JP3298174B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a hybrid semiconductor device in which a compound semiconductor substrate on which a light sensing element is formed and a semiconductor substrate on which a signal processing element is formed are connected by metal bumps, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As shown in FIG. 4, a conventional hybrid type semiconductor device has a structure in which a compound semiconductor substrate 1 such as p-type mercury-cadmium tellurium (HgCdTe) is formed by ionizing n-type impurities in a predetermined pattern. Introduced by a method such as injection, and n
Photodetector 2 formed of a photodiode by forming a mold layer
To form

On the other hand, a signal processing element such as a charge transfer element for processing a signal obtained by the light detecting element 2 is formed on a silicon (Si) substrate 3, and an input diode 4 of the signal processing element and the signal processing element described above. A hybrid semiconductor device is formed by bump-connecting the light-detecting element 2 with the metal bump 5. Incidentally, reference numeral 6 in the drawing denotes an insulating film.

[0004]

In order to avoid the influence of thermal noise, such a semiconductor device is usually cooled at the temperature of liquid nitrogen and used at room temperature when not operating. It will be exposed to temperature fluctuations from temperatures as low as 77 ° K) to room temperature.

On the other hand, the HgCdTe compound semiconductor substrate 1 has a coefficient of thermal expansion of 5 × 10 ⁻⁶ , and the Si substrate 3 has a coefficient of thermal expansion of 3 × 10 ⁻⁶ . While the above-described semiconductor device is exposed to the temperature fluctuation, the degree of expansion and contraction of the two substrates 1 and 3 due to the temperature fluctuation is different, so that the metal bumps 5 are deformed or peeled off from the substrates 1 and 3. This deformation and peeling cause metal bumps 5
The inconvenience of contact between them occurs.

When the metal bumps 5 come into contact with each other as described above, the pixel signals of the pixels connected to the metal bumps 5 that have come into contact with each other overlap each other, and therefore both become defective pixels.
When the temperature change is repeated as described above, there is a problem that a defective pixel is easily generated.

The present invention solves the above-mentioned problems, prevents the metal bumps from being peeled or deformed by movement or the like due to the above-mentioned temperature fluctuation, and prevents the metal bumps from contacting each other, so that defective pixels do not occur. It is an object of the present invention to provide a semiconductor device as described above.

[0008]

According to a first aspect of the present invention, there is provided a semiconductor device and a method of manufacturing the same, wherein a light sensing element formed on a compound semiconductor substrate and a signal processing element formed on the semiconductor substrate are formed by metal bumps. Wherein the metal bump is surrounded by a columnar or plate-shaped polymer resin having a low expansion coefficient in a circular or square shape.

According to a second aspect of the present invention, the columnar polymer resin is a prism or a column. According to a third aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the present invention, comprising the steps of:
Alternatively, after forming a photosensitive or non-photosensitive polymer resin film on one of the semiconductor substrates on which the signal processing elements are formed, a resist film for pattern formation of the polymer resin film is formed on the substrate. A step of applying, after forming a resist film for forming a pattern of the polymer resin film in a predetermined pattern, a step of forming the polymer resin film in a columnar or plate-shaped predetermined pattern using the resist film as a mask, A burying resist film and a metal pattern forming resist film buried between the polymer resin films are formed on a substrate including a polymer resin film formed in a columnar or plate-like predetermined pattern. Forming the resist film for forming a metal pattern in a predetermined pattern, and forming a lower buried resist film in a predetermined pattern using the resist film for forming a metal pattern as a mask After depositing and forming a metal film on the substrate, the buried resist film formed in a predetermined pattern is removed, thereby removing the metal pattern formation resist film and the metal film thereover, and removing the metal film. The method is characterized by including a step of forming a columnar or plate-like polymer resin film pattern and a metal film pattern.

According to a fourth aspect of the present invention, the polymer resin film is a spacer film for joining metal bumps formed on both substrates.

[0011]

According to the semiconductor device of the present invention, the periphery of the metal bump connecting the elements is formed into a circular or square state with a coefficient of thermal expansion.
It has a low coefficient of thermal expansion of 5 × 10 ^-6 , and is surrounded by a square or cylindrical columnar or plate-like polyimide resin.

