CN101643903A

CN101643903A - PCB board step hole molding method

Info

Publication number: CN101643903A
Application number: CN200910306696A
Authority: CN
Inventors: 缪桦; 朱正涛
Original assignee: Shennan Circuit Co Ltd
Current assignee: Shennan Circuit Co Ltd
Priority date: 2009-09-08
Filing date: 2009-09-08
Publication date: 2010-02-10

Abstract

The invention relates to a PCB board step hole molding method, comprising: a step of forming protection film: forming a layer of protection film for covering the circuit at the surface of PCB board and copper layer on the inner wall of PCB board through hole on the inner wall of the through hole and surface of PCB board that is transferred after the last procedure is completed by using protectionfilm material, and exposing the end surface of the copper layer on the inner wall of the through hole that is needed to be machined into step hole; etching step: etching the PCB plate by using etchingsolution, etching the copper layer on the inner wall of through hole of PCB board from exposed end surface to deep position until the etching depth reaches the requirement; de-coating step: treatingthe PCB board by using the de-coating solution capable of dissolving the protection film, dissolving the protection film in the de-coating solution to remove the protection film, and obtaining the required step hole. Depth and precision of the step hole molded by the invention can reach +/10.2 mm; the molded step hole can effectively reduce stubbing effect of high-frequency signal in transportation of PCB board; the phenomenon of drill leakage in mechanical machining process can be effectively avoided; and the machining cost is lower than the mechanical cost.

Description

The pcb board step hole molding method

Technical field

The present invention relates to the pcb board field, refer in particular to the pcb board step hole molding method.

Background technology

Usually need to process some shoulder holes on the pcb board to satisfy specific demand.At present, the modal method of machine-shaping shoulder hole is a back drill on pcb board, promptly utilizes the dark lathe of control to mold a through hole earlier, in the hole that existing through hole respective end is bored certain depth, forms shoulder hole again.Existingly thisly mainly there are following defectives by machining process moulding shoulder hole:

1, easily produce leakage in the mechanical processing process and bore, and subsequent detection is difficult to identify;

2, existing machinery processing shoulder hole depth accuracy only can reach ± 0.13mm, and the requirement of shoulder hole depth accuracy is high more, and mechanical workout stepped hole difficulty is big more;

3, mechanical workout shoulder hole cost is higher.

Summary of the invention

Technical problem to be solved by this invention is, a kind of pcb board step hole molding method is provided, and improving the step hole molding precision, and can effectively cut down finished cost.

For solving the problems of the technologies described above, the present invention adopts following technical scheme: a kind of pcb board step hole molding method comprises the steps:

Form the protective membrane step: pcb board surface that transfers after being finished by last process with the protective membrane material and through-hole wall form one deck and cover the circuit on pcb board surface and the protective membrane of the copper layer on the pcb board through-hole wall, and the end face of the copper layer on the inwall of the through hole that need further be processed into shoulder hole is exposed;

Etching step: with etching solution pcb board is carried out etch processes, make the copper layer of pcb board through-hole wall etched gradually to the depths, reach requirement until etch depth from the end face that exposes;

Take off the film step: with the coating solution that takes off that can dissolve protective membrane pcb board is handled, taken off but protective membrane in the coating solution, obtain required shoulder hole thereby protective membrane is dissolved in takes off.

Beneficial effect of the present invention is as follows: the depth accuracy of moulding shoulder hole of the present invention can reach ± 0.02mm, is better than the depth accuracy ± 0.13mm of traditional mechanical workout; The shoulder hole of moulding can effectively reduce the stub effect that high-frequency signal exists in the pcb board transmission; And, can effectively avoid leaking in the mechanical processing process and bore phenomenon; Tooling cost is lower than machining cost.

Description of drawings

Fig. 1 is the schema of the inventive method.

Fig. 2 has carried out the pcb board diagrammatic cross-section that shoulder hole to be formed is handled in outer erosion.

Fig. 3 is the pcb board diagrammatic cross-section after the present invention forms protective membrane.

Fig. 4 is the pcb board diagrammatic cross-section after the etching of the present invention.

Fig. 5 is that the pcb board diagrammatic cross-section that obtains shoulder hole behind the film is taken off in the present invention.

