JPH06104578A - Multilayer wiring board and production thereof - Google Patents

Abstract

PURPOSE:To provide a multilayer wiring board, and production method thereof, in which high density wiring is realized through simple production process while incorporating a capacitor having high capacity. CONSTITUTION:A first ground layer 10 having potential of 0V, a first dielectric layer 3 having high dielectric constant, a power supply layer 11 to be applied with a DC voltage for driving an IC, a second dielectric layer 4, a second ground layer 12 connected with the first ground layer 10, a first low dielectric layer 5 having low dielectric constant, a first signal wiring layer 13, a second low dielectric layer 6, a second signal wiring layer 14, and a third low dielectric layer 7 are laminated sequentially on a multilayer wiring board 1. A die attach 16 and pads 15 are also formed on the surface of the board 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board used for a device for high-speed and large-capacity information processing in the field of computers or communications.

[0002]

2. Description of the Related Art Conventionally, multilayer wiring boards used for semiconductor substrates, IC packages and the like have been manufactured by using screen printing technology and photoengraving technology. For example, there are roughly two techniques for manufacturing a multilayer wiring board using a screen printing method. One is a green sheet lamination technology, and the other is a thick film paste multilayer technology.

Among these, in the green sheet laminating technique,
After preparing a plurality of ceramic green sheets, using a screen printing method to form a wiring circuit with a conductive metallizing paste for each sheet, and after forming a via hole for obtaining interlayer conduction as necessary The green sheets are laminated and integrated, and then the ceramic layer and the metallized layer are simultaneously fired to produce a multilayer wiring board.

On the other hand, in the thick film paste multi-layer technology, a conductive paste is screen-printed on a ceramic sintered body substrate,
After that, a wiring circuit is formed by baking, a dielectric thick film paste is screen-printed thereon, and then an insulating layer is formed by baking, and this is repeated alternately to produce a multilayer wiring board.

When the photoengraving technique is used,
First, a metallized surface is formed on a ceramic sintered body substrate by using a thin film technique such as sputtering, and then a photoresist is applied, followed by exposure and development to form a wiring pattern. Further, a photosensitive paste obtained by mixing and kneading a photosensitive emulsion, a binder, an organic solvent and the like with crystallized glass powder is printed thereon, and then exposed and developed to form a via hole for ensuring continuity between insulating layers. An unfired insulating layer having is provided and then fired to form the insulating layer. In this way, the multilayer wiring board is manufactured by alternately forming the wiring patterns and the insulating layers.

[0006]

However, the above technique is not always suitable because of the following problems. In other words, among the screen printing techniques, the green sheet laminating method uses an ultrathin sheet (thickness 30 to
50μm) and stack a large number of layers to incorporate a capacitor,
High density fine wiring was performed on the substrate surface using thin film technology I
C packages have been reported. However, with this technology, the dielectric constant of the ultra-thin sheet co-fired in the multilayer wiring board must be made relatively low (because the thermal expansion coefficient of the other layers must match), resulting in a large capacitance. There was a problem that I could not. In addition, the ultra-thin sheet is not preferable because it is difficult to process vias for connecting the conductive layers and is easily damaged during processing, resulting in poor workability and increased cost.

On the other hand, in the thick film paste multi-layer method, a paste of a material having a high dielectric constant is printed and baked to relatively easily manufacture a multi-layer wiring board having a large-capacity capacitor for reducing switching noise. However, such a multilayer wiring board has a problem that the wiring density is low and it is not suitable for high-speed signal processing.

In the case of using the photoengraving technique,
Although fine and high-density wiring is possible, a fine wiring pattern is not required for the power supply layer connected to the power supply or the ground layer used for grounding, and even when a large-capacity capacitor is built in, There is a problem that it takes more time than the screen printing technique, and thus the manufacturing process of the multilayer wiring board becomes complicated and causes an increase in cost.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a multilayer wiring board having a built-in large-capacity capacitor and capable of high-density wiring by a simple manufacturing process, and a manufacturing method thereof. And

[0010]

In order to achieve the above object, the invention of claim 1 provides a signal wiring layer having conductivity,
A ground layer, a power layer, and an insulating layer disposed between the layers,
And a high dielectric constant material is used as one or more thick first insulating layers sandwiched between the ground layer and the power supply layer, and one or more of the signal wiring layer side is used. A gist of a multi-layer wiring board is that a low dielectric constant material is used as a thick second insulating layer.

