JPS63273337A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the stress due to the collapse of the bump at the bonding time from being applied to the semiconductor substrate by forming a polyimide layer in the outer periphery of the region where the bump of the electrode is to be formed. CONSTITUTION:On a semiconductor substrate 101, an Al electrode 103, a passivation film 104, an Al film 105 for a plating electrode, a patterned titanium film 106 and a platinum film 107 are formed through an insulating film 102. Then, an independent polyimide layer 108 is formed in the region where a bump is to be formed, a photoresist pattern 109 is stacked which opens the region where a bump is to be formed, a gold bump 110 is formed by plating, the layer 109 is removed, and with the bump 110 and the layer 108 as a mask the layer 105 is etched away, whereby a semiconductor device with a bump is formed. In this semiconductor device, because of the existence of the polyimide layer on the surface of the bump and the semiconductor device, the stress due to the bonding pressure when bonding the lead wire to the bump is reduced, whereby the occurrence of cracks in the semiconductor chip is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for forming bumps.

[Conventional technology]

In recent years, as the demand for IC cards has increased, 'l'
AB (Tape Automated Bondin)
g) The importance of IC is increasing.

One method for forming TABIC is to form bumps on a wafer. A conventional bump forming method will be described below with reference to FIG.

First, as shown in FIG. 2(a), a semiconductor element is formed on a semiconductor substrate 101, and then an insulating film 102 is formed.9 Next, a metal wiring layer, for example, made of aluminum, is formed on a bonding pad forming area on this insulating film 102. Electrodes 103 are formed. Next, a passivation 11% 104 made of an insulator is formed on the entire surface, a bonding pad formation area and a dicing area are opened, and a metal wiring layer, for example, an aluminum film 105, which will be an electrode when plating metal that will become a bump, is formed on the entire surface. and then the metal for bump formation,
For example, platinum pA 107 is formed by sputtering as a metal for preventing a reaction between the titanium film 106 and the gold and aluminum film 105 to improve adhesion with gold, and is patterned to cover the region where the bonding pad is to be formed.

Next, as shown in FIG. 2(b), a photoresist layer 109A with openings in the bonding pad forming area is formed by ordinary photolithography, and then gold is deposited by gold plating. A bump 110 is formed.

Next, as shown in FIG. 2(c), a photoresist layer 10
After removing 9A, the aluminum film 105 is removed using the gold bumps 110 and the platinum film 107 as a mask, thereby completing a semiconductor device having the gold bumps 110.

[Problem that the invention seeks to solve]

In the bump structure by the conventional bump formation method described above,
During gold plating, the gold extends laterally across the upper part of the photoresist N9A, which serves as a mask, so the shape of the completed bubble is formed between the gold bump 110 and the surface of the semiconductor device, as shown in Figure 2 (' A void 112 as shown in C) is formed.

When bonding a lead electrode to an IC chip with bumps, the gold bumps 11 are bonded by bonding pressure.
There is a drawback that the 0 is crushed and not only fills the void 112, but also causes cracks in the IC chip, which impairs yield and reduces reliability.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device with improved yield and reliability, which has a bump structure in which less stress is applied to a semiconductor substrate due to crushing of the bump during bonding.

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes a step of selectively forming a polyimide layer on the outer periphery of a bump formation region of an electrode wiring formed on a semiconductor substrate, and a step of selectively forming a polyimide layer on the outer periphery of a bump formation region of an electrode wiring formed on a semiconductor substrate. The method includes a step of forming a photoresist layer covering between the polyimide layers, and a step of forming a bump in a bump forming region of the electrode wiring by a plating method.

〔Example〕

Next, embodiments of the present invention will be described using the drawings.

FIGS. 1A to 1C are cross-sectional views of a semiconductor chip shown in the order of steps for explaining an embodiment of the present invention.

First, as shown in FIG. 1(a), as in the conventional case, an aluminum electrode 103 is formed on a semiconductor substrate 101 via an insulating WA 102, and then passivation 1104.
An aluminum film 105, a patterned titanium film 106, and platinum plA 107 are respectively formed for plating electrodes.

Next, an opening is made on the electrode wiring made of platinum film 107 or the like on which bumps are to be formed, and a polyimide layer 108 is formed, which is independent of the bump forming area 120, to cover the periphery of the bump forming area 120. It is formed by etching with hydrazine using a photoresist as a mask using a photolithography method.

Next, as shown in FIG. 1(b), after forming a photoresist pattern 109 with an opening on at least the bump forming region 120 of the electrode wiring by a normal photoetching method, gold is deposited by a plating method. Gold bumps 110 are formed by plating to a thickness of about 10 μm.

As shown in FIG. 1(c) below, photoresist J'1
109 is removed to form gold bumps 110 and polyimide layer 10.
By etching and removing the aluminum film 105 using 8 as a mask, a semiconductor device with bumps is completed.

In the semiconductor device formed in this way, since the polyimide layer 108 exists between the gold bumps 110 and the surface of the semiconductor device, bonding will be difficult when lead electrodes are bonded to the gold bumps 110 in a later process. Stress caused by pressure is alleviated. This prevents cracks from occurring in the semiconductor chip.

Incidentally, in the above embodiment, a case has been described in which gold is used as the metal for forming the bumps, but it goes without saying that copper may also be used.

〔Effect of the invention〕

As explained above, in the present invention, by forming a polyimide layer on the outer periphery of the bump forming area of the electrode wiring, the stress caused by crushing the bumps when bonding the lead electrodes is reduced on the semiconductor substrate. effective. Therefore, the manufacturing yield and reliability of semiconductor devices are improved.

[Brief explanation of the drawing]

1(a) to 1(C) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining one embodiment of the present invention, and FIG. 2(a)
) to (C) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining a conventional method of manufacturing a semiconductor device. 101... Semiconductor substrate, 102... Insulating film, 103
... Aluminum film electrode, 104 ... Passivation film, 105 ... Aluminum film, 106 ... Titanium film, 107 ... Platinum film, 108 ... Polyimide layer, 109 ... Photoresist layer, 110...Gold bump, 112...Gap, 120...Pub formation area. Agent Patent Attorney Oto Uchihara −〈

Claims (1)

[Claims] selectively forming a polyimide layer on the outer periphery of a bump formation region of an electrode wiring formed on a semiconductor substrate;
It is characterized by comprising the steps of: forming a photoresist layer covering between the polyimide layers except for at least the bump formation area of the electrode wiring; and forming a bump in the bump formation area of the electrode wiring by a plating method. A method for manufacturing a semiconductor device.