JP2001102695A - Ceramic circuit board and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic circuit board, by which electrical short circuits can be easily prevented using a simple constitution and to provided a method for manufacturing the ceramic circuit board. SOLUTION: Since first and second convex parts 21 and 22 have a thickness of 20 μm-40 μm, their thickness is equal to or larger than that of burrs 23 and 24 respectively generated at sections 25 and 26. Accordingly, when resistor paste is printed on the surface layer of a glass ceramic multilayer substrate 10, the printing plate can be protected surely, the printing plate can be prevented surely from being damaged by the burrs 23 and 24, and electrical short circuits can be prevented surely. Further, since the first and the second convex parts 21 and 22 are formed by partially increasing the thickness of a conductor wiring layer, the first and the second convex parts 21 and 22 can be formed easily on the conductor wiring layer. Consequently, electrical short circuits can be prevented easily using a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic circuit board and a method of manufacturing the same, and more particularly, to a ceramic circuit board having a conductor wiring layer on a surface layer and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a semiconductor device, an IC chip or an LS
2. Description of the Related Art A semiconductor element such as an I-chip is mounted on a semiconductor element mounting portion provided on a substrate and put to practical use. Ceramics such as alumina are suitable as a material for this substrate because they have excellent heat resistance, durability, thermal conductivity, and the like, and ceramic semiconductor substrates are currently being used actively.

[0003] However, the alumina substrate has a relatively large relative dielectric constant, causing transmission signal delay, and has a larger coefficient of thermal expansion than silicon, so that reliability against temperature changes when components are mounted is ensured. There was a problem that it was difficult to do. Furthermore, since the firing temperature of alumina is as high as about 1600 ° C., it is necessary to use W or Mo having a high melting point and a large electric resistivity as the wiring of the inner layer. There was a problem of becoming larger.

For this reason, low-temperature fired ceramic substrates that can be fired simultaneously with low-resistance wiring materials such as Ag and Cu have been developed. Among them, the relative dielectric constant is relatively small, so that the transmission loss is small. In addition, since the thermal expansion coefficient is close to that of silicon, a glass ceramic substrate containing glass that can be mounted by a flip-chip method has been attracting attention. Glass materials used for this glass ceramic substrate include borosilicate glass, MgO-Al ₂ O ₃ -Si
O ₂ -based glass, CaO—Al ₂ O ₃ —SiO ₂ -based glass and the like can be mentioned. Usually, a glass ceramic substrate is manufactured using a raw material obtained by adding an aggregate to these glass powders.

In order to reduce the size of the glass ceramic substrate, improve the mounting density on the mounting board, and further improve the electrical characteristics, generally, a plurality of glass ceramic green sheets are laminated and fired. As a result, a glass ceramic multilayer substrate is manufactured.

[0006]

By the way, in a ceramic circuit board generally used for an integrated circuit, in addition to a built-in resistor provided between layers of a multi-layer circuit board, a conductor wiring layer provided on a surface layer of the ceramic circuit board is provided. A circuit composed of an external resistor and the like is provided, contributing to higher performance and lower cost of the ceramic circuit board.

The method of forming a conductor wiring layer on such a ceramic circuit board is roughly classified into a thin film method, a plating method, a thick film method, and the like. A conductor wiring layer having sufficient adhesion strength to the substrate can be formed at low cost.

When a fine conductor pattern is formed on a ceramic circuit board, a conductor paste is printed by the above-mentioned thick film method, dried and fired, and then the conductor wiring layer is irradiated with laser light to form a cut portion. To form a conductor pattern having a pattern interval of, for example, 100 μm or less.

When a thick-film resistor layer is formed on the surface layer of a ceramic circuit board, generally, a resistor obtained by adding a conductive material to a glass composition is printed in a paste form, sintered, and sintered. Layers. At this time, for the purpose of protecting the resistor layer and improving the weather resistance, an overcoat layer is formed by printing and baking the resistor layer with a glass-based material. Further, the resistance value of the resistor layer is finely adjusted using a technique such as laser trimming.

