JP2000044332A - Glass ceramic composition for wiring board and package for housing semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a glass ceramic composition for developing a stable and high coefficient of linear thermal expansion by carrying out baking simultaneously with metallizing wiring at the same cost as that of conventional method, a carrier for mounting a semiconductor element and a package for housing a semiconductor element using the glass ceramic composition. SOLUTION: This glass ceramic composition for a wiring board is obtained by baking at 800 deg.C to 900 deg.C, comprises 35-45 wt.% of SiO2, 4-13 wt.% of B2O3, 17-22 wt.% of Al2O3, 17-22 wt.% of ZnO, 8-18 wt.% of BaO+CaO+MgO+SrO and 0-7 wt.% of TiO2+ZrO2 and has 10-18 ppm/ deg.C coefficient of linear thermal expansion at a room temperature to 300 deg.C. The composition is used for a carrier 2 for mounting a semiconductor element and a package for housing a semiconductor element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass ceramic composition for a wiring board, a carrier for mounting a semiconductor element, and a package for accommodating a semiconductor element, and more particularly to a wiring board having a metallized wiring layer for mounting a semiconductor element. The present invention relates to a glass ceramic composition for a wiring board, a semiconductor element mounting carrier, and a semiconductor element housing package which are suitable and have a linear thermal expansion coefficient close to the high linear thermal expansion coefficient of an organic resin substrate such as a glass-epoxy substrate. .

[0002]

2. Description of the Related Art The degree of integration of semiconductor devices is increasing year by year, and accordingly, the number of electrodes formed on semiconductor devices is also increasing. Generally, a semiconductor element is used while being mounted on a carrier or in a physically protected state while being housed in a sealed package in which the carrier is housed. Increase
As it is, the number of leads of the carrier or package increases.

Conventionally, a quad flat package (QFP) having leads drawn out from four sides has been used to keep the size of the package small.

In order to increase the number of leads while maintaining the miniaturization of the package, a measure has been taken to reduce the distance between the leads (lead pitch). But,
When the lead pitch is reduced to about 0.3 mm, when soldering the package to the motherboard, the solder frequently spreads between the leads and short-circuits between the leads frequently occur. Has reached.

A ball grid array (BGA) connection method or a land grid is used in which pad electrodes arranged in a grid on the bottom surface of a carrier or a package and pad electrodes formed of wiring conductors on a motherboard are connected by soldering or the like. Array (LGA) connection methods are emerging and being used. In the BGA connection method and the LGA connection method, a semiconductor element is mounted on the upper surface of a carrier, which is a wiring board, and a lead electrode on the upper surface of the carrier connected to pad electrodes arranged on the bottom surface is bonded to an electrode on the semiconductor element. Connect with wires. The carrier is sealed with a resin or stored in a package as necessary. The pad electrode on the bottom surface of the carrier or package is connected to the pad electrode made of a wiring conductor on the motherboard by soldering or the like, so that power is supplied to the semiconductor element and input / output electric signals are connected.

A carrier or package used for the BGA connection method or the LGA connection method includes, for example, a wiring board using ceramic. As the material of the ceramic,
In addition to the most widespread alumina ceramics, glass ceramics are widely used.

Next, a method of manufacturing a wiring board using glass ceramic will be described.

A ceramic green sheet is prepared from a mixture of a ceramic filler such as glass powder and alumina powder, a resin, a plasticizer and the like. A through hole is formed in the ceramic green sheet, and A is formed in the through hole.
A via is filled with g paste or the like, and a predetermined conductive pattern is printed. Here, when a multilayer wiring board is formed, a necessary number of the ceramic green sheets are laminated. Further, firing is performed at 800 to 950 ° C. to obtain a wiring board using glass ceramic.

Since the wiring board using this glass ceramic is obtained by firing at a temperature of 950 ° C. or lower, Ag or Au having a low melting point, which cannot be obtained with an alumina substrate requiring a firing temperature of about 1500 ° C. or higher, is used. Can be simultaneously fired with a metal. By being able to use these metals,
There is an advantage that a wiring board having highly conductive wiring can be obtained.