In this way, even if the metal bumps are deformed or peeled off due to the difference in the coefficient of thermal expansion between the substrates, the metal bumps can be prevented from contacting each other.

The polymer resin film serves as a spacer film when joining the metal bumps formed on both substrates, and the height of the joining position of the metal bumps is defined by the spacer film. , And the interval at which the metal bumps are joined is maintained at a predetermined value.

[0014]

FIG. 1 (a) is a sectional view showing an embodiment of a semiconductor device according to the present invention, and FIG. 1 (b) is a plan view, as shown in FIG.
As described above, the compound semiconductor substrate 1 made of HgCdTe
A light sensing element 2 composed of a photodiode is formed by introducing a type impurity to form a pn junction. On the other hand, the input diode 4 of the charge transfer device is formed on the Si substrate 3 and both elements are formed.
2 and 4 are joined by metal bumps 5.

A columnar polymer resin film 11 made of polyimide resin having a coefficient of thermal expansion of 5 × 10 ⁻⁶ is provided so as to surround the metal bump 5. This polymer resin film 11
May be cylindrical as shown, or may be prismatic as another embodiment.

As another embodiment, as shown in the plan view of FIG. 1 (c), a metal bump 5 is formed by using a plate-shaped polymer resin film 11A instead of the column-shaped polymer resin film 11 described above. May be formed so as to surround the periphery of.

The shape surrounding the periphery of the metal bump 5 may be circular or rectangular. When the above-described columnar polymer resin film 11 is provided in close contact with the metal bumps 5, the deformation of the metal bumps 5 causes the columnar polymer resin film 11 to deform.
Therefore, an accident such as contact between adjacent metal bumps 5 can be prevented.

When this polymer resin film is used to press-bond metal bumps to each other, a constant interval is maintained as a spacer film between the two substrates, and the pressure at which the metal bumps are bonded is regulated to a predetermined value or less. This prevents deformation of the metal bumps during pressure bonding.

Hereinafter, a method of manufacturing a semiconductor device according to the present invention will be described with reference to the drawings. As shown in FIG. 2A, a polymer resin film 11 made of a polyimide resin having a coefficient of thermal expansion of 5 × 10 ^-6 and a viscosity of several hundred centipoise was formed on the compound semiconductor substrate 1 or the Si substrate 3 by 13 μm. Is spin-coated with a spinner to a thickness of

Next, as shown in FIG. 2B, a positive type pattern forming resist film (Tokyo Ohka Co., Ltd.) for forming the polymer resin film 11 in a predetermined pattern on the substrates 1 and 3 is used.
(Product name: OFPR) 12 is spin-coated with a spinner to a thickness of 3 μm.

Next, as shown in FIG. 2C, the positive resist film 12 is exposed to ultraviolet rays, and a polymer resin film 11 made of a lower polyimide film is simultaneously patterned using an alkaline developer.

Next, the polymer resin film 11 made of the polyimide film is baked at a temperature of 300 to 400 ° C. and thermally cured. Next, as shown in FIG. 2 (d), a positive type burying resist film 12A for burying between the polymer resin films 11 is applied on the substrates 1 and 3 having the polymer resin film 11 made of a polyimide film. I do. Next, a metal pattern forming resist film 13 for forming a metal film to be described later in a predetermined pattern with a negative resist film is applied thereon, and then the metal pattern forming resist film 13 is baked.

Next, as shown in FIG. 3A, the metal pattern forming resist film 13 is exposed and developed in a predetermined pattern. Next, as shown in FIG. 3 (b), using the patterned metal pattern forming resist film 13 as a mask, the underlying positive-type buried resist film 12A is exposed and developed to be removed. Then, the periphery of the polymer resin film 11 is surrounded by the unexposed positive type burying resist film 12A.

Next, as shown in FIG. 3C, a metal film 14 made of an indium film is formed on the substrates 1 and 3 by vapor deposition to a thickness of 9 μm. Next, a positive type buried resist film
When the resist film 12A is removed with a removing solution of 12A, the negative type metal pattern forming resist film 13 and the In metal film 14 thereon are removed by a lift-off method, and as shown in FIG. An In metal film 14 having a predetermined pattern surrounded by the polymer resin film 11 is formed, and serves as the In metal bump described above.

