KR20060134512A - Manufacturing method for embedded printed circuit board - Google Patents

Abstract

A method for fabricating an embedded printed circuit board is provided to reduce process time without restriction on post-process by reducing error rate. In a method for fabricating an embedded printed circuit board, a hole is formed on a copper clad laminate where a circuit pattern is formed(S10). The copper clad laminate and a prepreg and a copper foil are sequentially located and pre-attached(S20). An electric device is fixed in the hole(S30). The inside of the hole is filled and then hardened(S40). A prepreg and a copper foil are additionally located and stacked on another plane of the copper clad laminate and then a via hole is formed(S50).

Description

Manufacturing Method for Embedded Printed Circuit Board

1 is a flow chart showing a method for manufacturing an embedded printed circuit board according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which copper foil laminated plates having copper foil, prepreg and holes are sequentially formed on a flat plate.

3 is a cross-sectional view showing a state in which a copper foil, a prepreg and a copper foil laminated plate are temporarily bonded onto a flat plate.

Figure 4 is a cross-sectional view showing a state in which the electrical element is placed after applying the resin inside the hole of the copper-clad laminate.

5 is a cross-sectional view showing a state where the inside of the hole is filled with a filler.

6 is a cross-sectional view showing a state in which a prepreg and a copper foil are laminated on the other surface of the copper clad laminate.

7 is a cross-sectional view illustrating a state in which a via hole is formed in a printed circuit board to connect an inner layer circuit.

8 is a cross-sectional view illustrating a state in which an MLCC is embedded in a hole.

* Description of the reference numerals for the main parts of the drawings *

10: copper clad laminate 11: hole 13: circuit pattern

15: beer hall 20: prepreg 30: copper foil

40: electric element 50: resin 60: filler

70: reputation

The present invention relates to a method of manufacturing an embedded printed circuit board, and more particularly, to a method of manufacturing an embedded printed circuit board without fear of the electrical element is removed during the embedding process.

BACKGROUND Recently, electronic devices requiring high speed operation have been widely used with the spread of portable terminals and notebook computers. Accordingly, a printed circuit board capable of high speed operation has been demanded. Such high speed operation requires high density of wiring and electronic components in a printed circuit board.

As a means for achieving such a high density, a build up method is known. The build-up method is, for example, after the photosensitive resin is applied to the surface of a core substrate made of a double-sided copper glass epoxy or the like on which wiring is formed by copper foil etching or the like, and then exposed and developed via holes ( After forming an insulating layer having a via hole, electroless copper plating is performed on the surface. The via hole conductor and the wiring circuit layer are formed by coating, etching, and removing the resist on the resist. After repeating the formation of the insulating layer by the photosensitive resin and the formation of the via hole conductor and the wiring circuit layer, a through hole is formed by a drill or the like and a plating layer is formed in the through hole to form an interlayer wiring circuit layer. To connect.

In a conventional printed circuit board, copper foil is laminated on the surface of a flat plate containing an organic resin called prepreg, and then etched to form a fine circuit. After the through-hole is punched out using a micro-drill, the metal is attached to the inside of the hole by a plating method to form a through-hole conductor to electrically connect each layer. Moreover, the wiring board which filled the metal powder inside the via hole formed in the insulating layer, formed the via-hole conductor, laminated another insulating layer, and multilayered is also proposed.

As described above, the method of forming the via hole conductor by filling the metal powder is advantageous in that the via hole conductor can be downsized and the via hole can be formed at an arbitrary position. In addition, high density wiring is also possible with a printed circuit board formed by the build-up method. However, when various electric elements are mounted on a printed circuit board, there is a limit to the miniaturization of the board because it can only be mounted on the surface of the board.

In order to solve such a problem, a method of embedding a substrate into an insulator or the like has recently been proposed. That is, after forming a hole in which the electronic device is embedded in the insulator, the electronic device is positioned and fixed using a filler or the like. According to such an embedding process, not only the electric element is embedded on the surface of the substrate but also embedded in the substrate, so that the substrate can be made smaller and higher in density, and the substrate can be made more efficient.

However, in the conventional embedding process, there is a possibility that the electric element together with the filler material is removed from the insulating layer during the operation. As such, when the electric element is pulled out of the insulating layer, not only does it cause a later process in the production line but also a defect rate of the substrate is increased and the process time is long.

