JPH05343376A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To firmly attach a semiconductor substrate to a support substrate to realize thinning by laminating an Si compound film, an Si-containing organic compound film and an Si compound film on the semiconductor substrate, forming an Si compound film on the support substrate, joining both substrates and removing the Si compound film from the rear of the semiconductor substrate. CONSTITUTION:Coatings of an Si compound film 11, an organic Si-coated glass film 12 the Si compound film 11 are laminated on a surface of an Si substrate 3 with a semiconductor element formed. On the other hand, a coating of the Si compound film 11 is formed on a support substrate 6, and after both substrates 3, 6 are cleaned, the substrates 3, 6 are joined with their coatings in contact, so that the Si substrate 3 is thinned from the rear of the Si substrate 3, the joined substrates 3, 6 are etched and the Si compound film 11 is removed. Then the thinned Si substrate 3 is separated from the support substrate 6. Thus a semiconductor substrate formed with a thinned semiconductor element can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device including a step of thinning a semiconductor substrate having a semiconductor element formed thereon.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3 (a), a compound semiconductor substrate 1 such as mercury, cadmium, tellurium (HgCdTe), which has a high sensitivity to infrared rays and a narrow energy gap, has a reverse conductivity of the substrate. Type impurity atoms are introduced to form the infrared detecting element 2, and impurity atoms are introduced to the silicon (Si) substrate 3 to process the detection signal obtained by the detecting element 2 as an input diode 4 of a charge transfer element. To form indium (In) between semiconductor elements formed on both substrates 1 and 3.
The infrared detection device is formed by pressure bonding and joining with the metal bumps 5.

The HgCdTe compound semiconductor substrate 1 has a higher coefficient of thermal expansion than the Si substrate 3, and the infrared detector formed as described above is used at liquid nitrogen temperature. Since the room temperature is stored at room temperature, the semiconductor elements of the two semiconductor devices will be affected by the difference in the coefficient of thermal expansion between the substrates 1 and 3 while the infrared detector is exposed between room temperature and liquid nitrogen temperature. There is a problem in that the metal bumps 5 connecting with each other are disengaged or cracks are generated, resulting in poor connection between the semiconductor elements.

Therefore, as shown in FIG. 3 (b), the HgCdTe substrate 1 on which the infrared detecting element is formed is polished into a thin layer having a length as long as possible, and the thinned substrate 1 is supported by a Si substrate. It is adhered to the substrate 6 with an adhesive 7 made of an epoxy resin (trade name: Araldite, manufactured by Ciba Geigy).

Next, as shown in FIG. 3 (c), the thin HgCdTe substrate 1 and the Si substrate 3 which are adhered to the supporting substrate 6 and form the infrared detecting element are pressure bonded to each other with In metal bumps 5. To form a three-dimensional infrared detector.

In this way, since the HgCdTe substrate 1 is thinned and adhered to the Si substrate 3, the coefficient of thermal expansion of the Si substrate 3 becomes more dominant than the coefficient of thermal expansion of the HgCdTe substrate 1. Accidents in which the metal bumps 5 are peeled off or cracks occur are eliminated.

[0007]

However, according to this method, in the step of adhering the HgCdTe substrate 1 and the Si substrate 3 with the adhesive 7, bubbles easily enter the inside of the adhesive 7, The HgCdTe substrate 1 to be polished by air bubbles may be cracked or cracked during the polishing process from the location where the air bubbles are present. The HgCdTe substrate 1 on which the infrared detection element 2 is formed has a thickness of 30 μm or less. It is difficult to polish.

The present invention eliminates the above-mentioned problems, and an HgCdTe substrate on which the infrared detection element is formed, or another semiconductor substrate such as a Si substrate on which a semiconductor element is formed, is used as an adhesive agent in which bubbles are easily generated. An object of the present invention is to provide a method for manufacturing a semiconductor device, which can be firmly adhered to a supporting substrate and can be thinned without using.

