kind of manufacturing approach of thick Copper Foil PCB.

Background technology

In existing PCB manufacturing approach; No matter be single sided board, double sided board, or multi-layer sheet; All be to adopt the copper-clad plate that the Copper Foil pressing has been bonded on the dielectric to make raw material, make the resist layer corresponding with line pattern earlier on its surface, chemical corrosion forms then; The PCB that produces like this, general copper thickness is all below 2OZ (ounce).Do thicker Copper Foil, must adopt graphic plating, it is thick to increase copper, but the copper that increases thick also be limited, generally also all below 4OZ, also increased considerably production cost simultaneously.Therefore, in actual production, copper thickness is accomplished that the PCB more than the 4OZ is considerably less.When the thick Copper Foil of needs, generally be when design PCB domain, solve through increasing the PCB number of plies, promptly adopt two-layer or multilayer copper foil is parallelly connected realizes.

In the manufacture process of existing PCB; All be to adopt the copper-clad plate that the Copper Foil pressing has been bonded on the dielectric base material to make raw material; A face of Copper Foil bonds together with dielectric; Etching can only be from the inwardly etching of another one surface of Copper Foil, and till exposing dielectric, it is the single face etching.In this process, Copper Foil is corroded, the direction that is corroded is existing inside, also oriented side, and this copper lines edge that can cause etching is an arc, and the face width of copper lines is reduced, the amount that this face width reduces is side etching quantity.Copper thickness is thick more, and side etching quantity is big more.When the width of copper lines designs very narrowly, and during near copper thickness, side etching quantity is just big especially to the influence of the width of copper lines, even breaks off easily.On the other hand, after copper thickness increased, when doing the multi-layer sheet pressing working procedure, the gummosis degree of depth of prepreg strengthened, and filler is difficulty more, easily at inner cavity or the pore of forming of PCB.More than two factors are one of the main reasons of the thick Copper Foil PCB quality of influence.

Summary of the invention

In sum, the objective of the invention is to make in the thick Copper Foil PCB process, have above-mentioned technical problem to existing, and a kind of method of making thick Copper Foil PCB that proposes.

For solving technical problem proposed by the invention, first kind of technical scheme of employing is: a kind of method of making thick Copper Foil PCB is characterized in that: described method adopts following steps:

1) makes resist layer in the front of Copper Foil according to the line pattern of design, all apply resist layer at the Copper Foil reverse side and protect;

2) Copper Foil is carried out etching, when the etching region degree of depth in front greater than 1/3rd of copper thickness, o'clock stop etching less than three of copper thickness/two;

3) remove the resist layer on the positive and negative two sides of Copper Foil, front and the pressing of dielectric prepreg is bonding;

4) dielectric that above-mentioned pressing is bonded with Copper Foil carries out hole metallization to be handled;

5) once more the reverse side of Copper Foil make with the front on line map form the resist layer of mirror image;

6) once more Copper Foil is carried out etching, when the etching region of reverse side penetrates with positive etching region etching, stop.

The described the 2nd) in the step,, the etching region degree of depth in front is optimum depth when reaching to stop etching two of copper thickness/a period of time.

Selected Copper Foil preferred thickness is 8OZ.

Selected dielectric adopts prepreg.

For solving technical problem proposed by the invention, second kind of technical scheme of employing is: a kind of method of making thick Copper Foil PCB is characterized in that: described method adopts following steps:

1) makes resist layer in the front of Copper Foil according to the line pattern of design, form the resist layer of mirror image at the reverse side making and the line map on the front of Copper Foil;

2) Copper Foil is carried out etching, when the etching region of reverse side penetrates with positive etching region etching, stop;

3) then that itself and dielectric pressing is bonding.

Dielectric adopts prepreg.

Beneficial effect of the present invention is: first kind of technical scheme of the present invention is: the two-sided etching method of substep especially is suitable for the PCB that needs plated via; Second kind of technical scheme is: the synchronous double-side etching method is suitable for especially that not need the network of plated via and all line patterns are the PCB that link together; Comparing with conventional method of two kinds of methods: for the Copper Foil of same thickness, it is than the single face etching method of routine, and side etching quantity has reduced half the, is perhaps requiring under the prerequisite of same side etching quantity, and the thickness of etching Copper Foil can double.On the other hand, when the multi-layer sheet pressing, gummosis is that from Copper Foil two carry out towards interior, makes thick Copper Foil PCB with conventional method and compares, and the gummosis degree of depth reduces half the, and gummosis is easier, has reduced the possibility that forms cavity or pore in the PCB.So the present invention helps producing the PCB of thicker Copper Foil.

