JP2017168493A - Wiring board and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preferred singulation method when singulating wiring boards having core substrates made of brittle material, and a wiring board manufactured by the method.SOLUTION: A wiring board includes a core substrate; an interlayer insulation resin layer laminated on the core substrate; a wiring layer laminated on the core substrate or the interlayer insulation resin layer; and a stress relief resin formed on the core substrate so as to surround the wiring layer. In a step for singulating the wiring board, the stress relaxation resin is cut.SELECTED DRAWING: Figure 2

Description

The present invention relates to a wiring board and a manufacturing method thereof.

  Semiconductor devices using semiconductor chips and external connection members are used in various fields such as image processing, communication, and in-vehicle. As semiconductor devices become more sophisticated and smaller and lighter, semiconductor wiring boards used in semiconductor devices are also required to be smaller, have more pins, and have finer pitches for external terminals. The demand is growing.

  As the conventional core material, an organic core material typified by a glass epoxy resin and a silicon material have been used. In recent years, glass has attracted attention. This is because glass, like silicon, has flat and smooth characteristics suitable for forming fine wirings than organic materials, has less moisture absorption and heat deformation, and is electrically superior to silicon.

  The wiring substrate is formed by laminating the wiring layer and the interlayer insulating resin layer 40 a plurality of times on a core substrate which is a support body in productivity to form a large-sized wiring substrate, and then dicing the wiring substrate to a required size and separating the wiring substrate into individual pieces. Turn into.

However, although glass is excellent in dimensional stability and electrical characteristics, it is a material having a fragile cut surface and is likely to crack.
Due to the structure of the wiring board, a resin layer and a wiring layer having a different linear expansion coefficient from that of the glass substrate are laminated several times. Therefore, if there is a temperature change, the linear expansion coefficient is different between the resin layer, the wiring layer and the core board due to the difference in the linear expansion coefficient. Changes, and internal stress is generated inside each layer. In a large-sized wiring board, the internal stress is in a state where positive and negative stresses are balanced in order to maintain the equilibrium state of the object. However, if there is a portion where a crack occurs when it is separated into individual pieces, it tends to be a stress concentration portion. Therefore, it is known that in the case of a brittle material such as glass that is easily cracked, a minute crack is generated in the cross section of the core substrate due to an impact at the time of singulation. The cracks in the cross section of the core substrate may be separated into pieces, and the internal stress accumulated in the core substrate may be released by using the crack portion as a trigger, and the crack may progress in the direction in which the core substrate is torn.

  As an individualization method that does not cause such cracking, for example, a metal layer is formed on the outer periphery of the package substrate of the core substrate, and the metal layer exposed after the individualization is removed by etching to insulate the core substrate. Grooves defined by layers are made. This groove part can suppress that stress is added to the outer periphery vicinity of a core board | substrate. This can effectively prevent the core substrate from being broken by a simple configuration (see, for example, Patent Document 1).

  However, since this method cuts the metal layer on the core substrate with a dicing blade, there is a concern that many cracks may be generated in the cross section of the core substrate due to a reduction in cutting force due to clogging of the dicing blade. Further, there is a concern that the core substrate may be broken immediately after being separated into pieces by the dicing process.

JP-A-2005-231005

  In view of this, the present invention may cause damage to the cut surface of the core substrate when the wiring substrate in which the interlayer insulating resin layer 40 and the wiring layer are laminated on the core substrate made of a brittle material or when the temperature changes thereafter. It is an object of the present invention to provide a wiring board that is not used and to singulate it, and to provide a wiring board that is manufactured by this method and is used for a semiconductor package.

  As a result of intensive studies, the present inventor has been able to solve the conventional problems as described above.

  One embodiment of the present invention includes a core substrate, an interlayer insulating resin layer stacked on the core substrate, a wiring layer stacked on the core substrate or the interlayer insulating resin layer, and the core substrate so as to surround the wiring layer. A wiring board including a stress relaxation resin formed thereon.

