JP3059658B2 - High-density circuit wiring board, manufacturing method thereof, and multi-chip module using high-density circuit wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-density circuit wiring board suitable for mounting a high-density semiconductor integrated circuit chip, a method for manufacturing the same, and a multichip module using the high-density circuit wiring board.

[0002]

2. Description of the Related Art In recent years, technologies related to the semiconductor industry have been remarkably developed, and the degree of integration of semiconductor circuits has been dramatically improved. If the degree of integration of the semiconductor circuit is improved, the size of the embedded device can be reduced and the driving power can be reduced, which is convenient for handling. Further, when a high-density semiconductor integrated circuit (LSI) chip is highly integrated, a wiring distance between gates in the LSI chip is shortened, and a signal transmission delay generated according to the wiring distance is reduced, so that the LSI chip is driven at high speed. be able to.

However, at present, even if the speed of the LSI chip is increased, the signal transmission delay of the high-density wiring board on which the LSI chip is mounted becomes a bottleneck, and the speed of the system incorporating the LSI element cannot be increased as expected. There is.

Further, as the density of LSI chips has increased and the chip size has increased, the incidence of defective products in the chip manufacturing process has drastically increased and the yield has deteriorated, making it difficult to provide inexpensive LSI chips. There is also the problem of becoming.

The degree of integration of the LSI chip is improved by increasing the area of the Si substrate on which the LSI chip is formed, or by adopting a so-called fine processing technique for reducing the line width or interval of the wiring on the Si substrate. However, it is extremely difficult to avoid a reduction in yield due to the increase in the density of LSI chips by any of the methods.

Accordingly, recently, as a method for improving the system speed by eliminating a factor that hinders the improvement of the driving speed of the system incorporating the LSI chip and improving the manufacturing yield, a relatively small-scale LSI is used. A so-called multi-chip module (MCM), in which a plurality of chips are mounted on a circuit wiring board to create a circuit having a function equivalent to that of a large-scale integrated circuit, has attracted attention.

The MCM is composed of a plurality of LSI bare chips (unsealed LSI chips) on a high-density wiring circuit board.
Are mounted directly, wiring is connected to the LSI bare chip, and then packaging is performed.

As such an MCM, an MCM using a high-density printed wiring board such as a conventionally known glass epoxy is used.
CM-L, MCM-C using a ceramic substrate such as alumina or aluminum nitride, MCM-D having an organic thin film formed on a silicon substrate or a metal substrate, or MCM-C having a silicon dioxide dielectric layer formed on a silicon substrate. Known are Si, MCM-D / C in which a thin film layer is formed on a ceramic substrate, and the like.

The MCM has been attracting attention as a method for improving the driving speed and the production yield of a system incorporating an LSI chip, but in order to exhibit its original characteristics, the following required characteristics are required. Needs to be satisfied.

[0010] (1) In the MCM, the bare chip of the LSI is in direct contact with the high-density wiring circuit board. However, the LSI chip generates a large amount of heat due to an increase in power consumption due to high-speed driving.
The material constituting the high-density wiring circuit board constituting the MCM is required to have high thermal conductivity in order to obtain good heat dissipation.

(2) If the thermal expansion coefficients of the high-density wiring circuit board and the LSI chip are significantly different, the chip may be mechanically broken by thermal stress generated by heat generation of the chip when driving the integrated circuit. Therefore, it is required that the coefficient of thermal expansion of the material forming the high-density wiring circuit board forming the MCM is equivalent to that of the silicon forming the LSI chip.

(3) If the dielectric constant of the high-density wiring circuit board is large, the parasitic capacitance of the wiring on the high-density wiring circuit board increases,
Since the signal transmission characteristics of the circuit on the wiring deteriorate and high-speed driving becomes difficult, the material forming the high-density wiring circuit board is required to have a low dielectric constant.

(4) Further, the high-density wiring circuit board is an LSI
Since various types of machining are performed to mount the chip, high mechanical strength is required in order to withstand this and to hold the element structurally.

