JP2014022669A - Primer composition and optical semiconductor device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical semiconductor device with high reliability that is improved in adhesion between a substrate mounted with an optical semiconductor element and a sealing material, and prevents a metal electrode formed on the substrate from corroding.SOLUTION: In an optical semiconductor device 1 constituted by bonding together a substrate 4 mounted with an optical semiconductor element 3 and a sealing material 5 made of an addition reaction curing type silicone composition sealing the optical semiconductor element 3, a primer composition 2 bonding the substrate 4 and the sealing material 5 together contains (A) an alkoxysilane compound having at least one mercapto group in one molecule, (B) a titanium compound, and (C) a solvent.

Description

  The present invention relates to a primer composition and an optical semiconductor device using the same.

  An LED device known as an optical semiconductor device has a light emitting diode (LED) as an optical semiconductor element and has an LED mounted on a substrate sealed with a sealing material made of a transparent resin. As a sealing material for sealing the LED, an epoxy resin-based composition has been widely used conventionally (see, for example, Patent Document 1).

  However, epoxy resin-based encapsulants are prone to cracking and yellowing due to increased heat generation and shorter wavelength of light due to recent miniaturization of semiconductor packages and higher brightness of LEDs, resulting in lower reliability. Was invited. Then, the silicone composition is used as a sealing material from the point which has the outstanding heat resistance. In particular, an addition reaction curable silicone composition cures in a short time by heating and thus has high productivity and is suitable as an LED sealing material (see, for example, Patent Document 2).

  However, it cannot be said that the adhesion between the substrate on which the LED is mounted and the sealing material made of the cured product of the addition reaction curable silicone composition is sufficient. As a substrate for mounting an LED, a polyphthalamide resin is frequently used from the viewpoint of excellent mechanical strength, and a primer useful for the resin has been developed (for example, see Patent Documents 3 and 4).

  However, for LEDs that require high power, the polyphthalamide resin has no heat resistance and discolors, and recently, ceramics typified by alumina, which has better heat resistance than the polyphthalamide resin, becomes the substrate. There are many cases. Peeling tends to occur between the substrate made of alumina ceramic and the cured product of the silicone composition.

  Moreover, since the silicone composition generally has gas permeability, it is easily affected by the external environment. When the LED device is exposed to sulfur compounds or exhaust gas in the atmosphere, the sulfur compounds pass through the cured product of the silicone composition, and the metal electrode on the substrate sealed with the cured product, particularly an Ag electrode Has the disadvantage of corroding and blackening over time.

JP 2000-198930 A JP 2004-292714 A JP 2008-179694 A JP 2010-168596 A

  The present invention has been made in view of such problems, and improves the adhesion between a substrate on which an optical semiconductor element is mounted and an encapsulant made of an addition reaction curable silicone composition that seals the optical semiconductor element. It is another object of the present invention to provide a primer composition capable of preventing corrosion of a metal electrode formed on a substrate and a highly reliable optical semiconductor device using the same.

In order to achieve the above object, the present invention provides a primer composition for adhering a substrate on which an optical semiconductor element is mounted and a sealing material made of an addition reaction curable silicone composition for sealing the optical semiconductor element. The following component (A) alkoxysilane compound having at least one mercapto group in one molecule,
(B) a titanium compound,
(C) solvent,
The primer composition characterized by containing this is provided.

  Such a primer composition is formed on a substrate while firmly adhering a substrate on which the optical semiconductor element is mounted and a sealing material made of an addition reaction curable silicone composition for sealing the optical semiconductor element. Corrosion of the metal electrode, particularly the Ag electrode, can be prevented.

  The blending amount of the component (A) is preferably 3% by mass or less of the entire composition.

  With such a blending amount of the component (A), the metal electrode formed on the substrate, particularly the Ag electrode, is more difficult to be sulfided.

  Moreover, it is preferable to further contain the silane coupling agent (except for the component (A) that is the same as the component (A)) as the component (D).

  By including such a silane coupling agent, the adhesiveness of the primer composition can be further enhanced.

