JPS60130846A - Manufacture of bump electrode type semiconductor device - Google Patents

Abstract

PURPOSE:To form a bump electrode having high reliability by forming the pump electrode consisting of a low melting-point metal on laminated metallic films composed of Ti/Al/Ti while using the laminated metallic films as foundation metallic films and removing the laminated metallic films through etching by using an alkali group etchant. CONSTITUTION:An insulating film 23 with openings is formed on input sections 22 consisting of Al electrodes on a CCD substrate 21. A laminated film 24 in which a Ti film 241, an Al film 242 and a Ti film 243 are evaporated on the whole surface in succession is shaped. Cu films 25 as plating layers are formed at positions where bump electrodes are shaped through evaporation and patterning. A photo-resist 26 is formed according to a pattern, and Cu layers 27 and In layers 28 are shaped. The photo-resist 26 is removed, only foundation metallic layers just under laminated electrodes consisting of the Cu layers 27 and the In layers 28 are left while using the laminated electrodes as masks, and the laminated metallic films 24 except these layers 27, layers 28 and foundation metallic layers are removed gradually through etching by an alkali group etchant in succession.

Description

[Detailed description of the invention] [Field of technology 11j of Hanamei] This Komei is a semiconductor device in which a hump electrode made of a low melting point metal is further formed on a small number of metal electrode layers in ohmic contact on a semiconductor substrate. of! This invention relates to a Fl manufacturing method.

[Technical backstory of the invention and its problems] A COD sensor is an integrated sensor that has the function of receiving the brightness and darkness of an image using a large number of two-dimensionally arranged photodetecting elements, converting this into a time-series electrical signal, and extracting it. It is well known as a sensor. Conventionally, sensors that extract two-dimensional physical quantities have been limited to such photodetecting elements. Recently, with the development of mechanical technology, the demand for two-dimensional detection of physical quantities other than light, such as pressure and tactile signals, has begun to increase.

As an element for detecting these physical quantities, a semiconductor piezoresistive element is used, for example. For example, if diffused resistance elements are formed in a two-dimensional array on an 81 substrate and an external stress is applied to them, the resistance value at that point changes and a signal can be obtained. And such detection elements are CC, D
When integrated with the sensor, an integrated sensor can be obtained that detects stress distribution and processes its electrical signals. In this case, in order to integrate the sensing element substrate and the COD substrate, a so-called bump electrode (6/j4) is used in which a plurality of corresponding terminal electrodes are directly butted and connected.

FIG. 1 shows an example of the manufacturing process of a conventional hump electrode type CCD. First, as shown in (a'), the board surface 1 of the cc'om board 11 is connected to the input section 12 (12a, 1
21+, . . . ), an insulating film 13 having an opening is formed. Although not shown in the figure, a large number of feed gates 1 and electrodes are arranged in the CCD sensor (ff111), and the input section 1
2 is formed by the A-C electrodes. After this, (1+
As shown in ), a Cr film 14 serving as a barrier metal is deposited, and a plating resist (C11 resist 15) is deposited.Next, as shown in (C,), a Cr film 14 is deposited.
A pattern of 6 was formed, and J:Tsu00 layer 17 (17a, 17b) was formed using the selective plating method.

-), HA ite I n layer 18 (18a, 18
b , −> is formed 4. Next, as shown in (1), the first resist 16 is removed, and then the CIJ film 15 is removed.
Then, the Cr film 14 is removed one by one in order to form a 7n bump electrode.

In such a conventional method, the plating electrode C
1L film 15 and the Cr film 1 which is a barrier metal thereunder.
Etching to remove 4: Since jl is used with yarn, I n G 18 is attacked by the etching solution. As a result, the 111 layer 18 becomes thinner, and in the worst case, the CLI layer 17 is exposed, resulting in the disadvantage that the desired ln bump electrode cannot be formed.

[Object of the Invention] The present invention provides a method for manufacturing a semiconductor device that eliminates these drawbacks and makes it possible to form highly reliable bump electrodes.

[Summary of the Invention] The present invention provides a Ti/A1. Using the laminated metal film of 'T-i as a base metal layer, a bump electrode made of a low melting point metal is formed on this by selective plating, and then the laminated metal film is removed by etching using an alkaline edger. It is characterized by what it did.

[Effects of the Invention] According to the present invention, the bump electrode is not immersed in the edgeant, and the 4-
11. A highly reliable semiconductor device I can be produced.

