JPH03266478A - Semiconductor device - Google Patents

Abstract

PURPOSE:To eliminate the positional deviation of both elements by a method wherein semiconductor crystals different from each other in thermal expansion coefficient are made to grow on support substrates whose thermal expansion coefficients are close to each other to provide a first and a second semiconductor substrate, a photodetective element and a signal processing element are provided to the semiconductor substrates respectively, and the elements concerned are electrically connected. CONSTITUTION:Semiconductor crystals 12 and 22 different from each other in thermal expansion coefficient are made to grow on support substrates 11 and 21 whose thermal expansion coefficients are close or equal to each other to provide a first and a second semiconductor substrate, 13 and 23, a photodetective element and a signal processing element are provided to the semiconductor substrates respectively, and the elements concerned are electrically connected together. That is, an InSb crystal 12 is provided to the support substrate 11 of sapphire to form a semiconductor substrate where a photodetective element is formed, and an Si crystal 22 is provided to the support substrate 21 of sapphire to form a semiconductor substrate where a charge transfer element is formed. By this setup, the positional deviation of a metal bump which connects both elements is eliminated.

Description

[Detailed Description of the Invention] [Summary] Regarding a semiconductor device, a semiconductor device consisting of a photodetector element and a signal processing element formed on different semiconductor substrates and electrically connected is exposed to a low temperature environment during operation of the device. The purpose of the semiconductor device is to prevent misalignment of both elements due to thermal strain due to temperature history during non-operating room temperature conditions, and a supporting substrate with similar or equal coefficients of thermal expansion. A first semiconductor substrate and a second semiconductor substrate are provided by growing or adhering semiconductor crystals having different coefficients of thermal expansion, respectively, a photodetecting element and a signal processing element are provided on each of the semiconductor substrates, and a photodetecting element and a signal processing element are provided on each of the semiconductor substrates. It is configured by electrically connecting between the two.

[Industrial application field]

The present invention relates to a semiconductor device, and more particularly to a semiconductor device in which a first semiconductor element and a second semiconductor element are bonded by metal bumps.

A photodetector element is formed on a compound semiconductor substrate with a narrow energy bandgap, and a signal processing element is formed on a semiconductor substrate made of silicon (Si), on which insulating films such as oxide films can be easily formed, and both are connected using metal bumps. An electrically coupled semiconductor device is formed.

[Conventional technology]

As such a semiconductor device, patent application No. 63-308970
As shown in Figure 2 in the issue, N was added to a P-type mercury-cadmium-tellurium (Hg+-x Cdx Te) substrate 1.
A mold layer 2 is formed to form a photodetector element. Further, a charge transfer element is formed on an indium antimony (InSb) substrate 3 whose coefficient of thermal expansion is close to that of this P-type Hg+-x caX Te substrate 1, and an input diode 4 of this charge transfer element is formed.
A semiconductor device is proposed in which the photodetector and the photodetector are electrically connected using metal bumps 5.

In this way, by reducing the difference in thermal expansion coefficient between the substrate on which the photodetector element is formed and the substrate on which the charge transfer element is formed, the environment when the semiconductor device is operated at a low temperature of 77 degrees, The difference in thermal strain that occurs on the substrate on which the above elements are formed is reduced due to the temperature history of the environment when the device is brought to room temperature when not in operation, causing positional deviations in the metal bumps that connect both of the above elements. I try not to.

In addition, in FIG. 2, 6 is an N-type well region for accumulating charges;
7 is a transfer gate electrode, 8 is a transfer electrode of a charge transfer device, and 9 and 10 are insulating films formed on each substrate.

[Problem to be solved by the invention]

However, the technique of forming the insulating film 9, transfer electrode 8, etc. on the above-mentioned InSb substrate 3 in order to form a charge transfer element on the substrate is slower than the technique of forming the insulating film and transfer electrode on the Si substrate. This method has not been established yet, and there is a drawback that it is not easy to manufacture charge transfer devices.

The present invention eliminates the above-mentioned problems, is easy to manufacture, and the substrate on which both elements are formed has a small difference in thermal distortion due to temperature fluctuations, and the metal bumps that connect the two elements are free from misalignment. An object of the present invention is to provide a semiconductor device in which this phenomenon does not occur.

[Means to solve the problem]

A semiconductor device of the present invention that achieves the above object includes a first semiconductor substrate, in which semiconductor crystals having different coefficients of thermal expansion are grown or adhered to a support substrate having close or equal coefficients of thermal expansion, and A second semiconductor substrate is formed, a photodetecting element and a signal processing element are provided on each of the semiconductor substrates, and the elements are electrically connected.

[Function] In the semiconductor device of the present invention, a semiconductor substrate forming a photodetecting element is injected into a support substrate made of sapphire (Al!zo3).
A Sb crystal is provided and formed. Further, the semiconductor substrate forming the charge transfer element is placed on the supporting substrate made of sapphire.
Provide and form crystals.

The Si crystal formed on the above sapphire substrate is used for IC and LSI.
An insulating film, ie, Sin, is used in semiconductor devices such as, for forming the charge transfer element.

The manufacturing technology for films and transfer electrodes has been established, and high-quality charge transfer elements can be easily obtained.

In addition, the thermal expansion coefficient of the above InSb crystal is 8 from 300°K.
It shrinks by 0.06% due to temperature fluctuation to 0°, but on the other hand, Si
In this case, the shrinkage is only 0.03%.

