JPH01243555A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To obtain an infrared image sensing element at a good yield by a method wherein openings are formed in parts where two or more bump electrodes are to be formed and in a peripheral part of a substrate where the bump electrodes are not formed and two or more bumps are formed at the openings by a plating method. CONSTITUTION:Signal input contact parts 12 are formed on the surface of an Si substrate 11; Al electrodes 13 and an insulating layer 14 are formed on the surface. A Ti film 15 and, then, a Cu film 16 are formed on this surface. Openings 17c, 17d are formed in photoresist films 17a, 17b in parts where bump electrodes are to be formed and in parts which are adjacent to the parts and where the bump electrodes are not formed. The photoresist film in the parts where the bump electrodes are not formed is exposed to light. A Cu layer 18 and, then, an In layer 19 are formed by a plating method. An exposed photoresist film 27 in the parts where the bump electrodes are not formed is developed and removed. The substratum Cu film 16 in an exposed part and a bump in the parts where the bump electrodes are not formed are removed. By this setup, it is possible to obtain an infrared image sensing element at a good yield.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a semiconductor device, and particularly to a semiconductor device in which a plurality of metal electrodes are formed on a substrate and bump electrodes are formed thereon. Applicable to the manufacture of

(Prior Art) A method for manufacturing a semiconductor device having bump electrodes according to the present invention will be described below by exemplifying a method for manufacturing an infrared imaging device (RNFRA-Red CCD, hereinafter abbreviated as Ir1CCD).

IRCCD uses semiconductor materials that are good for infrared sensors, such as In5b (indium antimony).
The light receiving section is a grid of photodiodes formed on a substrate such as IIgCdTe (mercury, cadmium, tellurium), etc., and the electrons generated in this light receiving section are divided into 5
It is transferred to the i-COD device to obtain an image. This method is the most commonly used method because it can optimize the characteristics of the light receiving section and the 5i-CCD section. To connect each cell, a so-called bump electrode structure is usually used in which a soft metal such as In is formed on both sides and the corresponding electrodes are butted and connected.

Next, a method for manufacturing a conventional 5i-CCD having bump electrodes, which is used for the above-mentioned applications, will be described with reference to FIG.

FIG. 2a shows a cross section of the main part of the 5i-CCD before forming the bump electrodes. On the surface of the Si substrate 101, 64×64 signal input contact portions 102 are formed, and on one surface there is an A1 electrode. 103 and an insulating layer 1 of SiO□, for example.
04 is formed. A Ti film 105 is deposited on the entire surface by vapor deposition or sputtering. Cu films 106 are sequentially formed. Next, photoresist 19107 is formed,
An opening 107a is formed in the photoresist film 107 in a portion where a bump electrode is to be formed (FIG. 2b). Subsequently, a Cu layer 108 is formed using a selective plating method. (2) N-layers 109 are sequentially formed.

(Figure 2C). Next, after removing the photoresist film 107 (FIG. 2d), using the In layer 109 as a mask, the Cu film 106. The Ti film 105 is sequentially removed by etching to form In bump electrodes (FIG. 2e).

In the bump electrode formed by the conventional method, as shown in FIG. 2e, the height of the bump electrode at the periphery of the area where the bump electrode is formed is higher than that at the center. Become.

(Problems to be Solved by the Invention) The height of the bump electrode formed on the substrate by the above-mentioned conventional method is higher at one peripheral portion than at the central portion. This is a phenomenon unique to electroplating, and is due to the fact that the current density increases at the periphery of the pattern. Because of this variation in the plating thickness, when the light receiving area on which In bumps are formed and the corresponding terminal electrodes are butted together and integrated, the height of the In bump electrodes at the center of the substrate will be There was a problem to be solved in that it was not connected because it was low, resulting in an image defect in that part.

The present invention has been made in view of the above points, and provides an improved bump electrode that makes the height of a plurality of bump electrodes uniform, thereby making it possible to reliably butt connect the terminal electrodes of the opposing substrate. An object of the present invention is to provide a method for manufacturing a semiconductor device having the following methods.

[Structure of the invention]

(Means for Solving the Problems) A method for manufacturing a semiconductor device according to the present invention includes a step of forming a metal film on a substrate on which a plurality of electrodes are formed, and a step of forming a 2-odresist film on the metal film. a step of forming openings in the photoresist film at a portion where a plurality of bump electrodes are to be formed and at a peripheral edge of the substrate where no bump electrodes are to be formed; and forming a plurality of layers of bumps in the openings by selective plating. The method includes a step of forming a photoresist film, a step of exposing and removing a photoresist film at a portion of the peripheral edge of the substrate where the bump electrode is not formed, and a step of removing the bump at the portion of the peripheral edge of the substrate.

