KR20130092208A - Filling method of insulating material on circuit board - Google Patents

Abstract

Disclosed is a method of filling an insulating material in a circuit board that can significantly reduce the number of front faces in a frontal treatment process by filling an insulating material in a filled portion of a conductive raw material and removing an overcoated insulating material. The present invention comprises the steps of: (a) forming a foamable photo solder resist layer on the conductive raw material other than the grooves in the conductive raw material having one or more grooves and bumps; (b) applying an insulating material on the grooves and the foamable photo solder resist layer; And (c) heating the conductive element material coated with the insulating material to remove the expandable photo solder resist layer and the insulating material applied on the expandable photo solder resist layer. Provide a method.

Description

FILLING METHOD OF INSULATING MATERIAL ON CIRCUIT BOARD

The present invention relates to a method of filling an insulating material in a circuit board, and more particularly, to planarize a surface including a filling element by applying an insulating material to a filling element of a circuit board, such as a printed circuit board, and removing an over-applied insulating material. It relates to a method for filling insulating material in a circuit board.

BACKGROUND ART In the field of manufacturing a circuit board having a pattern such as a semiconductor package, a flat panel display, a printed circuit board, a semiconductor field, and the like, a method of applying an insulating material such as resin to a desired portion on a substrate is widely applied.

For example, in the manufacture of a chip scale package (CSP) or a ball grid array package (BGA) of a semiconductor package, a circuit board formed of multiple layers may be provided. In the multilayer circuit board, minute holes are formed at predetermined portions, and By forming a conductive line pattern on the inner surface, the circuit patterns on the front and rear surfaces of the substrate are electrically interconnected, and then a hole is filled so that the space except the conductive pattern formed on the inner surface is filled with an insulating material such as photo solder resist. plugging). In this case, the front surface process may be performed to form a surface exposed to the outside after filling the hole with an insulating material, for example, the coating amount on the substrate is controlled to 15㎛ or less by the screen coating method.

In addition, the via hole processing for the interlayer electrical connection of raw materials such as copper clad laminates involves expensive drill processes and thus electroless / electrolytic plating processes, and as the number of input / output (I / O) increases, In order to solve the problem of increasing the additional drill process time and the resulting cost, a via hole is required. According to the type of semiconductor package, a half-etch on one side of the conductive raw material, an insulating material on the etching site, and the other is hardened Attempts have been made to replace via holes by performing half etching again on one surface. For example, in Korean Unexamined Patent Application Publication No. 2011-0021407, as shown in FIG. 1, a conductive base substrate 10 is prepared (FIG. 1A) and at least one surface is etched according to a predetermined pattern to form a base pattern layer. (11) is formed (FIG. 1 (b)), the etched portion 12 of one surface of the base pattern layer 11 is filled with the insulating material 13 (FIG. 1 (c)), and the pattern layer 11 Disclosed is a method of fabricating a semiconductor package including removing the insulating material 13 formed on the substrate) to form the support 14 (FIG. 1D).

As such, in the prior art, a process of applying an insulating material to a hole or an etching site space is involved, and in general, a mechanical frontal process using a brush for the planarization of the surface of the raw material through the removal of the over-coated material, or a transient If the amount of entrapped material is small, chemical etching is used.

After applying the insulating material to the etched space during the front process will be described with reference to Figure 2 the front process using a brush. Figure 2 (a) shows the state before performing the front process using a brush, Figure 2 (b) shows an example of performing a front process several times using a brush, Figure 2 (c) is a front process is completed An example is shown. As shown in FIG. 2 (a), an insulating material 23 such as resin is applied to a surface on which the bumps 22 of the conductive element material 21 are formed, and the front surface is treated using a brush 24. The resin thickness d applied to the surface of the bump 22 may be 100 μm or more, and at this time, considering that the front surface thickness per axis of the brush 24 is 5 to 10 μm, at least 10 More than shafts are needed. Therefore, not only the loss of the resin amount by the over-coated thickness, but also causes the inefficiency of the mechanical front process, it is difficult to control the thickness of the bump according to the increase of the consumable cost and the resin thickness variation due to brush wear.