The present invention is derived to solve the problems of the prior art as described above,

An object of the present invention is to provide an embedded printed circuit board manufacturing method that can reduce the processing time because there is no problem that the electrical element is missing in the process, the defect rate is reduced and there is no restriction on the post-process.

The present invention is implemented in an embodiment having the following configuration to solve the problems of the prior art as described above.

Embedded printed circuit board manufacturing method according to an embodiment of the present invention, the step of forming a hole in the copper-clad laminate plate circuit pattern is formed, the step of placing the copper foil laminated plate, prepreg and copper foil in sequence to be welded, Fixing the electric element, and filling the inside of the hole and curing, and further comprising the step of placing the prepreg and copper foil further laminated on the other surface of the copper clad laminate plate to form a via hole.

Embedded printed circuit board manufacturing method having such a configuration is completed without the inner layer process, such as the formation of the circuit pattern before placing the electrical element and immediately stacked as soon as the position of the electrical element, there is no fear that the electrical element is missing and limited to the later process Will not receive.

According to another aspect of the present invention, there is provided a method of manufacturing an embedded printed circuit board, the method comprising: forming a circuit pattern after forming a hole in a copper-clad laminate, sequentially placing and contacting the copper-clad laminate, a prepreg, and a copper foil; Fixing an electric element therein, filling the hole inside and then curing, and further pre-preg and copper foil laminated on the other surface of the copper-clad laminate plate to form a via hole.

Since the embedded printed circuit board manufacturing method according to the embodiment forms a circuit pattern after forming a hole in the copper-clad laminate, the design of the circuit pattern is not affected by the hole formation process.

The hole may be formed by punching or routing. In addition, lamination may be facilitated by performing a blackening process on one side or both sides of the copper-clad laminate after forming the hole. After copper foil is adhere | attached on the flat surface using double-sided tape, after prepreg and copper foil laminated board are located, it is temporarily bonded by heating a prepreg more than predetermined temperature.

In the fixing of the electric element inside the hole, the resin may be printed or coated inside the hole and the resin may be cured while the electric element is positioned, or the electronic element may be heat-bonded onto the prepreg using a flip chip bonder. .

By using a filler having a low coefficient of thermal expansion (CTE) and a high glass transition temperature (Tg), it is possible to prevent the filler from expanding out of the hole or outflow by heat generated in a later lamination process. And filling the filler only to a predetermined height of the hole it is possible to prevent the leakage of the filler by the heat generated in the lamination process.

Further, by removing the foreign matter through a plasma cleaning process or a soft etching process, it is possible to further facilitate lamination later. It is also possible to further facilitate lamination by further performing a blackening process on the copper foil.

Hereinafter, a method of manufacturing an embedded printed circuit board according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings, and in the following description with reference to the accompanying drawings, the same or corresponding components are the same regardless of reference numerals. Reference numerals will be given and duplicate description thereof will be omitted.

1 is a flowchart illustrating a method of manufacturing an embedded printed circuit board according to an exemplary embodiment of the present invention. In the method of manufacturing an embedded printed circuit board as illustrated in FIG. 1, the method may include forming holes in a copper foil laminated plate on which a circuit pattern is formed (S10), sequentially placing and contacting copper foil laminated plates, a prepreg, and copper foil (S20), Fixing the electric element inside the hole (S30), and filling the inside of the hole and hardening (S40), laminating the prepreg and copper foil on the other surface of the copper-clad laminate plate to form a via hole (S50). .

Hereinafter, the steps S10 to S50 will be described with reference to FIGS. 2 to 8.

2 is a cross-sectional view of the step S10 in which the holes 11 are formed in the copper-clad laminate 10 on which the circuit pattern 13 is formed.

The copper foil laminated plate 10 is formed with a circuit pattern 13. Since the method of forming the circuit pattern 13 corresponds to a known technique, a detailed description thereof will be omitted. The hole 11 is drilled by punching or routing at a predetermined position of the copper-clad laminate 10. The size of the hole 11 is slightly larger than the size of the electrical element embedded in the hole 11. The hole 11 may be perforated after the circuit pattern 13 is formed in the copper-clad laminate 10, but after the hole 11 is first drilled into the copper-clad laminate 10, the circuit pattern 13 is formed. It is also possible.

