JP2774403B2 - Method of forming bump electrodes - 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 substrate in which light detecting elements such as infrared sensors are arranged one-dimensionally or two-dimensionally.
Alternatively, the present invention relates to a method for forming a protruding electrode for forming a signal processing element such as a CCD on a semiconductor substrate or the like in which one-dimensional or two-dimensional array is provided.

[0002]

2. Description of the Related Art An outline of a conventional method for forming a bump electrode will be described with reference to FIG. First, base metal films 31 and 32 for a plating electrode are formed on the surface of a semiconductor substrate 30, and then a resist film is pattern-formed on the surface to expose regions where a plurality of projected electrodes are to be formed. Next, electroplating is performed to deposit an electrode material in the region where the bump electrode is to be formed. After the electrode material is deposited to a predetermined thickness (height), the above-mentioned resist film which has formed the region where the bump electrode is to be formed is removed, and the bump electrode 33 is formed.

After forming the protruding electrodes 33 on the semiconductor substrate 30 in this way, the semiconductor substrate is cut out using a dicing apparatus in order to obtain a desired chip shape.

[0004]

However, this dicing apparatus requires high-pressure water at the time of cutting out chips, and the high-pressure water blown from the dicing apparatus onto the semiconductor substrate 30 as shown by an arrow a in FIG. In some cases, the formed protruding electrode 33 was deformed by water.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the formation of a protruding electrode for preventing deformation of the protruding electrode caused at the time of cutting a chip due to high-pressure water sprayed from a dicing apparatus. The aim is to provide a method.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and its gist is to form a base metal film for a plating electrode on a semiconductor substrate such as a photodetection substrate or a signal processing substrate. A step of selectively forming a resist film on the surface of the formed base metal film, exposing regions where a plurality of projected electrodes are to be formed, and performing electroplating on the surface of the base metal film on which the resist film is formed, A step of depositing an electrode material of the projection electrode in a region where each projection electrode is to be formed, and a step of cutting a semiconductor substrate having the electrode material deposited into a predetermined shape,
Removing the resist film from the semiconductor substrate cut into a predetermined shape.

[0007]

After depositing the electrode material in the region where each bump electrode is to be formed, the semiconductor substrate is cut out without removing the resist film forming the region where the bump electrode is to be formed. Therefore, when the semiconductor substrate is cut out, a resist film is formed around the deposited electrode material, and the resist film acts to protect the deposited electrode material from the water pressure of water blown by the dicing device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for forming a bump electrode according to the present invention will be described below in the order of steps with reference to the accompanying drawings.

The CCD substrate 10 as a signal processing substrate includes:
CCDs are arranged in a two-dimensional array and have internal circuits for processing input electric signals. As shown in FIG. 1, a plurality of input electrodes 12
A contact hole electrode 13 made of an Al film for forming a protruding electrode is formed on the upper portion. Although omitted in the figure, since a large number of signal line electrodes are formed on the surface of the CCD substrate 10, a passivation film 14 such as an insulating film is formed to protect the surface of the substrate.

The CCD substrate 10 formed as described above
Then, a Ti film 15 and an Au film 16 are sequentially deposited on the entire surface to form a base metal film (FIG. 2). The Ti film 15 is a barrier metal, and the Au film 16 is a plating electrode.

Next, a resist film 17 is pattern-formed on the surface of the Au film 16 (see FIG. 3A), and regions where a plurality of projecting electrodes are to be formed are exposed on the surface of the Au film 16.

Next, using the formed resist film 17 as a protective film for electroplating, an electrode material 11 'made of a low-melting metal, for example, In, is deposited on a region where each protruding electrode is to be formed by selective plating (FIG. 3 (a)). Specifically, the CCD substrate 10 is immersed in an alkaline In plating solution, and the Au film 16 is used as an electrode to perform plating at room temperature with a predetermined current value for several tens minutes.

Next, the CCD substrate 10 is cut into a predetermined chip size by a dicing device (FIG. 3).
(B)). This dicing apparatus requires high-pressure water at the time of cutting out chips, and at the time of cutting out, the surface of the CCD substrate 10 on which the electrode material 11 ′ is deposited,
High pressure water is sprayed from a dicing device. On this occasion,
A resist film 17 is formed around the deposited electrode material 11 ′, and the electrode material 11 ′ is protected from the water pressure of the sprayed water by the resist film 17.

