BACKGROUND

Technical Field

The present disclosure relates to an electrically conductive adhesive agent composition, and an electrically conductive adhesive film and a dicing-die bonding film using the same.

Background Art

In general, a semiconductor device is produced by a step of forming a die mounting material for bonding a semiconductor element (chip) onto an element-supporting part of a lead frame or onto a circuit electrode part of an insulating substrate, a step of mounting the semiconductor element onto the surface of the die mounting material on the lead frame or the circuit electrode to bond the semiconductor element to the element-supporting part of the lead frame or to the circuit electrode part of the insulating substrate, a wire-bonding step in which an electrode part of the semiconductor element is electrically bonded with a terminal part of the lead frame or with a terminal part of the insulating substrate, and a molding step in which the thus assembled semiconductor device is coated with a resin.

A bonding material is used for bonding a semiconductor element to an element-supporting part of a lead frame or to a circuit electrode part of an insulating substrate. For example, a lead solder comprising 85% by mass or more of lead having a high melting point and heat resistance has been widely used as a bonding material for power semiconductors such as IGBT and MOS-FET. However, hazardousness of lead has become a problem in recent years, and there is an increasing demand for lead-free bonding materials.

Also, SiC power semiconductors have features such that lower loss and operation at higher speed and higher temperatures compared with Si power semiconductors can be realized, and SiC power semiconductors are therefore considered to be a next-generation power semiconductor. Such SiC power semiconductors are theoretically capable of operations at 200° C. or higher, but improvement of the heat resistance of the surrounding materials including bonding materials is desired so as to actually realize high output and high density of systems such as inverters.

Under these circumstances, various lead-free, high-melting-point bonding materials have been valued in recent years. Au-based alloys such as Au—Sn-based alloys and Au—Ge-based alloys disclosed in Japanese Laid-Open Patent Publication No. 2006-032888, for example, can be mentioned as such high-melting-point lead-free bonding materials, and these alloy materials are noticed as having good electrical conductivity and thermal conductivity and being chemically stable. However, since such Au-based alloy materials which contain a noble metal are expensive, and since expensive high-temperature vacuum reflow machines are necessary for attaining higher mounting reliability, Au-based alloy materials are not yet in practical use.

Also, there is a problem such that many lead-free solders have poor wettability compared with lead solders. Due to this poor wettability, there is a higher risk that the solder will not wet over the die pad part and that bonding defects such as insufficient soldering will occur when using a lead-free solder as a bonding material. Since the problem of wettability particularly tends to become worse as the melting point of a lead-free solder increases, it was difficult to attain both heat resistance and mounting reliability at the same time.

In order to solve these problems, studies on diffusion sintering-type solders such as Cu-based and Sn-based solders have been pursued as described in Japanese Laid-Open Patent Publication Nos. 2007-152385 and 2002-263880. Since these diffusion sintering-type solders have a low melting point in a state before sintering and the mounting temperature can therefore be reduced, and since diffusion sintering-type solders will irreversibly have a high melting point in a state after the diffusion sintering reaction, diffusion sintering-type solders are expected to attain both heat resistance and mounting reliability at the same time, which was difficult with conventional lead-free solders. However, since diffusion sintering-type solders also have the problems of wettability as with conventional lead-free solders, the risk of insufficient soldering cannot be avoided when bonding a large surface area. Also, since diffusion sintering-type solders in a state of a sintered body are hard and brittle, there are problems of poor stress relaxation properties and low thermal fatigue resistance. Sufficient bonding reliability therefore has not yet been attained.

A flux such as a carboxylic acid or an alcohol is generally added to many lead solders and lead-free solders so as to remove the oxide film formed on a metal. However, these flux components easily absorb moisture and easily bleed out, and the absorbed moisture and the bleed-out are known to adversely affect the reflow resistance reliability (MSL) after moisture absorption in a sealed semiconductor element package. Flux is therefore generally washed off after the solder reflow mounting, but said treatment has problems of consuming time and the treatment of the washing wastewater. On the other hand, reduction of the added amount of the flux component, such as a carboxylic acid or an alcohol, that causes moisture absorption and bleed-out so as to avoid the aforementioned problems will cause another problem such that removing capability of the oxide film becomes poor and that sufficient electrical conductivity and other properties cannot be exerted. The problems therefore have not yet been fully solved.

SUMMARY

It is therefore an object of the present disclosure to provide an electrically conductive adhesive agent composition which is suitable for use as an electrically conductive bonding material for bonding a semiconductor chip (particularly a power device) onto an element-supporting part of a lead frame or onto a circuit electrode part of an insulating substrate, for example, and which is capable of forming, between a semiconductor chip and an element-supporting part of a lead frame or a circuit electrode part of an insulating substrate, a bonding layer that particularly excels both in heat resistance after bonding and sintering and in mounting reliability while being lead-free, and an electrically conductive adhesive film and a dicing-die bonding film using said the electrically conductive adhesive agent composition.