[0009]

According to the method of manufacturing a semiconductor device of the present invention, as described in claim 1, a compound film of silicon or an organic compound containing silicon is formed on the surface side of a semiconductor substrate on which a semiconductor element is formed. A film and a silicon compound film are laminated, a silicon compound film is formed on a supporting substrate, both substrates are washed, and then the coating films formed on the both substrates are made to face each other. The substrates are adhered, the semiconductor substrate is thinned from the back surface side of the semiconductor substrate, and the both adhered substrates are etched by using the selective etching solution for the compound film of silicon to remove the compound film of silicon. By doing so, a step of separating the thinned semiconductor substrate from the supporting substrate is included.

According to a second aspect of the present invention, the supporting substrate is a transparent substrate.

[0011]

[Function] A mirror-polished Si substrate is washed with pure water to obtain a mirror-finished Si substrate with a clean surface or SiO ₂ or the like.
When the Si substrate having the Si compound film formed on the surface is cleanly washed with pure water, and the compound films are opposed to each other and the Si substrates are adhered to each other, the Si substrate or the Si compound film is washed at the time of cleaning. Since the formed OH groups form a hydrogen bond and are strongly bonded to each other, the Si substrates or the Si substrates on which the Si compound film is formed are said to adhere to each other at room temperature without applying pressure.

[0012] It is said that when the Si substrates thus closely adhered to each other are heated, the adhesion further proceeds. This is described in the literature “R.Stengl.Tan and U.Goesele; Jpn.J.Appl.Phy.
s. Vol 28, page 1735 (1989) ".

Utilizing the above, the present inventors form a Si compound film consisting of a phosphosilicate glass film (PSG film; Phosph Silicate Glass film) film on the surface side of a Si substrate on which a semiconductor element is formed. After that, an organic silicon-coated glass film (S0G film; Spin On Glass film) is applied thereon to make the surface flat, and a film having a three-layer structure of a phosphosilicate glass film is further formed thereon.

On the other hand, after forming a film of a phosphosilicate glass film on an insulating supporting substrate such as sapphire or quartz, and adhering the films formed on both substrates so as to face each other,
Polishing from the back side of the Si substrate on which the semiconductor element is formed
Thin the substrate.

When the Si substrate is thinned to a predetermined size, a semiconductor element is formed on the surface using an etching solution for selectively etching the phosphosilicate glass film, and the Si thinned layer is formed. Take out the substrate.

In this way, a semiconductor element was formed.
The Si substrate can be easily thinned to a predetermined size without cracking or chipping. Further, since no adhesive is used, there is no accident that bubbles are generated and cracks are generated from the portion where the bubbles are generated during polishing for thinning the Si substrate.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 1 (a), a semiconductor element is formed on the surface and a Si substrate 3 having an uneven shape is prepared.

Then, as shown in FIG. 1 (b), the semiconductor element is formed, and phosphorous silicate is formed on the Si substrate 3 having an uneven shape by chemical vapor deposition (CVD). A Si compound film 11 made of a glass film is formed.

Then, a silicon compound [RnSi (O
H) _4-n ], a vitreous-forming agent and an organic solvent mixture (trade name; OCD, manufactured by Tokyo Ohka Co., Ltd.)
Organosilicon coated glass film called (SpinOn Glass film) 1
Spin-form the forming agent of 2 using a spinner. Then, the organic silicon-coated glass film 12 is formed by burying it so that the surface of the Si substrate 3 having the uneven shape becomes flat. Then, the substrate 3 is further baked at a temperature of around 400 ° C.

Further, a phosphorus silicate glass film 11 is formed thereon by the CVD method, and a film having a three-layer structure is formed to a thickness of about 10 μm. The three-layered film thus formed is polished to a surface roughness of about 5 nm or less.

On the other hand, as shown in FIG. 1C, a supporting substrate 6 made of quartz or a sapphire substrate is prepared. Then, as shown in FIG. 1 (d), the above-mentioned CVD is performed on the supporting substrate 6.
By phosphorous silicate glass film or SiO ₂ film
A Si compound film 11 is formed.

