CN113950192A

CN113950192A - HDI plate direct laser hole forming method

Info

Publication number: CN113950192A
Application number: CN202110997668.8A
Authority: CN
Inventors: 毛永胜; 孙炳合; 盛利召; 覃新; 徐缓; 王楠
Original assignee: Jiangsu Bomin Electronics Co ltd
Current assignee: Jiangsu Bomin Electronics Co ltd
Priority date: 2021-08-27
Filing date: 2021-08-27
Publication date: 2022-01-18

Abstract

The invention provides a HDI plate direct laser hole forming method which comprises the steps of firstly processing inner drill holes penetrating through a base plate, then carrying out positioning processing on laser holes according to position coordinates of the inner drill holes, simultaneously processing a first surface and a second surface, wherein the processed hole patterns are the same inverted trapezoids, and after the two surfaces are processed, 2 inverted trapezoids are intersected to form X-shaped laser holes. The invention has the advantages of shortening the process flow, reducing the production cost, improving the production efficiency, avoiding ICD generation at the bottom of the blind hole and the like.

Description

HDI plate direct laser hole forming method

Technical Field

The invention relates to the field of High Density Interconnect (HDI) manufacturing, in particular to a direct laser hole forming method.

Background

In the field of High Density Interconnection (HDI) manufacturing, the industry often adopts a copper window opening method (Conformal Mask) and an ldd (laser Direct drill) flow to manufacture a laser hole, the two process flows are tedious, the production efficiency is low, and the quality is unstable, if resin glue is left at the bottom of the laser hole and the glue removing effect is poor, the electroplated copper is separated from the bottom copper of the substrate, and a blind hole icd (inner Connection defects) occurs, and the reliability of the blind hole is problematic. The manufacturing flows of the two processes are as follows:

open copper Window method (Conformal Mask): drilling (inner drilling) → inner layer circuit copper window → inner layer AOI → laser → degumming (Desmear) → blind hole AOI → micro-etching copper reduction → PTH → hole filling electroplating.

Ldd (laser Direct drill) flow: drilling (inner drilling) → laser browning → laser → degumming (Desmar) → blind hole AOI → micro-etching copper reduction → PTH → hole filling electroplating.

Therefore, there is a need to provide a new solution.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention discloses a method, which comprises the following specific technical scheme:

the invention provides a direct laser hole forming method for an HDI plate, which comprises the following steps:

a: machining an inner drilling hole penetrating through the substrate on the substrate, so that the substrate is conveniently aligned in the subsequent machining process;

b: carrying out surface treatment on the copper foil on the surface of the substrate by adopting blackening solution or browning solution;

c: positioning by using an inner drilling hole, performing laser drilling on the substrate, firstly processing the first surface of the substrate, wherein the processing hole shape is an inverted trapezoid, the substrate is not drilled through, and the integrity of the copper foil of the second surface of the substrate is reserved;

d: positioning by using the inner drilling hole again, and performing laser drilling on the second surface of the substrate, wherein the processing hole patterns are the same inverted trapezoids and do not drill through the substrate;

e: after laser processing is completed on both sides of the substrate, 2 inverted trapezoidal drilling holes are intersected to form an X-shaped laser hole, and laser hole metallization is completed through copper (PTH) melting, hole filling and electroplating processes.

Further, at least 4 inner drill holes are arranged, and the aperture of each inner drill hole is 3.175 mm.

Further, the surface treatment is as follows: the browning liquid or the blackening liquid reacts with copper to generate a layer of copper oxide and a mixture containing a trace amount of cuprous oxide which are three-dimensionally interwoven into honeycomb-shaped fluff.

Furthermore, when the substrate is subjected to laser processing, the laser holes are positioned and processed by the position coordinates of the inner drill holes, and when the inner drill holes are replaced, the machine table moves in the X direction and the Y direction according to the position coordinates of the inner drill holes.

Further, the laser drilling uses the principle of photothermal ablation.