[0010]

The linear thermal expansion coefficient of a conventional ceramic used for a carrier or a package is, for example, the linear thermal expansion coefficient of alumina ceramic is 7 ppm / ° C.
And the linear thermal expansion coefficient of the glass ceramic is 4 to 8 ppm / ° C.
And the linear thermal expansion coefficient of silicon constituting the semiconductor element is close to 3 to 4 ppm / ° C. For this reason, ceramic carriers and packages are suitable for semiconductor elements made of silicon.

However, the linear thermal expansion coefficient of a glass-epoxy substrate, which is most frequently used as a motherboard on which carriers and packages are mounted, is 12 to 18 ppm / ° C., which is higher than the linear thermal expansion coefficient of silicon. This is because in the BGA connection method or LGA connection method that connects a motherboard, which is a glass-epoxy substrate, to a carrier or package made of ceramic, there is no stress relaxation portion called a lead, so the stress due to the difference in coefficient of linear thermal expansion is reduced. Indicates that it is difficult to do.

[0012] Therefore, when the temperature cycle is repeated by turning on and off the power supply of the circuit of the semiconductor element to generate heat, the BGA connection method and the LGA connection method are compared with the connection method using a package such as a QFP having leads. Therefore, there is a high risk that a connection failure will occur. Especially glass ceramics
Since the strength is lower than that of alumina ceramic, there is a problem that a crack occurs under the electrode even with a slight temperature cycle.

It is known that if the solder connection portion of the BGA connection method or the LGA connection method is sealed with a resin such as an epoxy resin, the stress due to the difference in the coefficient of linear thermal expansion is dispersed, so that this problem can be solved. . However, since the number of steps for injecting the resin after the solder connection increases, there is a problem that the cost increases.

On the other hand, the purpose of protecting the wiring of the semiconductor element is to bond the semiconductor element and the carrier with a resin or the like, or to seal the wiring portion with a resin or the like in the same manner as described above. For this reason, sufficient strength is generated against stress due to the difference in linear thermal expansion coefficient.

Therefore, ceramics having a linear thermal expansion coefficient closer to the linear thermal expansion coefficient of the glass-epoxy resin constituting the motherboard, rather than the linear thermal expansion coefficient of silicon constituting the semiconductor element, are used for a carrier or a package. It is conceivable to solve the above problems.

Glass ceramic having a high coefficient of linear thermal expansion is obtained by adding a large amount of alkali or PbO to glass powder of the material.
Or a crystal having a high expansion coefficient is precipitated. However, there is a problem that a large amount of alkali deteriorates the insulating property of the carrier as the wiring substrate. Also, Pb
The use of O has environmental problems, such as causing adverse effects on the environment due to waste. Thus, by precipitating a crystal having a high coefficient of expansion, a glass ceramic having a high coefficient of linear thermal expansion can be obtained.

First, in order to realize simultaneous firing with the metallized wiring, the melting point (9
62 ° C.), the melting point of Cu (1085 ° C.) or Au (1
(064 ° C.) or lower.

During the firing process, the temperature of the glass powder of the material reaches the softening temperature, and the temperature of the molten glass reaches the crystallization temperature of the crystal having a high expansion coefficient. When the precipitation of the crystal having the expansion coefficient starts, the densification of the glass ceramic by firing is hindered. That is, the difference between the softening temperature of the material and the crystallization temperature needs to be large.

Further, since the linear thermal expansion coefficient of the obtained glass ceramic varies depending on the amount of crystals having a high expansion coefficient to be precipitated, it is necessary to strictly control the particle diameter of the glass powder of the material and to strictly control the firing temperature. There were issues that needed to be managed.

Accordingly, the present invention provides a glass-ceramic composition exhibiting a stable and high coefficient of linear thermal expansion by performing simultaneous firing with metallized wiring at the same cost as conventional ceramics, and the glass-ceramic composition and semiconductor element. It is an object of the present invention to provide a mounting carrier and a semiconductor element storage package.