The glass epoxy material used in the MCM-L is easy to handle and inexpensive, but is unsuitable for high-speed and high-density MCM because of its low thermal conductivity and poor heat dissipation. Although ceramic substrates such as alumina and aluminum nitride, which constitute the substrate material of MCM-C and MCM-D / C, have good heat dissipation properties and are suitable in terms of strength, they have a different coefficient of thermal expansion from that of silicon. It is difficult to apply to high power devices due to the possibility of cracks in the substrate or chip at the time of warming, and because the dielectric constant is relatively large, the wiring capacity increases and it is not suitable for ultra-high speed driving There's a problem. Furthermore, in MCM-Si using a circuit wiring substrate in which an insulating layer is formed on a single crystal silicon substrate for semiconductor production, thermal conductivity and thermal expansion coefficient are as follows.
Although it has the best characteristics as a substrate that constitutes the MCM, single crystal silicon is difficult to machine, and chipping due to cutting etc. occurs, so the yield is low, and the bending strength of the single crystal silicon itself is low. The MCM using this has a problem of poor reliability.

[0015]

SUMMARY OF THE INVENTION The present invention relates to the aforementioned M
Another object of the present invention is to provide a high-density circuit wiring board that satisfies the required characteristics of a CM, a multi-chip module using the same, and a method of manufacturing the same.

[0016]

According to the present invention, there is provided a high-density circuit wiring board comprising a plate of granular silicon in which silicon particles are bonded to each other.
And it is characterized in that consisting of Jo sintered body.

As the granular silicon which is a raw material for manufacturing the high-density circuit wiring board of the present invention, single crystal silicon, amorphous silicon, polysilicon and the like can be used.
Among them, polysilicon is easily available and has high bending strength of the sintered body, and therefore is particularly suitable as the material for the high-density wiring circuit board of the present invention. When polysilicon is used as the raw material, a part of the microstructure of the granular polysilicon raw material remains in the sintered plate-like body, which can be confirmed microscopically.

The high-density circuit wiring board of the present invention and the MC using this
M and details of their manufacturing methods will be described. However, the high-density circuit wiring board of the present invention is not limited to the one using granular polysilicon, and is similarly applied to granular single crystal silicon and granular amorphous silicon. It is possible. Since the granular polysilicon used in the present invention is also used as a material for manufacturing a silicon single crystal for a semiconductor, a conventional semiconductor manufacturing technology can be diverted, and the raw material can be easily obtained. Very high purity substrates can be manufactured. The granular polysilicon has a particle size distribution of 100 μm or less, preferably 50 μm or less, and has an average particle diameter of 50 μm to 10 μm. Such granular polysilicon is manufactured by a method of pulverizing bulk polysilicon or a method of evaporating silicon followed by rapid cooling to obtain a granular aggregate. The pulverization of the polysilicon bulk can be performed using a conventional powder production apparatus for producing metal powder, such as a vibration mill or a jet mill. The silicon oxide insulating film is an important factor for the dielectric characteristics. However, since the silicon oxide insulating film is formed by oxidizing the surface of the substrate, high-purity granular polysilicon is preferably used. A grade having an impurity concentration of 100 ppm or less corresponding to the purity of polysilicon for single crystal production is preferable.

The granular polysilicon thus obtained is subjected to pressure molding, heating and sintering as described below to obtain a high-density wiring circuit board.

First, granular silicon is filled into a mold made of a material which is non-reactive with silicon and which can withstand a high temperature of 1400 ° C. or more, and calcined by hot pressing in an inert atmosphere such as nitrogen or argon. By doing so, a high-density wiring circuit board used in the present invention can be manufactured.

The pressing conditions are 200 kg / cm ² to 300 kg / cm ²
Is desirable. If the pressure is below this range, the packing density of the granular polysilicon decreases, and the required strength cannot be obtained. Further, even if it exceeds this range, the effect of improving the properties of the plate-shaped granular silicon sintered body cannot be obtained, which is economically disadvantageous.

The firing temperature must be a temperature at which the granular silicon is softened or partially melted to cause plastic deformation, and is preferably in the range of 1000 ° C. to 1400 ° C., and more preferably in the range of 1300 ° C. to 1400 ° C.

As the molding material, materials such as carbon, molybdenum, and a combination of carbon and molybdenum can be used.