  Further, the present invention is such that the primer composition includes a substrate on which the optical semiconductor element is mounted and a sealing material made of an addition reaction curable silicone composition that seals the optical semiconductor element. An optical semiconductor device is provided.

  The primer composition is formed on the substrate while firmly adhering the substrate on which the optical semiconductor element is mounted and the sealing material made of the addition reaction curable silicone composition for sealing the optical semiconductor element as described above. Corrosion of the formed metal electrode, particularly the Ag electrode, can be prevented. For these reasons, the optical semiconductor device can be highly reliable.

  In this case, the optical semiconductor element is preferably an LED (light emitting diode).

  Since the LED is a highly efficient light source, it can be suitably used.

  Furthermore, the constituent material of the substrate is preferably ceramics.

  A ceramic substrate is preferable because it has high heat resistance and is free from discoloration and deterioration.

  The cured product of the addition reaction curable silicone composition is preferably rubbery.

  If the cured product of the addition reaction curable silicone composition is rubbery, it has stronger adhesiveness and can prevent corrosion of metal electrodes, particularly Ag electrodes, formed on the substrate.

  The cured product of the addition reaction curable silicone composition is preferably a transparent cured product.

  If the cured product of the addition reaction curable silicone composition is a transparent cured product, it is suitable as a sealing material for an optical semiconductor element such as an LED.

With the primer composition of the present invention, it is possible to firmly bond a substrate on which an optical semiconductor element is mounted and a sealing material made of an addition reaction curable silicone composition that seals the optical semiconductor element, Corrosion of the metal electrode formed on the substrate, particularly the Ag electrode, can be prevented.
Moreover, since the primer composition of this invention has such a function, the optical semiconductor device using this primer composition can have high reliability.

It is sectional drawing which shows an example of the optical semiconductor device (LED) of this invention. It is the figure which showed an example of the test piece for an adhesion test which tests the adhesiveness (adhesion strength) of the primer composition in an Example and a comparative example.

Hereinafter, the present invention will be described in more detail.
As described above, conventionally, the adhesion between the substrate on which the optical semiconductor element is mounted and the sealing material made of the addition reaction curable silicone composition for sealing the optical semiconductor element is not sufficient, and the optical semiconductor device Is exposed to sulfur compounds or exhaust gas in the atmosphere, the sulfur compounds pass through the cured product of the silicone composition, and the metal electrode on the substrate sealed with the cured product, particularly the Ag electrode, is aged over time. There was a drawback that it was corroded and turned black.

  As a result of intensive studies to solve the above problems, the present inventors have mounted an optical semiconductor element by blending an alkoxysilane compound containing at least one mercapto group in one molecule into the composition. A substrate and a sealing material made of an addition reaction curable silicone composition for sealing the optical semiconductor element can be firmly bonded, and corrosion of a metal electrode formed on the substrate, particularly an Ag electrode, can be prevented. The inventors have found that a primer composition that can be used and a highly reliable optical semiconductor device using the primer composition can be obtained, and have reached the present invention.

That is, the primer composition of the present invention is a primer composition for adhering a substrate on which an optical semiconductor element is mounted and a sealing material made of an addition reaction curable silicone composition for sealing the optical semiconductor element, The following component (A) an alkoxysilane compound having at least one mercapto group in one molecule,
(B) a titanium compound,
(C) solvent,
It is a primer composition characterized by containing.

<Primer composition>
Hereinafter, the primer composition of the present invention will be described in detail.
The primer composition of the present invention contains the following components (A) to (C).

[(A) component]
Component (A) is an alkoxysilane compound containing at least one mercapto group in one molecule. For example, sufficient adhesion to a substrate on which a semiconductor element is mounted, particularly a ceramic substrate or a polyphthalamide resin substrate. Is a component that suppresses corrosion over time of a metal electrode (particularly an Ag electrode) formed on the substrate.

Examples of the alkoxysilane compound containing at least one mercapto group in one molecule include compounds having a structure represented by the following formula.