[0021]

According to the present invention, Ag or Au is used.
In order to co-fire with a metallized wiring having high conductivity such as, for example, a glass ceramic composition capable of obtaining a predetermined coefficient of linear thermal expansion by firing at 800 to 900 ° C. was specified.

That is, the glass ceramic composition for a wiring board of the present invention is obtained by firing at 800 to 900 ° C.
In _{weight%, SiO 2: 35~45, B} 2 O 3: 4~13,
_{Al 2 O 3: 17~22, ZnO} : 17~22, BaO +
CaO + MgO + SrO: 8 to 18, TiO ₂ + Zr
O ₂ : 0 to 7, having a linear thermal expansion coefficient from room temperature to 300 ° C. of 10 to 18 ppm / ° C.

The SiO ₂ preferably contains 40 to 45% by weight.

B ₂ O ₃ preferably contains 6 to 10% by weight.

BaO + CaO + MgO + SrO preferably contains 9 to 14 by weight.

TiO ₂ + ZrO ₂ preferably contains 0 to 5 by weight.

Further, the carrier for mounting a semiconductor element of the present invention comprises a substrate layer comprising the glass ceramic composition for a wiring substrate, a metallized wiring on a surface of the substrate layer, and an electrode for mounting a semiconductor element on one surface. And an electrode to be mounted on the other surface.

Alternatively, a plurality of substrate layers made of the glass-ceramic composition for a wiring substrate, metallized wiring between layers and on the surface of the substrate layer, a semiconductor element mounting electrode on one surface, and a metallized wiring on the other surface. And an electrode to be mounted.

Further, the package for accommodating a semiconductor element of the present invention comprises a substrate layer comprising the glass ceramic composition for a wiring substrate, a metallized wiring on a surface of the substrate layer, and an electrode for mounting a semiconductor element on one surface. , A semiconductor element mounted on the semiconductor element mounting electrode, and a connection line with the semiconductor element are housed therein, and pad electrodes are arranged on the bottom surface.

Alternatively, a multi-layer wiring board having a plurality of substrate layers made of the glass ceramic composition for a wiring substrate, metallized wiring between layers and surfaces of the substrate layers, and electrodes for mounting semiconductor elements on one surface. A semiconductor element mounted on the semiconductor element mounting electrode and a connection line with the semiconductor element are housed therein, and pad electrodes are arranged on the bottom surface.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been developed in order to enable simultaneous firing with metallized wiring made of Ag or Au.
The composition of a glass ceramic which was sufficiently densified at ~ 900 ° C and precipitated a crystal having a high coefficient of expansion such as quartz or cristobalite to exhibit a high coefficient of linear thermal expansion was specified.
That is, the glass ceramic composition for a wiring board of the present invention is obtained by firing glass powder at 800 to 900 ° C.,
In _{weight%, SiO 2: 35~45, B} 2 O 3: 4~13,
_{Al 2 O 3: 17~22, ZnO} : 17~22, BaO +
CaO + MgO + SrO: 8 to 18, TiO ₂ + Zr
O ₂ : 0 to 7, having a linear thermal expansion coefficient from room temperature to 300 ° C. of 10 to 18 ppm / ° C.

The reasons for specifying each composition range will be described below.

SiO ₂ is indispensable for forming a glass-ceramic network structure, and is a supply source for depositing crystals such as quartz and cristobalite. Therefore S
If iO ₂ is less than 35%, the linear thermal expansion coefficient of the glass ceramic composition does not increase.

On the other hand, if the content of SiO ₂ is more than 45%, the softening point becomes too high, so that densification cannot be achieved sufficiently at a firing temperature of 800 to 900 ° C. More preferably, 4 in the above range
It is in the range of 0-45%.

B ₂ O ₃ is used as a flux component in producing glass powder. If it is less than 4%, the material becomes difficult to dissolve. Even if it can be made into a glass powder, the crystallization temperature during the firing process is too high. On the other hand, if it exceeds 13%, the acid resistance of the fired glass ceramic decreases, and the glass ceramic is easily eroded by the plating solution. Preferably it is in the range of 6 to 10%.