However, the problem of the frontal treatment through the removal of such a supersaturated resin is not specifically mentioned in the prior arts, and there is a need for a method capable of efficiently and economically performing smooth frontal treatment.

Accordingly, the present invention is to provide a method for filling an insulating material in a circuit board that can significantly reduce the number of fronts in the front-side treatment process by filling the insulating material in the filled portion of the conductive element material and removing the over-insulated material.

In one aspect of the present invention for solving the above problems, (a) forming a foamable photo solder resist layer on a conductive raw material other than the groove in the conductive raw material having one or more grooves and bumps; (b) applying an insulating material on the grooves and the foamable photo solder resist layer; And (c) heating the conductive element material coated with the insulating material to remove the expandable photo solder resist layer and the insulating material applied on the expandable photo solder resist layer. Provide a method.

In addition, the step (a), the step (a), (a1) forming the expandable photo solder resist layer on both sides of the plate-like conductive raw material; And (a2) etching the exposed conductive element material after the exposure and development with respect to the expandable photo solder resist layer according to a predetermined pattern. .

In addition, the forming of the expandable photo solder resist layer in the step (a1) provides a method for filling insulating material in a circuit board, characterized in that is performed by laminating the expandable dry film photoresist.

In addition, the foam dry film photoresist provides a method for filling an insulating material in a circuit board, characterized in that laminated to a thickness of 10 ~ 100㎛.

In addition, the exposure of the step (a2) provides an insulating material filling method in a circuit board, characterized in that performed with a light amount of 50 ~ 300mJ / ㎠.

In addition, the insulating material filling method of the step (b) is filled in the grooves and the insulating material filling method for a circuit board, characterized in that is carried out to be applied on the foamed photo solder resist layer to a thickness of 5 ~ 100㎛. do.

In addition, the heating of the step (c) is performed at a temperature at which the insulating material filled in the groove is cured at the same time as the foaming photo solder resist layer and the insulating material applied on the foamable photo solder resist layer are removed. An insulating material filling method in a circuit board is provided.

In addition, the heating temperature is 220 ~ 280 ℃ to provide an insulating material filling method in a circuit board.

In addition, (d) the front surface of the insulating material and the bumps filled in the grooves to be flattened; provides a method for filling an insulating material in a circuit board, characterized in that it further comprises.

In another aspect of the present invention to solve the above problems, (A) forming a foamable photo solder resist layer on one surface of the conductive element material on the plate and attaching a carrier to the other surface; (B) etching the exposed conductive raw material material after the exposure and development of the expandable photo solder resist layer according to a predetermined pattern to form one or more through grooves and lands; (C) applying an insulating material on the through groove and the expandable photo solder resist layer; (D) heating the conductive element material coated with the insulating material to remove the expandable photo solder resist layer and the insulating material applied on the expandable photo solder resist layer; And (E) removing the front surface and the carrier so that the insulating material and the land filled in the through grooves are planarized.

According to the method of filling an insulating material in the circuit board of the present invention, by applying the insulating material on the foamed photo solder resist layer and then thermally foamed to be removed together, the number of front faces can be greatly reduced, thereby greatly improving the process efficiency. have.

In addition, it is possible to minimize the amount of the insulating material to be applied on the bumps, significantly reducing the amount of wear of the front equipment such as brushes to reduce the cost or improve productivity.

In addition, as the number of front faces decreases, the exposed surface may be formed more homogeneously and flatly, thereby providing a circuit board having excellent reliability.

