CN-118973142-B - Manufacturing method of thick copper bottom thin copper metallized trapezoidal blind groove on PCB side wall

CN118973142BCN 118973142 BCN118973142 BCN 118973142BCN-118973142-B

Abstract

A manufacturing method of a trapezoid blind groove with thick copper on the side wall and thin copper on the bottom of a PCB comprises the steps of providing a plate, arranging a plurality of copper layers on the plate at intervals, slotting, downwards opening a groove on the copper layer at the top, depositing copper, forming a copper deposition layer on the outer surface of the copper layer at the top and the side wall and the bottom surface of the groove, pressing a dry film, laterally pressing a film layer on the copper deposition layer, exposing, developing, removing the film layer outside an exposure area, and forming a bump in the exposure area. Step seven, electroplating copper on the outer surface of the top copper layer and the gap area to form an electroplated layer, step eight, film stripping, forming a blind groove in the middle of the electroplated layer, and step nine, microetching. The invention forms the film bump in the middle of the groove by grooving and film pressing exposure development, controls the distance between the edge of the dry film and the edge of the groove body, and utilizes the principle of hole filling to plate the copper thickness, which is far superior to the traditional method.

Inventors

ZHOU YONGSHENG
CHEN SONG
ZHAO BOJI
DU JUN

Assignees

南通康源电路科技有限公司
东莞康源电子有限公司

Dates

Publication Date: 20260505
Application Date: 20240902

Claims (4)

1. The manufacturing method of the trapezoidal blind groove with the thick copper on the side wall and the thin copper on the bottom of the PCB is characterized by comprising the following steps: providing a plate, wherein a plurality of copper layers are arranged on the plate at intervals, the copper layers are provided with four layers, and the interval between the top copper layer and the second copper layer is larger than the interval between other adjacent copper layers; step two, grooving, namely downwards opening a groove in the top copper layer, wherein the groove is in a trapezoid shape and is in a structure with a large outer side and a small inner side, and the bottom end of the groove extends to the top surface of the second copper layer; thirdly, depositing copper, and forming a copper deposition layer on the outer surface of the top copper layer, the side wall and the bottom surface of the groove; Pressing a dry film, namely, laterally pressing a film layer outside the copper deposition layer, wherein the film layer covers the groove and the top copper layer; step five, exposing, wherein an exposure area is arranged on the film layer and is arranged at the middle position of the groove; removing the film layer outside the exposure area, forming a bump in the exposure area, wherein a gap area exists between the bump and the side wall of the groove, and the gap distance of the gap area is 60-125 mu m; Electroplating copper on the outer surface of the top copper layer and the gap area to form an electroplated layer, wherein the electroplated layer is arranged on the outer side of the copper deposition layer; removing the middle film bump to expose the electroplated layer and forming a blind groove in the middle of the electroplated layer; And step nine, microetching, namely microetching the outer surface of the electroplated layer, and etching away the electroplated layer at the bottom of the blind groove to expose the second copper layer.
2. The method of claim 1, further comprising a plating step of forming a plating layer on the outer side of the copper deposit layer.
3. The method of claim 1, wherein the plate comprises an effective area and process slitter edges arranged on the periphery of the effective area, copper layer structures are arranged on two outer side surfaces of the process slitter edges, the copper layer structures comprise a plurality of copper protruding parts arranged at intervals, and the copper protruding parts on two sides of the plate are arranged in a staggered mode.
4. The method of claim 3, wherein the copper protrusions are uniformly distributed on the waste sides of the process, and the copper protrusions are in one of a circular shape, a diamond shape and a cross shape.

Description

Manufacturing method of thick copper bottom thin copper metallized trapezoidal blind groove on PCB side wall Technical Field The invention relates to the technical field of circuit boards, in particular to a method for manufacturing a trapezoidal blind groove with thick copper on the side wall and thin copper on the bottom of a PCB. Background The blind grooves are regions having different heights formed by lamination, milling, or the like in a partial region on the printed board. The blind slot has the main functions of realizing the input and output ports of electric signals of each layer inside, being used as a cavity and a carrier for pasting and mounting components such as chips, capacitors, resistors and the like, and being used as a channel for interconnecting microwave components and being cascaded in a gold wire, gold belt and other modes. At present, a common method for metallizing a blind groove of a PCB is to sink copper after grooving and then to carry out thickening electroplating. However, the copper thickness of the metallized blind via made by this method is generally uniform, and it is difficult to make a special blind via structure with thin bottom copper and thick sidewall copper. Disclosure of Invention Based on the above, it is necessary to provide a method for manufacturing a trapezoidal blind groove with a copper bottom and a thin copper metallization on the side wall of a PCB, aiming at the defects in the prior art. A manufacturing method of a trapezoidal blind groove with thick copper on the side wall and thin copper on the bottom of a PCB comprises the following steps: Step one, providing a plate, wherein a plurality of copper layers are arranged on the plate at intervals; step two, grooving, namely downwards opening a groove in the top copper layer, wherein the groove is in a trapezoid shape and is in a structure with a large outer side and a small inner side, and the bottom end of the groove extends to the top surface of the second copper layer; thirdly, depositing copper, and forming a copper deposition layer on the outer surface of the top copper layer, the side wall and the bottom surface of the groove; Pressing a dry film, namely laterally pressing a film layer outside the copper deposition layer, wherein the film layer covers the groove and the top copper layer; step five, exposing, wherein an exposure area is arranged on the film layer and is arranged at the middle position of the groove; And step six, developing, removing the film layer outside the exposure area, and forming a bump in the exposure area, wherein a gap area is formed between the bump and the side wall of the groove, and the gap area is 60-125 mu m. Electroplating copper on the outer surface of the top copper layer and the gap area to form an electroplated layer, wherein the electroplated layer is arranged on the outer side of the copper deposition layer; removing the middle film bump to expose the electroplated layer and forming a blind groove in the middle of the electroplated layer; And step nine, microetching, namely microetching the outer surface of the electroplated layer, and etching away the electroplated layer at the bottom of the blind groove 31 to expose the top copper layer. Further, the film layer is filled in the groove, and the top surface of the film layer is flush; Further, the electroplated layer fills the gap region, and the electroplated layer is arranged on the periphery of the bump in a concave cambered surface shape. Further, the copper layer is provided with four layers, wherein the spacing between the top copper layer and the second copper layer is larger than the spacing between other adjacent copper layers. Further, in the third and fourth steps, an electroplating step is further included to form an electroplated layer on the outer side of the copper deposit layer. Further, the plate comprises an effective area and process slitter edges arranged on the periphery of the effective area, copper layer structures are arranged on two outer side surfaces of the process slitter edges, each copper layer structure comprises a plurality of copper protruding portions arranged at intervals, and the copper protruding portions on two sides of the plate are arranged in a dislocation mode. Further, the copper protruding parts are uniformly distributed on the process waste edge, and the copper protruding parts are in one of a round shape, a diamond shape and a cross shape. In summary, the method forms the film bump in the middle of the groove by grooving and film pressing exposure development, controls the interval between the edge of the dry film and the edge of the groove body, and utilizes the principle of hole filling to plate the copper thick. The method can plate the side wall copper to the thickness of about 100-120 mu m, and the side wall copper is much thicker than the side wall copper which can be processed by the traditional method. The invention has strong practicability and has stronger