However, when a cut portion is formed by irradiating the conductor wiring layer with a laser beam, the projection of the laser beam may cause a fusion protrusion having a thickness of, for example, 20 μm or less, so-called burrs, to the cut portion. . When burrs are generated in the cut portion, when the resistor layer is formed by printing in a later step, the printing plate of the resistor paste is damaged by the above burrs, and the resistor paste adheres to the cut portion of the conductor pattern and after firing, However, there is a problem that the circuit may be electrically short-circuited.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a ceramic circuit board which can easily prevent an electrical short circuit with a simple configuration and a method of manufacturing the same. I do.

[0012]

According to the ceramic circuit board of the present invention, a cut portion for dividing the conductive wiring layer into the first and second conductive patterns is formed in the conductive wiring layer. First and second protrusions are provided on the second conductor pattern so as to sandwich the cut portion. For this reason, even if burrs are generated at the cut part,
When the resistor layer is formed by printing in a later step, the printing plate of the resistor paste is protected by the first and second protrusions,
The printing plate is prevented from being damaged by burrs.
Therefore, it is possible to prevent the resistor paste from adhering to the cut portion, and to ensure good electrical characteristics of the ceramic circuit board without short-circuiting the circuit after firing.

According to the ceramic circuit board of the second aspect of the present invention, the first and second projections have a thickness of not less than 20 μm and not more than 40 μm. Can be made larger than the thickness of the burrs generated on the surface. Therefore, when printing the resistor paste on the surface layer, the printing plate can be reliably protected, the printing plate can be reliably prevented from being damaged by burrs, and the electrical short circuit of the circuit can be reliably prevented.

If the thickness of the first and second projections is less than 20 μm, the thickness of the burr generated at the cut portion may be larger than the thickness of the first and second projections, and the surface layer may have a resistance. When printing the body paste, the printing plate may not be able to be protected from the burrs of the cut portion. If the thickness of the first and second projections exceeds 40 μm, it becomes difficult to form the first and second projections on the conductor wiring layer, the manufacturing process becomes complicated, and the manufacturing cost is reduced. May rise.

According to the method for manufacturing a ceramic circuit board according to the third aspect of the present invention, the first and second ceramic circuit boards are formed on the conductor wiring layer.
Are formed, the conductor wiring layer is divided into first and second conductor patterns between the first and second protrusions, and cut portions are formed in the conductor wiring layer. For this reason, even if burrs are generated in the cut portion, when the resistor layer is formed by printing in a later step, the printing plate of the resistor paste is protected by the first and second convex portions, and the burrs described above are used. Prevents the printing plate from being damaged. Therefore, it is possible to prevent the resistor paste from adhering to the cut portion, and to ensure good electrical characteristics of the ceramic circuit board without short-circuiting the circuit after firing.

According to the method for manufacturing a ceramic circuit board according to the fourth aspect of the present invention, since the first and second projections are formed by partially thickening the conductor wiring layer, printing and drying of the conductor paste are performed in a plurality. It is possible to easily form the first and second projections on the conductor wiring layer by repeating firing once, performing multi-layer printing, firing once, or repeating printing, drying and firing of the conductor paste a plurality of times. it can. Therefore, an electrical short circuit can be easily prevented with a simple configuration.

According to the method of manufacturing a ceramic circuit board according to the fifth aspect of the present invention, since the cut portion is formed by irradiating a laser beam, the spot diameter of the laser beam is reduced using, for example, a YAG laser or an excimer laser. Thereby, a desired location between the first and second projections is irradiated with a laser beam so that the conductor wiring layer is easily and accurately formed between the first and second projections into the first and second conductor patterns. Can be well divided. Therefore, a finer conductive pattern can be formed on the surface layer of the ceramic circuit board.

The ceramic circuit board of the present invention may be a single-layer or multi-layer as long as ceramic is used as an insulator. In the case of a multilayer ceramic circuit board, a green sheet laminating method, a green sheet printing method and the like may be used. Law. Further, a circuit board having only one surface or a double-sided circuit board may be used.

As the ceramic material used in the present invention,
Is not particularly limited, and alumina (Al _TwoO_Three), Aluminum nitride
(AlN), silicon carbide (SiC) and these
And various ceramics whose main component is. Also, alumina
Low-temperature firing glass ceramic mixed with glass powder
Can also be used. The conductor material used for the inner layer is
Depending on substrate material, alumina or aluminum nitride
Then, like molybdenum (Mo) or tungsten (W)
Refractory metals are used. Substrate material that can be fired at a relatively low temperature
In case of charge, gold (Au), silver (Ag), silver-palladium
Alloy (Ag-Pd), copper (Cu), nickel (Ni)
Which metal is used.

