A method for filling mechanical through holes of an IC package board

Abstract

The application relates to a manufacturing method of mechanical via hole filling of an IC packaging board, which comprises the following steps: S1. inner layer processing is performed on the IC packaging board until the inner layer pattern is completed, and then the IC packaging board is pressed; S2. a via hole is formed on the pressed IC packaging board through a mechanical drilling process; S3. horizontal copper sinking is performed on the via hole drilled by the mechanical drilling process; S4. first via hole filling electroplating is performed on the via hole after the horizontal copper sinking; S5. after film stripping, second via hole filling electroplating is performed on the via hole; S6. a physical scraping process is used to physically scrape and flatten the recess of the via hole after the second via hole filling electroplating; and S7. copper thinning is performed on the IC packaging board until the required copper thickness is obtained, and then outer layer circuit manufacturing is completed through image transfer on the IC packaging board. The manufacturing method can realize mechanical via hole filling, reduce the processing flow of a multilayer board, save costs, shorten the manufacturing period, and improve the product competitiveness.

Description

TECHNICAL FIELD

[0001] The application relates to a manufacturing method of mechanical via hole filling of an IC package carrier board. BACKGROUND

[0002] Due to the thinness requirement of electronic products, the core IC package is also thinner and denser, and part of high-end carrier boards have higher requirements for chip heat dissipation. Usually, a copper block or hole filling method is used for manufacturing. In the carrier board industry, due to the high cost of copper blocks, in addition to the process of using plated copper columns (such as Figure 1 The application relates to a manufacturing method of mechanical via hole filling of an IC package carrier board. SUMMARY

[0003] The application aims to realize mechanical via hole filling and reduce the processing flow of multi-layer boards.

[0004] Therefore, a manufacturing method of mechanical via hole filling of an IC package carrier board is provided, which comprises the following steps:

[0005] Step S1. After inner layer processing of the IC package carrier board is completed and inner layer patterns are finished, the IC package carrier board is pressed;

[0006] Step S2. A via hole is formed on the pressed IC package carrier board by a mechanical drilling process;

[0007] Step S3. The via hole drilled by the mechanical drilling process is horizontally copper-plated;

[0008] Step S4. First hole filling electroplating is performed on the via hole after horizontal copper plating;

[0009] Step S5. After film removal, second hole filling electroplating is performed on the via hole;

[0010] Step S6. The via hole after the second hole filling electroplating is physically flattened by a grinding process;

[0011] Step S7. The IC package carrier board is thinned until the required copper thickness is obtained, and then outer layer circuit manufacturing is completed by image transfer.

[0012] As an improvement, before the step S4 performs the first hole filling electroplating, the following steps are further performed:

[0013] A dry film is attached to the outer layer of the IC package carrier board after horizontal copper plating by using a film attaching process;

[0014] A window hole is formed on the position of the dry film aligned with the via hole, and the aperture of the window hole is configured to be smaller than the aperture of the via hole.

[0015] As an improvement, the aperture of the window hole is configured to be 75%-85% of the aperture of the through hole.

[0016] As an improvement, the attaching method of the dry film further comprises: automatically pressing the film after the DF pretreatment, then exposing by LD I, and then performing MSAP vertical development.

[0017] As an improvement, after the windowing, the following is further performed:

[0018] The dry film at the windowing is checked by AOI for falling off, and the first hole filling plating is performed in the case of no falling off.

[0019] As an improvement, in the step S4, the through hole is changed into an X-shaped through hole by the first hole filling plating, and the step S5 is performed to fill the through hole in the second hole filling plating.

[0020] As an improvement, the filling method further comprises: synchronously plating the through hole and the outer layer of the IC package carrier in the second hole filling plating.

[0021] As an improvement, the method for thinning the copper of the IC package carrier in the step S7 further comprises:

[0022] The horizontal line of the IC package carrier is cleaned by using a chemical micro-etching solution to thin the copper thickness of the outer layer of the IC package carrier.

[0023] The present application is directed to a multilayer board product with high heat dissipation requirements, which is made by mechanical drilling, processed by a two-layer hole filling process, and matched with a post-processing grinding and polishing process. This method can realize the processing of mechanical through hole filling, reduce the processing flow of the multilayer board, save costs, shorten the production cycle, and improve the product competitiveness. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 A Yuetai copper plating column process is shown.

[0025] Figure 2 A schematic structure of the IC package carrier after processing and pressing is shown.