ここで、Ｍｅはメチル基、Ｅｔはエチル基を示す。 Specific examples of the structure include the following.

Here, Me represents a methyl group, and Et represents an ethyl group.

  (A) The compounding quantity of a component has preferable 0.01-3 mass% of the whole composition. If it is 0.01 mass% or more, the discoloration component which invades from the surrounding environment can be suppressed, and if it is 3 mass% or less, the metal electrode formed on the substrate, particularly the Ag electrode, is more Difficult to sulfidize. More preferably, it is 0.05-1 mass% of the whole composition.

[Component (B)]
(B) A component is a titanium compound and acts as a curing catalyst. Specifically, titanium alkoxide or titanium chelate is preferable, and specifically, titanium tetraisopropoxide, titanium tetrabutoxide, bis-2.4-pentandionate titanium diisopropoxide, bisacetylacetonato titanium diiso Examples include propoxide. These may be used alone or in combination of two or more.

  (B) The compounding quantity of a component has the preferable amount which advances the hydrolysis reaction of (A) component. Specifically, 0.01-5 mass% is preferable with respect to the compounding quantity of (A) component, More preferably, it is 0.05-2 mass%.

[Component (C)]
The component (C) is a solvent, and is not limited as long as the above-described components (A) and (B), the component (D) described below, and other optional components can be dissolved. Can be used. Specifically, xylene, toluene, benzene, heptane, hexane, trichloroethylene, perchloroethylene, methylene chloride, ethyl acetate, methyl isobutyl ketone, methyl ethyl ketone, ethanol, isopropanol, butanol, ligroin, cyclohexanone, diethyl ether, rubber volatile oil, Examples include silicone solvents. Depending on the evaporation rate during the primer application operation, one kind may be used alone, or two or more kinds may be used in combination as a mixed solvent.

  The amount of component (C) may be any amount, but is preferably 70% by mass or more, more preferably 80 to 99.9% by mass, based on the entire composition.

[(D) component]
It is preferable that the said primer composition contains the silane coupling agent (except for what becomes the same as (A) component) of (D) component in said (A)-(C) component further. As the component (D), a general silane coupling agent can be used.
Specific examples include vinyltrimethoxysilane, vinyltriethoxysilane, glycidoxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, and the like.

  (D) As a compounding quantity of a component, 0.01-5 mass% of the whole composition is preferable, More preferably, it is 0.01-2 mass%.

[Other ingredients]
In addition to the components (A) to (C), benzotriazole, butylhydroxytoluene, hydroquinone, or a derivative thereof may be blended as a metal corrosion inhibitor as necessary.
These are the cases where the optical semiconductor device is exposed to a harsh external environment and, for example, when sulfur compounds in the air permeate the sealing material of the optical semiconductor device (cured product of addition reaction curable silicone composition). It is a component that more effectively suppresses corrosion of a metal electrode on a substrate sealed with a stopper, particularly an Ag electrode.

  Moreover, in order to improve the adhesive force between the SiH group in the component (A) and the addition reaction curable silicone composition, a platinum catalyst that is a catalyst for the addition reaction can be added as an optional component.

Furthermore, reinforcing fillers, dyes, pigments, heat resistance improvers, antioxidants, adhesion promoters, and the like can be added as other optional components.

[Method for producing primer composition]
Examples include a method of uniformly mixing the components (A) to (C) and the optional component with a mixing stirrer at room temperature.

  By using the primer composition of the present invention, a substrate on which an optical semiconductor element such as an LED is mounted and a sealing material made of an addition reaction curable silicone composition can be firmly bonded, and the optical semiconductor device is severely damaged. When the primer composition of the present invention is used, the metal electrode on the substrate, particularly when the sulfur compound in the atmosphere permeates into the cured product of the silicone composition when exposed to an external environment. Corrosion of the Ag electrode can be suppressed.

<Optical semiconductor device>
The optical semiconductor device of the present invention is formed by bonding a substrate on which the optical semiconductor element is mounted and a sealing material made of an addition reaction curable silicone composition that seals the optical semiconductor element, with the primer composition. This is an optical semiconductor device.

