JPS606091B2 - semiconductor equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat dissipation structure for semiconductor elements mounted on various substrates.

Conventional heat dissipation structures for the above-mentioned semiconductor devices generally have a structure in which a heat sink is polymerized onto the semiconductor device via an electrical insulator such as a Mylar sheet or an insulating washer, but due to space constraints, etc. Polymerization and fixation to semiconductor elements may not be possible.

In view of the above points, it is an object of the present invention to provide a semiconductor device that has an effective heat dissipation effect even when a heat sink cannot be superimposed and fixed on a semiconductor element due to spatial constraints. be.

In order to achieve the above object, the semiconductor device of the present invention includes:
Utilizing a beryllium oxide film that is an electrical insulator and has high thermal conductivity, ``the beryllium oxide film is deposited on an arbitrary substrate, and a semiconductor element and a heat sink are placed side by side on this beryllium oxide film. This allows the heat generated from the semiconductor element to be transmitted and dissipated to the side heat sink side via the beryllium oxide film, regardless of location constraints.

More preferably, the beryllium oxide film is formed to have c-axis orientation on the adhering surface of the substrate.

With this configuration, as will be described later, the beryllium oxide film has good heat transfer characteristics in the c-axis direction, so that the heat of the substrate heated by the heat emitted from the semiconductor element is transferred to the Heat is radiated to the heat sink side along the c-axis of the beryllium oxide film, and the heat of the semiconductor element and the substrate is effectively radiated.

The present invention will be explained below with reference to one embodiment of the drawings.

FIG. 1 is a perspective view of a semiconductor device according to the present invention.

In the figure, 101 is a substrate for a semiconductor device, and any material can be used regardless of its thermal characteristics, such as glass, iron, or synthetic resin with an A coating on the surface. A portion can also be used as the substrate 101.

A film 102 is formed on the surface of the substrate 101.
A semiconductor chip 103 is formed on a part of the upper surface of this film 102 by crystal growth, and adjacent to this chip 103, a semiconductor chip 103 is deposited with c-axis orientation. Heat sink 10 made of highly conductive metal
4 are arranged in parallel.

With this configuration in which the semiconductor chip box 03 and the heat sink 104 are arranged side by side on the same substrate, a sufficient heat dissipation effect can be obtained even if a material with low thermal conductivity is used as the substrate 101. can be constructed from inexpensive materials.

Here, the crystal of Mr.○ has a hexagonal crystal form, and the state in which the long axes of the hexagonal crystals, that is, the c-axes, grow in the same direction is called c-axis orientation.

In this case, if the a-axis of the hexagonal crystal is also oriented in the same direction, it will become a single crystal, but in the case of the present invention, the substrate does not necessarily have the conditions for single crystal growth, so this cannot be expected. From the standpoint of thermal conductivity, the c-axis direction is a problem. Therefore, in the above example, the a-axis direction of the sheath film was not particularly concerned, but instead the crystal film oriented in the c-axis direction was used. Using.

Furthermore, even if the substrate on which the film is to be formed is polycrystalline or amorphous, if it is deposited under specific conditions as described below, the film has the property of being oriented along the c-axis; , the c-axis is oriented substantially perpendicular to the surface to which it is deposited.

Next, an example of a method for forming a BeO film oriented in the c-axis direction by vapor deposition will be described with reference to FIG. The deposition layer shown in FIG. 2 is entirely enclosed within a vacuum container.

However, 0.5 side ~ 2. A closed crucible 21 having one or more nozzles 22 of approximately the same size as the skin is filled with metal particles e in the form of flakes or pellets and heated by a heating device 24.

On the other hand, via the oxygen supply pipe 35, the nozzle 36
Oxygen 36a is supplied into the vacuum container from the vacuum container, and the pressure inside the vacuum container is maintained at approximately 10-6 Tom to 10-3 Ton.

Here, the steam 23a of the metal bush inside the crucible 21 is jetted out of the crucible 21 as a steam flow 23b by the nozzle 22 due to the pressure difference between the inside and outside of the crucible 21, Due to the cooling phenomenon, vapor atoms and molecules are loosely bound together by van der Waals forces, forming clusters.

The vapor flow 23b enters the ionization chamber 26, and the electrons emitted from the heated filament 28 are accelerated by a voltage of about 100 to 1000 V applied between the filament 28 and the net-like anode 27. The vapor flow 23b collides with the vapor flow 23b and ionizes a part of it.This partially ionized vapor flow 23b mixes with oxygen in the passage, is accelerated by the accelerating electrode 37, and is ionized. 31. When the substrate 1 is held in the direction of the target substrate 1 and the substrate 33 is open, it hits the surface of the substrate 1 through the opening of the mask turtle Q and has a c-axis orientation. The 4th army is formed.In addition, in Figure 2, 25
is a heat shield plate ~ 29 is a shield plate. The vapor stream 23b of the metal e is ejected from the nozzle 22 of the closed crucible and impinges on the adherend substrate with the energy obtained at the time of ejection.

At this time, the effect of ions contained in the vapor flow promotes nucleation and growth, resulting in a c-axis oriented &○ crystal film.

The c-axis orientation of this stage ○ crystal film is greatly influenced by the presence of ~ ions, and is
Orientation in the c-axis direction does not occur in the Be◯ film formed by the em amount caIVaporDeposition method or the sputtering method.

Furthermore, the above-mentioned conditions for producing the crucible are determined by the heating temperature of the crucible 21 and the pressure within the surrounding vacuum container.

That is, the pressure of the vapor of the metal e in the crucible 21 is P'
When the pressure inside the vacuum container is Po, P/PoZI is preferably set so that P no Po≧1.