  Another aspect of the present invention includes a step of laminating a wiring layer and an interlayer insulating resin layer on the core substrate, and stress relaxation on the core substrate so as to surround the wiring layer closest to the core substrate. And a step of forming a resin.

  Another embodiment of the present invention includes a core substrate, an interlayer insulating resin layer stacked on the core substrate, a wiring layer stacked on the core substrate or the interlayer insulating resin layer, and a core so as to surround the wiring layer. A package substrate including a stress relaxation resin formed on the substrate.

  According to the method for dividing a wiring board according to the present invention, even a wiring board using a fragile material as a core material has a large temperature at the time of production or mounting with respect to the wiring board after being singulated. Even if there is a change, cracks in the cross section from the outer periphery of the core substrate can be suppressed and a highly reliable wiring board can be provided.

It is a figure which shows the cut part end surface of schematic structure of a wiring board. FIG. 3 is a diagram illustrating a cut portion end face in a state where a wiring board is separated into pieces according to Example 1; It is a figure which shows the cut part end surface of the state which separated the wiring board by Example 2. FIG. It is the figure which expanded the cut part end surface of a wiring board. 6 is a diagram illustrating a state where a separation groove is formed on one surface of a wiring board in Example 1. FIG. It is a figure which shows the state which formed the separation groove in both surfaces of the wiring board in Example 1. FIG. FIG. 3 is an enlarged view of a part obtained by dividing a wiring board in Example 1; It is the figure which expanded the part which separated the wiring board in Example 2. FIG. It is a figure which shows the state which formed stress relaxation resin in the core board | substrate in one Embodiment of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a wiring board and a method for manufacturing the same according to the present invention will be described in detail with reference to the drawings.
The following embodiment is merely an example of the present invention, and those skilled in the art can change the design as appropriate.
In this specification, the “package substrate” refers to an individual laminated body. Further, the “wiring board” means a state in which package boards before being separated into pieces by dicing are connected.

(Configuration of wiring board)
FIG. 1 is a diagram illustrating a cut end surface of a schematic configuration of an embodiment of a wiring board.
The wiring substrate 100 according to the present embodiment includes the core substrate 10, the wiring layer 30, the interlayer insulating resin layer 40, and the stress relaxation resin 20 stacked on both surfaces of the core substrate 10 in the thickness direction.

(Core substrate processing)
The core substrate 10 may be any material that improves the electrical characteristics of the wiring substrate 100 and the package substrate 200 or 202 after the wiring substrate is singulated. For example, as the core substrate 10, a glass substrate, a silicon substrate, a ceramic substrate, a plastic plate, a plastic tape, or the like can be used. A glass substrate is preferable. Examples thereof include soda lime glass and aluminosilicate glass. The glass substrate used for the core substrate 10 of the present invention may have a surface treated by a method generally performed in the art. For example, the surface may be roughened or treated with hydrofluoric acid, or the glass substrate surface may be treated with silicon. In one embodiment of the present invention, the glass substrate used for the core substrate 10 may have a base layer formed on the surface.
The thickness h ₁ of the core substrate 10 is not particularly limited, but is preferably 50 μm to 700 μm.
Alternatively, a through hole may be opened in the core substrate, and then electrical connection may be performed by plating or a filling method.

(Formation of wiring layer)
The wiring layer 30 is formed on the surface of the core substrate 10 in the thickness direction or on the surface of the interlayer insulating resin layer 40. In one embodiment of the present invention, at least a part of the wiring layer 30 is formed in contact with the core substrate 10. In another embodiment of the present invention, the wiring layer 30 may not be in contact with the core substrate. The wiring layer 30 may be a single layer or a plurality of layers. Further, in a portion where the wiring layer is electrically connected on the front and back of the core substrate, a form penetrating the core substrate is taken.
The wiring layer 30 can be formed using a conductive material usually used in this field. Specifically, the wiring layer 30 can be formed using copper, silver, tin, gold, tungsten, conductive resin, or the like. Preferably, copper is used.

The wiring layer 30 can be formed by a method generally performed in this field. Although the formation method of the wiring layer 30 is not limited to these, The subtractive method performed using electroless plating and electroplating, a semi-additive method, an inkjet method, screen printing, and gravure offset printing can be used. A semi-additive method is preferred.
The following method is used in the semi-additive method. First, a seed layer such as a copper layer is formed on the core substrate 10. Next, a resist having a desired pattern is formed on the seed layer. Subsequently, a plating film to be a wiring layer formed in a pattern is formed in the exposed opening of the seed layer using electrolytic plating or the like. Thereafter, the resist is removed and the thin seed layer is etched to obtain the wiring layer 30. The thickness of the wiring layer 30 to be formed is 1 μm to 100 μm although it depends on the forming method.
In one embodiment of the present invention, from the viewpoint of cost, electrical characteristics, and manufacturability, it is preferable to form a fine wiring using a semi-additive method and to use copper as a metal species.

(Formation of stress relaxation resin pattern)
In the present invention, a pattern is formed using the stress relaxation resin 20 on the front and back of the cut surface of the core substrate. The formation method is not limited to this, but a screen printing method, a transfer method, a drawing method, and the like are conceivable. The width of the formed wiring is not limited, but is, for example, 250 μm to 400 μm. Since the width of the dicing blade B described later is about 150 μm, the width of the stress relaxation resin is preferably about 200 μm or more. In one embodiment of the present invention, from the viewpoint of cost and manufacturability, a screen printing method is used to form a wider width than a line that is separated by dicing. With respect to the thickness h _5, it is preferable counted from the side closer to the core substrate of the wiring layer 30 is not less than the height of the first layer. The pattern of the stress relaxation resin 20 is preferably provided so as to follow the singulation cutting line of the wiring board 100. FIG. 9 schematically shows a state in which the stress relaxation resin 20 is formed so as to surround the wiring layer 30. As will be described later, the width of the stress relaxation resin remaining after dicing the wiring board is preferably 25 μm or more. As shown in FIGS. 7 and 8, in order to dice the stress relaxation resin, the stress relaxation resin is in a state of being formed up to the surface end portion of the core substrate. Depending on the dicing conditions, the stress relaxation resin may be partly peeled off and not formed to the end of the core substrate, but it can be said that it is included in the scope of the present invention.

  The linear expansion coefficient of the stress relaxation resin 20 is preferably 1000 ppm or less. More preferably, it has a linear expansion coefficient comparable to that of the interlayer insulating resin layer 40. Further, the stress relaxation resin is preferably a material having a lower elastic modulus than the interlayer insulating resin layer 40. Thereby, when the wiring substrate 100 is diced or when the semiconductor chip is mounted, even if there is a large temperature change in the wiring substrate 100 or the package substrate 200, it is possible to suppress the cracking of the cross section from the outer periphery of the core substrate. it can. Examples of the material include materials mainly containing urethane resin.

(Formation of interlayer insulating resin layer 40)
In one embodiment of the present invention, the interlayer insulating resin layer 40 is formed on the wiring layer 30.
In another embodiment of the present invention, the interlayer insulating resin layer 40 is also formed on the core substrate 10.
One or more interlayer insulating resin layers 40 may be provided.

  The interlayer insulating resin layer 40 can be formed using an insulating material usually used in this field. Specifically, the interlayer insulating resin layer 40 can be formed using an epoxy resin material, an epoxy acrylate resin, a polyimide resin, or the like. These insulating materials may contain a filler. As the insulating material for forming the interlayer insulating resin layer 40 of the present invention, an epoxy compounded resin having a linear expansion coefficient of 7 ppm to 130 ppm is generally easily available and preferable.