The high-density circuit wiring board of the present invention has a density of 2.0
g / cm ³ to 2.3 g / cm ³ , and its surface is L
Various machining can be performed for mounting the SI chip.

The thickness of this high-density circuit wiring board is
It is determined from the mechanical strength of the module, but is generally preferably in the range of 1 mm to 1 cm, more preferably in the range of 2 mm to 5 mm. The reason is that if it is less than 1 mm, the required strength cannot be obtained, and it is easily broken by bending. On the other hand, if it exceeds 1 cm, not only the heat radiation property is reduced, but also the cost is increased because a large amount of material is used, which is not desirable.

If the desired high-density circuit wiring board has a small thickness and the required flexural strength cannot be obtained, the high-density circuit having high bending strength is reinforced with a cloth material made of an inorganic material. A wiring board can also be obtained. Such a reinforced granular silicon sintered body, for example, arranges granular silicon in a layer in a mold, arranges an inorganic material-made cloth thereon, and further arranges granular silicon thereon in a layer, They can be obtained by pressurizing and heating them and firing them integrally. Examples of such a cloth made of an inorganic material include ceramic fiber, woven fabric or nonwoven fabric made of inorganic fiber such as glass fiber or metal fiber, and in particular, woven fabric made of ceramic fiber is preferred because of its easy handling and availability. preferable.

In the multichip module of the present invention, an insulating coating layer is formed on the surface of the plate-like granular silicon sintered body thus obtained, and a metal wiring layer of a required circuit is formed on the surface. A plurality of LSI bare chips are mounted, and a metal wiring layer and the LSI bare chips are electrically connected to form a module.

The MCM of the present invention and its manufacturing method will be described in detail with reference to the drawings.

FIG. 1 is a diagram schematically showing an embodiment of the MCM of the present invention. In FIG. 1, an insulating coating layer 2 is formed on a substrate 1 made of a plate-like granular polysilicon sintered body. Then, a plurality of LSI bare chips 3 are joined to the insulating coating layer via a brazing material 4 on the insulating coating layer. Further, a circuit wiring 5 made of a metal thin film is formed on the insulating coating layer, and the LSI bare chip 3 and the circuit wiring 5 are electrically connected by bond wires 6.

The wiring pattern of the present invention may be a single-layer wiring as shown in FIG. 1, but as shown in FIG. 2, a plurality of circuit wirings 5a, 5a are provided via a plurality of insulating coating layers 2a, 2b.
holes (via holes) formed in b and formed in the insulating coating layer
7 may be filled with an electrically conductive material to connect the wiring layers to each other to form a multilayer wiring board. In FIG. 2, portions common to FIG. 1 are denoted by common reference numerals, and redundant description is omitted. In the present invention, the insulating coating layer formed on the surface of the plate-like granular polysilicon sintered body can be formed by oxidizing the surface of the polysilicon sintered body to form a silicon dioxide layer. In this step, an oxidation technique usually employed in a semiconductor integrated circuit manufacturing technique can be used. Since it is necessary to reduce the wiring capacity of the insulating coating layer as much as possible, it is desirable that the thickness of the oxide film is large, and it is usually desirable that the thickness be in the range of 300 nm to 1000 nm. If the thickness is smaller than this, the capacity of the wiring increases and the signal transmission delay increases, which is unsuitable for high speed operation. On the other hand, if the film thickness is larger than this, it takes a long time to form the film, resulting in an increase in manufacturing cost. For these reasons, it is necessary to set the dielectric layer thickness in this range.

In a multilayer wiring board, the insulating coating layer can be formed of an organic thin film. As such an organic thin film, an insulating material having excellent heat resistance and electrical insulation such as polyimide is suitable.As a method for forming the organic thin film, an organic solvent solution of the insulating material is applied and dried to form a thin film. A well-known method such as a method of coating or a method of depositing and coating an organic material can be employed.

As a material for forming the metal wiring layer provided on the insulating coating layer, a high-melting metal material such as tungsten or molybdenum, a low-resistance metal material such as gold, silver, copper, palladium or aluminum or an alloy thereof is used. Can be used.

