JP2002270731A - Wiring board, its manufacturing method and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board wherein mounting reliability can be ensured while dehumidifying action inside the board is ensured, a method for manufacturing the wiring board, and a semiconductor device. SOLUTION: This wiring board 30 has a lamination structure of core material of a thermosetting resin film 31, and thermoplastic resin films 32 which are laminated on both surfaces of the core material 31 and whose hygroscopicity is smaller than that of the core material 31. A vent hole 40 of a non-penetrating shape which has a bottom 40a in the core material 31 is arranged on a back face 30B side of the wiring board 30. As a result, adhesive material 38 spread on a surface 30A on which a semiconductor chip 36 is mounted is prevented from flowing out to the back face 30B side while effective dehumidifying action is ensured, and deterioration of mounting reliability can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board provided with gas vent holes for avoiding peeling of a board and destruction of components during reflow mounting, a method of manufacturing the same, and a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, thermosetting resins such as glass epoxy have been used as substrates for wiring boards. This is because the adhesive strength and the thermosetting strength at the time of thermosetting, electrical insulation properties and heat resistance are excellent. Further, the wiring layer is generally formed by patterning a copper foil provided on the front surface or the front and back surfaces of the substrate.

On the other hand, a thermoplastic resin film is adhered to the front and back surfaces of a thermosetting resin film as a core material, and the thermoplastic resin film is molded to form a concave pattern, and a conductive material is filled in the concave groove. A wiring board filled with a wiring layer has been proposed by the present applicant (Japanese Patent Application No. 2000-257466).

According to this configuration, a wiring layer having a fine wiring pattern can be formed with higher precision than a conventional wiring board having a wiring layer formed by etching a copper foil, and the quality among the substrates varies. Is reduced. Also, since the heat shrinkage of the thermoplastic resin during lamination pressing is absorbed by the thermosetting film, a wiring board without warpage is obtained, and load deflection, tensile properties, bending properties, etc. due to heat are improved, and so-called thermal strength. In addition, a wiring substrate having excellent mechanical strength can be finished.

[0005] The wiring board having the above configuration is suitably used as an interposer board in a chip size type semiconductor package (CSP) component. FIG. 7 shows an example of the configuration.

The wiring board 10 has, for example, a core material composed of two thermosetting resin films 11 and 11, and thermoplastic resin films 12 and 12 laminated on both surfaces thereof.
Then, a conductive material 15 is filled in a concave groove (concave pattern) 13 formed on the thermoplastic resin film 12 on the front surface side, thereby forming a wiring layer to which a bump electrode (bump) 17 of a semiconductor chip 16 is bonded. Is formed. The semiconductor chip 16 and the wiring substrate 10 are integrated with each other via an adhesive material 18, and a sealing resin 19 is molded as required to complete the process.

The conductive material 15 in the through hole 14 exposed on the back side of the wiring board 10 is used as an external terminal.
Either the form of GA or the form of BGA in which a solder ball separately provided on the conductive material 15 is used as an external terminal is adopted.

By the way, the wiring board 1 having the above configuration
In the case of No. 0, peeling of the wiring board 10 and destruction of components, which is called a popcorn phenomenon, becomes a problem during reflow mounting due to the difference in moisture absorption between the thermosetting resin film 11 and the thermoplastic resin film 12.

In general, thermosetting resins have greater hygroscopicity than thermoplastic resins. However, since the exposed surface of the core material 31 to the outside is small, the efficiency of dehumidification of the moisture absorbed by the core material 11 is poor, and the sudden heat application during the reflow mounting causes the core material 11 to expand, thereby causing Peeling between the wiring board and the semiconductor chip and between the inner wall of the through hole 14 and the conductive material 15 (indicated by P in FIG. 7).
).

To solve this problem, Japanese Patent Application Laid-Open No.
Japanese Patent No. 163022 describes a configuration in which a gas vent hole penetrating a wiring board is formed, thereby enabling dehumidification from the inside of the wiring board during reflow mounting and preventing peeling of the board. .

