JPS61150251A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain multichip modules of high reliability by a method wherein direct heat-dissipation from the circuit part is enabled by providing the top of a pellet crystal substrate with non-conduction metallic bumps directly connected in a thermal manner without interposing an insulation film. CONSTITUTION:In the cavity of a package, an Si mother chip 11 on which pellets 9 are bonded by face-down with solder bumps 10 is mounted on the device stage substrate 1 with solder 12, and this mother chip 11 is electrically connected to the inner ends of leads 4 with wires 13. The non-conduction bumps 10a purposing heat dissipation are directly connected in a thermal manner to both of the crystal substrate 9a of the pellet 9 and the main body substrate 11a of the mother chip 11. Providing the top of the pellet crystal substrate with non-conduction metallic bumps in the state of thermal direct connection enables direct heat-dissipation from the circuit part formed in the crystal substrate through the metallic bumps.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technology for dissipating heat from pellets, and is a technology that is effective when applied to semiconductor devices in which pellets are face-down bonded.

[Background Art] An example of a semiconductor device in which pellets are face-down bonded is a so-called multi-chip module in which a large number of pellets are attached to a single pellet attachment substrate.

In the module, each pellet generates a large amount of heat during operation, so it is essential to promote heat dissipation more efficiently than the pellets in order to maintain and improve the reliability of the semiconductor device.

By the way, the pellet can radiate heat to the pellet mounting board via the metal bump body or electrode on the circuit forming surface. This metal bump body includes conductive metal bumps for the purpose of electrical connection (hereinafter referred to as conductive bumps) and non-conductive metal bumps for the purpose of heat dissipation or pellet support that are not electrically connected (hereinafter referred to as conductive bumps). , called non-conducting bumps).

The conduction bumps are connected to the surface wiring formed of one or more layers via an insulating layer on the surface of the crystal substrate, which is the circuit formation surface of the pellet, and therefore improve heat dissipation from the crystal substrate. However, since non-conducting bumps are formed on the surface of the uppermost insulating layer of the surface wiring, they are not only electrically affected, but also thermally It is also blocked.

Even though conduction bumps have a certain degree of heat dissipation, it is natural that the heat dissipation is through extremely thin wiring, so it is insufficient. The inventors have discovered that this has a significant effect on the heat dissipation properties of the pellets.

In addition, the so-called mother chip, which is a pellet mounting board made of silicon or the like on which the pellets are mounted, is also formed on the top surface of a silicon main board with an insulating layer interposed therebetween for reasons such as high-density mounting of pellets. There is also a trend toward multilayer wiring.

As a result, the thickness of the insulating layer with high thermal resistance increases, and the inventor also found that there is a problem in that the heat from the mounted pellets cannot be efficiently radiated to the main body substrate. .

In addition, multi-chip module published by McGraw-Hill, 1 Nikkei Electronics J19
It is described in detail in the March 26, 1984 issue, pages 155-184.

[Purpose of the invention]

An object of the present invention is to provide a technology for heat dissipation from pellets that is effective when applied to improve the reliability of a semiconductor device in which the pellets are face-down bonded.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief summary of typical inventions disclosed in this application is as follows.

In other words, for a semiconductor device in which pellets are face-down bonded, non-conducting metal bumps are provided on the top surface of the crystal substrate of the pellet, which are directly thermally connected without intervening an insulating film. Since heat can be dissipated directly from the formed circuit,
The above objective is achieved.

In addition, regarding the pellet mounting board on which the pellet is mounted, the bump mounting part applied to the non-conducting metal bump of the pellet is thermally directly connected to the main board of the pellet mounting board without intervening an insulating layer. By doing so, it becomes possible to efficiently radiate heat from the pellets to the main body substrate through the non-conducting bumps, thereby achieving the above object.

[Example 1] FIG. 1 is a partially enlarged cross-sectional view of a semiconductor device according to Example 1 of the present invention, and FIG. It is shown in a cross-sectional view.