Next, the optical semiconductor device of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing an example of an optical semiconductor device according to the present invention, and shows an LED device.
As shown in FIG. 1, the optical semiconductor device 1 of the present invention includes a substrate 4 on which an LED 3 is mounted and a cured product of an addition reaction curable silicone composition that seals the LED 3 with the primer composition 2 described above. The stopper 5 is bonded. A metal electrode 6 such as an Ag electrode is formed on the substrate 4, and an electrode terminal (not shown) of the LED 3 and the metal electrode 6 are electrically connected by a bonding wire 7.

  The optical semiconductor element is preferably an LED, and has been described using an LED as an example of an optical semiconductor element, but other specific examples include, for example, a phototransistor, a photodiode, a CCD, a solar cell module, an EPROM, a photocoupler, and the like. Is mentioned.

  The constituent material of the substrate 4 includes polyphthalamide resin, various fiber reinforced plastics, ceramics, and the like. Ceramics are preferable from the viewpoint of good heat resistance, and alumina ceramics are particularly preferable from the viewpoint of good heat resistance.

  The sealing material 5 made of addition reaction curable silicone is obtained by curing an addition reaction curable silicone composition containing at least a vinyl group-containing polyorganosiloxane, polyorganohydrogensiloxane, and a platinum-based catalyst.

  The cured product of the addition reaction curable silicone composition is preferably rubbery.

  Moreover, it is preferable that the cured product of the addition reaction curable silicone composition is a transparent cured product.

  Addition reaction curable silicone compositions may contain other optional components such as reaction inhibitors, colorants, flame retardants, heat resistance improvers, plasticizers, reinforcing silica, and adhesion promoters. it can. Any of those conventionally used can be used without particular limitation depending on the purpose.

[Method for Manufacturing Optical Semiconductor Device]
Although the manufacturing method of the optical semiconductor device of this invention is not specifically limited, It can manufacture as follows.
The LED 3 is bonded to the substrate 4 on which the metal electrode 6 such as an Ag electrode is formed in advance by Ag plating with an adhesive, and the electrode terminal (not shown) of the LED 3 and the metal electrode 6 are electrically connected by wire bonding. To do. Thereafter, the substrate 4 on which the LED 3 is mounted is cleaned as necessary, and then the primer composition 2 of the present invention is applied to the substrate 4 with a coating device such as a spinner or a sprayer. Thereafter, the solvent in the primer composition 2 is volatilized by heating, air drying, etc., and a film of preferably 10 μm or less, more preferably 0.01 to 1 μm is formed. After the primer treatment, the addition reaction curable silicone composition is applied with a dispenser or the like, and the LED 3 is sealed with a cured product (sealing material) 5 that is cured by being left standing or heated at room temperature.

  The optical semiconductor device of the present invention using the primer composition has high reliability because the substrate on which an optical semiconductor element such as an LED is mounted and the sealing material made of the addition reaction curable silicone composition are firmly bonded. Even when exposed to a harsh external environment and sulfur compounds in the atmosphere permeate into the cured product of the silicone composition, corrosion of metal electrodes on the substrate, particularly Ag electrodes, is suppressed. be able to.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples. The primer compositions obtained in the examples and comparative examples are shown in Table 1 as a list. The composition was evaluated as follows and the results are shown in Table 2. The characteristics shown in Table 2 are values measured at 23 ° C.

[Example 1]
0.5 parts by mass of γ-mercaptopropyltrimethoxysilane and 0.2 parts by mass of tetrabutoxytitanium were added to 100 parts by mass of ethyl acetate and mixed uniformly with a mixing stirrer at room temperature to obtain a primer composition.

[appearance]
The obtained primer composition was brush-coated on alumina ceramic, allowed to stand at 23 ° C. for 30 minutes and dried, and then the surface was baked at 180 ° C. for 20 minutes to form a primer composition film. On this primer composition, an addition reaction curable silicone rubber composition (manufactured by Shin-Etsu Chemical Co., Ltd., KER-2500) was applied and cured at 150 ° C. for 1 hour, and the appearance was observed.