A second aspect of the present invention is the method for manufacturing a multilayer wiring board according to the first aspect, wherein the ground layer and the power supply layer are formed of a conductive material, and the ground layer and the power supply are provided. The first insulating layer sandwiched between the layers is formed by a screen printing technique using a paste made of a dielectric material having a high dielectric constant, and the second insulating layer on the signal wiring layer side is photosensitive to a low dielectric constant inorganic material. A gist of the present invention is a method for manufacturing a multilayer wiring board, which is characterized in that it is formed by a photoengraving technique using an insulating paste to which an emulsion is added.

Further, according to the invention of claim 3, the paste of the conductive material is applied by screen printing to form the ground layer and the power supply layer, and the paste of high dielectric constant dielectric material is also applied by screen printing. A method of manufacturing a multilayer wiring board according to claim 2 is characterized in that the first insulating layer is formed by coating.

Here, as the material of the first insulating layer having a high dielectric constant, for example, lead titanate having a relative dielectric constant of about 20 to 2000 and a glass component added (εr = 10).
0) or lead zirconate titanate (εr = 1000)) or the like, and as the material of the second insulating layer having a low dielectric constant, alumina or aluminum nitride having a relative permittivity of about εr = 5 to 10 is used. , Mullite, cordierite, etc. can be adopted.

As a material for the signal wiring layer, the ground layer, and the power supply layer, Ag / Pd, Au paste, etc. can be adopted.
Especially for the signal wiring layer that requires high-density wiring,
It is also possible to perform thin film metallization by sputtering or plating of i / Pd / Au, Ti / Mo / Cu / Ni / Au, etc., and form a wiring pattern by using a photoengraving technique. Furthermore, since the flatness and dimensional accuracy of the pads are strictly required in the outermost surface layer where the bonding pads of the IC are formed, it is desirable to form the wiring pattern using the photoengraving technique.

As the dielectric paste having a high dielectric constant for the first insulating layer, a material made of barium titanate, strontium titanate, lead titanate, calcium titanate or a solid solution composition thereof can be used. On the other hand, as the insulating paste for the second insulating layer, a photosensitive emulsion obtained by adding a photosensitive emulsion, a binder, a solvent and the like to a low dielectric constant inorganic material can be adopted. Further, as the inorganic material, mullite, cordierite, alumina, anorthite, a composite system thereof, or crystallized glass can be adopted, and it is desirable to appropriately select these in accordance with the expansion coefficient of the entire multilayer wiring board. .

[0016]

According to the invention of claim 1 having the above structure, since a high dielectric constant material is used as the first insulating layer sandwiched between the ground layer and the power layer of the multilayer wiring board, it is sandwiched between the ground layer and the power layer. The first insulating layer functions as a large-capacity capacitor that can reduce switching noise.

The capacitance of the capacitor (electrostatic capacity C) is defined by the following equation (1). C = ε ₀ εr S / d (1) (S: electrode area, d: dielectric thickness, ε ₀ : vacuum permittivity, εr: relative permittivity) Further, in the present invention, the second on the signal wiring layer side. Since a low dielectric constant material is used for the insulating layer, signals can be transmitted at high speed. That is, as shown in the following equation (2), the signal transmission speed is affected by the relative permittivity εr of the signal wiring layer,
This is because in the case of transmitting a signal at a high speed, the relative permittivity should be as small as possible.

V = c / εr ^1/2 (2) (c: Speed of light in vacuum (3 × 10 ⁸ m / s)) The second insulating layer having a low dielectric constant has a high dielectric constant. Also has the function of overglazing to cover the first insulating layer with a dense layer.

According to the second aspect of the present invention, since the first insulating layer sandwiched between the ground layer and the power supply layer is formed by the screen printing method using the paste of the high dielectric constant material, it is easy to manufacture and has a large capacity. It is possible to manufacture a capacitor having a capacitance without damaging it.