[Fruit of invention 1JI! Example] An example of the present invention will be described below using FIG. 2. Second
Figure (a) is the same as Figure 1 (a), and the CCD substrate 2
Input section 22 (22a, 22
b, . As shown in II(b), a laminated film 24 is formed by sequentially depositing a 7i film 24t, an Af film 242, and a Ti film 243 on the entire surface.

TillA241.243 is a barrier metal, Δ
,,e Ill 242 is a plating electrode. next(
As shown in C), the plating base layer is placed at the position where the bump electrode is placed (25a, 25b).
, -> are formed by vapor deposition and patterning. After this, a pattern of the resist 26 is formed as shown in (1), and Cl1127 (2
7a.

271+, ・), then [n lii! 28 (
28a, 281+.

...) is formed. To form the 011 layer 27, the substrate is immersed in a CLI plating solution such as a copper sulfate bath at a temperature of 1°, and the AJL film 242 is used as an electrode to first perform reverse plating for several seconds to clean it, and then perform normal plating. Cu plating is performed by applying current at a predetermined current value for several tens of minutes. As a result, an 011 layer 27 having a thickness of several μIll is formed. The In1ffi 28 is formed to a thickness of several μm by immersing this semiconductor substrate in an In plating solution such as a borofluoride bath and performing electroplating at a predetermined current value for several tens of minutes. Next, as shown in (C), the photoresist 26 is removed, the laminated electrode of the Cu layer 27 and the ln layer 28 is used as a mask, and only the base metal layer immediately below is left, and the rest of the laminated metal film 24 is sequentially coated with alkali. The system edge 1- is etched and removed. First, the Ti film 24: +(, j, for example A
Using a p) lit solution consisting of water 1-e, 24 g of ethylenediaminetetraacetic acid, and 180 cc of ammonia water, and hydrogen peroxide as the B solution, A: r2: B solution = 2:1.
Remove and cover by etching for about 1 minute at room temperature with an etching solution with a mixing ratio of . Next, the Affi membrane 242 is coated with, for example, water 5
pH 1 obtained by thoroughly decomposing 75g of potassium hydroxide in 00CC
Remove by edging with solution 1 for about 2 minutes. At that time, it is cooled with running water to generate heat.The next Ti film 241 is etched and removed in the same manner as the above Ti film 243 using the same etching solution.

As described above, according to this embodiment, after forming the ln bump electrode, the underlying laminated gold B film is sequentially etched using an alkaline etchant, thereby making it possible to perform di-V strip etching without removing the bump electrode by 12J.

In addition, by making it possible to reliably perform di-IT stretching as described above, for example, A! The advantage of using a metal film is that mask construction can be simplified.

The present invention is not limited to the above embodiments. For example, C, 11 layer 2
Reference numeral 7 denotes an auxiliary metal layer of the ln bump electrode, and it is also possible to omit this and directly plate the ln layer 28 to form the bump electrode. In addition to ln, Sb and Bf can be used as the bump electrode total bending layer.

Low melting point metals such as pl+, Δu, 3n, Zll can be used.

[Brief explanation of the drawing]

FIGS. 1(a) to ((1) are cross-sectional views showing the steps of a conventional COD bump electrode formation method, and FIGS. 2(a) to (e) are COD bump electrode formation according to an embodiment of the present invention. It is a sectional view showing steps of the method. 21 COD substrates, 22a, 22b, 22c -
...Input section, 23 River insulating film, 24... Laminated metal film, 2
41...Ti film, 242...A-e 1! , 24
3...Ti film, 25a, 25+),';!
5cm Qu film, 26-...Flu 11-resist, 27a
, 27b, 27cmC; u layer, 28a, 28
b, 2′8 cmIn layer. Applicant's agent Patent attorney Takejin Suzue

Claims (1)

[Claims] A base metal film is formed on the entire surface of the semiconductor substrate to make A-mink contact in a plurality of bump electrode formation regions, and a plurality of bump electrodes made of a low melting point metal are formed on this base metal film by selective plating. J3 is a method for manufacturing a semiconductor device in which an unnecessary portion of the base metal film is removed by removing a hump electrode as a mask, and Ti is used as the base metal film.
/'A-(1/' Ti stacked metal film is used, and this laminated metal film is etched with an alkaline etchant. The person who manufactured the device.