The metal wiring layer provided on the insulating layer is formed by selectively etching a metal thin film layer formed by vapor deposition, plating, or attaching a metal thin film, or selectively on the insulating layer of the substrate. It can be formed by a plating method or the like.

The thickness of the metal wiring layer is 0.5 μm to 10 μm.
It is preferably in the range of μm. Below this range, disconnection is likely to occur during the formation of the wiring layer, which not only lowers the production yield, but also increases the risk of disconnection during use. On the other hand, if the thickness of the metal wiring layer is larger than this, it takes a long time to form the metal wiring layer, so that a reduction in manufacturing cost cannot be expected.

The line width of the wiring layer is 1 μm to 20 μm.
Is desirable. Below this range, fine processing is difficult and disconnection is likely to occur during the manufacturing process, further increasing the resistance and causing heat generation. In addition, if it exceeds this range, high integration becomes impossible.

Next, LS is placed on the substrate obtained in the above step.
The I bear chip is mounted. The mounting of LSI bare chip
After bonding the chip on the board via brazing material, LSI
This is performed by electrically connecting the bare chip and the metal wiring layer on the substrate by a wire bonding technique.

The device thus obtained is packaged. As the package, a well-known package such as a ceramic package, an organic resin package, and a metal can package can be used, but it is necessary to use a package technology that does not impair heat dissipation. As such a package, a ceramic material package or a metal can package is desirable.

In the above embodiment, an example was described in which granular polysilicon was used as granular silicon.
The present invention is not limited to such an embodiment, and it is also possible to use single crystal silicon or amorphous silicon as granular silicon.

[0039]

The plate-shaped granular silicon sintered body used in the present invention is:
Not only does it have high thermal conductivity and excellent heat dissipation as well as aluminum nitride, but also has no thermal destruction when the temperature rises because its thermal expansion coefficient is equivalent to that of an LSI chip mounted on a substrate. In addition, the dielectric constant of the substrate is lower than that of a ceramic rare substrate such as aluminum nitride, and the wiring capacity can be reduced. Therefore, the substrate is suitable for ultra-high-speed driving. The reliability has been greatly improved.

[0040]

【Example】

(Example 1) As shown in Table 1, three types of granular silicon having different average particle sizes were prepared. These samples have an average particle size of 1
This is obtained by putting lump of 2 mm bulk polysilicon into a vibrating mill and operating the mill for a required time to pulverize. The average particle size of each sample was approximately 7 μm, and the particle size distribution was 30-0.1 μm. These samples are 300mm in diameter,
The mixture was filled in a steel mold having a thickness of 100 mm, kept at a pressure of 300 kg / cm ² and a temperature of 1300 ° C. for 4 hours by using a hot press and fired. The firing was performed in a non-oxidizing atmosphere of 10 to 4 torr.

Table 1 also shows the characteristics of the obtained sintered body.
In addition, the results of measuring the characteristics of a silicon single crystal substrate and an aluminum nitride substrate having the same dimensions as a comparative example are also shown.

As is clear from the table, the granular polysilicon sintered body of this embodiment has a bending strength of 166 MPa, which is about 150% improved from the silicon single crystal. Also, it can be seen that the same strength is obtained as compared with aluminum nitride.

[0043]

[Table 1] Example 2 Using the same sample as in Example 1, a sintered plate was manufactured under the same conditions as in Example 1 except that a heating pretreatment was performed prior to the firing step. In this embodiment, 1200
℃ 10-4tor 3 hours after pre-heating, pressure 300kg / cm
^2. Heating and firing at 1300 ° C and 10 to 4 torr for 4 hours. The properties of the obtained sintered plate were equal to those of Example 1. The plate-shaped granular silicon sintered body that has been subjected to the heating pretreatment has a higher bending strength than the plate-shaped granular silicon sintered body that has not been subjected to the heating pretreatment, and the impurities contained in the silicon raw material have been subjected to the heating pretreatment. It was found that sinterability was improved because of volatilization, and high density was achieved and high purity was achieved.