Embodiment

As shown in Figure 1, the invention provides a kind of pcb board step hole molding method, it is used in the middle of the existing P CB plate preparation technology, molds shoulder hole on pcb board.In existing P CB plate preparation method; at first need the PCB substrate 1 that is drilled with through hole 10 is carried out outer figure in regular turn; figure is electric and lose treatment step outward to form outer graphics 2 at the pcb board superficies; the pcb board cross-section structure of formation outer graphics 2 as shown in Figure 2; described substrate 1 is by substrate layer 11; medium layer 12 and interior copper layer 13 form according to the sequential cascade of design in advance; and the inwall of the through hole 10 of this moment also is formed with a bronze medal layer 3; because these steps have all obtained ripe the application in the middle of existing pcb board preparation technology; and be not the claimed content of the present invention, seldom give unnecessary details at this.Pcb board step hole molding method provided by the present invention promptly is used for being used for molding shoulder hole on pcb board after the outer erosion treatment step, comprises the steps:

Form protective membrane: the pcb board surface that transfers after being finished by last process (erosion treatment step promptly) with the protective membrane material forms layer protecting film 4, circuit with protection pcb board surface, and copper layer 3 end face 30 on the inwall of the through hole 10 that need further be processed into shoulder hole are exposed, the protective membrane material can adopt at least a in the following material: photosensitive-ink, exposure printing ink, blue glue, these protective membrane materials all can use separately or arbitrary combination is used, evenly form in the surface and the through-hole wall of pcb board, in addition, also can the said protection film material not be adopted at through hole 10 inwall positions, and one deck tin that is shaped is in addition protected, by the protective membrane material evenly being coated on the pcb board surface and through-hole wall has promptly formed protective membrane, as shown in Figure 3;

Etching: pcb board is carried out etch processes with etching solution, utilize the copper layer on through hole 10 inwalls of oxide-reduction method etching certain depth, make the copper layer 3 of pcb board through hole 10 inwalls etched gradually to the depths from the end face that exposes, reach requirement until etch depth, pcb board structure after the etching as shown in Figure 4, described etching solution can specifically can adopt the bivalent cupric ion basic solution, main component is a chlorion, cupric ion, wherein, copper ion concentration is 130～150g/L, chlorine ion concentration is 165 ± 15g/L, pH value: 8.0～8.7, and proportion: 1.195 ± 0.02;

Take off and remove protective membrane: pcb board is handled with the coating solution that takes off that can dissolve protective membrane; protective membrane 4 is dissolved in takes off and promptly take off but protective membrane in the coating solution; obtained required shoulder hole 5; as shown in Figure 5; take off coating solution and can adopt NaOH solution; utilize the NaOH characteristic to make protective membrane be dissolved in its solution, the strength of solution scope is generally mass percent concentration 15% ~ 25%, and the temperature of solution is 85 ~ 95 ℃.

Claims

1. a pcb board step hole molding method is characterized in that, comprises the steps:

2. pcb board step hole molding method as claimed in claim 1; it is characterized in that: the protective membrane material is at least a in the following material: photosensitive-ink, exposure printing ink, blue glue evenly are coated on the pcb board surface with the protective membrane material and through-hole wall promptly forms protective membrane.

3. pcb board step hole molding method as claimed in claim 1; it is characterized in that: the protective membrane material that adopt on pcb board surface is at least a in the following material: photosensitive-ink, exposure printing ink, blue glue, and the protective membrane material on each through-hole wall on the pcb board is a tin.

4. as claim 1 or 2 or 3 described pcb board step hole molding methods, it is characterized in that: described etching solution is the bivalent cupric ion basic solution.

5. pcb board step hole molding method as claimed in claim 4, it is characterized in that: in the described bivalent cupric ion basic solution, copper ion concentration is 130～150g/L, and chlorine ion concentration is 165 ± 15g/L, the solution pH value: 8.0～8.7, proportion: 1.195 ± 0.02.

6. pcb board step hole molding method as claimed in claim 2 is characterized in that: taking off coating solution is NaOH solution.

7. pcb board step hole molding method as claimed in claim 6 is characterized in that: the mass percent concentration of described NaOH solution is 15% ~ 25%, and solution temperature is 85 ~ 95 ℃.