One of the co-fired ceramic circuit boards for simultaneously firing the ceramic green sheet and the wiring conductor paste is to use W or Mo as a wiring conductor of a substrate such as alumina or aluminum nitride so that the conductor is not oxidized. There are ceramic circuit boards that are co-fired in a reducing atmosphere. However, a highly reliable R that needs to be fired in an oxidizing atmosphere
When a uO ₂ -based or Bi ₂ Ru ₂ O ₇ -based resistor is formed, there is a problem that the conductor is oxidized. In contrast, A
g, Ag-Pd, Ag-Pt, Ag-Pd-Pt, etc., which have small conduction resistance and can be oxidized and fired, can be used as an Ag-based conductor, and can be fired at a melting point (900 to 1200 ° C.) or lower of these conductive materials. A low-temperature fired glass-ceramic multilayer wiring board using a ceramic material as an insulator has been developed, and is particularly preferable as the ceramic board of the present invention.

Generally, a ceramic substrate fired at about 1200 ° C. or lower is called a low-temperature fired glass ceramic substrate, and the inner layer and the surface layer are made of Ag or Cu as a conductor. As described above, as the glass ceramic insulator material, it is preferable to use a material that can be fired at a temperature lower than the melting point of, for example, an Ag-based conductor material contained therein. A
In the case of using a g conductor or an Ag alloy-based conductor having a low content of Pd and Pt, the melting point of the metal formed in these multilayers is as low as about 900 to 1200 ° C.
It is necessary to use a material that can be fired at 00 ° C. Typical examples are borosilicate glass and several types of oxides (eg, MgO, CaO, Al ₂ O ₃ , PbO, K ₂
O, Na ₂ O, ZnO, Li ₂ O, etc.) and a ceramic powder such as alumina or quartz as a raw material, or a glass powder in which cordierite-based or α-spodumene-based crystallization occurs. There is something to do. Specifically, those consisting of _{CaO-Al 2 O 3 -SiO 2} -B 2 O 3 system or _{MgO-Al 2 O 3 -SiO 2} -B 2 O 3 based glass and alumina.

Although the above materials can be used as a single layer, a green sheet laminating method using a green sheet is used for laminating a multilayer substrate. For example, a ceramic insulator material powder is formed by a doctor blade method to obtain a green sheet having a thickness of about 0.1 to 0.5 mm. Then, the necessary wiring patterns are Ag, Ag-
Screen printing is performed using a conductive material paste such as Pd, Ag-Pt, or Ag-Pd-Pt. Further, a through-hole of about 0.1 to 2.0 mmφ is formed in the green sheet by a punching die or a punching machine so that another conductor wiring layer can be connected. The wiring via hole is filled with an Ag-based conductor material. Print wiring patterns on other green sheets as needed to form circuits in a similar manner. After accurately stacking these green sheets using the positioning holes formed in the green sheets, the green sheets are integrated by thermocompression bonding at 80 to 150 ° C. and 10 to 250 kg / cm ² .

In the case where the circuit includes an internal resistance, an oxidizing atmosphere
RuO fired by air_Two, Bi_TwoRu _TwoO₇Forming system resistance
I do. In that case, paste the resistor paste together with the electrode
Print on the green sheet.

The above-mentioned components are simultaneously fired in an oxidizing atmosphere to obtain a ceramic multilayer substrate with a built-in conductor. The low-temperature firing glass ceramic has been described above as an example, but these are preferred embodiments of the present invention, but are not limited thereto.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. An example of applying the present invention to the glass ceramic multilayer substrate using the CaO-Al ₂ O ₃ -SiO ₂ -based glass, will be described with reference to FIGS.

First, a method for manufacturing a glass ceramic green sheet laminate will be described. Here, the raw material powder of the glass ceramic is CaO—Al ₂ O ₃ —SiO ₂
Glass powder 60 wt% of -B ₂ O ₃ system and the Al ₂ O ₃ powder 40
wt.%, and has a mean particle size of about 3.5 μm.