Even though the difference in coefficient of thermal expansion between these two crystals is large, the same sapphire substrate is used as the support substrate forming the above crystals, and the thickness of this sapphire substrate is the same as that of both crystals. Since the temperature is large compared to the thickness, only this supporting substrate is affected by the temperature fluctuation, and there is no difference in thermal strain occurring between the two semiconductor substrates.

In addition, by selecting and using materials with similar coefficients of thermal expansion for the support substrates used for both semiconductor substrates, a highly reliable semiconductor device can be obtained in which the metal bumps that connect the elements of both devices are not misaligned. .

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the semiconductor device of the present invention.

As shown in FIG. 1, a first semiconductor crystal 12 made of N-type In5b crystal with a thickness of about 10 μm is formed on a supporting substrate 11 made of sapphire using a vapor phase epitaxial growth method or the like. A first semiconductor substrate 13 is formed, and magnesium (Mg) ions are implanted into predetermined positions of the substrate to form a P'' region 14.

The supporting substrate 11 made of sapphire shrinks by 0.06% between 300° and 80°.

The surface of the first semiconductor substrate 13 is coated with zinc sulfide (Zn
An insulating film 15 made of S) film is formed, and P″ of the insulating film
An opening is formed above the head region 14, and a metal electrode 16 made of In, which serves as a connection pad, is formed on the region.

On the other hand, on the other support substrate 21 made of sapphire,
A second semiconductor crystal 22 made of N-type Si epitaxial crystal is formed by a vapor phase growth method, and a second semiconductor substrate 23 is formed. This second semiconductor substrate 23
A 5i02 film 24 is formed on the surface of the second semiconductor substrate, and a transfer gate electrode and a transfer electrode of the charge transfer device (not shown) are formed on the surface of the second semiconductor substrate. A diode 25 is formed. An opening is formed above the input diode 25 to form a metal electrode 26 of A2 which becomes a connection pad.

Metal bumps 27 and 28 made of In are placed on each of the metal electrodes 16 and 26 that serve as connection pads.
These metal bumps 27 and 28 are connected by pressure bonding.

According to the semiconductor device of the present invention, the semiconductor substrates used in the device include the supporting substrates 11.
Semiconductor crystals 12 and 22 for forming each element on 21
is formed to be extremely thinner than the thickness of the support substrate 11.21, and is hardly affected by the difference in thermal expansion coefficient of the semiconductor crystal for forming the element.

Therefore, after cooling the semiconductor device formed using the first and second semiconductor substrates to a temperature of 77° and operating it,
Since there is no difference in thermal strain between the two semiconductor substrates due to the temperature history when the temperature is set to the non-operating temperature of room temperature, phenomena such as misalignment of metal bumps do not occur, and a semiconductor device with high reliability can be obtained. .

This semiconductor substrate is made of Indium on the sapphire support substrate mentioned above.
Instead of epitaxially growing an Sb crystal substrate or a Si crystal substrate, it may be attached using an adhesive or the like, and this crystal substrate may be polished or etched to a predetermined thickness.

Further, as a second embodiment, as the support substrates 11 and 21,
Instead of the sapphire substrate, a Si or GaAs substrate may be used as the support substrate.

This Si is 0.03% between 80”K by 300°
, the GaAs substrate shrinks by 0.06%.

Further, as a third embodiment, a GaAs substrate is used as the support substrate 11, and a photodetector element is formed on a semiconductor substrate on which InSb crystal is grown by vapor phase epitaxial growth.
A charge transfer element is formed on a semiconductor substrate using a sapphire substrate on which a Si crystal is grown by vapor phase epitaxial growth. The elements may be connected using metal bumps.

In this case, the coefficients of thermal expansion of the GaAs substrate and the sapphire substrate are close to each other, and the difference in coefficient of thermal expansion of the two supporting substrates is due to the difference between the InSb crystal and the Si substrate formed on the supporting substrate.
It is smaller than the difference in thermal expansion coefficient of crystals.

Therefore, the first and second semiconductor substrates on which semiconductor crystals for forming elements are formed are not affected by thermal distortion due to temperature history.

As described above, according to the semiconductor device of the present invention, a photodetecting element is formed in a compound semiconductor crystal that can obtain good characteristics as a photodetecting element, and a charge transfer element can be easily formed using S.
By forming the charge transfer element on an i-crystal, and forming a semiconductor device by growing both crystals on a support substrate with similar thermal expansion coefficients even if the two crystals have different coefficients of thermal expansion, the metal bumps will not be misaligned. A semiconductor device with high reliability can be obtained.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to obtain a highly reliable semiconductor device in which the metal bumps that connect the photodetecting element and the charge transfer element do not shift in position even depending on the temperature history during operation and non-operation. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a semiconductor device of the present invention, and FIG. 2 is a sectional view showing an embodiment of a conventional semiconductor device. In the figure, 11.21 is a support substrate, 12 is a first semiconductor crystal, and 13
is a first semiconductor substrate, 14 is a P0M region, 15 is an insulating film,
16. 26 is a metal electrode, 22 is a second semiconductor crystal, 23
24 is a SiO□ film, 25 is an input diode, and 27 and 28 are metal bumps.

Claims (2)

[Claims] (1) A first semiconductor substrate ( 13) and a second semiconductor substrate (23), an element is provided on each of the first and second semiconductor substrates, and the elements are electrically connected. (2) When the coefficients of thermal expansion of each of the support substrates (11, 12) are A and B, and the coefficients of thermal expansion of the semiconductor crystals formed on the support substrates (11, 12) are a and b, A claim characterized in that the following relationship (1) is satisfied (
1) The semiconductor device described. A-B<a-b...(1) (However, A<a, B<b)