Moreover, since the second insulating layer on the signal wiring layer side is formed by photolithography using an insulating paste obtained by adding a photosensitive emulsion to a low dielectric constant inorganic material, fine vias and the like are provided (wiring pattern The second insulating layer (corresponding to the above) can be easily formed. Therefore, since a dense signal wiring layer can be easily formed on the second insulating layer by, for example, sputtering or the like, high density wiring can be realized.

Particularly, when the grounding layer and the power supply layer are formed and the first insulating layer is formed by the screen printing method, the manufacturing is further simplified.

[0022]

EXAMPLES Next, examples of the multilayer wiring board and the method for manufacturing the same according to the present invention will be described. The multilayer wiring board of the present embodiment has a large number of fine wirings formed thereon, and for example, an IC
It is used for the board etc.

As shown in FIG. 1, the multilayer wiring board 1 of this embodiment has five layers of insulating layers 3 to 7 composed of high dielectric constant and low dielectric constant layers on a ceramic substrate 2 made of alumina. Conductive layer 10 formed between the insulating layers 3 to 7 and on the surface thereof
To 16 are laminated and formed. Of the insulating layers 3 to 7, the lower two layers correspond to the first insulating layer (of the present invention) and the upper three layers correspond to the second insulating layer.

That is, the multi-layer wiring board 1 is provided with D layers for driving the first ground layer 10 grounded at a potential of 0 V, the first high dielectric layer 3 having a large relative dielectric constant 3, and the IC from the lower layer thereof.
It serves as a power supply layer 11 to which a C voltage is applied, a second high dielectric layer 4, a second ground layer 12 connected to the first ground layer 10, a first low dielectric layer 5 having a small relative dielectric constant 5, and a signal line. The first signal wiring layer 13, the second low-dielectric layer 6, the second signal wiring layer 14, and the third low-dielectric layer 7 are sequentially stacked, and further on the surface of the substrate 1 (IC shown in FIG. 2). Die attach 16
And a pad 15 (to which a bonding wire extending from the IC is connected) and the like are formed.

The first and second high dielectric layers 3 and 4 each have a thickness of 30 μm and are made of lead zirconate titanate having a relative permittivity of εr = 1000. Therefore, in this embodiment, the high dielectric layers 3 and 4 sandwiched between the ground layers 10 and 12 and the power supply layer 11 each function as a large-capacity decoupling capacitor of 300 pF / mm ² . On the other hand, each of the first to third low dielectric layers 5 to 7 has a thickness of 60 μm and is made of crystallized glass having a relative dielectric constant of εr = 8.5 to 9.

Both the ground layers 10 and 12 and the power supply layer 11
Is formed by firing an Ag / Pd paste, while both signal wiring layers 13 and 14 are formed by forming an Au plating layer on a Ti / Pd layer formed by sputtering. . In addition, each signal wiring layer 13, 1
4 has a line width of 50 μm and a pitch of 100 to 200 μm, and the signal wiring layers 13 and 14 have a microstrip structure having the ground layer 12 on one side.

The conductive layers 10 to 15 are connected via vias 19 as shown in the enlarged view of the portion A in FIG. Part 2
0 is set to prevent connection. The diameter of the via 19 is φ5 in the first insulating layer formed by the screen printing method.
00μm, φ in the second insulating layer formed by photoengraving technology
It is set to 100 μm.

Next, a method of manufacturing the multilayer wiring board 1 having the above-mentioned structure will be described. 1) First, on the surface of the ceramic substrate 2 made of alumina,
An Au (or Ag / Pd) paste is applied by screen printing, dried, and then fired at 900 ° C. in the atmosphere to form the first ground layer 10.

2) A dielectric such as lead zirconate titanate and a frit component: 65.5% by weight, a glass component: 4.5% by weight, and a binder: 30 on the first ground layer 10 by screen printing. A dielectric paste consisting of wt% is applied, dried and then fired at 920 ° C. in the atmosphere to form the first high dielectric layer 3 (having the via hole 22).
In addition, this work is done in 3 steps so that the thickness after firing becomes 30 μm.
Repeat times.

