JPH0719797B2 - Semiconductor device mounting tool - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to bonding in the case of bonding an electrode on a semiconductor element and an external metal lead.

[Technical background of the invention and its problems]

In recent years, semiconductor elements such as ICs and LSIs have been introduced into various home electric appliances and industrial equipment. From the viewpoints of power saving, utilization of effective space, etc., these electronic devices are progressing toward miniaturization and thinning, that is, so-called lightness, thinness and shortness.

For this purpose, semiconductor devices are strongly demanded to be miniaturized and thinned for this purpose. Also, semiconductor devices are packaged for handling or mechanical protection after completed as devices by various processes. However, only the electrode leads must be taken out of the package because of the need for electrical connection. Usually, a semiconductor device is connected to the outside of the package by a lead frame, wire bonding, metal projections (bumps), substrate wiring, or tape carrier method. Among them, there is a tape carrier system which has a particularly large number of connections and is suitable for a demand for miniaturization and thinning.

In the tape carrier system, a multilayer metal film called a barrier metal is provided on the electrode terminals on the semiconductor element, and a metal protrusion is further provided on the barrier metal by electroplating. Then, a long polyimide tape having a certain width provided with metal lead terminals is prepared, and the metal lead terminals and the metal protrusions are simultaneously bonded to the electrodes on the same chip at the same time regardless of the number of electrode terminals. This method is TAB (Tape
It is also called Automatid Bonding) method and is spreading in the field of multi-terminal thin type, but there are problems that the number of electrode connection steps is large and the cost is high, and the element yield is reduced because of processing to the element.

Therefore, recently, a lead bump is formed by etching the lead or a transfer bump method (for example, Japanese Patent Laid-Open No. 57-1
A TAB method using a method in which a protruding electrode (bump) is formed on the lead side in advance by a method called Japanese Patent No. 52147) has also appeared. According to these methods, the device side may be a normal Al pad (electrode), and the applicable range is widened. However, if you want to make protrusions by etching,
The limitation of the etching ability prevents the leads from becoming higher in density, and in the transfer bump method, it is necessary to prepare and optimize a bump forming substrate called a transfer substrate, and to control the Sn plating thickness of the lead surface. Problems remain, such as the time required to obtain stable joining conditions. Further, as shown in FIG. 3, after forming a film 22 and a metal wiring 21 on the metal wiring 21, a metal projection in which a metal projection electrode 23 is formed on the opposite side through the through hole of the film 22 at the tip of the metal wiring 21. There is also a method of electrically connecting the film carrier with electrodes and the electrode portion 26 of the semiconductor device. However, in this method, it is difficult to deal with the fine pitch or the small electrode pad 26 due to the influence of the etching angle. Therefore, there is a method of thinning the entire polyimide film 32 as shown in FIG. 4 in order to cope with the small electrode pad, but there is a problem that the rigidity of the entire film is lost and the reliability of the joint is lowered.

[Object of the Invention]

The present invention solves the above problems and improves reliability.
The purpose is to provide technology.

[Outline of Invention]

The present invention is, for example, an improved TAB film having a structure as shown in FIG. 4 as a mounting tool for a semiconductor device. That is, as the mounting tool, for example, a polyimide film thick enough not to lose the rigidity of the whole is prepared, and metal wiring is provided on the polyimide film. It is assumed that the element is placed on the film side, and when the wiring pattern and the element electrode pad are aligned with each other, a metal protruding electrode (bump) is formed in a portion corresponding to the element electrode pad by penetrating the polyimide from the metal wiring. At this time, since the polyimide thickness allows only excessive bump formation due to the limitation of etching ability, a part of the film connected to the element electrode pad is made thin by etching.
As a result, bumps can be formed with a fine pitch.
(Inner Lead Bonding) Can be bonded.

〔The invention's effect〕

According to the present invention, bumps can be formed with a finer pad pitch than that of the structure of FIG. 3 and the TAB having a higher rigidity than that of the structure of FIG.
Film can be made. Since it has higher rigidity, it is possible to obtain high reliability for bonding the metal leads and bumps to the pads. Further, compared to FIG. 3, the element fits into the etched portion, so that it can be mounted thinner.

Example of Invention

An embodiment of the present invention is shown in FIG. 1, and therefore a configuration according to this embodiment will be described below.

In Fig. 1, C is placed on the polyimide film 12 of about 125 μm.
The u wiring 11 and the pattern are formed by electroless plating, and the central portion of the polyimide film is etched to about 25 μm. Then, a portion corresponding to the Al pad 16 is etched to form a through hole, and then a Cu bump 13 connected to the Cu wiring 11 is formed.
To form. And to improve the reliability of bonding, Cu bump
Au plating layer 14 is applied to 13.

Cu bumps on polyimide film made in this way
Align 13 with Al pad 16 and use ILB (Inner Lead Bond
ing) Join.

[Other Embodiments of the Invention]

(1) In the above example, copper was used as the bump material,
Au or the like may be used in order to improve the bonding reliability.

(2) In the above example, the Au plating layer 14 was applied on the Cu bumps 13. However, in order to make the bumps cheaper, the Cu bumps 13 alone may be bonded in an atmosphere that does not oxidize.

(3) Although etching was used to thin the central portion of the polyimide film, the peripheral portion can be thickened by sticking a polyimide film serving as an outer frame to the originally thin film with an adhesive or the like as shown in FIG.

(4) It is also effective to thicken the Cu wiring 41 partially or entirely as shown in FIG. 2 instead of providing the polyimide film with a thickness difference.

[Brief description of drawings]

FIG. 1 is a sectional view of a joint portion showing the structure of the present invention.
The drawing is a cross-sectional view of the joint portion of another embodiment, and FIGS. 3 and 4 are
FIG. 10 is a cross-sectional view of a joint portion according to a conventional method. 11,21,31,41 …… Metal wiring 12,22,32,42 …… Polyimide film 13,23,33,43 …… Copper bump by plating 14,24,34,44 …… Gold plating layer 15,25, 35,45 …… passivation film 16,26,36,46 …… electrode pad 17,27,37,47 …… silicon element

Claims (3)

[Claims] 1. A frame member which is formed by laminating a metal wiring at least on a side connected to an electrode of a semiconductor element on a thin film, and which connects the electrode on the semiconductor element and an external electrode by the metal wiring. According to another aspect of the present invention, there is provided a mounting tool for a semiconductor device, wherein the frame member on a side connected to an electrode of the semiconductor element is thinner than other portions. 2. The mounting tool for a semiconductor device according to claim 1, wherein a part of the metal wiring is thin. 3. A mounter for a semiconductor device according to claim 1, wherein a part of the film is thin.