(1) A plasticizer of dioxyl phthalate, a binder of an acrylic resin, and a solvent such as toluene, xylene and alcohol are added to a glass ceramic powder, and the mixture is sufficiently kneaded to obtain a slurry having a viscosity of 2000 to 40000 cps. Was prepared, and 0.3 was obtained by the doctor blade method.
Three glass ceramic green sheets having a thickness of mm are formed.

(2) The glass-ceramic green sheet is processed into a desired shape using a punching die, a punching machine, or the like.
Are formed by punching, and each via hole is filled with an Ag-based conductor material. Ag or Ag- for internal wiring is provided on the front or back surface of the glass ceramic green sheet.
Conductive paste such as Pd, Ag-Pt, Ag-Pd-Pt, and Cu is screen-printed. The printing and drying of the conductor paste is repeated twice on the glass ceramic green sheet to be the surface layer, and a dried conductor paste of two layers is formed, and a desired portion is partially thickened.

(3) The glass ceramic green sheet laminate obtained by laminating the respective glass ceramic green sheets is integrated by thermocompression bonding at 110 ° C. and 100 kg / cm ² .

By the above steps (1) to (3), a glass ceramic green sheet laminate 1 shown in FIG. 2 is obtained. In FIG. 2, a green sheet laminate 1 is a laminate of glass ceramic green sheets 1a, 1b, and 1c, and has wiring layers 2 and 3, a through hole 4, and a partially thickened portion 2a.

(4) The above green sheet laminate 1 is fired in air using an electric continuous belt furnace at 900 ° C. for 20 minutes. When the conductive paste is Cu, the paste is reduced or fired in a neutral atmosphere. As shown in FIG. 3, the glass-ceramic multilayer substrate 10 manufactured as described above includes conductor wiring layers 20 and 30, a through-hole 40, and first and second protrusions 21 and 22. .

(5) After firing, as shown in FIGS. 1, 4 and 5, a desired portion between the first and second convex portions 21 and 22 is irradiated with a laser beam using, for example, a YAG laser or the like. Then, the conductor wiring layer 20 shown in FIG. 3 is divided into first and second conductor patterns 201 and 202, and cut portions 25 and 26 are formed. At this time, by narrowing the spot diameter of the laser beam, the conductor wiring layer 20 is moved between the first and second projections 21 and 22 so that the first and second conductor patterns 2 are formed.
01 and 202 can be easily and accurately divided. Therefore, a fine conductor pattern having a pattern interval of, for example, 100 μm or less can be formed on the surface layer of the glass ceramic multilayer substrate 10. Here, burrs 23 may occur at the cut portions 25 of the first conductor pattern 201 and burrs 24 may occur at the cut portions 26 of the second conductor pattern 202. As shown in FIG. 1, when the thicknesses of the burrs 23 and 24 generated in the cut portions 25 and 26 are t ₃ and t ₄ , t ₃ ≦ 20 μm and t ₄ ≦ 20 μm. Further, assuming that the thicknesses of the first and second convex portions 21 and 22 are t ₁ and t ₂ , 20 μm ≦ t ₁ ≦ 40 μm 20 μm ≦ t ₂ ≦ 40 μm. Therefore, the first and second protrusions 21 and 22 are formed by the first and second conductor patterns 201 and 2 respectively.
02 are provided so as to sandwich the cut portions 25 and 26, and the thickness thereof is equal to or greater than the thickness of the burrs 23 and 24.

(6) As shown in FIG. 6, a resistor layer 50 is screen-printed on the upper surface of the glass-ceramic multilayer substrate 10 using a RuO ₂ -based resistor paste.
An overcoat layer 60 is screen-printed thereon using an overcoat paste. At this time, since the thickness of the first and second convex portions 21 and 22 is equal to or greater than the thickness of the burrs 23 and 24, the printing plate of the resistor paste is protected and the burrs 23 and 24 damage the printing plate. This can prevent the resistor paste from adhering to the cut portions 25 and 26. The RuO ₂ -based resistor paste used here is obtained by adding an organic binder and a solvent to RuO ₂ powder and kneading the resin, and the overcoat paste is obtained by adding an organic binder and a solvent to glass powder and kneading the powder.

(7) The above glass ceramic multilayer substrate 10
The resistor layer 50 and the overcoat layer 60 are baked at a temperature slightly lower than the substrate baking temperature in the step (4) (for example, 890 ° C.) for 10 minutes.