Solution to Problem

As a result of intensive study, the inventors of the present disclosure found that an electrically conductive adhesive agent composition suitable for use as an electrically conductive bonding material capable of forming, between a semiconductor chip (particularly a power device) and an element-supporting part of a lead frame or a circuit electrode part of an insulating substrate, for example, a bonding layer that is lead-free and greatly excels both in heat resistance after bonding and sintering and in mounting reliability can be obtained particularly by combining a prescribed metal particle (Q) with a prescribed organophosphorus compound (A). The present disclosure was completed based on said finding.

The embodiments of the present disclosure are as follows.

[1] An electrically conductive adhesive agent composition comprising:

a metal particle (Q); and

an organophosphorus compound (A) represented by the general formula (1) below,

wherein the metal particle (Q) comprises a first metal particle (Q1) made of a single metal selected from the group of copper, nickel, aluminum and tin or an alloy comprising two or more metals selected from said group
(RxPOR)y(1)

in the general formula (1), each R independently represents an organic group, R may be the same or different with each other, both x and y are an integer from 0 to 3, and the sum (x+y) of x and y is 3.

[2] The electrically conductive adhesive agent composition as described in [1], wherein, in the general formula (1), each R is independently selected from an alkyl group, an aryl group, an organic group including a functional group, an organic group including a heteroatom, and an organic group including an unsaturated bond.
[3] The electrically conductive adhesive agent composition as described in [1], wherein, in the general formula (1), each R independently comprises, in its moiety, one or more group selected from a vinyl group, an acrylic group, a methacrylic group, a maleic acid ester group, a maleic acid amide group, a maleic acid imide group, a primary amino group, a secondary amino group, a thiol group, a hydrosilyl group, a hydroboron group, a phenolic hydroxyl group and an epoxy group.
[4] The electrically conductive adhesive agent composition as described in [1], wherein the organophosphorus compound (A) has a number average molecular weight of 260 or more.
[5] The electrically conductive adhesive agent composition as described in [1], further comprising a resin (M), wherein at least a portion of the resin (M) is a thermosetting resin (M1).
[6] The electrically conductive adhesive agent composition as described in [5], wherein the thermosetting resin (M1) comprises a maleic acid imide compound including two or more units of an imide group in a single molecule.
[7] The electrically conductive adhesive agent composition as described in [6], wherein the maleic acid imide compound comprises a backbone derived from an aliphatic amine having a carbon atom number of 10 or more.
[8] The electrically conductive adhesive agent composition as described in [6], wherein the maleic acid imide compound has a number average molecular weight of 3000 or more.
[9] The electrically conductive adhesive agent composition as described in [1], wherein the metal particle (Q) is a mixture comprising the first metal particle (Q1) and a second metal particle (Q2) based on a metal component different from the first metal particle (Q1), and

the first metal particle (Q1) and the second metal particle (Q2) comprise a metal component capable of mutually forming an intermetallic compound.

[10] The electrically conductive adhesive agent composition as described in [9], wherein the second metal particle (Q2) is made of a single metal selected from the group of copper, nickel, aluminum, tin, zinc, titanium, silver, gold, indium, bismuth, gallium and palladium or an alloy comprising two or more metals selected from said group.
[11] The electrically conductive adhesive agent composition as described in [9], wherein at least one of the first metal particle (Q1) and the second metal particle (Q2) is an alloy particle comprising two or more metal components.
[12] The electrically conductive adhesive agent composition as described in [1], wherein at least one endothermic peak is observed in a temperature range of from 100 to 250° C. in DSC (differential scanning calorimetry) in a state before sintering, and the endothermic peak disappears in a state after sintering.
[13] An electrically conductive adhesive film, comprising the electrically conductive adhesive agent composition as described in [1] formed in the form of a film onto a substrate.
[14] A dicing-die bonding film, comprising:

a dicing tape; and

the electrically conductive adhesive film as described in [13] adhered to the dicing tape.

According to the present disclosure, an electrically conductive adhesive agent composition comprises a metal particle (Q) and a prescribed organophosphorus compound (A), and the metal particle (Q) comprises a first metal particle (Q1) made of a single metal selected from the group of copper, nickel, aluminum and tin or an alloy comprising two or more metals selected from said group. Thus, there is provided an electrically conductive adhesive agent composition suitable for use as an electrically conductive bonding material capable of forming, between a semiconductor chip (particularly a power device) and an element-supporting part of a lead frame or a circuit electrode part of an insulating substrate, for example, a bonding layer that is lead-free and greatly excels both in heat resistance after bonding and sintering and in mounting reliability, and an electrically conductive adhesive film and a dicing-die bonding film using the electrically conductive adhesive agent composition.