Next, C which is cut out to a predetermined chip size
From the CD substrate 10, the resist film 1 functioning as a protective film
After removing 7, the exposed Au film 16 and the Ti film 15 immediately below the exposed Au film 16 are sequentially etched and removed using the electrode material 11 'as a mask. As a result, the projecting electrodes 11 are formed, and the CCD substrate 10 cut into a predetermined chip shape is obtained (FIG. 3C).

After the protruding electrodes 11 are formed on the CCD substrate 10 as described above, as shown in FIG. 4, the CCD substrate 10 and the sensor substrate 20 are connected to manufacture a semiconductor device. In addition, the sensor board 20 as a light detection board is
The infrared detectors are two-dimensionally arranged on the front surface, and the rear surface has a plurality of output electrodes 21 to which electric signals detected by the respective detectors are applied. When connecting the two substrates, first, each output electrode 21 on the lower surface of the sensor substrate 20 is connected to C
The alignment with each protruding electrode 11 of the CD substrate 10 is performed,
Next, the two substrates are connected to each other by abutting each other. At this time, since each protruding electrode 11 is formed in a state protected from the water pressure blown from the dicing device, it does not deform even under this water pressure, and its height and shape are all uniform. The electrodes 11 are all connected to the respective output electrodes 21 of the sensor substrate 20, and the CCD substrate 10 and the respective elements of the sensor substrate 20 can be reliably connected.

In this embodiment, the example in which the protruding electrodes 11 are formed on the CCD substrate 10 has been described. However, the protruding electrodes 11 may be formed on the sensor substrate 20 side.

In this embodiment, a CCD substrate is exemplified as a signal processing substrate. However, a semiconductor substrate having an internal circuit for processing an input electric signal, such as a MOS integrated circuit substrate, may be used. it can. Furthermore, although an infrared detection element has been exemplified as the light detection element constituting the sensor substrate 20, any light detection element that converts a detected light signal into an electric signal, such as a light detection element that detects light in the visible light region, There is no particular limitation.

[0018]

As described above, according to the method of forming a projecting electrode according to the present invention, the electrode material is deposited in a region where each projecting electrode is to be formed by electroplating, and then the projecting electrode is formed. Without removing the resist film that forms the planned area,
A method of cutting a semiconductor substrate into a predetermined shape and thereafter removing the resist film was adopted.

Therefore, when the semiconductor substrate is cut out, a resist film is formed around the deposited electrode material. Even when high-pressure water is sprayed from a dicing apparatus, the electrode material deposited by the resist film is removed. It is possible to protect and prevent the deformation of the protruding electrode caused by the water pressure of the sprayed water.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a CCD substrate.

FIG. 2 is a partial cross-sectional view of the CCD substrate in a state where a base metal film is formed.

FIG. 3A is a partial cross-sectional view of a CCD substrate showing a state where an electrode material is deposited in a region where a protruding electrode is to be formed by electroplating, and FIG. 3B is a cut-out of a chip. FIG. 3C is a partial cross-sectional view of the CCD substrate showing the state, and FIG.
It is a fragmentary sectional view of D board.

FIG. 4 is a partial cross-sectional view showing a state in which a CCD substrate and a sensor substrate are connected by abutting each other.

FIG. 5 is a partial cross-sectional view of a semiconductor substrate showing a state in which a conventional bump electrode is formed.

[Explanation of symbols]

10: CCD substrate (semiconductor substrate), 11: projecting electrode, 1
1 ': electrode material, 16: Au film (base metal film), 17 ...
Resist film, 20: sensor substrate (semiconductor substrate).

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-281356 (JP, A) JP-A-49-40669 (JP, A) JP-A-5-67620 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) H01L 21/321 H01L 21/60 311 H01L 27/146

Claims (3)

(57) [Claims] 1. A step of forming a base metal film for a plating electrode on a semiconductor substrate, and selectively forming a resist film on a surface of the formed base metal film to expose regions where a plurality of bump electrodes are to be formed. A step of: electroplating the surface of the base metal film on which the resist film is formed, and depositing an electrode material of the bump electrode in a region where each bump electrode is to be formed; and a semiconductor substrate on which the electrode material is deposited. And a step of cutting the resist film from the semiconductor substrate cut into a predetermined shape. 2. The semiconductor substrate according to claim 1, wherein said semiconductor substrate has a detection unit for converting an optical signal into an electric signal, and said electric signal obtained by said detection unit.
2. The method according to claim 1, wherein the substrate comprises a plurality of output electrodes for extracting light. 3. The signal processing board according to claim 1, wherein the semiconductor substrate has a plurality of input electrodes and includes an internal circuit for processing an electric signal input to the input electrodes. Forming method of the bump electrode.