Method of minimizing depth of blind via hole (BVH) of printed circuit board

Abstract

A method of minimizing the depth of a BVH of a printed circuit board includes a raw material preparing step (S10) forming a circuit after cutting raw materials with a roll state into a constant size; a coverlay punching step (S20) punching a coverlay to be laminated on one surface or both surfaces of the raw materials prepared in the raw material preparing step (S10); a step (S30) of attaching and laminating the punched coverlay on one surface or both surfaces of the raw materials; a step (S40) of laminating a prepreg layer and a copper layer on the upper part of the laminated coverlay obtained in the step (S30); a copper layer hole processing step (S50) forming a hole on the laminated copper layer for forming the BVH; a prepreg layer hole processing step (S60) forming a hole on the upper part of the prepreg layer exposed by the hole formed in the copper layer hole processing step (S50); a de-smear processing step (S70) de-smearing the processed BVH; and a plating step (S80) performing plating after the de-smear processing step (S70).

Description

technical field [0001] The present invention relates to a method for minimizing the depth of a printed circuit board BVH, and more particularly, the present invention relates to a printed circuit board BVH that minimizes the depth (DEPTH) to ensure the reliability of the BVH when processing the BVH, thereby ensuring the stability of the gold plating operation Depth minimization method. Background technique [0002] At present, there is a demand for high-functionality of FPCB products, along with the formation of multi-layer and blind via holes (BVH). [0003] The blind hole (BVH) uses thin film (prepreg) and thin cover film (coverlay) that determine the depth of BVH. Although the depth of BVH becomes shallower, it cannot meet the total thickness required by customers, and the problem of deeper BVH depth occurs instead. . [0004] However, the deeper the BVH, the more difficult it is to ensure the reliability of the BVH. For this reason, most enterprises such as figure 1 A...

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Problems solved by technology

[0005] When the pre-treatment process such as plasma or desmear process cannot be satisfied, or the conditions required by BVH, such as figure 2 As shown, pollution and resin (resin) are not completely eliminated on the bottom surface and smear (smear) is produced. If the treatment is excessive, such as image 3 As shown, there is a void defect, so that the gold plating solution cannot penetrate smoothly during gold plating, resulting in a defect

[0006] As mentioned above, in addition to the plasma and desmear treatment, the aspect ratio can be secured due to the increase in the size of the surface BVH WINDOW, but when the BVH size is increased, such as Figure 4 As shown, misalignment and hole bursts occur during patterning work, so there are problems in reducing productivity and increasing the defective rate

[0007] In addition to this, other methods have been used to try to ensure the reliability of BVH, but other undesirable phenomena continue to occur, so it is difficult to ensure the reliability of BVH

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