Al ₂ O ₃ improves the chemical resistance of the fired glass ceramic and also improves the garnitite Al ₂ O ₃ during firing.
O ₃ · ZnO is precipitated to increase the content of SiO ₂ in the glass ceramic, thereby promoting the precipitation of quartz and cristobalite.

However, if the content of Al ₂ O ₃ is more than 22%, the softening temperature of the glass powder becomes too high.
The range is 2%.

ZnO is used as a flux component during the production of glass powder. If it is less than 17%, the material becomes difficult to dissolve. On the other hand, if it is more than 22%, SiO2 will be generated during the firing process.
Willemite 2ZnO.SiO ₂ with low expansion rate combined with ₂
(Linear thermal expansion coefficient μ = 3.2 ppm / ° C.), which is not preferable.

BaO + CaO + MgO + SrO is added to improve the melting property during the production of glass powder. 8%
If less, devitrification tends to occur during the production of glass powder.
If it is more than 8%, quartz and cristobalite do not precipitate during the firing process. More preferably, it is in the range of 9 to 14%.

Although TiO ₂ + ZrO ₂ is not essential, it is 7%
By adding the following, the chemical resistance of the fired glass ceramic is improved, and the crystals are easily precipitated stably. It is more preferably at most 5%.

The glass-ceramic composition of the present invention has the above composition range, and a carrier for mounting a semiconductor element as a multilayer wiring board using the glass-ceramic composition is produced, for example, as follows.

A resin, a plasticizer, and a solvent are added to a glass powder having an average particle diameter of 1 to 2 μm and in the above composition range, and mixed with a ball mill for 2 hours to obtain a slurry. As the resin, a butyral resin, an acrylic resin, or the like is used. As the plasticizer, dibutyl phthalate, dioctyl phthalate, or the like is used. As the solvent, alcohol, methyl ethyl ketone, toluene or the like is used.

The slurry obtained is degassed in vacuum and, at the same time, the viscosity is adjusted to 10,000 to 30,000 cps, and formed into a green sheet by a generally known doctor blade method.

Next, holes for via holes are made in the green sheet, and Ag paste or the like is filled. As a filling method, screen printing or press-fitting is used. Further, a circuit is formed by screen printing of an Ag paste or the like. Next, a predetermined number of green sheets on which circuits are formed are stacked and integrated by thermocompression bonding. The conditions for thermocompression bonding need to be adjusted depending on the type and amount of the resin used, but are generally 70 to 90 ° C. and 50 to 200 kg / cm ² . The laminate is heated, the resin is sufficiently thermally decomposed at a temperature of 300 to 500 ° C., and fired at a temperature of 800 to 900 ° C. Thus, a carrier for mounting a semiconductor element, which is a multilayer wiring board, is manufactured.

[0045]

EXAMPLES In order that the components shown in Table 1 have a predetermined composition,
Mix the raw materials of each component, put them in a platinum crucible,
The mixture was heated at 1500 ° C. for 2 hours to be melted and poured into water to obtain a glass. At this time, when SiO ₂ is more than 45%, when B ₂ O ₃ is less than 4%, Al ₂ O ₃ is 22%.
When the content is larger, when the content of ZnO is less than 17%, the oxides of alkaline earth metals (BaO, CaO, MgO,
In any of the glass powders in which the sum of O) is less than 8% and the content of TiO ₂ + ZrO ₂ is more than 7%, the glass does not melt or devitrify at 1500 ° C. even if other components are within the range. . Those that did not melt and that were devitrified were discarded.

The vitrified composition was coarsely pulverized by a stamp mill and pulverized by a ball mill so that the average particle diameter became 1 to 2 μm. Table 1 shows the composition of the obtained sample.

Examples A to H show examples of the present invention, and comparative examples I to M having deviated composition ranges are also shown for reference.

9 parts by weight of polyvinyl butyral, 7 parts by weight of diisobutyl phthalate, 1 part by weight of oleic acid, 40 parts by weight of isopropyl alcohol, and 20 parts by weight of methyl ethyl ketone were added to 100 parts by weight of each glass powder.
A slurry was prepared by mixing with a ball mill for 24 hours, and a green sheet having a thickness of 200 μm was obtained by a doctor blade method.