3) Next, a via hole 2 with Ag / Pd paste
2 is filled and it is baked at 900 ° C. in the atmosphere. 4) Then, the same processing as 1) to 3) above is repeated again to form the power supply layer 11 and the second high dielectric layer 4.

5) Next, on the second high dielectric layer 4, A
The u (or Ag / Pd) paste is applied, dried, and then fired at 900 ° C. in the atmosphere to form the second ground layer 12. 6) Furthermore, on the second ground layer 12, an inorganic material powder made of glass, alumina, etc., and an organic polymer binder poly (methyl methacrylate / β-hydroxyethyl acrylate), etc .: 85% by weight, a photopolymerization simple substance A photosensitive crystallized glass paste mixed with a vehicle consisting of diethylene glycol diacrylate, etc., 12.5% by weight, and diacetyl, etc., photopolymerization initiator: 2.5% by weight is printed. afterwards,
This paste is exposed and developed to form via holes 22, and then baked at about 920 ° C. in the atmosphere. Then, this process is repeated three times to form the first low dielectric layer 5 (having the via hole 22).

7) Then, the via hole 22 is filled with Au paste in the same manner as described above, and the paste is fired at 900 ° C. in the atmosphere. 8) Next, Ti / Pd is sputtered on the first low dielectric layer 5, and Au is further plated on the first low dielectric layer 5 and then etched to form the first signal wiring layer 13 which is a wiring pattern. Form.

9) Next, a photosensitive crystallized glass paste similar to 6) above is printed on the first signal wiring layer 13,
Similarly, exposure, development and baking are performed. Then, this process is repeated three times to form the second low dielectric layer 6. 10) Then, the processes 7) to 9) are repeated to form the second signal wiring layer 14 and the third low dielectric layer 7.

11) Next, the via hole 22 is filled with Au paste and baked in the air at 900 ° C. 12) Finally, Ti / Pd is sputtered on the third low dielectric layer 7, Au is further plated on the third low dielectric layer 7, and then etching is performed to form pads 15 and die attach 16 on the substrate surface. To do.

As described above, in this embodiment, by using the screen printing technique, the high dielectric layers 3 and 4 are formed, and the ground layers 10 and 12 and the power supply layer 11 are formed to form a multilayer structure. A large-capacity decoupling capacitor can be easily formed on a part of the wiring board 1.

Further, the low dielectric layer 5 having the via holes 22 corresponding to the fine wiring pattern is formed by using the photolithography technique.
1 to 7, the signal wiring layers 13 and 14 having a dense pattern can be easily and accurately formed on the surfaces of the low dielectric layers 5 to 7 by sputtering or the like.

Further, since both sides of the signal wiring layers 13 and 14 are sandwiched by the first to third low dielectric layers 5 to 7 having small relative permittivity, it is possible to transmit signals at high speed. There is. Further, generally, a substance having a high relative dielectric constant is often porous and inferior in moisture resistance, but in the present embodiment, the surface of the second high dielectric constant layer 4 has a dense first low dielectric constant layer. Since it is covered with No. 5, it is possible to prevent such defects of the high dielectric layer from appearing.

Next, a method of manufacturing a multilayer wiring board of another embodiment will be described. In this embodiment, as the material of the signal wiring layer, Ti / Pd sputtering and Au plating are not used, but Ti / Mo / Cu sputtering and Cu plating are used. Not specifically shown.

The items 1) to 5) are the same as those in the above embodiment, and the items 6) are the same as those in the above embodiment except that “in the atmosphere” is changed to “into nitrogen”, and therefore the description is omitted. 7) In this embodiment, the via hole is filled with Cu paste and baked at 900 ° C. in nitrogen.

8) Ti / Mo / on the first low dielectric layer
Cu is sputtered, Cu is further plated thereon, and then etching is performed to form a first signal wiring layer which is a wiring pattern. 9) Next, print the same photosensitive crystallized glass paste as the above 6) on the first signal wiring layer, and similarly expose, develop,
Bake. Then, this process is repeated three times to form the second low dielectric layer.