Examples of the method for forming the interlayer insulating resin layer 40 include a printing method, a vacuum pressing method, a vacuum laminating method, a roll laminating method, a spin coating method, a die coating method, a curtain coating method, a roller coating method, a photolithography method, a doctor blade method, Known methods such as screen printing can be mentioned.
In one embodiment of the present invention, a spin coating method, a vacuum laminating method, and a vacuum pressing method are used from the viewpoint of ease of manufacture. The total thickness of the interlayer insulating resin layer 40 is not limited. Depending on the forming method, for example, it is 10 μm to 90 μm. The interlayer insulating resin layer 40 formed as described above may be cured by heating or light irradiation.

It is known that when the interlayer insulating resin layer 40 and the wiring layer 30 are formed on the core substrate having the thickness h ₁ and singulation (dicing) is performed, cracks are likely to occur near the interface with the core substrate 10. ing. This is because minute cracks are generated on the end face of the core substrate due to the impact generated during dicing, and the thermal stress of the wiring resin composite layer, which is a composite layer of the wiring layer 30 and the interlayer insulating resin layer 40, is applied to the core substrate 10. This is because it acts as a tensile stress and enlarges cracks in the core substrate 10.

  Therefore, in the experiment, the interlayer insulating resin layer 40 is removed from the cut surface to an arbitrary position, and then separated into pieces by a procedure of cutting into glass.

  Although the wiring board which is one Embodiment of this invention is not limited to these, According to the process shown in FIGS. 4-8 which expanded the cutting part of this wiring board of the wiring board 100 multi-faced. Can be formed.

FIG. 1 shows a state in which the wiring layer 30, the stress relaxation resin 20, and the interlayer insulating resin layer 40 are formed on the surface in the thickness direction of the core substrate 10 using the above-described method.
Then, a predetermined cutting position in the wiring substrate 100, by using a dicing blade A50 having a width w _2, singulating plural wiring package substrate 200 fold.

FIG. 4 is an enlarged view of the end surface of the cut portion of the wiring board 100. The total thicknesses of the wiring layer 30 and the interlayer insulating resin layer 40 laminated on both surfaces of the core substrate 10 are h ₂ and h ₃ , respectively. First, the sum of the stress relaxing resin 20 and the thickness of the thickness h ₅ laminated on one surface of the core substrate 10 by the dicing blade A50 to cut the interlayer insulating resin 40 is h _4. The thickness h ₆ is the distance between the surface of the core substrate 10 and the interlayer insulating resin layer 40 farthest from the surface. In FIG. 4, the sum of _{h 4} and _{h 5.} The dicing blade A cuts a portion having a width of w ₁ in FIG. 4 between the wiring layers 30 and separates the wiring substrate 100 into each package substrate 200.
The dicing blade A only needs to be a material used in a general dicing method. For example, the dicing blade A is a diamond blade in which diamond abrasive grains are buried in a resin or the like. The width w ₂ of the dicing blade A is not limited, but is preferably 200 μm.

In Figure 5 an enlarged view of the cutting section, from one side surface of the wiring substrate 100 a wiring layer 30 are stacked in the thickness direction of the substrate on the core substrate 10 to form a groove of depth h _8. This groove becomes the separation groove 60.

As shown in FIG. 5, after the formation of the separation groove 60, the stress relaxation resin 20 having the width w ₃ remains on the surface layer of the core substrate 10 with the thickness h ₇ . For this reason, it is possible to prevent the dicing blade A50 from coming into contact with the core substrate 10. Further, the development of the tensile stress of the wiring resin composite layer in which the stress is unbalanced due to the formation of the separation groove 60 can prevent the crack at the interface of the core layer 10 from progressing.

FIG. 6 shows a state in which the separation groove 60 is similarly formed from the side opposite to the separation groove 60 shown in FIG.
Thereafter, as shown in FIG. 7, in the groove of the separation groove 60, the wiring substrate 100 is diced into pieces by a dicing blade B <b> 70 at the position of the central portion within the width. As a result, the stress relaxation resin 20 has a stepped shape (hereinafter referred to as a stepped portion 22). Width _{w 4} of the tip of the dicing blade B70 is smaller width than the upper surface width _{w 2} of the isolation trench _60, this value does not matter as long as _{w 1> w 2> w 4} . For example, it is 150 μm. The gap w ₅ between the dicing blade B and the separation groove is preferably 50 μm or less.
At this time, it is necessary to prevent the interlayer insulating resin layer 40 covering the outer surface of the core substrate 10 from being removed by the dicing blade B70.

As another embodiment, as shown in FIG. 8, the core substrate may be cut as it is in the step of opening the separation groove using the dicing blade A at the stage of FIG. In this case, 0 μm ≦ w ₃ <100 μm is preferable, and 25 μm <w ₃ ≦ 50 μm is more preferable. In this case, no step is formed in the stress relaxation resin 20, and the wiring layer 30 or the interlayer insulating resin 30 is covered. Hereinafter, the stress relaxation resin 20 may be referred to as a covering portion.

In the package substrate 200 shown in FIG. 2 and the package substrate 202 shown in FIG. 3 in which the singulation method is changed, a part of these cut surfaces is made of the stress relaxation resin 20. In FIG. 5, the step portion 22 is shown, and in FIG. The step portion 22 and the covering portion 24 are formed with widths of w ₃ + w ₅ and w ₃ from the interface with the wiring layer 30, respectively. The small thickness portion at the step portion 22, the covering portion 24 has a thickness h ₇ respectively. When the core substrate 10 is cut, it is possible to reduce the difference in thermal stress caused by the difference in thermal expansion between the wiring resin mixed layer having the thicknesses h ₂ and h ₃ and the core substrate 10. The tensile stress of the laminate of the wiring resin mixed layers h ₂ and h ₃ composed of the wiring layer 30 and the interlayer insulating resin layer 40 generated at the cutting interface when heated after singulation can be relaxed.

  One embodiment of the present invention is a method for manufacturing a package substrate in which the wiring substrate is separated into pieces so as to cut the stress relaxation resin in the step of separating the wiring substrate.

  Furthermore, in the step of dividing into pieces, the manufacturing method of the package substrate uses at least two types of dicing blades, and the width of the dicing blade used for dividing into pieces is narrower than other dicing blades. Is preferred.

  Hereinafter, examples using the present invention will be described in detail.

Example 1
The thickness of the core substrate 10 (aluminosilicate glass) was 300 μm.
A wiring layer 30 having a thickness of 4.5 μm was formed on the surface in the thickness direction of the core substrate 10 by copper plating by a semi-additive method. A stress relaxation resin 20 having a width of 300 μm was formed by printing so as to surround the wiring layer 30 with a width w ₁ of 300 μm and a thickness of 4.5 μm. As the stress relaxation resin 20, a urethane resin (manufactured by Hitachi Chemical Co., Ltd., urethane resin KU-7002 for casting electronic / electric parts) was used. The stress relaxation resin 20 had a linear expansion coefficient of 150 ppm, a Young's modulus at 25 ° C. of 0.07 MPa, and a tensile strength at 25 ° C. of 0.08 MPa. After the wiring layer 30 was formed, an insulating material, which is an epoxy compounded resin having a linear expansion coefficient of 34 ppm, was laminated on the front and back surfaces by vacuum lamination to form an interlayer insulating resin layer 40. The wiring board 100 was obtained by repeating the formation of the wiring layer and the interlayer insulating resin layer.

Next, as shown in FIG. 5, at a predetermined position to be separated into the package substrate 200 later, a dicing blade A50 is used to diminish 200 μm width and depth 25 μm from one side surface of the wiring substrate 100 in the plate thickness direction. The separation groove 60 was provided. Further, as shown in FIG. 6, a separation groove 60 having a width of 250 μm and a depth of 25 μm was also provided from the other surface of the wiring board 100.
After the separation groove 60 was produced, the wiring board 100 was diced by the dicing blade B70 at the position of the central portion within the groove width of the separation groove 60 as shown in FIG. The width of the tip of the dicing blade B70 was 150 μm.
The test MIL-STD-883H which gives a temperature change from 125 ° C. to −55 ° C. was performed 1000 cycles on 10 package substrates according to Example 1. As a result, no deterioration in reliability such as cracking of the core substrate occurred.

