JPH0311740A - Formation of bump electrode of semiconductor element - Google Patents

Abstract

PURPOSE:To enable bump electrodes to fulfill both functions of an electrical connection and a mechanical joining at the time of bonding of the electrodes to a conductive pattern of a substrate by a method wherein a photosensitive resin material containing an electrically conductive substance and a thermally adhesive substance is applied on the surface, on which there are electrodes, of a semiconductor element and the bump electrodes are formed. CONSTITUTION:A modified acrylate resin, a phenolic novolak resin, an epoxy resin or the like is used as a base material and a photo-setting initiator to correspond to the respective resins, an electrically conductive component, such as Ag, Ni or the like, and a thermally adhesive component, such as a thermoplastic resin, a rosin or the like, are added to the base material and moreover, a proper catalyst is added to the base material according to the need to prepare a bump electrode formation material. This material is applied on the surface, on which electrodes are provided, of a semiconductor element to form bump electrodes by a photolithography technique. In the mounting of the element to a substrate, the electrodes are aligned to a conductive pattern of the substrate, a heating is performed from the side of the element along with a pressing and both functions of an electrical connection and a mechanical joining can be obtained by the electrodes.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for forming protruding electrodes (bumps) on the electrodes of semiconductor devices such as IC (integrated circuits) and LSIC large-scale integrated circuit (LSIC) chips. It can be used in the field of connection technology between a semiconductor element on which a protruding electrode is formed and a conductive pattern on a mounting board.

Conventional technology In the field of electronic devices and equipment, there is a social demand for miniaturization, which is lighter, thinner, and smaller. It is necessary to implement it.

This can especially be seen in devices developed for devices such as hybrid ICs, card-like devices, and liquid crystal televisions.

In order to achieve such high-density packaging, paired chips are much more advantageous than semiconductors mounted on a board in the form of a packaged product. Furthermore, it does not use wires and is more effective than the so-called wire bonding method, in which wires of gold or aluminum are welded to the electrodes of the semiconductor element and the conductive pattern on the substrate to connect them. Wireless bonding, which connects multiple electrodes and conductive patterns on a substrate all at once, is extremely effective.

Examples of wireless bonding include a flip chip method and a film carrier method.

The flip-chip method is a method in which a protruding electrode is formed on a semiconductor element electrode, and the protruding electrode and a conductive pattern on a substrate are joined by soldering.

The film carrier method electrically and mechanically connects the inner edge of a conductive finger for external connection supported on a film and the electrode of a semiconductor element, but in order to avoid the edge of the semiconductor element from coming into contact with the finger. A protruding electrode is formed on the electrode of the semiconductor element or on the finger, and the devices are connected to each other via the protruding electrode.

Problems to be Solved by the Invention The protruding electrodes in the above method are all made of Au, Ag, and N+.
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It is made of a metal such as solder or a metal compound. These metal-based protruding electrodes have high temperatures during bonding, and the bonded parts are firmly fixed by alloys, etc., so they are susceptible to thermal stress due to the difference in thermal expansion coefficient between the semiconductor element base material and the wiring board, and from external damage. When pressure due to mechanical or thermal impact is applied, deformation of the wiring board, etc. may occur, or peeling of the bonded portion may occur.

In addition, metal-based protruding electrodes are usually formed by electrolytic plating, etc., but excess plating liquid causes short circuits between element electrodes, so it is necessary to narrow the electrode spacing or perform fine processing. It is difficult.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for forming a novel protruding electrode for a semiconductor device, which eliminates the above-mentioned defects that metal-based protruding electrodes have. shall be.

Means for Solving the Problems According to the present invention, a photosensitive resin material containing an electrically conductive substance and a thermally adhesive substance is coated on the surface of a semiconductor element on which an electrode is located, and a photosensitive resin material containing an electrically conductive substance and a thermally adhesive substance is applied onto the electrode of the semiconductor element by photolithography. Provided is a method for forming protruding electrodes for a semiconductor device, characterized in that protruding electrodes are formed on the substrate.