Next, as shown in FIG. 2 (a), the Si substrate 3 on which the semiconductor element is formed and the supporting substrate 6 are sufficiently washed with pure water until dust-free, and the Si substrate 3 and the supporting substrate 6 on both substrates 3 and 6 are cleaned. Formed into
The Si compound films 11 are made to face each other, and are laminated and bonded at room temperature.

At the time of this superposition, both substrates 3, 6 are
If the bonding is carried out by using a so-called electrostatic pulse pressure bonding method in which a DC pulse voltage is applied, the bonding can be further strengthened. Then, it is observed from the side of the transparent support substrate 6 such as a quartz plate or a sapphire substrate using a microscope or the like, and both substrates 3,
6 Inspect whether or not there are air bubbles in the bonded area, and if there are air bubbles, consist of a phosphorus silicate glass film
Using the selective etching solution for the Si compound film 11, both substrates 3, 6
Then, the Si compound film 11 or the organic silicon-coated glass film 12 is formed again.

Next, when there is no bubble, both substrates 3, 6 are
Is heat-treated at a temperature of 200 to 500 ° C to further strengthen the adhesion. After this, as shown in FIG. 2 (b), the Si substrate 3
The substrate 3 is polished from the back surface side thereof by a polishing device to a thickness of 10 μm or less. In this case, an abrasive is selected and the surface to be polished has a surface roughness of about 0.1 μm.

Si comprising the above-mentioned phosphorus silicate glass film
The compound film 11 of FIG. 3 has a higher etching rate than the organic silicon-coated glass film 12, and thus is made of a phosphosilicate glass film.
Selective etching is performed by using an etching solution for the Si compound film 11.

Then, as shown in FIG. 2 (c), a thin layer is formed,
The Si substrate 3 having the semiconductor element formed on the surface is separated from the bonding portion. It should be noted that instead of the sapphire substrate or the quartz plate used as the support substrate 6 of this embodiment, SOS (Silicon
A con On Sapphir) substrate may be used. In this case, it is not necessary to form a phosphorus silicate glass film or a Si compound film such as a SiO ₂ film on the substrate.

On the Si substrate 3 on which the semiconductor element is formed,
Instead of forming the phosphorus silicate glass film as the Si compound film, a SiO ₂ film may be formed.

[0028]

As described above, according to the method of the present invention, the Si substrate on which the semiconductor element is formed is cracked to a predetermined thickness,
Since it is thinned in a state that no chipping occurs, it is extremely advantageous to use the method of the present invention in a method of manufacturing a semiconductor device that adopts such a thinning step, and an effect that a semiconductor device can be formed with high yield There is.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the method of the present invention.

FIG. 2 is a sectional view showing an embodiment of the method of the present invention.

FIG. 3 is an explanatory diagram of a conventional semiconductor device and a method of manufacturing the same.

[Explanation of symbols]

 3 Si substrate 6 Support substrate 11 Si compound film 12 Organic silicon coated glass film

Front page continuation (72) Inventor Yamada Racing 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (2)

[Claims] 1. A semiconductor substrate having a semiconductor element formed on the surface thereof.
A silicon compound film (11), a silicon-containing organic compound film (12) and a silicon compound film (11) are laminated on the surface side of (3), and a silicon compound film is formed on the supporting substrate (6). After the film (11) is formed and the both substrates (3, 6) are washed, the both substrates (3, 6) are
6) Make the coatings formed on each other face each other and make the substrates (3, 6)
The semiconductor substrate (3) is thinned from the back surface side of the semiconductor substrate (3), and the two substrates (3, 6) are adhered using a selective etching solution for the silicon compound film (11). ) Is removed and the silicon compound film (11) is removed to separate the thinned semiconductor substrate (3) from the support substrate (6). Method. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the supporting substrate (6) is a transparent substrate.