Description of drawings

Fig. 1 makes in the single face PCB process cross section structure sketch map before the etching with conventional method;

Fig. 2 makes in the single face PCB process cross section structure sketch map after the etching with conventional method;

Fig. 3 is for adopting the two-sided etching method of substep of the present invention, the Copper Foil cross section structure sketch map after the front of Copper Foil is according to the line pattern etching of design;

Fig. 4 is for adopting the two-sided etching method of substep of the present invention, the cross section structure sketch map in the Copper Foil front with the bonding formation of dielectric pressing;

Fig. 5 is for adopting the two-sided etching method of substep of the present invention, the cross section structure sketch map after the reverse side etching of Copper Foil;

Fig. 6 is for adopting synchronous double-side etching method of the present invention, the Copper Foil cross section structure sketch map after the positive and negative etching simultaneously of Copper Foil.

Embodiment

Below in conjunction with accompanying drawing and preferred embodiment, be example to make single face PCB, method of the present invention is done explanation further:

Shown in seeing figures.1.and.2, existing method is made single face PCB, and it is to adopt the single-side coated copper plate etching to form.On a face of the base material that dielectric 1 constitutes, be covered with Copper Foil 2, press line pattern making resist layer on the surface of Copper Foil 2, directly Copper Foil 2 is carried out etching, lost until the etching area of Copper Foil 2; Just form copper foil circuit, from one of them copper foil circuit, its design width is X; But after etching,, produced a side etching quantity Y in the side of Copper Foil; Make the surface of copper foil circuit obviously attenuate, it influences big more for thicker or the thin more Copper Foil of width; So the etching that will solve thick Copper Foil must reduce side etching quantity.

Shown in Fig. 3, Fig. 4 and Fig. 5, the alleged two-sided etching method of substep of the present invention comprises the steps:

1) selecting thickness for use is the Copper Foil 3 of 8OZ; In the practical implementation process, copper thickness is selected as required, and for example thickness is 4OZ, 8OZ or 12OZ; Line pattern in the front 32 of Copper Foil 3 according to design is made resist layer, all applies resist layer at the reverse side 33 of Copper Foil 3 and protects;

2) Copper Foil 3 is carried out etching; Etching region 31 degree of depth when positive 32 are greater than 1/3rd of Copper Foil 3 thickness; Stopped etching in 2/3rds o'clock less than Copper Foil 3 thickness; Etching region 31 degree of depth reach the best results that stops etching two of copper thickness/a period of time, and the cross sectional shape that forms after Copper Foil 3 positive 32 etchings as shown in Figure 3;

3) remove the resist layer on Copper Foil 3 positive and negative two

sides

32,33,, form cross sectional shape shape as shown in Figure 4 positive 32 bonding with dielectric 1 pressing of prepreg material.Described dielectric 1 preferably adopts prepreg in the practical implementation process;

4) dielectric that above-mentioned pressing is bonded with Copper Foil carries out hole metallization to be handled, and reaches the purpose that each layer communicates, and concrete processing method adopts conventional at present hole metallization technology.

5) make and the 1st at the reverse side of Copper Foil 3 33 once more) go on foot on the front 32 of Copper Foil 3 line pattern become the resist layer of mirror image;

6) once more Copper Foil 3 is carried out etching, when the etching region of reverse side 33 penetrates with positive etching region etching, stop etching, operation is accomplished, and forms the line pattern of thick Copper Foil, and cross sectional shape is as shown in Figure 5.

Shown in Fig. 6, the alleged synchronous double-side etching method of the present invention comprises the steps:

1) selecting thickness for use is the Copper Foil 3 of 8OZ, makes resist layer in the front of Copper Foil 3 according to the line pattern of design, forms the resist layer of mirror image at the reverse side making and the line map on the front of Copper Foil;

2) etching is carried out on Copper Foil 3 positive and negative two sides simultaneously, when the etching region 31 of reverse side penetrates with positive etching region etching, stopped, reaching shape shown in Fig. 6;

3) then that the dielectric pressing of itself and prepreg material is bonding, form the PCB of the thick Copper Foil identical with Fig. 5.

When needs are made two-sided PCB, in aforementioned process, adopt two Copper Foils, operate simultaneously, and both can in the two sides that pressing simultaneously is bonded in dielectric.

Make PCB with the method among the present invention, not only make thick Copper Foil easily, and half of copper foil circuit be embedded in the dielectric, this also has good effect to the bonding force that improves copper foil circuit.This method is applicable to makes single sided board, double sided board and multi-layer sheet.

Claims

1. method of making thick Copper Foil PCB, it is characterized in that: described method adopts following steps:

3) remove the resist layer on the positive and negative two sides of Copper Foil, front and dielectric pressing is bonding;

2. a kind of method of making thick Copper Foil PCB according to claim 1 is characterized in that: the described the 2nd) in the step, stop etching two of copper thickness/a period of time when the etching region degree of depth in front reaches.

3. a kind of method of making thick Copper Foil PCB according to claim 1 is characterized in that: selected copper thickness is 8OZ.

4. a kind of method of making thick Copper Foil PCB according to claim 1 is characterized in that: selected dielectric adopts prepreg.

5. method of making thick Copper Foil PCB, it is characterized in that: described method adopts following steps:

3) then that itself and dielectric pressing is bonding.

6. a kind of method of making thick Copper Foil PCB according to claim 5 is characterized in that: dielectric adopts prepreg.