The glass-ceramic multilayer substrate 10 manufactured as described above includes the first and second conductive patterns 20.
Since the resistor paste is prevented from adhering to the cut portions 25 and 26 of 1 and 202, good electrical characteristics can be secured without an electrical short circuit.

In the embodiment of the present invention described above, the first and second projections 21 and 22 have a thickness of 20.
Since it is not less than μm and not more than 40 μm, it is not less than the thickness of the burrs 23 and 24 generated in the cut portions 25 and 26.
Therefore, when printing the resistor paste on the surface layer of the glass-ceramic multilayer substrate 10, the printing plate is surely protected, the printing plate is surely prevented from being damaged by the burrs 23 and 24, and an electrical short circuit is prevented. It can be reliably prevented.

Further, in the present embodiment, the first and second convex portions 21 and 22 are formed by partially thickening the conductor wiring layer 20, so that the first and second convex portions 21 and 22 are formed on the conductor wiring layer 20. 21 and 22 can be easily formed. Therefore, an electrical short circuit can be easily prevented with a simple configuration.

In the embodiment of the present invention described above, printing and drying of the conductor paste are repeated twice to form a two-layer dried conductor paste, and then baked once to form the first conductor paste on the conductor wiring layer 20. Although the first and second convex portions 21 and 22 are formed, in the present invention, printing and drying of the conductor paste are repeated three times or more, and three or more layers of the conductor paste dried body are formed, followed by firing once. The first and second protrusions may be formed on the conductor wiring layer, or the first and second protrusions may be formed on the conductor wiring layer by repeating printing, drying and firing of the conductor paste a plurality of times. It may be formed.

In this embodiment, the present invention is applied to a glass ceramic multilayer substrate composed of a plurality of glass ceramic layers. However, the present invention can be applied to a single glass ceramic substrate. It is needless to say that the various ceramic materials described above can be used.

[Brief description of the drawings]

FIG. 1 shows an embodiment in which the present invention is applied to a glass-ceramic multilayer substrate, and is an enlarged view of a main part of FIG.

FIG. 2 is a schematic cross-sectional view showing one embodiment in which the present invention is applied to a glass ceramic multilayer substrate and showing a green sheet laminate.

FIG. 3 is a schematic cross-sectional view showing one embodiment in which the present invention is applied to a glass ceramic multilayer substrate and showing the glass ceramic multilayer substrate after firing.

FIG. 4 is a schematic sectional view showing an embodiment in which the present invention is applied to a glass ceramic multilayer substrate.

FIG. 5 is a partial view taken in the direction of arrow V in FIG.

FIG. 6 is a schematic cross-sectional view showing an example in which the present invention is applied to a glass ceramic multilayer substrate, and showing a state where a resistor layer and an overcoat layer are formed on a surface layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Green sheet laminated body 2, 3 Wiring layer 10 Glass ceramic multilayer board 20, 30 Conductor wiring layer 21 First convex part 22 Second convex part 23, 24 Burr 25, 26 Cutting part 50 Resistor layer 201 First Conductor pattern 202 Second conductor pattern

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4E351 AA07 BB01 BB31 BB50 FF18 GG01 GG06 5E338 AA01 AA03 AA18 CC01 CD01 CD03 EE31 EE33

Claims (5)

[Claims] 1. A ceramic circuit board having a conductor wiring layer on a surface layer, the cutting portion being formed on the conductor wiring layer and dividing the conductor wiring layer into first and second conductor patterns. And a first and a second protrusion provided on the first and second conductor patterns so as to sandwich the cut portion. 2. The method according to claim 1, wherein the first and second projections have a thickness of 2
2. The ceramic circuit board according to claim 1, wherein the thickness is not less than 0 μm and not more than 40 μm. 3. A method for manufacturing a ceramic circuit board having a conductor wiring layer on a surface layer, the method comprising: forming a first and a second protrusion on the conductor wiring layer; Separating the first and second conductor patterns between the first and second protrusions to form cut portions in the conductor wiring layer. A method for manufacturing a ceramic circuit board, comprising: 4. The ceramic circuit board according to claim 3, wherein said first and second protrusions are formed by partially thickening said conductor wiring layer. 5. The method for manufacturing a ceramic circuit board according to claim 3, wherein the cut portion is formed by irradiating a laser beam.