(Example 2)
The wiring board 100 was produced in the same manner as in Example 1, and then the wiring board 100 was cut into pieces by cutting in the thickness direction of the wiring board 100 with a dicing blade A50 having a width of 250 μm as shown in FIG. .
In the same manner as in Example 1, a test for giving a temperature change from 125 ° C. to −55 ° C. was performed on 10 wiring boards. As a result, no deterioration in reliability such as cracking of the core substrate occurred.

(Comparative Example 1)
Unlike Example 1 and Example 2, the wiring board used as a comparative example did not form the stress relaxation resin layer on the core substrate 10. When the wiring board according to Comparative Example 1 was left at room temperature for 3 days, 7 of the 10 core boards were cracked.

As described above, on the side surface of the package substrate 200, the package substrate 200 according to the present embodiment having a shape obtained by removing a part of the stress relaxation resin 20 has the wiring resin mixed layers h ₂ and h ₅ at the dicing stage. The stress relaxation layer 20 is dispersed in the stress relaxation layer 20 to reduce the generation of minute cracks that lead to cracks in the core substrate 10, and the stress relaxation resin 20 remains after singulation so that the thicknesses are h ₂ and h respectively. It is considered that the crack progress due to the stress caused by the difference in the linear expansion coefficient between the wiring resin mixed layer ₅ and the core substrate 10 could be suppressed.

10 Core substrate 20 Stress relaxation resin 22 Step portion (consisting of stress relaxation resin)
24 Covering part (consisting of stress relaxation resin)
30 Wiring layer 40 Interlayer insulating resin layer 50 Dicing blade A
60 Separation groove 70 Dicing blade B
100 Wiring board of the present invention 200 Divided wiring board (with step)
202 Divided wiring board (no steps)

Claims (13)

A core substrate;
An interlayer insulating resin layer laminated on the core substrate;
A wiring layer laminated on the core substrate or the interlayer insulating resin layer;
A wiring board including a stress relaxation resin formed on the core board so as to surround the wiring layer.   The wiring board according to claim 1, wherein the stress relaxation resin has a width of 200 μm or more.   The wiring substrate according to claim 1, wherein the core substrate is made of glass. A step of laminating a wiring layer and an interlayer insulating resin layer on the core substrate;
Forming a stress relaxation resin on the core substrate so as to surround the wiring layer closest to the core substrate.   The wiring board manufacturing method according to claim 4, wherein the stress relaxation resin has a width of 200 μm or more.   The method for manufacturing a wiring board according to claim 4, wherein the core substrate is made of glass. A core substrate;
An interlayer insulating resin layer laminated on the core substrate;
A wiring layer laminated on the core substrate or the interlayer insulating resin layer;
A package substrate including a stress relaxation resin formed on the core substrate so as to surround the wiring layer.   The package substrate according to claim 7, wherein the stress relaxation resin has a width of 25 μm or more.   The package substrate according to claim 7 or 8, wherein the stress relaxation resin is formed up to a surface end portion of the core substrate.   The package substrate according to claim 7, wherein the core substrate is made of glass. In addition to the method for manufacturing a wiring board according to any one of 4 to 6,
A method for manufacturing a package substrate, comprising the step of separating the wiring substrate into pieces.   The method for manufacturing a package substrate according to claim 11, wherein in the step of dividing into pieces, the wiring substrate is divided into pieces so as to cut the stress relaxation resin.   The package according to claim 11 or 12, wherein at least two types of dicing blades are used in the individualizing step, and a width of the dicing blade used for individualizing is narrower than other dicing blades. A method for manufacturing a substrate.