JPH10284540A - Supporting substrate, method for producing supporting substrate, electronic component device and method for surface treating supporting substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve resistance against reflow crack caused by a bonding material by improving the adhesive strength of electronic component and supporting substrate. SOLUTION: The supporting substrate (such as lead frame or insulating substrate) for mounting the electronic component (such as semiconductor chip or transistor) is soaked in a solution containing urea or its dielectric in 0.001 to 10 wt.% for 0.5 sec to 10 min and this is taken out and dried while being heated. On the provided surface treated supporting substrate, the semiconductor chip is adhered while using the organic bonding material (such as a filmy adhesive agent containing silver paste or silver fillers). As the urea dielectric, γ- carbamyl propyltriethoxysilane or dimethyl urea formamide can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support substrate for mounting an electronic component such as a semiconductor device, a method of manufacturing the support substrate, an electronic component device, and a surface treatment method of the support substrate.

[0002]

2. Description of the Related Art As a method of bonding an electronic component such as a semiconductor element to a support substrate, a method of supplying a die bonding material onto the support substrate and bonding the electronic component has been used. As the die bonding material used for this purpose, for example, Au-Si eutectic, solder, resin paste, resin film adhesive and the like are known. Among them, the Au-Si eutectic is expensive and has a high modulus of elasticity, and has a problem that the bonded portion must be vibrated. Further, there is a problem that the solder cannot withstand the temperature higher than the melting point temperature and has a high elastic modulus. Resin pastes and resin film adhesives are inexpensive, have high heat resistance, and have a low modulus of elasticity. Therefore, they are most often used as adhesives for bonding electronic components to a support substrate.

[0003]

In recent years, the demand for high-density mounting due to the miniaturization and thinning of electronic devices has been rapidly increasing in recent years. The mounting type has become mainstream. This surface-mount type semiconductor package is mounted by heating by infrared reflow, vapor phase reflow, solder dip, or the like in order to solder it to a printed board or the like.
At this time, since the entire package is exposed to a high temperature of 210 ° C. to 260 ° C., if moisture exists inside the package, cracks (so-called “reflow cracks”) occur in the package due to rapid vaporization of the moisture. Since the reflow crack significantly reduces the reliability of the package, it has become a serious problem and technical problem especially in a thin package. An object of the present invention is to increase the adhesive strength between an electronic component and a support substrate to improve the reflow crack resistance caused by the bonding material.

[0004]

The mechanism of occurrence of reflow cracks caused by the bonding material is estimated to be as follows. In other words, (1) the bonding material absorbs moisture during storage of the package, (2) this moisture is vaporized by heating during mounting of reflow soldering, and (3) the vapor pressure causes destruction or peeling of the bonding material,
(4) Reflow cracks occur. The present inventors focused on increasing the adhesive strength between the electronic component and the support substrate, and as a result of various investigations, as a result, the surface of the support substrate was treated with urea or a urea derivative to increase the adhesive force with the electronic component, thereby increasing the resistance. It has been found that reflow crackability can be improved.

That is, the present invention provides a support substrate in which at least a surface of the support substrate on which electronic components are mounted via the organic bonding material is in contact with the organic bonding material, is treated with urea or a urea derivative. The present invention also provides a method of manufacturing a support substrate, wherein at least a surface of the support substrate on which the electronic component is mounted via the organic bonding material is in contact with the organic bonding material, with urea or a urea derivative. Further, the present invention provides a support substrate having at least a surface in contact with an organic bonding material treated with urea or a urea derivative, an organic bonding material layer formed on an electronic component mounting portion of the support substrate, and an electron mounted on the organic bonding material layer. An electronic component device including a component is also provided. The present invention also provides a surface treatment method for a support substrate, wherein the support substrate on which electronic components are mounted is treated with urea or a urea derivative via an organic bonding material.

The urea or urea derivative which can be used in the present invention is

Embedded image Is a compound having a group of

Examples of such a compound include N-alkyl ureas such as urea, N-methyl urea, N-ethyl urea, N-propyl urea, N-isopropyl urea and N-butyl urea (where the alkyl carbon number is 1 to 10), N, N-dialkyl urea such as N, N-dimethyl urea, N, N-diethyl urea, N, N-diisopropyl urea, N, N-dibutyl urea,

[0008] N-allylurea, N-acetylurea, N-
Dibenzoylurea, N-phenylurea, Np-ethoxyphenylurea, nitrosomethylurea, nitrourea, biurea, biuret, guanylurea, hydantoin, γ
-Carbamylpropyltriethoxysilane, semicarbazide compounds and the like. These may be used as a mixture of two or more.