[0011]

However, in the configuration described in the above publication, the gas vent hole is closed by the adhesive material applied to the semiconductor chip mounting surface, or the adhesive material is supplied to the substrate through the gas vent hole. It is conceivable that it flows out to the back surface (CSP electrode surface). In such a case, a mounting open defect may be caused, and mounting reliability may be impaired.

In order to avoid this, it is conceivable to form the gas vent hole at a position distant from the mounting area of the semiconductor chip. However, in this case, an efficient dehumidifying function cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a wiring board, a method of manufacturing the same, and a semiconductor device capable of securing mounting reliability while ensuring a dehumidifying action of the wiring board. And

[0014]

In order to solve the above problems, a wiring board according to the present invention has a wiring layer on a surface layer, and is laminated on at least a first core layer and both surfaces of the first core layer. In a wiring board having a second core layer having a smaller hygroscopic property than the first core layer, a bottomed gas vent hole penetrating the second core layer and having a bottom in the first core layer is formed. It is characterized by having.

That is, in the present invention, the gas vent hole for dehumidifying the wiring board is formed as a non-through hole having a bottom inside the first core layer having a higher hygroscopicity than the second core layer. With this configuration, it is possible to prevent the adhesive material applied to the mounting surface side of the semiconductor chip from flowing out to the opposite side while securing a highly efficient dehumidifying action of the wiring board.

The method of manufacturing a wiring board according to the present invention comprises the steps of laminating a thermoplastic resin film on both sides of a core material made of a thermosetting resin film, and forming the thermoplastic resin film on one side by molding. Forming a recessed pattern, filling a conductive material in the recessed grooves of the recessed pattern to form a wiring layer, and forming the inside of the core material on the surface opposite to the surface on which the wiring layer is formed. Forming a bottomed vent hole having a bottom portion.

In the step of forming the gas vent hole, a gas vent hole having a desired depth can be formed by, for example, drilling or dry etching.

As described above, it is possible to obtain a wiring board which can prevent the adhesive material applied to the mounting surface side of the semiconductor chip from flowing out to the opposite side while securing the efficient dehumidifying action of the wiring board. it can.

Further, in solving the above problems, in the semiconductor device according to the present invention, a wiring board on which a semiconductor chip is mounted is laminated on both sides of a core material made of a thermosetting resin material and both sides of the core material, On one side, there is provided a thermoplastic resin film on which the wiring layer is formed, and a bottomed vent hole having a bottom inside the core material and formed on the back surface side.

Thus, the opposite side of the adhesive material applied to the mounting surface side of the semiconductor chip (the side of the electrode surface mounted on the mother substrate) while ensuring the efficient dehumidifying action of the wiring substrate.
Can be prevented.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration of a semiconductor device according to an embodiment of the present invention. In the present embodiment, the semiconductor device 21 is a chip-size type semiconductor package component (CS
P), and mainly includes a wiring board 30 and a semiconductor chip 36 mounted on the wiring board 30. In this example, the wiring board 30 is configured as an interposer board interposed between the semiconductor chip 36 and a mother board (not shown).

In the present embodiment, the wiring board 30 is provided on both surfaces of a core material (corresponding to the first core layer according to the present invention) formed by laminating two thermosetting resin films 31 as surface layer materials. A thermoplastic resin film (corresponding to the second core layer according to the present invention) 32 is formed of a base material having a laminated structure.

In the present embodiment, for example, an epoxy-impregnated glass cloth prepreg in a B-stage state is used as the thermosetting resin film 31, and, for example, syndiotactic polystyrene (hereinafter abbreviated as SPS) as the thermoplastic resin film 32. .) Is used.