Example 3 Next, the sintered polysilicon substrate obtained in Example 2 was heated at 500 ° C. in an oxygen-containing steam atmosphere.
By heating for 3 hours, a silicon oxide film having a thickness of 10 μm was formed on the surface. A 2 μm copper film was formed on the thus formed insulating coating layer by plating. Then, after an etching resist film was coated on the copper film to form a desired pattern, it was immersed in an etching solution at 50 ° C. for 2 hours to obtain a high-density circuit wiring board having a required pattern.

At a required portion of the obtained high-density circuit wiring board,
A 10 mm square Si bare chip was connected via a brazing material. After that, use a wire bonder to make the LSI
After the bare chip and the wiring on the circuit board are electrically connected by a bonding wire, the obtained circuit element is sealed using a package housing formed of ceramic, and the MCM is mounted.
It was an element.

When 10 elements were subjected to a heating acceleration test for 100 hours in a constant temperature chamber at 100 ° C. and 60% humidity, no abnormalities were observed except that one chip became inoperable.

On the other hand, the same MCM as that of the present invention except that an aluminum nitride substrate was used was prepared for 10 pieces, and a heating and acceleration test was conducted at the same time. As a result, six chips became inoperable.

[0048]

The plate-like granular silicon sintered body used for the high-density circuit wiring board of the present invention has a high thermal conductivity equivalent to that of aluminum nitride, and is not only excellent in heat dissipation, but also Since the coefficient of thermal expansion is equal to that of an LSI chip mounted on a substrate, there is no thermal destruction when the temperature rises. Also, the flexural strength of the substrate is much higher than that of silicon single crystal, and the dielectric constant is smaller than that of other ceramic substrates such as aluminum nitride, so that the MCM can be driven at high speed and the characteristics and reliability of the MCM can be increased. Has improved.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing one embodiment of the present invention.

FIG. 2 is a sectional view schematically showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate which consists of plate-shaped granular polysilicon sintered compact 2, 2a, 2b ... Insulation coating layer 3 ... LSI bare chip 4 ... Brazing material 5, 5a, 5b ... Circuit wiring 6 ... Bond wire 7 ... Hole (via hole)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05K 1/03 C04B 35/14

Claims (10)

(57) [Claims] 1. A high-density circuit wiring board comprising a plate-like sintered body of granular silicon in which silicon particles are bonded to each other . 2. An inorganic material-made cloth and the inorganic material-made cloth
Baking granular silicon arranged in layers in contact with the body
Become a granular silicon plate with silicon particles bonded together
Sintered body and cloth body made of inorganic material integrated with this plate-shaped sintered body
High density circuit wiring board, characterized by comprising a. 3. An insulating coating layer is formed on the surface of a substrate made of a plate-like sintered body of granular silicon in which silicon particles are bonded to each other , a metal wiring layer of a required circuit is formed on the surface, and a plurality of LS bare chips are mounted. Then, the metal wiring layer and each LS
マ ル チ A multi-chip module characterized by being electrically connected to a bare chip. 4. The high-density circuit wiring board according to claim 1, wherein the granular silicon is granular polysilicon. 4. The multichip module according to claim 3, wherein the granular silicon is granular polysilicon. 5. Filling a mold with granular silicon and depressurizing
Under the atmosphere, the temperature is 1300-1400 ° C, the pressure 200-
A method for producing a high-density circuit wiring board, comprising hot-pressing at 300 kgf / cm ² for 1 to 5 hours. 6. A hot press under a reduced pressure atmosphere of 10 torr or less.
6. The method for manufacturing a high-density circuit wiring board according to claim 5, wherein top pressing is performed . 7. Hot pressing in a non-oxidizing reduced pressure atmosphere
7. The method of manufacturing a high-density circuit wiring board according to claim 5, wherein: 8. The granular silicon having a particle size distribution of 50 μm or less.
And an average particle size of 10 μm or less.
The high-density circuit arrangement according to any one of claims 5 to 7.
Manufacturing method of wire substrate. 9. The heating and baking of the granular silicon is performed by an inert gas.
9. The method according to claim 5, wherein the step is performed in an atmosphere.
2. The method for manufacturing a high-density circuit wiring board according to claim 1. 10. The granular silicon is granular polysilicon.
A high-density circuit wiring board according to any one of claims 5 to 9.
Plate manufacturing method.