In the semiconductor device of Example 1, the package is formed of a package substrate l made of a material containing silicon carbide as a main component, a frame body 2 made of mullite, and a cap 3 also made of mullite. A glue 4 is embedded and fixed around the package substrate 1 between the sealing glass 5 of the package substrate l and the frame 2, and the frame 2 and the cap 3 are also used for sealing. It is bonded with glass 6, and a cavity is formed inside the package.

Further, a heat radiation fin 7 made of aluminum is attached to the back surface of the package substrate 1 with a thermally conductive adhesive 8.

Incidentally, the package substrate 1 is made of silicon car-high F containing 0.1 to 3.5 as shown in Japanese Unexamined Patent Publication No. 57-2591.
It consists of a hot-pressed ceramic containing % helium by weight.

This material has excellent electrical insulation and thermal conductivity, a coefficient of thermal expansion close to that of silicon, and high mechanical strength.

In the cavity of the package, a mother chip 11 made of silicon (Si), on which pellets 9 are bonded face-down by solder bumps 10, is attached to the upper surface of the soldering material 12-deposited substrate 1. It is electrically connected to the inner end of 4 by a wire 13.

In the semiconductor device of Example 1, as shown in an enlarged view in FIG. It is directly thermally connected to both.

That is, a first insulating layer 14a made of silicon nitride or the like is formed on the surface of a crystal substrate 9a of Peresols 1 to 9, and a first wiring 15a made of aluminum, a second insulating layer 14b, and a second wiring are formed thereon. The third insulating layer 15b and the third insulating layer 14c are sequentially stacked to form a surface wiring having a two-layer structure.

However, in this embodiment, instead of bringing the non-conducting bump 10a into contact with the upper surface of the third insulating layer, heat is applied to the crystal substrate 9a through the base metal layer 16 made of a material with good solderability. This is a direct connection.

This base metal 16 can be formed of, for example, four layers of chromium, chromium-copper alloy, copper, and gold in order from the crystal substrate side.

Further, in the first embodiment, the bump mounting portion 17 of the mother chip, which is applied to the non-conducting bump 10a of the pellet 9, is formed in direct contact with the main substrate 11a. Therefore, the non-conducting bump 10a welded to the bump attachment portion 17 is directly thermally connected to the main substrate 11a. Incidentally, one insulating layer 18 is sequentially formed on the upper surface of the main substrate 11a using substantially the same material as the above-mentioned PETISOTO 9.
a1 first wiring 19a, second insulating layer 18b, second wiring 19
b, third insulating layer 1 B'C is deposited. Also,
The bump attachment portion 17 also includes the base metal layer 16 of the pellet.
It is similar to

As explained above, according to the first embodiment, it is possible to directly thermally connect the crystal substrate 9a, which is the circuit forming part of the pellet 9, and the main body substrate 11a of the mother chip 11.
This makes it possible to provide a semiconductor device with extremely high heat dissipation efficiency.

In fact, a remarkable effect has been recognized, and compared to non-conducting bumps formed by conventional methods, the bumps shown in this example can reduce the thermal resistance to about one-tenth, and the thermal resistance of Example 1 can be reduced to about one-tenth. Although the connection structure may require changing the wiring pattern, it can be easily formed using normal gluing and lithography techniques.

[Embodiment 2] FIG. 3 is an enlarged partial sectional view of a semiconductor device according to Embodiment 2 of the present invention.

The semiconductor device of the second embodiment is almost the same as that of the first embodiment shown in FIG. The same is true.

However, although the mother chip 11 has a two-layer structure similar to the above embodiment, a thick wiring layer and an insulating layer are formed. It is formed in direct contact with the substrate 11a.

The bump attachment portion 17 is made of copper, and gold 20 is deposited on its upper surface to improve solderability.

