Manufacturing method of HDI plate back drilling hole

Abstract

The invention discloses a manufacturing method of an HDI plate back drilling hole. The method comprises the steps that a production board is drilled, drilled holes comprise a through hole needing backdrilling, and the through hole is metalized through electroless plating copper; a layer of thin copper is flash-plated on the production board through full-board electroplating, wherein the thicknessof a thin copper layer formed during flash-plating is 5 to 8 microns; tin is electroplated on the production board to enable the board surface copper layer and the hole copper to be covered by the tin layer; depth-controlled back drilling is carried out on the through hole needing back drilling according to the design requirement, so that the copper layer at the back drilling part in the throughhole is removed, and a stepped back drilling hole is formed; acid etching treatment is carried out on the production board, and tin is removed; and full-board electroplating treatment is carried out on the production board, and the board surface copper layer and the hole copper are plated to the thickness required by the design. According to the method, by optimizing the production technological process, the problem that a conventional etching process cannot solve the problem of hole blocking of a back drilling burr copper wire is effectively solved; back drilling manufacturing of the HDI plate is achieved; and the percent of pass is high.

Description

Technical field

[0001] The invention relates to the technical field of printed circuit board manufacturing, in particular to a method for manufacturing HDI board back drilling. Background technique

[0002] The back drilling of the printed circuit board is a hole formed by plating a through hole after electroplating, using a controlled depth drilling method to remove a part of the hole copper, and leaving only the other part of the hole copper. The purpose is to reduce the excess copper in the high-speed signal The reflection and interference of the signal during the transmission process ensure the integrity of the signal transmission. Currently, back drilling is a commonly used low-cost manufacturing method for high-frequency and high-speed signal transmission of circuit boards. The conventional back drilling process includes: pre-process → pressing → drilling → sinking copper → full plate electroplating → outer layer pattern → pattern electroplating (including tin plating) → b...

Examples

Embodiment 1

[0024] The manufacturing method of HDI board back drilling shown in this embodiment, especially for the hole diameter less than 0.15mm, includes the following processing steps in sequence:

[0025] (1) Cutting: The core board is cut out according to the size of the puzzle board 320mm×420mm, the thickness of the core board is 1mm, and the thickness of the outer copper surface of the core board is 1OZ.

[0026] (2) Making the inner layer circuit (negative film process): According to the pattern positioning hole, use the vertical coating machine to coat the photosensitive film on the core board, the film thickness of the photosensitive film is controlled to 8μm, and the fully automatic exposure machine is used to 5-6 The grid exposure ruler (21 grid exposure ruler) completes the inner layer circuit exposure, and forms the inner layer circuit pattern after development; the inner layer is etched, and the exposed and developed core board is etched out of the inner layer circuit, and the i...

Embodiment 2

[0042] The manufacturing method of HDI board back drilling shown in this embodiment, especially for the hole diameter less than 0.15mm, includes the following processing steps in sequence:

[0043] (1) Cutting: The core board is cut out according to the size of the puzzle board 320mm×420mm, the thickness of the core board is 1mm, and the thickness of the outer copper surface of the core board is 1OZ.

[0044] (2) Drilling: Use the drilling data to drill the core board. The drilled holes include through holes that need to be back drilled.

[0045] (3) Immersion copper: metallize the hole on the core board, the backlight test is level 10, and the thickness of the sinking copper in the hole is 0.5μm.

[0046] (4) Flash plating: According to the existing technology and according to the design requirements, the whole board is electroplated for 22.5 minutes at a current density of 1.2ASD, so that a thin copper layer is flashed on the core board, and the thickness of the thin copper layer for...

Technical field

[0001] The invention relates to the technical field of printed circuit board manufacturing, in particular to a method for manufacturing HDI board back drilling. Background technique

[0002] The back drilling of the printed circuit board is a hole formed by plating a through hole after electroplating, using a controlled depth drilling method to remove a part of the hole copper, and leaving only the other part of the hole copper. The purpose is to reduce the excess copper in the high-speed signal The reflection and interference of the signal during the transmission process ensure the integrity of the signal transmission. Currently, back drilling is a commonly used low-cost manufacturing method for high-frequency and high-speed signal transmission of circuit boards. The conventional back drilling process includes: pre-process → pressing → drilling → sinking copper → full plate electroplating → outer layer pattern → pattern electroplating (including tin plating) → b...

Examples

Embodiment 1

[0024] The manufacturing method of HDI board back drilling shown in this embodiment, especially for the hole diameter less than 0.15mm, includes the following processing steps in sequence:

[0025] (1) Cutting: The core board is cut out according to the size of the puzzle board 320mm×420mm, the thickness of the core board is 1mm, and the thickness of the outer copper surface of the core board is 1OZ.

[0026] (2) Making the inner layer circuit (negative film process): According to the pattern positioning hole, use the vertical coating machine to coat the photosensitive film on the core board, the film thickness of the photosensitive film is controlled to 8μm, and the fully automatic exposure machine is used to 5-6 The grid exposure ruler (21 grid exposure ruler) completes the inner layer circuit exposure, and forms the inner layer circuit pattern after development; the inner layer is etched, and the exposed and developed core board is etched out of the inner layer circuit, and the i...

Embodiment 2

[0042] The manufacturing method of HDI board back drilling shown in this embodiment, especially for the hole diameter less than 0.15mm, includes the following processing steps in sequence:

[0043] (1) Cutting: The core board is cut out according to the size of the puzzle board 320mm×420mm, the thickness of the core board is 1mm, and the thickness of the outer copper surface of the core board is 1OZ.

[0044] (2) Drilling: Use the drilling data to drill the core board. The drilled holes include through holes that need to be back drilled.

[0045] (3) Immersion copper: metallize the hole on the core board, the backlight test is level 10, and the thickness of the sinking copper in the hole is 0.5μm.

[0046] (4) Flash plating: According to the existing technology and according to the design requirements, the whole board is electroplated for 22.5 minutes at a current density of 1.2ASD, so that a thin copper layer is flashed on the core board, and the thickness of the thin copper layer for...