A concave pattern 33 is formed on the surface 30A of the wiring substrate 30, and the conductive material 35 is filled in the concave groove of the concave pattern 33 to form a wiring layer. The concave pattern 33 is formed, for example, by molding the thermoplastic resin film 32. As the conductive material 35, for example, a conductive paste, in particular, a solvent-based silver paste using a thermoplastic resin as a binder is suitably applied. The wiring board 30 is provided with a through hole 34, and the through hole 34 is filled with the conductive material 35 having the above configuration.

On the other hand, on the back side 30 B of the wiring board 30,
A gas vent hole 40 according to the present invention is formed. The gas vent hole 40 is formed as a non-through hole that is formed in the surface opposite to the center of the mounting area of the semiconductor chip 36, penetrates the thermoplastic resin film 32, and has a bottom 40 a inside the core material 31.

The semiconductor chip 36 has a plurality of protruding electrodes (bumps) 37 arranged in a single row or a plurality of rows on a circuit surface serving as a main surface thereof, and these protruding electrodes 37 constitute the wiring layer. The conductive material 35 in the concave pattern 33
Embedded inside, electrical connections are made. An adhesive material 3 is provided between the wiring board 30 and the semiconductor chip 36.
8 are fixed and integrated.

In the semiconductor device 21 configured as described above, the conductive material 35 in the through hole 34 is exposed to the substrate back surface 30B side to form an electrode surface.
Are directly mounted on the motherboard as external terminals, or are mounted on the motherboard as external terminals using solder balls formed in a later step.

During the period from manufacturing to mounting of the semiconductor device 21,
As schematically shown in FIG. 3A, the core material 31 is exposed via the gas vent hole 40 and the exposed portion of the core material 31 on the side surface of the wiring board 30 and the conductive material 35 in the through hole 34.
Is performed (inevitably), but when the semiconductor device 21 is mounted (reflow mounting), the moisture absorbed by the core material 31 is transferred to the above-described moisture absorption path as schematically shown in FIG. 3B. Dehumidified to the outside via the same route as
Component destruction due to board expansion is avoided. As a result, the degree of freedom in component management up to mounting is increased.

In particular, in the present embodiment, since the gas vent hole 40 is constituted by a non-through hole having a bottom portion 40a in the core material 31, the dehumidifying efficiency inside the wiring board 30 can be improved, and The pores are closed by the adhesive material 38 applied to the surface, and the adhesive material 3
8 does not flow to the substrate back surface 30B side, so that mounting defects caused by the adhesive material 38 are eliminated, and a decrease in mounting reliability can be avoided.

FIG. 2 shows an example in which the present invention is applied to a semiconductor device 22 provided with a sealing resin 39 for sealing the entire semiconductor chip 36. The gas vent hole 40 is formed as a non-through hole. As a result, the potting resin (sealing resin 39) closes the gas vent hole 40 during the sealing resin molding step, or the substrate back surface 3 is formed through the gas vent hole 40.
It does not flow out to the 0B side.

Similarly, a known underfill resin is injected and filled between the wiring substrate 30 and the semiconductor chip 36 instead of the adhesive material 38 to form a semiconductor device (not shown) in which the two are integrated. The present invention is also applicable,
In this case, blockage of the gas vent hole by the underfill resin and outflow of the underfill resin through the gas vent hole are prevented.

Next, a method of manufacturing the wiring board 30 applied to the above-described semiconductor device 21 will be described with reference to FIGS.

First, a core material (first core layer) 31 made of two thermosetting resin films (in this embodiment, epoxy-impregnated glass cloth prepreg in a B-stage state)
A composite substrate having a laminated structure in which a thermoplastic resin film (second core layer) 32 made of SPS as a surface layer material is thermocompression-bonded on both surfaces of the substrate.

In the present embodiment, the thermosetting resin film 31 and the thermoplastic resin film 32 are both 1
One having a thickness of 00 μm is used. The thermocompression bonding is performed, for example, at a temperature of 160 ° C. to 180 ° C. for one hour.