[0026] Figure 3 A processing process of mechanical drilling, horizontal copper plating, and dry film opening of the IC package carrier is shown, wherein, Figure 3 a shows the structure of the IC package carrier before drilling, Figure 3 b shows the structure of the IC package carrier after drilling, Figure 3 c shows the structure of the IC package carrier after horizontal copper plating, Figure 3 d shows the dry film opening.

[0027] Figure 4 The structural changes of the through hole in the two plating processes are shown, wherein Figure 4 a shows the structure of the through hole after the first hole-filling plating, Figure 4 b shows the structure of the through hole after the second hole-filling plating.

[0028] Figure 5 The process of making a circuit after grinding and thinning the copper is shown, wherein Figure 5 a shows the structure of the IC packaging board after the whole-plate hole-filling plating after film removal, Figure 5 b shows the structure of the IC packaging board after grinding, Figure 5 c shows the structure of the IC packaging board after chemical micro-etching and thinning the copper, Figure 5 d shows the structure of the IC packaging board after making a circuit. DETAILED DESCRIPTION

[0029] The technical solutions of the present application are further described below in combination with the drawings and specific embodiments.

[0030] The method for making a mechanical through hole of an IC packaging board according to the present embodiment includes the following steps:

[0031] Step S1. Inner layer processing is performed on the IC packaging board until the inner layer pattern is completed, at which time the IC packaging board is formed with the CORE layer 1 as the substrate, the first copper clad 21 and the second copper clad 22 after image transfer are located on the two sides of the substrate, respectively, and the inner layer circuit processing structure, and then the structure is pressed, and the pressing is specifically performed by pressing the semi-cured sheet 3 and the copper foil 4 to the first copper clad 21 and the second copper clad 22, respectively, as shown in Figure 2 .

[0032] Step S2. A through hole 5 is formed on the IC packaging board (as shown in Figure 3 a) after pressing by a mechanical drilling process, such as using a high-precision mechanical milling machine or a drilling machine to process the through hole to obtain more precise parameters, as shown in Figure 3 b.

[0033] Step S3. The mechanical drilled through hole 5 is subjected to horizontal copper deposition, as shown in Figure 3 c.

[0034] Step S4. The first hole-filling plating is made on the through hole 5 after horizontal copper deposition.

[0035] Before the first hole-filling plating is performed, a film pasting process is used to paste a dry film 6 on the outer layer of the IC packaging board after horizontal copper deposition, and then a window hole is opened on the dry film 6 at the position aligned with the through hole 5, and the aperture of the window hole is configured to be smaller than the aperture of the through hole 5, as shown in Figure 3As shown in FIG. 6d. In this embodiment, in order to improve the dry film hole precision, the dry film 6 is attached by using the DF pre-treatment automatic film pressing, then exposed by LDI, and then developed by MSAP vertical development.

[0036] After the dry film 6 is opened, the AOI is used to check whether the dry film is detached at the opening, if the dry film is detached, the process is stopped, and if no detachment is found, the first hole filling plating is performed to reduce the processing failure rate.

[0037] Since the copper is preferentially deposited in the hole center rather than the hole opening during the via filling process, the plating filling via mechanism is an organic additive adsorption / consumption / diffusion mode. Considering the copper thickness on the surface and the requirement of reducing the plating area to improve the filling effect, a separate plating is required. In this embodiment, the dry film opening is used to reduce the copper thickness above the hole opening, thereby facilitating the hole filling (because of the dry film effect, the hole diameter is reduced after the first hole filling plating, so that the hole filling requirement is met). Through the dry film opening with reduced design, after the first hole filling plating, the surface copper at the hole opening does not increase, forming a plating structure as shown in FIG. 6a; if the dry film opening is designed to be large or equal to the window, the hole opening will have a boss A after plating, as shown in FIG. 6b, and the copper layer has a height difference, which is not conducive to the subsequent process. Figure 4 a; if the dry film opening is designed to be large or equal to the window, the hole opening will have a boss A after plating, as shown in FIG. 6b, and the copper layer has a height difference, which is not conducive to the subsequent process. Figure 4 b.

[0038] As an improved scheme, the hole diameter of the window hole can be configured to be 70%-95% of the hole diameter of the window hole, or 72%-90% of the hole diameter of the via hole, or 73%-89% of the hole diameter of the via hole. As the optimal interval, the hole diameter of the window hole can be configured to be 75%-85% of the hole diameter of the via hole, or as the optimal value, the hole diameter of the window hole is configured to be 80% of the hole diameter of the via hole, so as to achieve good first hole filling plating effect.