Furthermore, a Cr film or a Ti film is used for the base metal layer 21 in order to improve the adhesion between the bump attachment portion 17 and the main body substrate tia.

As in Example 2, by forming the pedestal-type bump attachment part with a material with high thermal conductivity, the wiring on the mother chip 11 can be reduced by reducing the resistance of the wiring, reducing the capacitance between wirings, or increasing the number of layers of wiring. Even when the layers are formed thick, it is possible to provide a semiconductor device with excellent heat dissipation.

The pedestal type bump attachment portion can be formed by etching holes in the insulating layers 18a to 18C, depositing copper by vapor deposition or the like, and depositing gold 20 thereon.

〔effect〕

(1) Regarding semiconductor devices in which pellets are bonded face-down, on the upper surface of the crystal substrate of the pellets,
By providing the non-conducting metal bumps in a directly thermally connected state, heat can be directly radiated from the circuit portion formed on the crystal substrate through the metal bumps.

(2) On the pellet mounting board on which the pellet described in the above ill is mounted, a bump mounting part applied to the non-conducting metal bump is formed in a state where it is directly thermally connected to the main board of the pellet mounting board. As a result, the heat transmitted from the pellet through the non-conducting bumps can be efficiently radiated to the main body substrate.

(3) According to (1) and (2) above, it is possible to provide a semiconductor device with extremely excellent heat dissipation.

(4) According to (1) above, it becomes possible to perform face-down bonding of pellets that generate a large amount of heat.

(5) According to (2) above, a multi-chip module with high reliability can be provided.

(6) By forming non-conducting metal bumps in contact with the top surface of a base metal layer consisting of one or more layers formed directly on the top surface of a crystal substrate, the material of the base metal layer can be changed. , the metal bumps can be formed from a variety of materials.

(7) By forming the bump attachment portion with one or more metal layers, it can be applied to non-conducting metal bumps made of various materials.

(8) By making the bump mounting part into a pedestal shape, it is also possible to use a pere-nod mounting board with a thick wiring layer.
Extremely high heat dissipation properties can be provided.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, it goes without saying that the structure of the heat dissipation section and the materials applied thereto are not limited to those shown in the above embodiments. The same applies to the pa-no-cage material.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to a so-called flat package type multi-chip knob module, which is the background field of application, but the invention is not limited to this.
For example, it is an effective technique that can be applied to any type of semiconductor device, as long as it is a semiconductor device in which two plates are bonded face-down.

[Brief explanation of drawings]

FIG. 1 is an enlarged partial cross-sectional view of a semiconductor device according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view showing a semiconductor device according to a first embodiment of the present invention, and FIG. FIG. 1 is an enlarged partial cross-sectional view of a certain semiconductor device.

Claims (1)

[Claims] 1. A semiconductor device formed by face-down bonding of one or more pellets on which two or more layers of wiring are formed via an insulating film or on the upper surface of a crystal substrate, which A semiconductor device in which a conductive metal bump body is directly thermally connected to the crystal substrate. 2. The non-conducting metal bump body is in contact with the upper surface of a base metal layer consisting of one or more layers formed directly on the upper surface of the crystal substrate, as set forth in claim 1. Semiconductor equipment. 3. The semiconductor device according to claim 1, wherein the non-conducting metal bump body is formed of solder, a gold-tin alloy, or a gold-silicon alloy. 4. The semiconductor device according to claim 1, wherein the crystal substrate is made of silicon. 5. The pellet mounting board to which the above pellets are face-down bonded has one or more layers of wiring formed on the top surface of the main board via an insulating film, and the bump mounting part applied to the non-conducting metal bump is 2. The semiconductor device according to claim 1, wherein the semiconductor device is provided in direct thermal connection to the main body substrate. 6. The semiconductor device according to claim 5, wherein the bump mounting portion is formed in the shape of a pedestal made of metal. 7. The semiconductor device according to claim 6, wherein the pedestal is mainly made of copper or aluminum.