Each of these green sheets was processed into a predetermined shape corresponding to the following test items, and was processed at 500 ° C. for 2 hours.
After holding for a period of time, sintering was performed at a firing profile of holding at 900 ° C. for 20 minutes.

[Bending strength test] Seven green sheets were laminated on each of the samples of the examples and comparative examples, and the length was 50 m.
m, a sample of a sintered body having a width of 10 mm was obtained. The breaking strength of this sample was determined by a three-point bending test.

[Denseness test] The cross section of the sample fractured by the bending strength test was observed, and the presence or absence of continuous pores was examined.
If no pores were observed, it was judged as OK.

[Linear coefficient of thermal expansion test] In each of Examples and Comparative Examples, seven green sheets were laminated, and the length was 50 mm.
A sample of a sintered body having a width of 10 mm was obtained. 5m diameter from this sample
m, a sample of 7 mm in length is cut out, and 3
The average coefficient of linear thermal expansion up to 00 ° C. was determined.

[Acid Resistance Test] In each of Examples and Comparative Examples, seven green sheets were laminated, and the length was 50 mm and the width was 1 mm.
A sample of a 0 mm sintered body was obtained. This sample was immersed in a hydrochloric acid aqueous solution of pH 2 for 30 minutes, washed with water, dried, and rubbed with the tip of tweezers.

[Reliability Test] In order to test the connection reliability with the printed board, the following carrier wiring board was prototyped and mounted on the printed board. FIG. 2 shows a cross-sectional view of the mounting state. FIG. 1 is an enlarged sectional view.

In each of the examples and comparative examples, via holes having a diameter of 100 μm were formed in a green sheet in a 17 × 17 lattice at a pitch of 1 mm, and an Ag paste was filled into the green sheets to form vias 4. The four green sheets with vias are laminated, and correspond to the position of the outermost via.
The connection pad 5 was provided by printing a circular pattern having a diameter of 600 μm using an Ag paste. This laminate is
After holding at 00 ° C. for 2 hours, firing was performed at a firing profile of holding at 900 ° C. for 20 minutes. A 3 μm thick Ni plating and a 0.1 μm thick
Thick Au plating was sequentially applied.

On the other hand, a connection pad 3 made of copper foil is formed at a position corresponding to the connection pad 5,
A glass-epoxy substrate 1 having a linear thermal expansion coefficient up to 50 ° C. of 18 ppm / ° C. was prepared.

The connection pads 3 on the printed circuit board 1
A solder paste 6 having a 37Pb / 63Sn composition was printed thereon, and the carrier wiring board 2 was aligned and mounted. Next, the solder paste 6 was melted under the condition of a peak temperature of 230 ° C. for 5 to 10 seconds, and the connection pads 5 of the carrier wiring board 2 and the connection pads 3 of the printed board 1 were connected.

Next, a temperature cycle in which 10 samples each having the carrier wiring board 2 mounted on the printed board 1 as described above are held at -55 ° C. and 100 ° C. for 30 minutes, respectively, is performed at 1000 cycles.
Repeated up to times. The electrical resistance between the connection pad 5 of the carrier wiring board 2 and the connection pad 3 of the printed circuit board 1 is measured every 100 temperature cycles, and the number of cycles when the average value of the electrical resistance increases by 20% is determined. I asked. Table 1 shows the results.

[0059]

[Table 1]

Examples A to H listed in Table 1 and Comparative Examples I to
M could be melted at 1500 ° C. or lower unlike alumina ceramic, and was sufficiently densified by firing at 900 ° C. The glass ceramic after firing had sufficient bending strength.

However, as apparent from Table 1, B ₂ O ₃
Comparative Example K, which has a large amount, had poor acid resistance and was unsuitable for electrode plating.

In Comparative Example I, BaO + CaO + MgO
+ SrO is large, Comparative Example J is low in Al ₂ O ₃ , Comparative Example K is high in B ₂ O ₃ , Comparative Example L is high in ZnO, and Comparative Example M is low in SiO ₂ . Thus, even if one component is out of the range of the present invention, the coefficient of linear thermal expansion is low.