[Transmissivity]
The heat resistance test of the primer composition was performed as follows.
The obtained primer composition was brush-coated on a slide glass, and the surface was baked at 180 ° C. for 20 minutes to form a primer composition film. After baking, air was measured as a blank (control) using a slide glass coated with a transmittance at 400 nm. Thereafter, the glass slide coated with the primer was subjected to heat deterioration at 150 ° C. for 500 hours, and the change in transparency of the primer film itself was confirmed.

[Adhesiveness (adhesive strength)]
The adhesion test of the primer composition was performed as shown in FIG.
The primer composition obtained on the two alumina ceramic substrates 11 and 12 was applied to a thickness of 0.01 mm, left to dry at 23 ° C. for 60 minutes, and then the surface was baked at 180 ° C. for 20 minutes to obtain a primer. A composition film was formed. As shown in FIG. 2, the end surfaces of the two alumina ceramic substrates face each other on the side on which the primer composition film is formed, and an addition reaction curable silicone rubber composition (Shin-Etsu Chemical Co., Ltd.) is interposed therebetween. Co., Ltd., prototype) is applied so as to be sandwiched by 1 mm thickness (adhesive area 25 mm × 10 mm = 250 mm ² ) and cured at 150 ° C. for 2 hours to produce a cured product 13 of an addition reaction curable silicone rubber composition. A test piece for adhesion test was prepared. Alumina ceramics (manufactured by KDS Inc.) were used.

  The alumina ceramic substrates 11 and 12 coated with the primer composition of this test piece were observed by pulling them at a tensile speed of 50 mm / min using a tensile tester (manufactured by Shimadzu Corporation, Autograph) in the direction of the arrow (see FIG. 2). The adhesive strength per unit area was expressed as MPa and confirmed.

[Corrosion test]
The obtained primer composition was brushed on a silver-plated plate, allowed to stand at 23 ° C. for 30 minutes and dried, and then the surface was baked at 180 ° C. × 20 minutes to form a primer composition film. An addition reaction curable silicone rubber composition (manufactured by Shin-Etsu Chemical Co., Ltd., KER-2500) was applied at a thickness of 1 mm and cured at 150 ° C. for 1 hour to prepare a test piece. This test piece is placed in a 100 cc glass bottle together with 0.1 g of sulfur crystals and sealed at 70 ° C., and the silicone rubber is peeled off every predetermined time (after 1 day, 7 days, and 12 days), and the degree of corrosion of the silver-plated plate Was visually observed.

[Example 2]
0.5 parts by mass of γ-mercaptopropyltrimethoxysilane and 0.2 parts by mass of tetrabutoxytitanium were added to 100 parts by mass of isopropyl alcohol, and uniformly mixed with a mixing stirrer at room temperature to obtain a primer composition. The properties of this primer composition were evaluated in the same manner as in Example 1.

[Example 3]
0.5 parts by mass of γ-mercaptopropyltriethoxysilane and 0.2 parts by mass of tetrabutoxytitanium were added to 100 parts by mass of ethyl acetate and mixed uniformly with a mixing stirrer at room temperature to obtain a primer composition. The properties of this primer composition were evaluated in the same manner as in Example 1.

[Example 4]
To 100 parts by mass of ethyl acetate, 0.3 part by mass of γ-mercaptopropyltrimethoxysilane and 0.1 part by mass of tetrabutoxytitanium were added and uniformly mixed at room temperature with a mixing stirrer to obtain a primer composition. The properties of this primer composition were evaluated in the same manner as in Example 1.

[Example 5]
To 100 parts by mass of ethyl acetate, 0.3 parts by mass of γ-mercaptopropyltrimethoxysilane, 0.2 parts by mass of methacryloxypropyltrimethoxysilane, and 0.1 parts by mass of tetrabutoxytitanium are added, and mixed with a stirrer at room temperature. The primer composition was obtained by uniformly mixing. The properties of this primer composition were evaluated in the same manner as in Example 1.