1 is a cross-sectional view sequentially showing a method of manufacturing a circuit board using a conventional conductive raw material;
2 is a cross-sectional view sequentially showing a front process using a brush after applying an insulating material to a conventional etched space,
3 is a flowchart for explaining a method of filling an insulating material in a circuit board according to a first embodiment of the present invention;
4 is a cross-sectional view sequentially showing a circuit board manufactured according to the first embodiment of the present invention;
5 is a schematic diagram illustrating the change of the foaming agent to the foamed particles of the expandable photo solder resist during foam heating in the present invention,
FIG. 6 is a schematic diagram illustrating a change in the adhesion state of the expandable photo solder resist on the conductive raw material upon heating and foaming of FIG. 5;
7 is a flowchart illustrating an insulating material filling method in a circuit board according to a second embodiment of the present invention.
8 is a cross-sectional view sequentially showing a circuit board manufactured according to the second embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the drawings, parts irrelevant to the description are omitted for clarity, and like reference numerals refer to like parts throughout the specification, and the up and down directions of the substrate will be described with reference to the drawings. Also, throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

First Embodiment

3 is a flowchart illustrating a method of filling an insulating material in a circuit board according to a first embodiment of the present invention, and FIG. 4 is a cross-sectional view sequentially illustrating a circuit board manufactured according to the first embodiment of the present invention.

3 and 4, in the insulating material filling method of the circuit board 100 according to the first embodiment of the present invention, a foamable photo solder resist layer 120 is formed on both surfaces of the conductive element material 110 (S101). And exposure and development (S102), half etching (S103), insulating material 130 coating (S104), heating foam (S105), and front surface treatment (S106) according to a predetermined pattern. Hereinafter, each step will be described in detail.

First, as shown in FIG. 4A, a foamable photo solder resist layer 120 is formed on both surfaces of the conductive element material 110 (S101). The conductive raw material 110 is not particularly limited as long as it is a material that realizes electrical conduction as a metal material, but may be essentially a material made of copper or a copper alloy prepared by mixing nickel, silicon, phosphorus, and the like.

The expandable photo solder resist layer 120 is made of a photo solder resist containing a foaming agent, and simultaneously has photosensitive and foaming characteristics. The blowing agent is a material that is mixed with the photo solder resist to induce bubble formation by heating, and removes the insulating material 130 applied on the expandable photo solder resist layer 120 in the heating foaming step (S105) described later. It does not specifically limit, if it contains the component which can be done. As such a blowing agent, isobutane, propane, butane, pentane and the like can be used, for example. In addition, the blowing agent content may be increased or decreased depending on the amount of the insulating material 130 to be applied, but based on the coating thickness of 5 to 100 μm of the insulating material 130, 100 parts by weight of the photo solder resist 5 to 50 parts by weight, preferably 10 to 30 parts by weight. In addition, the photo solder resist preferably includes an acrylate-based resin such that the radical reaction through light irradiation is smoothly performed in an exposure process to be described later.

The foamable photo solder resist layer 120 may apply and dry a liquid photoresist (LPR) containing a blowing agent or dry film photoresist (DFR) in a dry film form containing a blowing agent. It may be formed by laminating under pressure, and considering the uniformity of the thickness of the formed resist layer 120 and the resolution during exposure, it is preferable to use a foamable DFR.

When laminating using the foamable DFR 120, when the coating thickness of the insulating material 130 is based on 5 ~ 100㎛, it may be laminated to a thickness of 10 ~ 100㎛, preferably 20 ~ 50㎛. .

Next, the exposure and development step (S102) is a step for forming a mask of a predetermined pattern with respect to the expandable photo solder resist layer 120 having foaming characteristics and photosensitive characteristics. In FIG. Although an example in which exposure and development are performed on one surface of (110) is shown, it may be performed on both surfaces of the conductive raw material 110, of course.

The exposure may be performed by irradiating UV or the like, and the exposure intensity may be performed at a light amount of 50 to 300 mJ / cm 2, preferably 70 to 200 mJ / cm 2 when the foamable DFR 120 is laminated to the desired thickness. have.

Next, as shown in FIG. 4C, the half etching step S103 is half-etched on the surface of the conductive element material 111 exposed by the developing process to form the grooves 112 and the bumps 113. This is the step. The bumps 113 serve as electrical conduction between circuit patterns formed on the front and rear surfaces of the circuit board.