As the core material 31, glass cloth impregnated with epoxy resin is effective in suppressing thermal deformation and dimensional shrinkage, but is not limited thereto. Thermoplastic resin film 3
Also in 2, the material is not limited to SPS as long as the material has a small amount of moisture absorption with respect to the glass epoxy core material 31 and is excellent in thermoformability and machining.

In general, SPS is a crystalline thermoplastic resin and has a high melting point. However, SPS alone is not suitable as a substrate material due to large thermal deformation and dimensional change due to a heat treatment step. In the present embodiment, the thermoplastic resin film 32 during thermocompression bonding is used.
Is absorbed by the core material 31 and the warpage of the wiring substrate is suppressed. In addition, the load deflection due to heat, the tensile properties, and the bending properties are improved, and the wiring base material has excellent mechanical strength.

The thermoplastic resin film 32 is made of the core material 31.
Before lamination, the adhesive surface with the core material 31 is subjected to ultraviolet irradiation treatment or plasma surface treatment,
Modified chemically or physically. Thereby, good adhesion between the core material 31 and the thermoplastic resin film 32 is ensured.

Next, the laminate of the core material 31 and the thermoplastic resin film 32 is hot-pressed using a pair of upper and lower molds 25a and 25b (FIG. 4A), and the surface 30 of the wiring board 30 is pressed.
The concave pattern 33 is transfer-molded to the thermoplastic resin film 32 constituting A (FIG. 4B).

A concave / convex pattern 26 corresponding to the circuit pattern is previously formed on the upper mold 25a by, for example, sandblasting. The concave / convex pattern 26 having a depth of about 50 μm is heated and pressed against the thermoplastic resin film 32. 33 is transfer-molded. In the present embodiment, the transfer conditions are, for example, 230 ° C. and 5.88 MPa (60
kg / cm ² ) for 5 minutes.

In the thermoforming itself, the transferability generally improves as the temperature increases below the decomposition temperature of the base material. In the present embodiment, an epoxy resin having lower heat resistance than SPS is used as the core material 31 in the present embodiment. Since it is adopted, the temperature condition needs to be adjusted to the core material 31 having poor heat resistance.

Subsequently, as shown in FIG. 4C, through holes 34 are formed in the wiring substrate on which the concave pattern 33 has been transferred and formed. As a method of forming the through hole, a known method such as laser processing or drill processing is employed.

Next, as shown in FIG. 5A, a step of forming a wiring layer by filling a conductive material 35 in the concave groove of the concave pattern 33 and the inside of the through hole 34 is performed. Formed with high precision.

In the present embodiment, as the conductive material 35, a solvent-based silver paste using a thermoplastic resin as a binder is preferably used from the viewpoints of mountability of a semiconductor chip, solderability to a mother board, and conductive characteristics. . The conductive material 35 is filled by filling the concave pattern 33 and the through hole 34 with the conductive material 35 using a squeegee or the like, followed by drying and curing at a predetermined temperature.

Before the filling of the conductive material 35, the inside of the concave groove of the concave pattern 33 and the inner wall surface of the through hole 34 are modified by ultraviolet irradiation or plasma irradiation so that the conductive material 3
It is preferable to ensure the adhesiveness with the No. 5.

After the hardening of the conductive material 35, unnecessary portions are removed from the upper surface of the base material by surface polishing to form a wiring layer. Thereafter, by performing hot pressing, variations in the conductivity and resistance of the conductor layer can be suppressed. The hot pressing conditions are, for example, 150 ° C., 4.9 MPa (50 kg /
cm ² ) for 5 minutes. The conditions were within the dimensional accuracy of the substrate due to the substrate design, and it was confirmed that the conductivity was improved and the resistance variation was reduced and cured.

Subsequently, as shown in FIG.
A bottomed vent hole 40 is formed near the center of the semiconductor chip mounting portion from the side of the thermoplastic resin film 32 constituting the back surface 30B of the zero.

In this embodiment, the gas vent hole 40 is formed by drilling, plasma etching, or laser processing. At this time, it is necessary to stop the drilling operation when the core material 31 is reached. For example, the drilling can be controlled by the amount of drilling, and the etching can be controlled by the etching time.