After the hole 11 is formed in the copper foil laminated plate 10, a blackening process is performed on the copper foil of the copper foil laminated plate 10 to facilitate a later lamination process. The blackening process oxidizes the surface of the copper foil laminated | stacked on both surfaces of the copper foil laminated board 10, by which the surface of copper foil becomes rough and it becomes easier to laminate | stack.

3 is a cross-sectional view according to the step S20 of sequentially placing and joining the copper foil 30, the prepreg 20 and the copper foil laminated plate 10 on the flat plate 70.

The copper foil 30 is fixed on the flat plate 70 using a double-sided tape or the like. The double-sided tape is preferably adhesive at high temperature, does not deform, and leaves no residue on the surface after peeling off, and such double-sided tape includes a polyimide tape using a silicone adhesive component.

 The prepreg 20 refers to a sheet-like material which is hardened to stage B by impregnating a thermosetting resin in a base material such as glass cloth, and the stage B refers to a semi-cured state of the resin. Prepreg is generally used a high viscosity epoxy resin. The resin formed on the surface of the prepreg 20 is fixed in a state in which the copper foil 30, the prepreg 20, and the copper foil laminated plate 10 are sequentially positioned by using a resin having a property of adhesion at a predetermined temperature or more. It is preferable to heat at the temperature and pressure, and to weld the copper foil 30, the prepreg 20, and the copper foil laminated board 10. The copper foil 30, the prepreg 20, and the copper foil laminated plate 10 are completely bonded in a later lamination process.

4 is a cross-sectional view according to step S30 in which the electric element 40 is fixed inside the hole 11.

In the method of fixing the electric element 40, first, the resin 50 having the adhesive force and the heat resistance property is coated or printed inside the hole 11, and then the electrode 41 of the electric element 40 is lowered. To the resin 50. The resin 50 may use a chip bond used in fixing a general printed circuit board. Such a resin 50 is cured by thermal curing or ultraviolet irradiation. The resin 50 may be fully cured but may be temporarily cured. The temporary cured resin 50 is cured together with the filler in the curing process of the filler (not shown).

Another method of fixing the electric element 40 is to add a heating device to a general flip chip bonder for mounting the electric element so that the electric element is directly applied onto the prepreg 20 without applying resin. It is fixed. As described above, since the resin having the adhesive force is coated on the surface of the prepreg 20, the flip chip bonder bonds the electric element 40 by applying heat using a heating device while mounting the electric element.

The electric element 40 may be a passive element such as a resistor or a capacitor as well as an active element such as a CPU or an IC.

5 is a cross-sectional view according to step S40 in which the filler 60 is filled in the hole 11. The filler 60 is generally a resin used for encapsulant or underfill. The filler 60 may be filled with the same height as that of the hole 11, but is filled to a height slightly lower than the height of the hole 11, so that the filler 60 may be applied by heat applied later by a lamination process or the like. It is preferable not to expand or flow out of the hole 11. The unfilled portion of the hole 11 is later filled by the resin on the surface of the prepreg in the lamination process.

The filler 60 preferably has a low coefficient of thermal expansion (CTE) and a high glass transition temperature. This is a high heat is applied by the lamination process after the filling of the filler 60, if the thermal expansion coefficient of the filler 60 is high, the filler 60 is expanded and protrudes to the outside of the hole 11 as well as mounted This is because the position of the part may be deformed and cause mechanical and electrical defects. In addition, when the filler 60 has a high glass transition temperature, the filler may flow out of the hole 11 by heat. The glass transition temperature is a temperature at which the filler 60 begins to have fluidity, and the higher the temperature, the more the stability of the filler 60 in a subsequent process or use process.

The filler 60 is cured after being filled. At this time, the filler 60 is pressed using a weight body such as a weight on the copper laminate sheet 10 in order to secure the adhesive force between the prepreg 20 and the copper laminate sheet 10. You can also harden while.