The urea or urea derivative used for treating the surface of the supporting substrate is usually used as a solution (treatment liquid) obtained by dissolving the urea or urea derivative in water or an organic solvent. However, the above-mentioned treatment liquid includes epoxy resin, phenol resin, bismaleimide resin, cyanate ester resin, acrylic resin, methacrylic resin, polystyrene, polyimide, polyamide, polyester, siloxane polyimide, polyetherimide, polyesterimide, etc. It may contain a resin. When these resins are used, a curing agent, a curing accelerator, a catalyst, and the like may be used as necessary.

Here, the organic solvent is not particularly limited as long as it can dissolve urea or a urea derivative and other components. In addition to alcohols such as methanol, ethanol, propyl alcohol and isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, benzene, toluene, xylene, dimethylformamide, dimethylacetamide, N-methyl-2
-Pyrrolidone, methyl cellosolve, ethyl cellosolve,
Dioxane, tetrahydrofuran, ethylene glycol dimethyl ether and the like are used, and these may be used as a mixture of two or more kinds including water.

The concentration of the urea or urea derivative in the treatment solution is 0.001 to 10% by weight, preferably 0.01 to 10% by weight.
5% by weight. If it is less than 0.001% by weight, the effect of improving the adhesive strength is small, and if it is more than 10% by weight, the reliability of the package is reduced. The temperature and time of the treatment are not particularly limited, but are usually 0 to 100 ° C., 0.5 second to 1
0 minutes, preferably 20 to 50 ° C., 5 seconds to 3 minutes.
The support substrate treated with the treatment liquid is preferably used after drying. The drying condition at this time is not particularly limited as long as a solvent such as water and alcohol can be removed, but the drying can be usually performed at room temperature to 150 ° C. for 5 seconds to 2 hours.

As a method of treating the support substrate with the urea or urea derivative, a method of dipping the entire substrate into a treatment liquid, a commonly used coating method such as spraying, brush coating, spin coating, and the like are used. You. With respect to the surface of the support substrate to be processed, only the portion in contact with the organic bonding material may be processed, or the entire support substrate may be processed. Further, before the treatment with urea or a urea derivative, the support substrate may be pretreated. Examples of the pretreatment method include degreasing cleaning with an organic solvent, cleaning with an alkali, cleaning with an acid, and the like.
A suitable method is appropriately selected. This is particularly effective when the dispersion of the adhesive force is large. This treatment has a role of keeping the surface state of the support substrate constant, and is preferably performed immediately before the urea or urea derivative treatment.

An electronic component is bonded to the supporting substrate subjected to the surface treatment through an organic bonding material to obtain an electronic component device. In this case, the electronic component may be bonded after the organic bonding material layer is formed on the support substrate in advance, or the organic bonding material layer may be formed on the bonding surface side of the electronic component and then bonded to the support substrate. Alternatively, the support substrate, the organic bonding material, and the electronic component may be bonded together. In any case, the positional relationship between the support substrate, the organic bonding material, and the electronic component is a positional relationship in which the organic bonding material exists between the support substrate and the electronic component.

The support substrate used in the present invention includes:
Examples include a lead frame made of metal such as copper or 42 alloy, an insulating substrate such as a polyimide film, and a substrate with wiring such as a glass epoxy substrate and a glass polyimide substrate. In particular, a copper lead frame is preferably used. When a copper lead frame is used as the support substrate, a copper lead frame is obtained in which at least the surface of the copper lead frame in contact with the organic bonding material is surface-treated with urea or a urea derivative.

