JP2692344B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method for manufacturing the same, and more particularly to a semiconductor device having bumps with vertical sidewalls and a method for manufacturing the same.

[Conventional technology]

A conventional method for manufacturing a semiconductor device provided with bumps having vertical sidewalls will be described with reference to the drawings.

First, as shown in FIG. 3 (a), a photoresist having a thickness of 15 to 20 μm is applied on a semiconductor substrate 1 on which an element and a current path for plating are formed and then patterned to form a mask 2 having an opening. To do. Next, gold or copper is plated by a plating method to form the bumps 3 in the openings.
The bumps 3 are formed to have a vertical side wall by forming the bumps 3 to have a thickness equal to or smaller than that of the mask 2.

Next, as shown in FIG. 3B, the mask 2 is peeled off, and then the cover film 4 is formed on the entire surface. This cover film 4 is
For example, it may be an organic film such as polyimide or an inorganic film such as a silicon oxide film or a silicon nitride film. Next, a photoresist film 5A is formed on the cover film 4.

Next, as shown in FIG. 3C, after patterning the photoresist film 5A on the bumps 3, the cover film 4 is etched using the photoresist film 5A as a mask.
When the cover film 4 is an organic film such as polyimide, the photoresist film is generally a cyclized rubber-based negative type, and is generally etched with a mixed solution of hydrazine and ethylenediamine. When this negative type photoresist film is used, since the dimensional accuracy and the alignment accuracy are not good, it is necessary to etch the cover film 4 on the surface of the bump 3 to prevent the cover film 4 from remaining on the surface of the bump 3. .

Next, as shown in FIG. 3D, the photoresist film 5A
Peel off and remove.

When the inner leads 10 of the TAB tape are bonded to the bumps 3 thus formed, the bumps 3 are crushed and spread laterally as shown in FIG. The cover film 4 may not be provided after the bumps 3 are formed.

[Problems to be solved by the invention]

In recent semiconductor devices, the number of input / output pads has increased along with higher integration, and the bump shape has also been made smaller by reducing the pad size and the pad pitch by using bumps with vertical sidewalls. The bump of the semiconductor device of No. 1 does not have the cover film formed, or even if it is formed, it is not formed on the side wall portion of the bump having the vertical side wall.
There is a risk of shorts between bumps due to the spread of the bumps during inner lead bonding (hereinafter referred to as ILB). Therefore, it is necessary to set a large bump interval,
It is difficult to reduce the pad pitch, which hinders high integration of semiconductor devices.

[Means for solving the problem]

A semiconductor device according to a first aspect of the present invention is a semiconductor device including a bump having a vertical side wall formed on a semiconductor substrate, wherein an insulating resin having the same thickness is continuously formed on the semiconductor device surface and the side wall portion of the bump. It was formed part way through.

A method of manufacturing a semiconductor device according to a second aspect of the present invention includes a step of forming a bump having side walls whose entire side surfaces are vertical on a semiconductor substrate by a plating method, and a step of forming an insulating organic film on the entire surface including the bump. And a step of patterning the organic film to expose upper surfaces and a part of sidewalls of the bumps.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1A to 1D are sectional views of a semiconductor chip for explaining the first embodiment of the present invention.

First, as shown in FIG.
A photoresist film having a thickness of 15 to 20 μm is formed on the semiconductor substrate 1 on which the elements and the current path for plating are formed, and patterned to form the mask 2. Next, gold, copper or the like is plated to form bumps 3 having vertical side walls.

Next, as shown in FIG. 1 (b), an organic solution such as polyimide is applied to the entire surface including the bumps 3 by spin coating,
Heat treatment is performed at 130 to 150 ° C. for 30 to 60 minutes to form the cover film 4. At this time, the imidization ratio of the polyimide film is 5 to 30.
% And becomes soluble in an alkaline solution. Next, a positive photoresist film 5 is formed on this cover film.

Next, as shown in FIG. 1 (c), after exposing using a mask having a pattern having the same shape as the pattern used when forming the bumps 3, as a developer for a positive resist,
For example, tetramethylammonium hydride (TMA
Development is performed for 150 to 300 seconds using a 2-3% aqueous solution of H). At this time, at the same time as the patterning of the photoresist film 5, the cover film 4 made of polyimide is also patterned, and the cover film 4 is side-etched by the developing solution to be etched halfway along the vertical wall of the bump 3.

Next, as shown in FIG. 1 (d), after removing the photoresist film 5 with methyl ethyl ketone, butyl acetate or the like, heat treatment is carried out at 250 to 300 ° C. for about 60 minutes to completely imidize the polyimide film.

On the bumps 3 of the semiconductor device thus formed,
FIG. 2 shows a case where the inner lead 10 of the TAB tape is bonded.

In the inner lead bonding, a pressure of about 30 to 60 kg / cm ² is applied, but the side wall of the bump 3 and the semiconductor substrate 1
Since the cover film 4 is continuously formed on the upper side, the bumps 3 are less crushed and less laterally spread. Therefore, the pad pitch can be reduced.

〔The invention's effect〕

As described above, according to the present invention, by forming a cover film having substantially the same thickness and continuous on the side wall portion of a bump having a semiconductor substrate surface and a vertical side wall up to the middle of the side wall, bumps for inner lead bonding are formed. Since it is possible to suppress the collapse and lateral spread of the pad, it is possible to reduce the pad size and the pad pitch. Therefore, there is an effect that a semiconductor device having a higher degree of integration can be obtained.

[Brief description of the drawings]

1 (a) to 1 (d) are cross-sectional views of a semiconductor chip for explaining a first embodiment of the present invention, and FIG. 2 is a cross-section when an inner lead is bonded to a bump formed by the embodiment. FIGS. 3A to 3D are sectional views of a semiconductor chip for explaining a conventional example, and FIG. 4 is a sectional view of a conventional example in which an inner lead is bonded to a bump. 1 ... Semiconductor substrate, 2 ... Mask, 3 ... Bump, 4 ... Cover film, 5,5A ... Photoresist film, 10 ... Inner leads.

Claims (2)

(57) [Claims] 1. A semiconductor device having a bump having a vertical side wall formed on a semiconductor substrate, wherein an insulating film having the same thickness is formed halfway between the substrate surface and the side wall of the bump. Semiconductor device. 2. A step of forming on a semiconductor substrate a bump having a side wall whose entire side surface is vertical, a step of forming an insulating organic film on the entire surface including the bump, and patterning of the organic film. And a step of exposing the upper surface of the bump and the upper portion of the side wall of the bump.