The size, location and number of openings of the gas vent hole 40 are not limited as long as there is no restriction on the circuit pattern, so that the degree of freedom in design is high.

The wiring board 30 is manufactured through the above steps. The semiconductor chip 36 on this wiring board 30
Referring to FIG. 1, the surface 3 of the wiring board 30 is mounted in advance.
Semiconductor chip 36 from above adhesive material 38 applied to
Is mounted face down. Semiconductor chip 3
A protrusion electrode (gold bump in this embodiment) 37 is provided on 6.

As the adhesive material 38, a thermosetting resin adhesive applied to the substrate by, for example, screen printing or dispense printing is used. Also, the bonding material 38
The adhesive is not limited to a liquid or a film, but a liquid adhesive is preferable in consideration of prevention of air bubbles and productivity.

In this case, since the gas vent hole 40 is formed as a non-through hole, the adhesive material 38 does not enter the gas vent hole 40.

The mounting of the semiconductor chip 36 on the wiring board 30 is performed by heating the semiconductor chip 36 to a predetermined temperature in advance and thermocompression bonding the protruding electrodes 37 to the conductive material 35 on the wiring layer. As a result, the protruding electrodes 37 are embedded in the conductive material 35, and after cooling, are firmly connected by mechanical stress in the wiring layer.

In addition, if necessary, a molding step for sealing the semiconductor chip 36 with the sealing resin 39 is performed as shown in FIG.

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical concept of the present invention.

For example, in the above embodiment, the wiring board 3
Although a so-called single-sided through-hole substrate has been described as an example as 0, the present invention is not limited to this, and the present invention is also applicable to a so-called double-sided through-hole substrate having a wiring layer also on the substrate back surface 30B side.

In this connection, for example, as shown in FIG.
A multilayer wiring board 4 is formed by laminating a plurality of wiring boards 30 having the above-described configuration.
By configuring 5, it is possible to obtain the semiconductor device 23 in which the degree of freedom in wiring design is greatly improved. In this case, the same effect as in the above-described embodiment can be obtained by forming a plurality of gas vent holes 46A and 46B each having a bottom and communicating with the core material 31 of each wiring board 30. be able to.

In the above embodiment, the wiring board 3
Although it is configured as an interposer substrate applied to a chip-size semiconductor package component as 0, the present invention is not limited to this, and it is laminated on at least the first core layer and both surfaces of the first core layer and absorbs more moisture than the first core layer. The present invention is applicable to general wiring boards (for example, mother boards and the like) having a second core layer having low performance.

[0059]

As described above, according to the present invention, the following effects can be obtained.

That is, according to the wiring board of the first aspect of the present invention, the adhesive material applied to the mounting surface side of the semiconductor chip is applied to the opposite side while ensuring the efficient dehumidifying action of the wiring board. Outflow can be prevented.

According to the second aspect of the present invention, it is possible to prevent the adhesive material from entering the gas vent hole.

According to the third aspect of the present invention, it is rich in the function of maintaining the shape and suppressing the dimensional change, and has the load deflection due to heat and the tensile properties.
It is possible to obtain a wiring substrate having improved bending characteristics and excellent mechanical strength.

According to the fourth aspect of the present invention, it is possible to obtain a wiring board with greatly improved flexibility in wiring design.

According to the fifth aspect of the present invention, it is possible to form a wiring layer having a fine wiring pattern with high precision and to reduce variation in quality between substrates.

According to the sixth aspect of the present invention, the peeling of the substrate and the destruction of components during reflow mounting, which is called the popcorn phenomenon, can be effectively suppressed.

According to the method of manufacturing a wiring board according to the seventh aspect of the present invention, the adhesive material applied to the mounting surface side of the semiconductor chip is secured while ensuring the efficient dehumidifying action of the wiring board. It is possible to obtain a wiring board that can prevent the outflow to the opposite side.