Function: In the method for forming a protruding electrode according to the present invention, a resin-based protruding electrode having electrical conductivity and thermal adhesiveness is formed on a semiconductor element electrode by photolithography technology, and this protruding electrode itself becomes electrically conductive when bonded to a conductive pattern. It functions as both physical connection and mechanical bonding.

EXAMPLES Below, a method for forming protruding electrodes of a semiconductor device according to the present invention will be described in detail.

The material for forming the protruding electrodes formed according to the present invention is based on a resin such as a modified acrylate type, a phenol novolac type, or an epoxy type, and a photocuring initiator corresponding to each type of resin as a photosensitive component. , an inorganic or organic substance such as Ag or Ni as an electrically conductive component, and a thermoplastic resin or rosin as a thermal adhesive component. Furthermore, various properties of the protruding electrode forming material can be adjusted by adding an appropriate catalyst as necessary.

The protruding electrode forming material is applied to the surface of the semiconductor element on which the electrode is provided by an appropriate means such as spin cord or roll coating. At this time, the viscosity of the bump electrode forming material can also be adjusted using a reactive diluent or an organic solvent.

Thereafter, protruding electrodes are formed using normal photolithography techniques. That is, after drying the applied protruding electrode forming material, only the corresponding portions of the semiconductor element electrodes are exposed to, for example, UV (ultraviolet) light through a pattern mask to be cured.

Then, by removing the uncured portion of the protruding electrode forming material using a 6-component solvent such as ethyl acetate or methyl ethyl ketone, a resin-based protruding electrode is formed on the electrode of the semiconductor element.

When mounting on a wiring board, align the formed protruding electrodes with the corresponding conductive patterns on the wiring board,
Pressure is applied from the semiconductor element side and heating is applied. The pressing pressure at this time is 10 to 200 kg/cm', and the heating temperature is adjusted so that the temperature of the protruding electrode is 100 to 200°C by heat transfer from the pressing jig through the semiconductor element or by ultrasonic heating. The crimping time is about 5 seconds to 5 minutes.

Similar operations can be performed when attaching a semiconductor element with protruding poles to a resin film of a film carrier. That is, after inserting a semiconductor element into a hole made in a resin film and aligning the protruding electrode with the end of a copper foil finger for external connection that extends into the hole, both are pressurized and heated. to obtain electrical connection and mechanical bonding.

Effect of the invention According to the present invention, the following effects can be achieved.

(1) Since the protruding electrode is made of a polymeric material with a smaller Young's modulus than metals such as solder, it may be caused by external mechanical shocks, vibrations, or changes in the environmental temperature around the connection part. Thermal stress can be absorbed and alleviated by this protruding electrode, and unlike conventional metal protruding electrodes, the wiring board will not be deformed or
A highly reliable protruding electrode with adhesive function can be obtained without peeling of the bonded portion.

(2) Since the protruding electrodes exist only on the electrodes of the semiconductor element, there is no risk of short circuits occurring between the electrodes of the semiconductor element compared to the conventional method of forming metal protruding electrodes. It can also be applied to

(3) Since the protruding electrodes contain a thermally adhesive component, when bonding to the conductive pattern, it is necessary to use conductive pattern materials that are difficult to form alloys on the wiring board or conductive patterns that are difficult to process, such as ITO (indium tin oxide). ) and other materials can be easily electrically connected.

(4) If a defective semiconductor element is discovered at the stage of checking device characteristics after mounting, conventional soldering connections require heating to a high temperature of over 300°C to separate the semiconductor element. The protruding electrode according to the present invention allows the semiconductor element to be removed by applying a low temperature of, for example, 200° C. or less or by dissolving it with an organic solvent, and the semiconductor element can be glued together very easily.

Claims (1)

[Claims] A semiconductor element characterized in that a photosensitive resin material containing an electrically conductive substance and a thermal adhesive substance is applied to the surface of the semiconductor element where the electrodes are located, and protruding electrodes are formed on the electrodes of the semiconductor element by photolithography technology. method for forming protruding electrodes.