Further, when the first surface of the substrate is drilled by laser, the copper foil on the surface is gasified by 1shot of high energy, and then the resin is gasified by 4 shots of low energy; the process of laser drilling the second surface of the substrate is the same as the process of machining the first surface.

Further, the length of the inverted trapezoid at the time of laser processing exceeds half the thickness of the resin in the substrate.

The invention has the following beneficial effects:

1. compared with the conventional process in the industry, the HDI plate direct laser hole forming method provided by the invention shortens the processes by 3-4, reduces the cost of materials, water, electricity, gas and manpower, improves the production efficiency, and can improve the L/T by at least 1-1.5 days. .

2. According to the HDI plate direct laser hole forming method provided by the invention, the whole laser hole is a whole body of electroplated copper after being finished, the problem of the bonding force between the base copper of the substrate and the electroplated copper does not exist, and the possibility of generating ICD at the bottom of the blind hole is directly avoided in principle.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic structural diagram of a substrate after an HDI board is directly subjected to laser via-formation according to an embodiment of the present invention.

Wherein, 1-radium perforation; 2-a resin; 3-first side copper foil of the substrate; 4-second side copper foil of the substrate.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In one embodiment, referring to fig. 1, the pattern of the HDI plate directly after laser via-forming according to the present invention includes laser via 1, resin 2, first copper foil 3 of the substrate, and second copper foil 4 of the substrate.

In one embodiment, at least 4 inner drill holes are arranged, and the aperture of each inner drill hole is 3.175 mm.

The surface treatment is that the browning liquid or the blackening liquid reacts with copper to generate a layer of copper oxide and a mixture containing trace cuprous oxide which are three-dimensionally interwoven into honeycomb-shaped fluff.

In one embodiment, when the substrate is subjected to laser processing, the laser holes are positioned and processed by the position coordinates of the inner drill holes, and when the inner drill hole processing is replaced, the machine table moves in the X direction and the Y direction according to the position coordinates of the inner drill holes.

The laser drilling adopts the photo-thermal ablation principle. When the first surface of the substrate is drilled by laser, firstly, the copper foil on the surface is gasified by 1shot of high energy, and then, the resin is gasified by 4 shots of low energy; the process of laser drilling the second surface of the substrate is the same as the process of machining the first surface.

In one embodiment, the length of the inverted trapezoid during laser machining exceeds half the thickness of the resin in the substrate.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example" or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.

While embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications and variations may be made therein by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A HDI plate direct laser hole forming method is characterized by comprising the following steps:

2. The HDI board direct laser pore-forming method of claim 1, wherein the thickness of the copper foil on each side of the substrate is 11-12 μm.

3. The HDI plate direct laser hole-forming method as claimed in claim 1, wherein at least 4 inner drilling holes are provided, and the aperture of each inner drilling hole is 3.175 mm.

4. The HDI plate direct laser hole-forming method according to claim 1, wherein the surface treatment is: the browning liquid or the blackening liquid reacts with copper to generate a layer of copper oxide and a mixture containing a trace amount of cuprous oxide which are three-dimensionally interwoven into honeycomb-shaped fluff.

5. The HDI plate direct laser hole forming method according to claim 3, wherein laser processing is performed on the substrate, laser holes are positioned and processed by using position coordinates of the inner drilled holes, and when the inner drilled hole processing is replaced, the machine moves in an X direction and a Y direction according to the position coordinates of the inner drilled holes.

6. The HDI plate direct laser via-forming method of claim 1 wherein the laser drilling uses photothermal ablation principles.

7. The HDI board direct laser hole-forming method according to claim 6, wherein when laser drilling is performed on the first surface of the substrate, the surface copper foil is gasified by 1shot of high energy, and then the resin is gasified by 4 shots of low energy;

the process of laser drilling the second surface of the substrate is the same as the process of machining the first surface.

8. The HDI plate direct laser via-forming method of claim 1 wherein the length of the inverted trapezoid at the laser machining exceeds half the thickness of the resin in the substrate.