For example, since the melting point of metal Be is 1280°,
At a heating temperature of 1300°C, the vapor pressure P is approximately 5xlo-Zror.
r, 138000 becomes 1×10-ITon.

Therefore, the pressure inside the vacuum container is 10-6T to 10
-5 Torr, the heating temperature is 1300o
It may be set to about o to 1400oo. Further, the vapor flow 23b of the metal retainer that impinges on the adherend substrate 1 is transmitted to the ionization chamber 2.
6, some of them are ionized, and as mentioned above, the electric field of these ions promotes the formation of nuclei for crystal growth, and furthermore, atoms are formed around the formed nuclei. It effectively acts on so-called coalescence, which gathers together to form island-like regions.

For these reasons, by the method described above, it is possible to deposit a Mo film with c-axis orientation. The good crystallinity of this back-circle film is clear from the measurement results shown in FIGS. 3a and 3b and FIG. 4. Figure 3a is the copy above.
In order to evaluate the crystallinity of the film, a Be* film was deposited on a glass substrate by the method explained above with reference to FIG. 2, and a scanning electron micrograph image of the obtained Be* film is shown. Figure 2b shows a backscattered electron diffraction pattern (RHEED pattern) when a sapphire single-crystal substrate is used as the substrate, and a crystal is grown on the C-plane (that is, the (0001) plane) of this sapphire single-crystal substrate. According to Fig. 3b, the surface resistance of the TE film is extremely high, so it is charged by the electron beam irradiated with T, which lowers the RHEED pattern resolution. It can be seen that the crystals are growing.

FIG. 4 shows the X-ray diffraction pattern of the film deposited on the Si monocrystalline substrate by the method explained in FIG. 2. "
The stage film obtained through the above-mentioned process has a columnar structure characteristic of hexagonal crystals, and it is clear that it is preferentially oriented in the c-axis direction. However, ``A film with c-axis orientation has anisotropy in its thermal conductivity properties.

The present inventor measured the thermal conductivity K″ph in the direction parallel to the c-axis direction and the thermal conductivity Kph in the direction perpendicular to the c-axis direction (a-axis direction) in the above-mentioned Mr.○ film. ″
ph~2.6W/node・deg, Kph~0.6W/arc・
deg, and the thermal conductivity along the c-axis is about 4.0 degrees compared to the thermal conductivity in the direction perpendicular to the c-axis. I found out that the needle sound was loud.

Therefore, if the film is deposited so that the c-axis is oriented along the heat dissipation direction of the semiconductor chip, the heat dissipation effect can be greatly improved.
Since both h and temperature follow the temperature T-2, it was found that the Be○ crystal film has extremely few lattice defects that are the center of phonon scattering. The manufacturing procedure of the semiconductor device according to the above embodiment is as follows:
First, a substrate 101 is coated with a MO film 102 in the same manner as explained above with reference to FIG.
For example, a semiconductor chip 103 is formed by growing crystals of Si on top of the semiconductor chip 103.
is formed and the heat sink 104 is fixed.

Since the Be○ film 102 has a preferential orientation in the c-axis direction as described above, the substrate 1 on which the Be○ film 102 is formed
When Si is deposited on 01, polycrystalline Si can be grown at a low substrate temperature by appropriately selecting the deposition conditions.Crystal growth on Be○taka IQ2 can also be performed epitaxially. This is due to the action of the sapphire-on machine, which allows crystal growth to be regulated by the c-axis in silicon (SOS). This is a scanning electron micrograph image of a cross section of Example 1, in which a 0.6 μm thick film with c-axis orientation is formed between a silicon layer as a semiconductor layer and a substrate.

As a result, the heat generated in the silicon layer on which the semiconductor element is formed is transferred to the substrate side along the c-axis of the Be film, which has extremely high thermal conductivity, and heat is dissipated from the silicon layer and the substrate. .

Moreover, with Shigeru 0, a film having a preferential orientation of the c-axis can be obtained even on an amorphous film. Furthermore, the degree of preferential orientation can be controlled by controlling the manufacturing conditions.

Furthermore, since the thickness of the film can be easily controlled, it is possible to create a film with any desired thickness.
Since the electric resistance of the e○ film itself is extremely high at 13130.cm, sufficient insulation properties can be obtained even with a thin film.
As explained above, according to the semiconductor device according to the present invention, since the semiconductor chip and the heat sink are arranged side by side on an arbitrary substrate via the stage 0 film, the heat generated from the semiconductor chip is While electrical insulation is maintained, the heat is transmitted to the heat sink through the film and the substrate, and is effectively dissipated.

Therefore, even under conditions where the heat sink cannot be superimposed and fixed on the semiconductor chip, heat can be radiated from the side heat sinks, and furthermore, there is an effect that heating of the substrate can be prevented. Further, by depositing the &0 film on the surface of the substrate with c-axis orientation, the heat dissipation effect is further improved.

[Brief explanation of drawings]

FIG. 1 is a cutaway perspective view of a semiconductor device according to the present invention, and FIG.
The figure is a schematic configuration diagram of an apparatus for producing a beryllium oxide film with c-axis orientation, Figures 3a and b are scanning electron micrographs showing the metal structure of the same beryllium oxide film, and Figure 4
The figure shows the X-ray diffraction pattern of the same beryllium oxide film, and FIG. Substrate “IQ2 state beryllium oxide film, IQ
3... Semiconductor layer, 104... Heat sink. Turtle figure 2
Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A semiconductor device characterized in that a beryllium oxide film is deposited on a substrate, and a semiconductor layer in which an element portion is formed and a heat sink are arranged in parallel on the beryllium oxide film. . 2. The semiconductor device according to claim 1, wherein the beryllium oxide film is deposited on the adhesion surface of the substrate with c-axis orientation.