In the present embodiment, the polymer resin film 11 surrounding the metal bumps has a columnar shape, but may have a prismatic shape.
In addition, a structure in which the metal bumps are surrounded by the plate-shaped polymer resin film 11 may be adopted.

Further, instead of using a photosensitive polyimide resin film as in this embodiment, this polymer resin film 11 is replaced with a non-photosensitive polymer resin film (manufactured by Hitachi Chemical Co., Ltd., trade name: PIX , PIQ) and the like.

[0027]

As described above, according to the semiconductor device and the method of manufacturing the same of the present invention, since the periphery of the metal bump is surrounded by the polymer resin film, deformation such as movement and peeling of the metal bump is avoided. In addition, since an accident in which the metal bumps come into contact with each other is eliminated, an accident in which images overlap with each other can be prevented.

When the height of the polymer resin film is higher than the height of the metal bumps formed on the substrate, the polymer resin film can be used as a spacer film capable of restricting the coupling interval between both elements to a predetermined height. Thus, the metal bump bonding can be easily and reliably performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view and a plan view of a semiconductor device of the present invention.

FIG. 2 is a cross-sectional view illustrating steps of a method for manufacturing a semiconductor device according to the present invention.

FIG. 3 is a cross-sectional view illustrating a step of a method for manufacturing a semiconductor device according to the present invention.

FIG. 4 is a cross-sectional view of a conventional semiconductor device.

[Explanation of symbols]

1 Compound semiconductor substrate 2 Photodetector 3 Si substrate 4 Input diode 5 Metal bump 11 Polymer resin film 11A Plate-shaped polymer resin film 12 Resist film for pattern formation (positive resist film) 12A Resist film for burying (positive type) Resist film) 13 Resist film for metal pattern formation (negative resist film) 14 Metal film (In film)

Continuation of the front page (72) Inventor Masahiko Narita 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (56) References JP-A-63-268271 (JP, A) JP-A-5-13667 (JP, A) JP-A-5-315578 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/60 H01L 27/146

Claims (4)

(57) [Claims] A photodetector (2) formed on a compound semiconductor substrate (1) and a signal processing element (4) formed on a semiconductor substrate (3).
Are bonded by a metal bump (5), and the periphery of the metal bump (5) is circular or columnar or plate-shaped with a low expansion coefficient polymer resin film (11). A semiconductor device, wherein the semiconductor device is enclosed in a square shape. 2. The columnar polymer resin film according to claim 1, wherein
Is a prismatic or cylindrical shape. 3. A photo-sensitive layer on one of the compound semiconductor substrate (1) on which the photodetector (2) is formed or the semiconductor substrate (3) on which the signal processing element (4) is formed. Or a step of applying a resist film (12) for pattern formation of the polymer resin film (11) on the substrate after coating and forming a photo-insensitive polymer resin film (11); After forming the pattern-forming resist film (12) in a predetermined pattern, forming the polymer resin film (11) in a columnar or plate-like predetermined pattern using the resist film (12) as a mask, On a substrate (1,3) including a polymer resin film (11) formed in a columnar or plate-like predetermined pattern, the polymer resin film is formed.
(11) a step of laminating and forming a burying resist film (12A) and a metal pattern forming resist film (13) buried in between, after forming the metal pattern forming resist film (13) into a predetermined pattern; Forming a lower buried resist film (12A) into a predetermined pattern by using the metal pattern forming resist film (13) as a mask, and forming a metal film (14) on the substrate (1, 3) by deposition. Thereafter, by removing the buried resist film (12A) formed in a predetermined pattern, a metal pattern forming resist film (13) thereon,
Removing the metal film (14) to form a predetermined columnar or plate-shaped polymer resin film (11) pattern and a metal film (14) pattern. Method. 4. The polymer resin film according to claim 1, wherein
A metal film (5) formed on both substrates (1, 3) as a spacer film for joining together.