[Comparative Example 1]
An adhesion test and a corrosivity test were conducted in the same manner as in Example 1 except that the primer composition was not applied.

[Comparative Example 2]
Add 0.5 parts by mass of bis [3- (triethoxysilyl) propyl] tetrasulfide and 0.2 parts by mass of tetrabutoxytitanium to 100 parts by mass of ethyl acetate, and mix uniformly with a mixing stirrer at room temperature. I got a thing. The properties of this primer composition were evaluated in the same manner as in Example 1.

[Comparative Example 3]
0.5 parts by mass of benzothiazole and 0.2 parts by mass of tetrabutoxytitanium were added to 100 parts by mass of ethyl acetate, and mixed uniformly with a mixing stirrer at room temperature to obtain a primer composition. The properties of this primer composition were evaluated in the same manner as in Example 1.

○…腐食（変色）なし、△…多少の腐食（変色）あり、×…黒変あり

○… No corrosion (discoloration), △… Some corrosion (discoloration), ×… Black discoloration

  As is apparent from Table 2, the primer composition of each example in which the mercaptosilane compound was blended firmly bonded the alumina ceramic and the sealing material made of the addition reaction curable silicone composition.

  In the heat resistance test of the primer composition film formed on the slide glass, there is no discoloration, the film itself does not change, and the heat resistance is excellent.

  Further, in the corrosive test using an Ag plated plate instead of alumina ceramics, each example has no discoloration after 1 day and has the effect of suppressing discoloration (corrosion) even after 12 days.

  DESCRIPTION OF SYMBOLS 1 ... Optical semiconductor device, 2 ... Primer composition, 3 ... Optical semiconductor element (LED), 4 ... Board | substrate, 5 ... Hardened | cured material (sealing material) of addition reaction hardening type silicone composition, 6 ... Metal electrode, 7 ... Bonding wire, 11, 12 ... Alumina ceramic substrate, 13 ... Cured product of addition reaction curable silicone rubber composition.

[Component (B)]
(B) A component is a titanium compound and acts as a curing catalyst. Specifically, it is preferred alkoxide or titanium chelate titanium, specifically titanium tetraisopropoxide, titanium tetrabutoxide, bis -2, 4-pentanedionate titanium diisopropoxide, bis acetylacetonato titanium diisopropoxy Examples include propoxide. These may be used alone or in combination of two or more.

[Comparative Example 2]
Bis [3- (triethoxysilyl) propyl] Tetorasu Le Fido 0.5 to 100 parts by mass of ethyl acetate were added tetrabutoxytitanium 0.2 part by weight were uniformly mixed by a stirrer at normal temperature, A primer composition was obtained. The properties of this primer composition were evaluated in the same manner as in Example 1.

Claims (8)

A primer composition for adhering a substrate on which an optical semiconductor element is mounted and an encapsulating material made of an addition reaction curable silicone composition for sealing the optical semiconductor element, the following component (A) in one molecule An alkoxysilane compound having at least one mercapto group,
(B) a titanium compound,
(C) solvent,
A primer composition comprising:   2. The primer composition according to claim 1, wherein the blending amount of the component (A) is 3% by mass or less of the entire composition.   Furthermore, the primer composition of Claim 1 or Claim 2 containing the silane coupling agent (except what becomes the same as (A) component) of (D) component.   A primer composition according to any one of claims 1 to 3, comprising: a substrate on which the optical semiconductor element is mounted; and an encapsulant made of an addition reaction curable silicone composition that seals the optical semiconductor element. An optical semiconductor device characterized by being bonded.   The optical semiconductor device according to claim 4, wherein the optical semiconductor element is an LED (light emitting diode).   6. The optical semiconductor device according to claim 4, wherein the constituent material of the substrate is ceramics.   The optical semiconductor device according to any one of claims 4 to 6, wherein the cured product of the addition reaction curable silicone composition is rubber-like. The optical semiconductor device according to any one of claims 4 to 7, wherein the cured product of the addition reaction curable silicone composition is a transparent cured product.

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