According to the invention of claim 8, the conductivity of the conductive material forming the wiring layer can be improved, and
Variation in resistance can be suppressed.

Further, according to the semiconductor device of the ninth aspect of the present invention, it is possible to effectively suppress the peeling of the substrate and the destruction of components during reflow mounting, which is called the popcorn phenomenon, and to reduce the mounting reliability. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a side sectional view showing another configuration example of the semiconductor device according to the embodiment of the present invention;

FIG. 3 is a side sectional view illustrating a moisture absorption path (A) and a dehumidification path (B) in the semiconductor device according to the embodiment of the present invention.

FIG. 4 is a side sectional view showing a manufacturing process of a wiring substrate applied to the semiconductor device according to the embodiment of the present invention, wherein A and B show a transfer molding process of a concave pattern constituting a wiring layer, and C shows 4 shows a through-hole forming step.

FIG. 5 is a side sectional view showing a manufacturing process of a wiring board applied to the semiconductor device according to the embodiment of the present invention, wherein A shows a filling process of a conductive material, and B shows a gas vent hole of the present invention. 4 shows a forming process.

FIG. 6 is a side sectional view showing a modification of the configuration of the semiconductor device according to the embodiment of the present invention;

FIG. 7 is a side sectional view showing a configuration of a conventional semiconductor device.

[Explanation of symbols]

21, 22, 23: semiconductor device, 30, 45: wiring substrate, 30A: substrate surface, 30B: substrate back surface, 31: core material, thermosetting resin film (first core layer), 32: thermoplastic resin film (Second core layer), 33: concave pattern, 34: through hole, 35: conductive material, 36: semiconductor chip, 37: projecting electrode (bump), 38: adhesive material, 39: sealing resin, 40, 46A , 46B ... vent holes.

Claims (9)

[Claims] A first wiring layer provided on a surface of the first core layer; and a first wiring layer laminated on both surfaces of the first core layer.
A second core layer having a lower hygroscopicity than the core layer of the above, wherein a bottomed gas vent hole penetrating through the second core layer and having a bottom in the first core layer. A wiring board, comprising: 2. The wiring board according to claim 1, wherein the gas vent hole is formed on a surface opposite to a surface on which the wiring layer is formed. 3. The wiring board according to claim 1, wherein the first core layer is made of an epoxy-based thermosetting resin material, and the second core layer is made of a thermoplastic resin material. 4. A plurality of laminates of the first core layer and the second core layer are laminated, and the gas vent hole is directed toward each first core layer of the laminate. 2. The method according to claim 1, wherein a plurality of holes are formed.
The wiring board according to claim 1. 5. The wiring board according to claim 1, wherein the wiring layer is formed by filling a conductive material in a concave groove of a concave pattern formed on the second core layer. 6. The wiring board according to claim 1, wherein the wiring board is an interposer board for a chip size package component. 7. A method for manufacturing a wiring board, wherein a wiring layer is formed on at least one surface, comprising: laminating a thermoplastic resin film on both surfaces of a core material made of a thermosetting resin film; Forming a concave pattern by subjecting the thermoplastic resin film on the side to mold forming, filling a conductive material in a concave groove of the concave pattern to form the wiring layer, and a surface on which the wiring layer is formed. Forming a bottomed vent hole having a bottom inside the core material on a surface on the opposite side of the core material. 8. The method according to claim 7, wherein a hot pressing step of the wiring layer is performed immediately after the step of forming the wiring layer. 9. A wiring board having a wiring layer formed on a front surface and external terminals connected to the wiring layer formed on a back surface, and a semiconductor chip having a plurality of protruding electrodes joined to the wiring layer. In the semiconductor device, the wiring substrate is a core material made of a thermosetting resin material, a thermoplastic resin film laminated on both surfaces of the core material, and the wiring layer is formed on one side thereof, And a bottomed vent hole having a bottom inside the core material.