(Function) Since the bump electrodes formed according to the present invention have the same height, when the 5i-COD and the light receiving part are integrated by butting the corresponding terminal electrodes, the bump electrodes formed according to the present invention are crimped uniformly over the entire surface. Water retention is good because electrical continuity is obtained < IR-CCD
can be made.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1a shows a cross section of the main part of the 5i-CCD before bumps are formed, and 64×64 signal input contact portions 12 are formed on the surface of the Si substrate 110 at a pitch of 80 μm.
On the surface, there is Alff1 pole 13 and M such as 5un2.
Edge, 1Wi4 is formed. Ti film 15 on this surface
Then, a Cu film is formed by a vapor deposition method. rigts
is a barrier metal, and the Cu film 16 is an electrode film for plating.

Next, a positive photoresist film 17 is formed on the entire surface,
Next, a photoresist film 17a in a portion where a bump electrode is to be formed and a portion in which a bump electrode is not to be formed adjacent thereto;
17b has an opening 17c of 20 μm x 20 μm.

17d (Fig. 1b). The number of bump rows to be formed on the outside of the signal input contact section is preferably determined by looking at the uniformity of 64 x 64 bumps, but if five rows are formed, the number of bumps can be fairly uniform. A portion of the photoresist film where the bump electrode is not formed is exposed to light. 27 in the figure is a photoresist film exposed to light (FIG. 1C).

Next, the Cu layer 1 is made so that the photoresist film 17 is not exposed to light.
8 and then InJ119 is formed by plating (FIG. 1d).

Next, the Cu layer 18 is coated with a copper sulfate bath.
It is immersed in a plating solution and plated at room temperature using the Cu film 16 as the underlying metal film as an electrode for several minutes at a predetermined current. As a result, CuJ 118 having a thickness of more than ten μm is formed. Further, the In layer 19 is formed to a thickness of more than ten μm by immersing the substrate on which the Cu layer 18 is formed in a borofluoride bath and plating it at a predetermined electrode value for several tens of minutes. At this time, the height of the bump becomes higher at the periphery of the area where the bump is formed (the area where the bump electrode is not formed), but the height of the bump is approximately the same at the central area where the bump is formed (the area where the bump electrode is formed). . Next, the exposed portions of the photoresist film 27 where the bump electrodes will not be formed are developed and removed (FIG. 1e).

Next, the base Cu film 16 of the exposed portion is treated with a Cu etchant.
and remove bumps in areas where bump electrodes will not be formed (
Figure 1 f).

Next, the photoresist 1 to film 17 are removed, the underlying Cu film 16 between the remaining bump electrodes is removed by etching, and then the Ti film 15 is removed by etching. In this way, by removing unnecessary high bumps on the periphery of the bump-formed area, the 5i-
A CCD is obtained. (Figure 1g).

〔Effect of the invention〕

As described above, according to the present invention, the height of the bump electrodes is the same over the entire surface, so after forming bumps on the light receiving part in the same way, using a pressure welding device with high parallelism (not shown), The 5i-CCD substrate and the light receiving section are held facing each other and are pressed together at a predetermined temperature and pressure for several minutes to integrate them. In this way, the pressure of pressure welding is applied uniformly over the entire surface, ensuring that the terminal electrodes are connected reliably, resulting in a high yield.
can be obtained.

The present invention is not limited to the above-described embodiments, and can be modified in various ways without departing from the spirit thereof. For example, the size of the diameter of the bump removed by etching may be different from the size of the bump in a predetermined portion. Furthermore, the number of rows of openings in the portion where bump electrodes are not formed can be appropriately determined by considering the uniformity of plating.

[Brief explanation of the drawing]

FIGS. 1a to 1g are cross-sectional views showing a method for manufacturing a bump electrode according to an embodiment of the present invention in the order of steps. Figure 2g''-'e are cross-sectional views showing the conventional bump electrode manufacturing method in the order of steps. 11...Substrate 12...Signal input contact portion 13...AI electrode 14...・Insulating layer 15...
・Ti film 16...Cu film 17...Photoresist (unsensitized) film 27...Photoresist (photosensitive) film

Claims (2)

[Claims] (1) A step of forming a metal film on a substrate on which a plurality of electrodes are formed, a step of forming a photoresist film on the metal film, and a portion where a plurality of bump electrodes are formed on the photoresist film. and a step of forming an opening in a portion of the peripheral edge of the substrate where no bump electrode is formed, a step of forming a plurality of bumps in the opening by a selective plating method, and a photoresist film on a portion of the peripheral edge of the substrate where the bump electrode is not formed. A method for manufacturing a semiconductor device, comprising: exposing and removing bumps on the substrate; and removing bumps on a peripheral edge of the substrate. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the bumps at the peripheral edge of the substrate are removed using an etching agent that dissolves the metal film but does not dissolve the bumps.