On the other hand, the half-etched foaming photo solder resist layer 120 is not present on the groove 112.

Next, the insulating material applying step (S104) is a step of applying the insulating material 130 on the groove 112 and the expandable photo solder resist layer 120, as shown in FIG. 4 (d). The insulating material 130 is filled and cured only in the recess 112 after the final frontal treatment process (S106) to be described later to form the filling part 131, and the filling part 131 may be, for example, a conductive circle. Supporting the material 110 as a whole may serve to replace the core material such as FR-4 (flame retardant composition 4), BT (bisaleimide triazine) of the conventional copper clad laminate.

Although not particularly limited to the insulating material 130, as a polymer resin, a material having good insulating properties and adhesion to the conductive raw material 110 and having good rigidity and handling properties when cured may be used. For example, molding resin such as EMC, photosensitive polymer resin such as photo solder resist can be used.

In addition, the insulating material 130 may fill at least the grooves 112 and may be applied to the foamed photo solder resist layer 120 to a thickness of 5 to 100 μm, preferably to a thickness of 10 to 50 μm. Can be applied. When the thickness is to be applied to less than 5㎛ may not completely fill the groove 112, when applied to more than 100㎛ when considering the preferred thickness of the expandable photo solder resist layer 120 is heated foam ( In operation S105, the insulating material 130 on the expandable photo solder resist layer 120 may not be completely removed.

The insulating material 130 may be applied using a known coating method. For example, thin film coating may be implemented using a coating technique such as comma coater, screen printing, squeeze coater, slit coater, or injection.

Next, the heating foaming step (S105) is a step of removing the expandable photo solder resist layer 120 by heating the conductive raw material 110 coated with the insulating material 130, wherein the expandable photo solder resist is The insulating material 130 applied on the layer 120 is also removed at the same time.

FIG. 5 is a schematic diagram illustrating a change in the foaming agent or foamed particles of the expandable photo solder resist during the heating foaming, and FIG. 6 is a schematic diagram illustrating a change in the adhesion state of the expandable photo solder resist on the conductive raw material during the heating foaming.

Referring to FIGS. 5 and 6, when the foamable photo solder resist 120 is heated to a predetermined temperature, the solder particles, an insulating material, etc., which surround the foaming agent 121 by inflating hydrocarbon foam particles 121 due to internal expansion. The contact area of the resin component 122 with respect to the conductive raw material 110 is reduced, and is efficiently separated from the conductive raw material 110. At this time, the amount of the resin component 122 adhered to the foam particles 121 is increased in proportion to the increased surface area of the foam particles 121, so that the resin component 122 of the bump 113 surface of the conductive raw material 110 is increased. That is, the photo solder resist and the insulating material are almost removed. FIG. 4E shows an example in which the expandable photo solder resist 120 and the insulating resin 130 are almost removed from the bump 113 surface due to such heat foaming.

The insulating material 130 on the expandable photo solder resist 120 is removed together by the foamed particles 121 of the expandable photo solder resist when the thermal foaming is performed, but the insulating material 130 filled in the recess 112 is formed. Is not removed and is cured to form the filling part 131. Therefore, in terms of process efficiency, it is preferable to allow the insulating material 130 filled in the grooves 112 to be completely cured at the same time at the heating temperature for the foaming. According to the present invention, the heating is performed for the foaming and curing. It may be carried out at a temperature of ~ 280 ℃, preferably 240 ~ 260 ℃.

Next, the front treatment step (S106), despite the heat foaming and the insulating material 130 formed higher than the surface 114 of the bump 113 in the filling portion 131 after the heat foaming step (S105) As shown in FIG. 4F, the resin component on the bump 113 may be planarized so that the bump surface 114 and the filling surface 132 may be uniform. In the present invention, the front treatment can be achieved to obtain a very uniform surface accuracy (flatness) even in two front treatment steps, preferably one step.

The front treatment may be performed by a known method, for example, a mechanical front process using a buffer brush, a ceramic brush, or the like, or an etching process using a chemical agent.