As a result of X-ray analysis, quartz or cristobalite was detected as a crystal phase in the glass ceramic composition having a high coefficient of linear thermal expansion.

As the coefficient of linear thermal expansion of the carrier for mounting a semiconductor element or the package for mounting a semiconductor element is closer to the coefficient of linear thermal expansion of the motherboard, various connections can be made with higher reliability. The linear thermal expansion coefficients of Examples A to H are 11 to 18 ppm /
As shown in the graph, the linear thermal expansion coefficient of the ordinary glass-epoxy substrate can be almost matched with 12 to 18 ppm / ° C., and the composition can be selected according to the linear thermal expansion coefficient of the motherboard used. Possible and preferred.

Actually, as shown in Table 1, the number of cycles when the average value of the electric resistance increases by 20% is significantly larger in Examples A to H than in Comparative Examples I to M.

[0066]

As described above, by setting the composition range of the present invention, a glass ceramic having a high linear expansion coefficient can be obtained. Further, by using the lath ceramic, a semiconductor element mounting carrier and a semiconductor element housing package which can be manufactured by a conventional method and have high connection reliability with a printed circuit board can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a connection between a carrier and a glass-epoxy substrate.

FIG. 2 is an enlarged sectional view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass-epoxy board 2 Carrier 3 Copper foil connection pad 4 Ag via 5 Ag connection pad 6 Solder

Claims (11)

[Claims] 1. The composition according to claim 1, wherein the weight percentage of SiO ₂ : 35-45, B ₂ O
_{3: 4~13, Al 2 O 3} : 17~22, ZnO: 17~
22, BaO + CaO + MgO + SrO: 8 to 18, T
A glass ceramic composition for a wiring board, comprising iO ₂ + ZrO ₂ : 0-7. 2. The glass ceramic composition for a wiring board according to claim 1, wherein the glass ceramic composition is obtained by firing at 800 to 900 ° C. 3. The thermal expansion coefficient from room temperature to 300 ° C. is 10 to 18 ppm / ° C.
Or the glass-ceramic composition for a wiring board according to 2. 4. The glass ceramic composition for a wiring board according to claim 1, wherein the SiO ₂ contains 40 to 45% by weight. 5. The glass-ceramic composition for a wiring board according to claim 1, wherein B ₂ O ₃ contains 6 to 10% by weight. 6. The glass-ceramic composition for a wiring board according to claim 1, wherein BaO + CaO + MgO + SrO contains 9 to 14 by weight. 7. The glass-ceramic composition for a wiring board according to claim 1, wherein TiO ₂ + ZrO ₂ contains 0 to 5 by weight%. 8. A substrate layer comprising the glass-ceramic composition for a wiring substrate according to claim 1, a metallized wiring on a surface of the substrate layer, and a semiconductor element mounting electrode on one surface. And a carrier for mounting a semiconductor element, comprising a wiring board having a mounting electrode on the other surface. 9. A plurality of substrate layers comprising the glass-ceramic composition for a wiring substrate according to any one of claims 1 to 7, and metallized wiring between layers of the substrate layer and on a surface thereof.
A semiconductor element mounting carrier comprising a multilayer wiring board having a semiconductor element mounting electrode on one surface and a mounting electrode on the other surface. 10. A substrate layer comprising the glass-ceramic composition for a wiring substrate according to claim 1, a metallized wiring on a surface of the substrate layer, and a semiconductor element mounting electrode on one surface. A semiconductor device housing package in which a wiring board having the above, a semiconductor device mounted on the semiconductor device mounting electrode, and a connection line with the semiconductor device are housed inside, and pad electrodes are arranged on the bottom surface. 11. A plurality of substrate layers comprising the glass-ceramic composition for a wiring substrate according to claim 1, metallized interconnections between and between the substrate layers, and a semiconductor on one surface. A semiconductor element storage package in which a multilayer wiring board having element mounting electrodes, a semiconductor element mounted on the semiconductor element mounting electrodes, and connection lines with the semiconductor elements are housed inside, and pad electrodes are arranged on the bottom surface. .