When the hardening of the filler 60 is completed, the copper-clad laminate 10 is separated from the flat plate 70. In addition, when a small amount of residue remains in the copper foil laminated plate 10 or the copper foil 30, plasma cleaning, soft etching, or blackening may be performed to prepare for a later lamination process. Soft etching serves to clean the copper-clad laminate 10 or the copper foil 30 by thinly etching the copper-clad laminate 10 or the copper foil 30 to about 1 to 2 μm.

6 is a cross-sectional view of the step S50 in which the prepreg 20 'and the copper foil 30' are laminated on the other surface of the copper clad laminate 10. As shown in FIG. The prepreg 20 'and the copper foil 30' are sequentially stacked on the other surface of the copper-clad laminate 10, wherein the same prepreg 20 'is stacked below the prepreg 20 and the copper foil 30. ) And copper foil 30 'are preferably laminated so that warpage of the entire substrate does not occur.

FIG. 7 is a cross-sectional view illustrating a state in which circuit patterns 31 and 31 'are formed on the copper foils 30 and 30' and then electrically connected to the electric element 40 using the via holes 13. The circuit patterns 31 and 31 'are manufactured by a general printed circuit forming method. The via hole 13 is drilled by a general process such as a laser drill or a laser. The via hole 13 is plated or filled with a conductive metal such as copper. The via hole 13 electrically connects the circuit pattern 31 ′ and the electrode 41.

FIG. 8 is a cross-sectional view illustrating a passive element 40 'such as a multi-layer ceramic capacitor (MLCC) embedded in the hole 11. The electric element 40 may be a passive element such as a capacitor, a resistor, or MLCC as well as an active element such as a CPU and an IC.

Although the technical spirit of the present invention has been described in detail according to the above-described embodiments, the above-described embodiments are for the purpose of description and not of limitation, and a person of ordinary skill in the art will appreciate It will be understood that various embodiments are possible within the scope.

The present invention can reduce the defective rate as well as reduce the process time since there is no problem that the electrical element is missing during the process.

Claims (12)

(a) forming a hole in the copper-clad laminate in which the circuit pattern is formed; (b) sequentially placing and welding the copper-clad laminate, the prepreg and the copper foil; (c) fixing an electric element inside the hole; (d) hardening after filling the inside of the hole; (e) a method of manufacturing an embedded printed circuit board, the method comprising: forming a via hole after additionally placing a prepreg and a copper foil on the other surface of the copper foil laminated plate. (a) forming a circuit pattern after forming a hole in the copper-clad laminate; (b) sequentially placing and welding the copper-clad laminate, the prepreg and the copper foil; (c) fixing an electric element inside the hole; (d) hardening after filling the inside of the hole; (e) a method of manufacturing an embedded printed circuit board, the method comprising: forming a via hole after additionally placing a prepreg and a copper foil on the other surface of the copper foil laminated plate. The method according to claim 1 or 2, In the step (a), the hole is formed by punching or routing embedded printed circuit board manufacturing method. The method according to claim 1 or 2, After the hole is formed in the step (a), the one or both sides of the copper-clad laminate plate blackening process is performed. The method according to claim 1 or 2, The step (b) is an embedded printed circuit board manufacturing method for positioning the prepreg and the copper foil laminated plate after bonding the copper foil using a double-sided tape on a flat surface. The method according to claim 1 or 2, In the step (b), the temporary printed circuit board is temporarily bonded by heating the prepreg to a predetermined temperature or more. The method according to claim 1 or 2, The step (c) is a printed circuit board manufacturing method for curing the resin in a state in which the electrical device is placed after printing or coating a resin inside the hole. The method according to claim 1 or 2, The step (c) is a method of manufacturing an embedded printed circuit board by heat-bonding the electrical element on the prepreg using a flip chip bonder. The method according to claim 1 or 2, The step (d) is an embedded printed circuit board manufacturing method using a filler having a low coefficient of thermal expansion (CTE) and a high glass transition temperature (Tg). The method according to claim 1 or 2, The step (d) is a method for manufacturing an embedded printed circuit board to fill the filling material only up to a predetermined height of the hole. The method according to claim 1 or 2, After the step (d) further comprising the step of removing the foreign matter through a plasma cleaning process or a soft etching process. The method according to claim 1 or 2, And further comprising performing a blackening process on the copper foil after the step (d).

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