Second Embodiment

7 is a flowchart illustrating a method of filling an insulating material in a circuit board according to a second embodiment of the present invention, and FIG. 8 is a cross-sectional view sequentially illustrating a circuit board manufactured according to the second embodiment of the present invention.

7 and 8, in the method of filling the insulating material 230 in the circuit board 200 according to the second embodiment of the present invention, the foamable photo solder resist layer 220 is formed on one surface of the conductive raw material 210. (S201), attaching the carrier 240 to the other surface of the conductive element material 210 (S202), and exposing the expandable photo solder resist layer 220 according to a predetermined pattern (S203), through etching (S204), and insulating material ( 230, coating (S205), heating foam (S206), frontal treatment (S207), and removing the carrier 240 (S208). Hereinafter, a configuration different from the first embodiment will be mainly described.

In the method of filling the insulating material 230 in the circuit board 200 according to the second embodiment, the exposure and development process (S203) of the expandable photo solder resist layer 220 is performed using the conductive material 210. After performing only one side of), through etching (S204) is performed on the exposed conductive material surface 211. Even in this case, the application of the insulating material 230 (S205), the heating foam (S206), and the front surface treatment (S207) may be performed in the same manner as in the first embodiment. The method according to this second embodiment can be applied, for example, to a multi-row lead frame manufacturing process.

Unlike the first embodiment, the method according to the second embodiment forms a foamable photo solder resist layer 220 on only one surface of the conductive raw material 210 as shown in FIG. 240 is attached (S202). Here, the carrier 240 may be attached (S202), and then the foamable photo solder resist layer 220 may be formed (S201).

The carrier 240 serves to fix the conductive element material S210 during the subsequent etching process (S204) and the filling of the insulating material 230 (S205, S206), and a material having stiffness, preferably For example, the metal plate may be attached to the other surface of the conductive raw material 210 through an adhesive layer. The adhesive may be a polymer material having a property of being adhered and fixed, and the back side tape in order to prevent the adhesive component from remaining on the surface of the conductive element 210 in the removal process (S208) at the end of the circuit board 200 manufacturing process. It is preferable to use a material similar to the adhesive used for the back side tape.

Meanwhile, a plating pattern layer (not shown) may be formed on the other surface of the conductive raw material 210 as necessary. In this case, in the subsequent etching process (S204), the etching liquid intrudes into the other surface of the conductive element material 210 or the insulating material 230 is filled in the process (S205) of filling the insulating material 230 in the through groove 212. In order to prevent a phenomenon in which a kind of mold flash is generated by penetrating into the other surface of the conductive raw material 210, the adhesive layer is preferably formed to completely fill the plating pattern layer.

Subsequently, as illustrated in FIG. 8B, the exposed photoconductive resist layer 220 is exposed and developed (S203), and as illustrated in FIG. 8C, the exposed conductive material surface 211. ) Through through (S204) to form a through groove 212 and land (213). The land 213 may be, for example, a die pad and a row of leads in a lead frame.

Thereafter, as shown in FIG. 8 (d), the insulating material 230 is coated on the through grooves 212 and the expandable photo solder resist layer 220 in the same manner as in the first embodiment (S205). As shown in FIG. 8E, the conductive element 210 coated with the insulating material 230 is heated (S206) to form the expandable photo solder resist layer 220 and the expandable photo solder resist layer. The insulating material 230 applied on the 220 is removed, and as shown in FIG. 8F, the surface 232 and the land of the filling part 231 filled in the through hole 212 are removed. Front side treatment (S207) is carried out so that the surface 214 of 213 is planarized. Finally, as shown in FIG. 8G, the attached carrier 240 may be removed (S208) to complete the filling process of the insulating material on the circuit board 200. In this case, the front surface treatment (S207) may be performed after removing the carrier 240 (S208).