[0039] Step S5. The second hole filling plating is performed on the via 5. Specifically, after the film is removed, the whole plate hole filling plating is used to make the hole completely filled, and after the hole filling, there is a certain Dimple, as shown in FIG. 6a. Figure 5 a.

[0040] In this embodiment, the purpose of the two times of plating is because the mechanical via hole diameter is relatively large (generally ≥0.1mm), according to the principle of plating, the copper is preferentially deposited in the hole center rather than the hole opening. Since the mechanical hole is an H-shaped via hole, it is difficult to fill the hole by one time of plating. The first time of plating can reduce the hole diameter and change the hole type, so that the hole becomes an X-shaped via hole, which is convenient for the second time of plating. After the second time of plating, the hole is completely filled and flattened. The flattening method further includes synchronously plating the via and the outer layer of the IC packaging carrier during the second hole filling plating, so as to increase the copper first, which is convenient for subsequent copper reduction control to obtain a good plane and copper thickness.

[0041] Step S6. Using a grinding process, the through holes after the second hole filling electroplating are grinded by using a grinding device to physically flatten the recesses at the through holes, and the recesses Dimp l e are removed, as shown in FIG. 6b. Figure 5

[0042] Step S7. The IC packaging board is thinned until the desired copper thickness is obtained, wherein the way of thinning the copper further comprises using chemical micro-etching solution to clean the IC packaging board to obtain a uniform thickness, as shown in FIG. 6c, and then, the outer layer circuit is completed by image transfer on the outer layer copper layer of the IC packaging board, as shown in FIG. 6d. Figure 5 Figure 5

[0043] The embodiment realizes the processing method of mechanical hole through hole filling by using the secondary electroplating method (first hole opening electroplating and second whole plate electroplating) and the processing method after hole filling, reduces the processing flow of the multi-layer board, saves the cost, shortens the production cycle, and improves the product competitiveness.

[0044] The above specific embodiments are only several preferred embodiments of the present application, and based on the technical solutions of the present application and the related inspiration of the above embodiments, the person skilled in the art can make various alternative improvements and combinations on the above specific embodiments.​​​

Claims

1. A method for filling mechanical through-holes in an IC packaging substrate, characterized in that, include: Step S1. Perform inner layer processing on the IC packaging substrate until the inner layer pattern is completed, then perform lamination; Step S2. Through holes are drilled on the laminated IC package substrate using a mechanical drilling process; Step S3. Perform horizontal copper plating on the through holes drilled by mechanical drilling; Step S4. Perform the first hole-filling electroplating on the through-hole after horizontal copper plating, wherein the first hole-filling electroplating changes the through-hole from H-type to X-type. Before performing the first hole-filling electroplating in step S4, the following steps are also performed: attach a dry film to the outer layer of the IC package substrate after horizontal copper plating using a film-attaching process, and make a window hole at the position of the dry film aligned with the through-hole. The diameter of the window hole is configured to be smaller than the diameter of the through-hole. Step S5. After removing the film, perform a second filling electroplating on the through holes to fill the through holes; Step S6. Use a grinding process to physically smooth out the depressions in the through holes after the second filling electroplating; Step S7. After thinning the copper on the IC package substrate to obtain the required copper thickness, the outer layer circuitry is fabricated on it through image transfer.

2. The manufacturing method according to claim 1, characterized in that, The aperture of the window is configured to be 75%-85% of the aperture of the through hole.

3. The manufacturing method according to claim 1, characterized in that, The dry film attachment method further includes: automatic lamination after DF pretreatment, followed by LDI exposure and then MSAP vertical development.

4. The manufacturing method according to claim 1 or 3, characterized in that, After the window is opened, the following steps are also performed: AOI inspection is performed to check for any peeling of the dry film at the window opening. If no peeling is found, the first hole-filling electroplating is carried out.

5. The manufacturing method according to claim 1, characterized in that, The filling method further includes: simultaneously electroplating the through holes and the outer layer of the IC packaging substrate during the second filling electroplating.

6. The manufacturing method according to claim 1, characterized in that, Step S7, the method of thinning the copper on the IC packaging substrate, further includes: The IC packaging substrate is horizontally cleaned using a chemical micro-etching solution, thereby reducing the thickness of the outer copper layer of the IC packaging substrate.

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