The organic bonding material used in the present invention includes epoxy resin, phenol resin, bismaleimide resin, cyanate ester resin, acrylic resin, methacrylic resin, polystyrene, polyimide, polyamide,
Polyester, siloxane polyimide, polyetherimide, and polyesterimide are preferably used. These resins may be used as a mixture of two or more kinds. Also,
As the organic bonding material, a liquid, a paste, a film, and the like can be used without any particular limitation. Further, in the case of a liquid or paste form, an organic solvent may be used.
A filler may be used as necessary for the organic bonding material. As the filler, conductive fillers such as silver, gold, copper, iron, aluminum and carbon, and non-conductive fillers such as boron nitride, aluminum nitride, silica, alumina and silicon carbide are used. It is not limited, and two or more kinds may be used as a mixture.

Examples of the electronic parts to be bonded include active elements such as semiconductor chips, transistors, diodes, and thyristors, and passive elements such as capacitors, resistors, and coils. The electronic component device on which the electronic component is mounted as described above is connected by wire bonding or the like as necessary, and is sealed with a mold resin, a potting resin, or the like to form a package.

[0017]

Embodiments of the present invention will be described below with reference to examples. The processing solutions (solutions of urea or urea derivatives) used in the following examples are as follows. <Treatment liquid 1> 0.1% by weight of urea in ethylene glycol dimethyl ether solution <Treatment liquid 2> 1.0% by weight of γ-carbamylpropyltriethoxysilane in methyl alcohol <Treatment liquid 3> 0.1% of dimethyl urea. 05% by weight acetone solution

Examples 1 to 6 The surface of a supporting substrate was treated using the treatment liquids 1 to 3 under the following conditions to produce a surface-treated supporting substrate. Example Supporting substrate Treatment liquid Treatment method Treatment time Drying conditions 1 42 alloy treatment liquid 1 dip 1 minute 120 ° C, 5 minutes L / F * 2 42 alloy treatment liquid 2 spray 5 minutes 80 ° C, 10 minutes L / F 3 copper L / F treatment liquid 3 dip 30 seconds 100 ° C, 1 minute 4 Copper L / F treatment liquid 1 dip 10 seconds 40 ° C, 30 minutes 5 Wiring poly treatment liquid 3 dip 5 minutes 50 ° C, 1 hour Imide substrate 6 FR-4 Glass treatment liquid 2 Dip 1 minute 100 ° C, 5 minutes Epoxy board * L / F: Lead frame

A semiconductor chip (size 8 mm × 8 mm) was bonded to the surface-treated support substrate thus obtained with an organic bonding material. At this time, as an organic bonding material, a silver paste (EN-4000 manufactured by Hitachi Chemical Co., Ltd.) was used for Examples 1, 3, and 5, and a film-shaped adhesive containing a silver filler (Example manufactured by Hitachi Chemical Co., Ltd.) was used for Examples 2, 4, and 6. DF-335) was used. Table 1 shows the measurement results of the adhesive strength.

[0020]

[Table 1] Example adhesive strength (kgf / chip) room temperature 240 ° C １ 1 1.9 1.5 2 2.8 2.4 3 1.7 1.7 1.4 4 2.6 2.0 5 2.3 1.8 6 2.1 1.6 ──────────────────────────── Surface treated with urea or urea derivative The thing had high adhesive strength.

[0021]

The support substrate of claim 1 or 2 and the electronic component device of claim 4 are expected to have improved reflow resistance. According to the manufacturing method of the third aspect, the support substrate of the first or second aspect can be manufactured. According to the surface treatment method of the fifth aspect, the adhesive strength between the electronic component and the support substrate is increased.

Claims (5)

[Claims] 1. A support substrate, wherein at least a surface of the support substrate on which an electronic component is mounted via an organic bonding material is in contact with the organic bonding material, is treated with urea or a urea derivative. 2. The support substrate according to claim 1, wherein the support substrate on which the electronic component is mounted via an organic bonding material is a copper lead frame. 3. A method for manufacturing a support substrate, comprising: treating at least a surface of the support substrate, on which the electronic component is mounted, with the organic bonding material in contact with the organic bonding material with urea or a urea derivative. 4. A support substrate having at least a surface in contact with an organic bonding material treated with urea or a urea derivative, an organic bonding material layer formed on an electronic component mounting portion of the support substrate, and electrons mounted on the organic bonding material layer. Electronic component device comprising components. 5. A method for treating a surface of a supporting substrate, wherein the supporting substrate on which the electronic component is mounted is treated with urea or a urea derivative via an organic bonding material.