Experimental Example

Using the method according to the first embodiment, a 30 μm thick foamable DFR containing 20% by weight of isobutane as a blowing agent was prepared, laminated on both surfaces of a copper alloy material, and then irradiated with UV at an intensity of 100 to 150 mJ / cm 2 and an optimum etching rate. Half etching was performed at the etching rate of 1-2.0 micrometer / min confirmed to show. Thereafter, the grooves formed by etching were completely filled using a photo solder resist, applied to the foamable DFR to a thickness of 30 μm, and then heated to 250 ° C. to completely cure the DFR defoamed and filled photo solder resist. Thereafter, a circuit board having a very uniform surface degree was manufactured using only one frontal treatment using a ceramic brush.

On the other hand, the circuit board was manufactured under the same conditions as in the experimental example except that the DFR containing no blowing agent was used. As a result, 8 to 10 frontal treatments were required to have a uniform surface accuracy.

Therefore, according to the present invention, by applying an insulating material on the expandable photo solder resist layer and then heat-foamed to be removed together, it can be confirmed that the number of front faces can be greatly reduced, thereby greatly improving the process efficiency.

The preferred embodiments of the present invention have been described in detail with reference to the drawings. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

100, 200: circuit board 110, 210: conductive raw material
111, 211: conductive raw material exposed surface 112: groove
113: bump 114: bump face
120, 220: expandable photo solder resist layer
121: foamed particle 122: resin component
130, 230: insulating material 131, 231: filling part
132 and 232: Filling surface 212: Through groove
213: Land 214: Land Side
240: carrier

Claims (10)

(a) forming a foamable photo solder resist layer on the conductive raw material except for the recess in the conductive raw material having one or more grooves and bumps;
(b) applying an insulating material on the grooves and the foamable photo solder resist layer; And
(c) heating the conductive element material coated with the insulating material to remove the expandable photo solder resist layer and the insulating material applied on the expandable photo solder resist layer;
Method for filling an insulating material in a circuit board comprising a. The method of claim 1,
The step (a)
(a1) forming the expandable photo solder resist layer on both sides of a plate-like conductive raw material; And
(a2) etching the exposed conductive element material after exposure and development with respect to the expandable photo solder resist layer according to a predetermined pattern;
Method for filling an insulating material in a circuit board comprising a. The method of claim 2,
The forming of the expandable photo solder resist layer in the step (a1) is performed by laminating the expandable dry film photoresist. The method of claim 3,
The foamable dry film photoresist is laminated with a thickness of 10 ~ 100㎛ method for filling an insulating material in a circuit board. The method of claim 2,
The exposure of the step (a2) is an insulating material filling method in a circuit board, characterized in that carried out with a light amount of 50 ~ 300mJ / ㎠. The method of claim 1,
The insulating material filling method of the circuit board is characterized in that the insulating material of step (b) is filled to fill all the grooves and applied to the foamed photo solder resist layer to a thickness of 5 ~ 100㎛. The method of claim 1,
The heating of the step (c) is performed at a temperature at which the insulating material filled in the groove is cured at the same time as the foaming photo solder resist layer and the insulating material applied on the foamable photo solder resist layer are removed. Method of filling insulative materials on a circuit board. The method of claim 7, wherein
The heating temperature is a method of filling an insulating material in a circuit board, characterized in that 220 ~ 280 ℃. The method of claim 1,
(d) front-facing the insulating material filled in the groove and the bump to be flattened;
Method for filling an insulating material in a circuit board further comprising. (A) forming a foamable photo solder resist layer on one side of the plate-shaped conductive element material and attaching a carrier to the other side;
(B) etching the exposed conductive raw material material after the exposure and development of the expandable photo solder resist layer according to a predetermined pattern to form one or more through grooves and lands;
(C) applying an insulating material on the through groove and the expandable photo solder resist layer;
(D) heating the conductive element material coated with the insulating material to remove the expandable photo solder resist layer and the insulating material applied on the expandable photo solder resist layer; And
(E) removing the front surface treatment and the carrier to planarize the insulating material and the land filled in the through grooves;
Method for filling an insulating material in a circuit board comprising a.

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