10) Then, the processes 7) to 9) of this embodiment are repeated to form the second signal wiring layer and the third low dielectric layer. 11) Next, fill the via holes with Cu paste and fire at 900 ° C. in a nitrogen gas atmosphere.

12) Finally, Ti is deposited on the third low dielectric layer.
/ Mo / Cu is sputtered, and then C
After u-plating, etching is performed to form pads 15 and die attach 16 on the substrate surface. Also in this embodiment, there is an effect that a large-capacity decoupling capacitor can be easily manufactured by the screen printing technique and a fine signal wiring layer can be formed by the photolithography technique.

Further, since Cu is used as the conductor material,
There is an advantage that an extremely low wiring resistance is realized. still,
It is needless to say that the present invention is not limited to the above embodiments and can be implemented in various modes within the scope of the gist of the present invention.

For example, the pads provided on the surface of the substrate include
A resistance portion may be provided for the signal wiring layer to provide a termination resistance function. The terminator resistance function is a function that eliminates reflection noise when a signal is transmitted from IC to IC and transmits the signal correctly. Further, as the both high dielectric layers, a material composed of lead titanate having a relative permittivity of εr = 100 and glass may be used. In that case, one layer has a capacitance of 30 pF / mm ² .

[0045]

As described in detail above, according to the first aspect of the present invention, the high dielectric constant material is used as the thick first insulating layer sandwiched between the ground layer and the power supply layer of the multilayer wiring board. 1
The insulating layer serves as a large-capacity capacitor and can reduce switching noise. On the other hand, since the low dielectric constant material is used as the second insulating layer on the signal wiring layer side, signals can be transmitted at high speed. Further, this second insulating layer becomes an overglaze in which the first insulating layer having a high dielectric constant is covered with a dense layer.

According to the second aspect of the present invention, the first insulating layer sandwiched between the ground layer and the power supply layer is formed by the screen printing technique using a paste made of a dielectric material having a high dielectric constant. Therefore, it is possible to manufacture a capacitor having a large capacitance without damaging it. Moreover, since the second insulating layer on the signal wiring layer side is formed by photolithography using an insulating paste obtained by adding a photosensitive emulsion to a low dielectric constant inorganic material, it is possible to easily form fine vias and signal wiring layers. And high density wiring is realized.

In particular, when the ground layer and the power supply layer are formed and the first insulating layer is formed by the screen printing method, the manufacturing can be further simplified.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a multilayer wiring board of an example.

FIG. 2 is an explanatory diagram showing an IC arranged on a multilayer wiring board according to an embodiment.

FIG. 3 is a perspective view schematically showing the structure of a via.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Multilayer wiring board 3, 4, 5, 6, 7 ... Insulating layer 10, 11, 12, 13, 14, 15, 16 ... Conductive layer

Claims (3)

[Claims] 1. A multi-layer wiring board comprising a conductive signal wiring layer, a ground layer, a power supply layer, and an insulating layer disposed between the respective layers, which is sandwiched between the ground layer and the power supply layer. A high dielectric constant material is used as the one or more thick first insulating layers, and a low dielectric constant material is used as the one or more thick second insulating layers on the signal wiring layer side. Multilayer wiring board. 2. The method for manufacturing a multilayer wiring board according to claim 1, wherein the ground layer and the power supply layer are formed of a conductive material, and the first layer is sandwiched between the ground layer and the power supply layer. The insulating layer is formed by a screen printing technique using a paste made of a dielectric material having a high dielectric constant, and the second insulating layer on the signal wiring layer side is an insulating paste obtained by adding a photosensitive emulsion to a low dielectric constant inorganic material. A method for manufacturing a multilayer wiring board, which is characterized in that it is formed by a photoengraving technique. 3. A first insulating layer formed by applying a paste of a conductive material by screen printing to form a ground layer and a power supply layer and also applying a paste of a high dielectric constant dielectric material by screen printing. 3. The method for manufacturing a multilayer wiring board according to claim 2, wherein: