JP4569109B2 - Metal-containing paste and semiconductor device - Google Patents

Description

  The present invention relates to a metal-containing paste and a semiconductor device.

  Conventionally, in order to manufacture a semiconductor device, a conductive adhesive that adheres a semiconductor element, a light emitting diode, or the like to a metal lead frame or a substrate is often used (for example, see Patent Document 1). Such a conductive adhesive is generally a paste obtained by mixing a conductive powder and a thermosetting resin, and is called a resin paste. This resin paste is required to have heat resistance, moisture resistance and the like in addition to adhesiveness.

  In order to bond the above semiconductor elements etc. with a resin paste, the resin paste is supplied on a metal lead frame or substrate, the semiconductor element etc. is pressed on this resin paste and then heated and cured in a heating furnace or the like. Has been done by. The lead frame or substrate to which the semiconductor element or the like is attached is further subjected to wire bonding and resin molding to complete the semiconductor device.

With recent reductions in weight, thickness, and size of electronic devices, these semiconductor devices are often installed outdoors and used, and accordingly, the above requirements are also applied to resin pastes used in semiconductor devices. In addition to the characteristics, weather resistance is strongly demanded.
However, a resin paste having both sufficient weather resistance and adhesiveness has not been obtained.

  Furthermore, due to the development of optical semiconductor elements (blue-white LEDs) with an emission wavelength of around 380 to 500 nm, organic materials used in the assembly process and around the optical semiconductor elements are required to have higher UV resistance than before. It came to be.

JP 2002-12738 A

  An object of the present invention is to provide a metal-containing paste excellent in adhesion and weather resistance and a semiconductor device using the same.

Such an object is achieved by the present invention described in the following (1) to ( 12 ).
(1) Semi-solid containing an organic resin, a first metal powder containing aluminum as a main component, and a second metal powder containing a metal different from the aluminum as a main component in a volume ratio of 5:95 to 40:60 A metal-containing paste composed of a composition having a shape, the ultraviolet reflectance [A] at 280 nm is 50% or more, and the ultraviolet reflectance [B] after irradiation with 280 nm ultraviolet rays for 250 hours is A metal-containing paste characterized by having a reflectance [A] of 80% or more .
(2) The metal-containing paste according to (1), wherein the content of the first metal powder is 1 to 30% by volume of the whole semi-solid composition.
(3) The metal-containing paste according to (1) or (2) above, wherein the metal constituting the second metal powder mainly contains silver.
(4) The content of the first metal powder and the second metal powder is 20 to 70% by volume of the whole semisolid composition, according to any one of (1) to (3) above. Metal-containing paste.
(5) The metal-containing paste according to any one of (1) to (4), wherein an average particle size of the first metal powder is larger than an average particle size of the second metal powder.
(6) The metal-containing paste according to any one of (1) to (5), wherein the first metal powder mainly includes a plate-like metal powder.
(7) The metal-containing paste according to any one of (1) to (6), wherein the organic resin includes an epoxy resin.
(8) The metal-containing paste according to (7), wherein the epoxy resin does not have an aromatic ring.
(9) The metal-containing paste according to any one of (1) to (8), wherein the organic resin includes a radical polymerizable material.
( 10 ) The metal-containing paste according to any one of (1) to ( 9 ), which is used for bonding semiconductor members.
( 11 ) A semiconductor device, wherein a semiconductor member and a support member are joined via the metal-containing paste according to any one of (1) to ( 10 ).
( 12 ) The semiconductor device according to ( 11 ), wherein the semiconductor member is an LED chip.

ADVANTAGE OF THE INVENTION According to this invention, the metal containing paste excellent in adhesiveness and weather resistance and a semiconductor device using the same can be obtained.
Moreover, when making 1st metal powder into specific content, it is excellent in both electroconductivity and weather resistance.
In addition, when an epoxy resin having no aromatic ring is used as the organic resin, it is possible to improve the reflectance particularly after irradiation with ultraviolet rays for 250 hours, thereby showing that the metal-containing paste is less deteriorated by ultraviolet rays.
Further, when the metal-containing paste of the present invention is used for the LED chip, it is possible to effectively prevent the deterioration of weather resistance.

Hereinafter, the metal-containing paste and semiconductor device of the present invention will be described.
The metal-containing paste of the present invention is a semi-solid composition comprising an organic resin, a first metal powder containing aluminum as a main component, and a second metal powder containing a metal different from the aluminum as a main component. A metal-containing paste configured, wherein the first metal powder and the second metal powder are used in a volume ratio of 5:95 to 40:60.
Moreover, the semiconductor device of the present invention is characterized in that the semiconductor member and the substrate are bonded via the metal-containing paste described above.

First, the metal-containing paste will be described.
The organic resin has a function as a binder of the metal-containing paste and a function of imparting adhesiveness. In addition, the first metal powder has excellent reflectivity for wavelengths in the ultraviolet region, and has an effect of improving the light reflectivity of the metal-containing paste. The second metal powder has an effect of improving the conductivity of the metal-containing paste. Further, by using the first metal powder and the second metal powder in a volume ratio of 5:95 to 40:60, adhesion and weather resistance of the metal-containing paste (especially in the ultraviolet region), Both are excellent. Furthermore, the heat dissipating property of the metal-containing paste is also improved.

Hereinafter, each component will be specifically described.
1. Organic resin The organic resin is not particularly limited as long as it is an organic resin having adhesiveness, and examples thereof include a curable resin and a radical polymerizable resin. Specific examples of the curable resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol type epoxy resin such as bisphenol AD type epoxy resin, novolak type epoxy resin such as phenol novolac type epoxy resin and cresol novolac type epoxy resin. Resin, brominated epoxy resin such as brominated bisphenol A type epoxy resin, brominated phenol novolac type epoxy resin, heterocyclic epoxy resin such as triglycidyl isocyanate, biphenyl type epoxy resin, naphthalene type epoxy resin, glycidyl ester Type epoxy resin and other epoxy resins having an aromatic ring, butanediol diglycidyl ether and aliphatic epoxy resin such as neopentyl glycol diglycidyl ether, vinylcyclohex Reaction with epichlorohydrin after hydrogenation of cycloaliphatic epoxy resins such as dioxide, dicyclopentadiene dioxide, alicyclic diepoxy adipate, bisphenol A, bisphenol F, phenol novolac, cresol novolac, etc., or polyglycidyl ether Directly hydrogenated hydrogenated polyglycidyl ether and other epoxy resins that do not have an aromatic ring, such as epoxy resins such as novolak type phenol resins and resol type phenol resins, silicone resins, urethane resins, acrylic resins, and acetal resins Etc. Among these, an epoxy resin is preferable, and an epoxy resin having no aromatic ring in its structure is particularly preferable. Thereby, the weather resistance of a metal containing paste can be improved especially. These curable resins may be used alone or in combination.

  When using the said curable resin as an organic resin, it is preferable to use a hardening | curing agent. Examples of the curing agent include imidazole compounds, dicarboxylic acid dihydrazide compounds, aliphatic amines, modified amines such as amine adducts, acid anhydrides, polyamides, dicyandiamides, melamine derivatives, ketimine compounds, and polymercaptans. One kind or a plurality of kinds can be used in combination.

  Specific examples of the radical polymerizable resin include alicyclic (meth) acrylic acid ester, aliphatic (meth) acrylic acid ester, monomer of a compound having at least one methacryl group or acrylic group in the molecule, Examples include acrylic ester polymers, urethane acrylates, oligomers such as (meth) acryl-modified polybutadiene, unsaturated polyester diallyl phthalate resins, vinyl ester resins, and bismaleimide resins. Among these, a radical polymerizable resin having a structure having a saturated fatty chain that does not absorb ultraviolet light is preferable. Thereby, absorption loss and ultraviolet degradation can be prevented. These radically polymerizable resins can be used alone or in combination.

When the radical polymerizable resin is used as an organic resin, it is preferable to use a radical polymerization initiation catalyst in combination.
Examples of the radical polymerization initiation catalyst include t-butylperoxyneodecanoate, dicumyl peroxide, 1.1-bis (t-butylperoxy) -2-methylcyclohexane, t-butylperoxyneodecano. Eate. These may be used alone or in combination. Among these, 1.1-bis (t-butylperoxy) -2-methylcyclohexane or t-butyl peroxyneodecanoate is preferable. Thereby, coexistence of sclerosis | hardenability and a pot life and the light reflectivity of a paste can be improved. The reason is that absorption loss of UV light can be prevented because the structure does not have an aromatic ring.

The decomposition initiation temperature of the radical polymerization initiation catalyst is not particularly limited, but is preferably 40 to 140 ° C, and particularly preferably 50 to 130 ° C. When the decomposition start temperature is less than the lower limit value, the storage stability of the metal-containing paste at normal temperature may be lowered, and when the upper limit value is exceeded, the curing time may become extremely long.
The decomposition start temperature can be evaluated by, for example, a rapid heating test (decomposition start temperature when 1 g of a sample is heated at a heating rate of 4 ° C./min on an electric heating plate).

The organic resin is not particularly limited, but is preferably a liquid at normal temperature. Thereby, workability | operativity at the time of mix | blending can be improved. Moreover, the viscosity of a metal containing paste can be made suitable.
In addition, liquid means what shows fluidity at normal temperature. Specifically, the viscosity of the paste is preferably 10 to 50 [Pa · s], particularly preferably 15 to 40 [Pa · s]. The viscosity can be measured using an E-type viscometer at room temperature, for example.

  The content of ionic impurities in the organic resin is not particularly limited, but is preferably 800 ppm or less, particularly preferably 600 ppm or less. If the content of ionic impurities exceeds the above range, a semiconductor conduction failure may occur.

  Although content of the said organic resin is not specifically limited, 30-80 volume% of the whole said semi-solid composition is preferable, and 50-75 volume% is especially preferable. When the content is less than the lower limit value, the effect of improving the light reflectivity may be reduced, and when the content exceeds the upper limit value, the viscosity may be increased and workability may be reduced.

2. The first metal powder said first metal powder containing aluminum as a main component, like for example metallic aluminum alone, A l-Mg system, Al-Mg-Si based aluminum alloys of Al-Cu-based and the like . Among these, metal aluminum simple substance is preferable. Thereby, ultraviolet reflectivity can be improved especially.

  Examples of the shape of the first metal powder include plate-like bodies such as spheres, flakes, scales, and thin plates, needle-like bodies, fibrous bodies, and resin branches. Among these, a plate-like first metal powder is preferable. Thereby, the light reflectivity can be improved.

The average particle diameter of the first metal powder is not particularly limited, but is preferably larger than the average particle diameter of the second metal powder. Thereby, especially the reflectivity of ultraviolet light can be improved.
Specifically, the average particle diameter of the first metal powder is preferably 3 to 30 μm, particularly preferably 5 to 20 μm. When the average particle size is less than the lower limit, the effect of improving the weather resistance may be reduced, and when the upper limit is exceeded, workability when filling the metal-containing paste may be reduced.

  The ionic impurity content of the first metal powder is not particularly limited, but is preferably 10 ppm or less, and particularly preferably 8 ppm or less. If the content of ionic impurities exceeds the above range, a semiconductor conduction failure may occur. Examples of the ionic impurities include halogen ions and alkali metal ions.

  Although content of the said 1st metal powder is not specifically limited, 1-30 volume% of the whole said semi-solid composition is preferable, and 2-12 volume% is especially preferable. If the content is less than the lower limit, the effect of improving the weather resistance may be reduced, and if the content exceeds the upper limit, the conductivity may be reduced.

Although the said 1st metal powder is not specifically limited, It is preferable that the surface is surface-treated. Thereby, long-term reliability can be improved. That is, the surface of the first metal powder is oxidized to prevent the UV resistance from decreasing.
Specifically, examples of the material for surface-treating the first metal powder include fatty acids such as saturated fatty acids such as stearic acid, oleic acid, lauric acid, and octylic acid, and unsaturated fatty acids.
Although carbon number of the said fatty acid is not specifically limited, 8-25 are preferable and 10-20 are especially preferable. When the carbon number is within the above range, aggregation of the first metal powders can be prevented, and the long-term reliability of the metal-containing paste can be particularly improved.

3. Second metal powder mainly composed of metal different from aluminum Examples of the metal constituting the second metal powder include conductive powder such as gold, silver, copper, nickel, iron, and stainless steel. Among these, silver is preferable. Thereby, both conductivity and reflectivity of ultraviolet light can be achieved.

  Examples of the shape of the second metal powder include a plate-like body such as a spherical body, a flake shape, a scale shape, and a thin plate shape, a needle-like body, a fibrous body, and a resin branch body. Among these, a plate-like second metal powder is preferable. Thereby, electroconductivity can be improved.

  The shape of the first metal powder and the shape of the second metal powder may be different, but are preferably the same shape. Thereby, workability | operativity can be improved.

The average particle diameter of the second metal powder is not particularly limited, but is preferably 0.05 to 50 μm, and particularly preferably 0.1 to 30 μm. If the average particle size is less than the lower limit, the viscosity of the metal-containing paste may increase and it may be difficult to supply to the semiconductor element. If the upper limit is exceeded, bleeding occurs when the metal-containing paste is applied. There is a case.
The maximum particle size of the second metal powder is preferably 50 μm or less, particularly preferably 20 μm or less. When the maximum particle size is within the above range, the workability when applying the metal-containing paste with a dispenser is particularly excellent.

  The content of ionic impurities in the second metal powder is not particularly limited, but is preferably 10 ppm or less, and particularly preferably 8 ppm or less. If the content of ionic impurities exceeds the above range, a semiconductor conduction failure may occur. Examples of the ionic impurities include halogen ions and alkali metal ions.

  Although content of the said 2nd metal powder is not specifically limited, 10-70 volume% of the whole said semi-solid composition is preferable, and 14-65 volume% is especially preferable. If the content is less than the lower limit, the effect of improving the weather resistance may be reduced, and if the content exceeds the upper limit, the conductivity may be reduced.

  As described above, the present invention is characterized in that the first metal powder and the second metal powder are used in a volume ratio of 5:95 to 40:60. Thereby, it is excellent in both the adhesiveness of a metal containing paste, and a weather resistance (especially the weather resistance in a ultraviolet region). The volume ratio of the first metal powder to the second metal powder is preferably 8:92 to 35:65, and particularly preferably 10:90 to 30:70. When the weight ratio is within the above range, the conductivity and ultraviolet light reflectivity are particularly excellent.

  Moreover, the content of the first metal powder and the second metal powder is not particularly limited, but is preferably 20 to 70% by volume, and particularly preferably 25 to 50% by volume, based on the whole semisolid composition. If the content is less than the lower limit, the effect of improving light reflectivity and conductivity may be reduced, and if the content exceeds the upper limit, the workability of the metal-containing paste may be reduced.

Further, the present invention includes an organic resin, a third metal powder having an ultraviolet reflectance of 280 nm of 60% or more, and a fourth metal powder having a resistivity of 2.0 × 10 ⁻⁸ (Ω · m) or less. A metal-containing paste composed of a semi-solid composition, wherein the third metal powder and the fourth metal powder can be used in a volume ratio of 5:95 to 40:60.
The resistivity is at a temperature of 20 ° C.

  Examples of the third metal powder include metal powders mainly composed of aluminum such as metal aluminum alone, and metal powders mainly composed of rhodium. Among these, metal powders mainly composed of aluminum are preferable. Thereby, especially the reflectivity of ultraviolet rays can be improved, and thereby the weather resistance of the metal-containing paste can be improved.

  Examples of the shape of the third metal powder include plate-like bodies such as spherical bodies, flakes, scales, and thin plates, needle-like bodies, fibrous bodies, and resin branches. Among these, a plate-like third metal powder is preferable. Thereby, the light reflectivity can be improved.

The average particle diameter of the third metal powder is not particularly limited, but is preferably larger than the average particle diameter of the fourth metal powder. Thereby, especially the reflectivity of ultraviolet light can be improved.
Specifically, the average particle diameter of the third metal powder is preferably 3 to 30 μm, and particularly preferably 5 to 20 μm. If the average particle size is less than the lower limit, the effect of improving the weather resistance may be reduced, and if it exceeds the upper limit, the workability when filling the metal-containing paste may be reduced.

  The ionic impurity content of the third metal powder is not particularly limited, but is preferably 10 ppm or less, and particularly preferably 8 ppm or less. If the content of ionic impurities exceeds the above range, a semiconductor conduction failure may occur. Examples of the ionic impurities include halogen ions and alkali metal ions.

  Although content of the said 3rd metal powder is not specifically limited, 1-30 volume% of the whole said semi-solid composition is preferable, and 2-12 volume% is especially preferable. If the content is less than the lower limit, the effect of improving the weather resistance may be reduced, and if the content exceeds the upper limit, the conductivity may be reduced.

Although the said 3rd metal powder is not specifically limited, It is preferable that the surface is surface-treated. Thereby, long-term reliability can be improved. That is, it is possible to prevent the anti-ultraviolet ray resistance from being lowered by oxidizing the surface of the third metal powder.
Specifically, examples of the material for surface-treating the third metal powder include fatty acids such as saturated fatty acids such as stearic acid, oleic acid, lauric acid, and octylic acid, and unsaturated fatty acids.
Although carbon number of the said fatty acid is not specifically limited, 8-25 are preferable and 10-20 are especially preferable. When the carbon number is within the above range, aggregation of the first metal powders can be prevented, and the long-term reliability of the metal-containing paste can be particularly improved.

  Examples of the fourth metal powder include a metal powder mainly containing silver, a metal powder mainly containing copper, and a metal powder mainly containing gold. Among these, a metal powder mainly composed of silver is preferable. Thereby, the electroconductivity of a metal containing paste can be improved.

  Examples of the shape of the fourth metal powder include plate-like bodies such as spherical bodies, flakes, scales, and thin plates, needle-like bodies, fibrous bodies, resin branch bodies, and the like. Among these, a plate-like fourth metal powder is preferable. Thereby, electroconductivity can be improved.

  The shape of the third metal powder and the shape of the fourth metal powder may be different, but are preferably the same shape. Thereby, workability | operativity can be improved.

The average particle diameter of the fourth metal powder is not particularly limited, but is preferably 0.05 to 50 μm, particularly preferably 0.1 to 30 μm. If the average particle size is less than the lower limit, the viscosity of the metal-containing paste may increase and it may be difficult to supply to the semiconductor element. If the upper limit is exceeded, bleeding occurs when the metal-containing paste is applied. There is a case.
The maximum particle size of the fourth metal powder is preferably 50 μm or less, and particularly preferably 20 μm or less. When the maximum particle size is within the above range, the workability when applying the metal-containing paste with a dispenser is particularly excellent.

  The content of ionic impurities in the fourth metal powder is not particularly limited, but is preferably 10 ppm or less, and particularly preferably 8 ppm or less. If the content of ionic impurities exceeds the above range, a semiconductor conduction failure may occur. Examples of the ionic impurities include halogen ions and alkali metal ions.

  Although content of the said 4th metal powder is not specifically limited, 10-70 volume% of the whole said semi-solid composition is preferable, and 14-65 volume% is especially preferable. If the content is less than the lower limit, the effect of improving the weather resistance may be reduced, and if the content exceeds the upper limit, the conductivity may be reduced.

  The third metal powder and the fourth metal powder are preferably used in a volume ratio of 5:95 to 40:60, more preferably 8:92 to 35:65, and most preferably 10:90 to 30:70. Is preferred. Thereby, it is excellent in both the adhesiveness of a metal containing paste, and a weather resistance (especially the weather resistance in a ultraviolet region). When the volume ratio between the third metal powder and the fourth metal powder is within the above range, the conductivity and the ultraviolet light reflectivity are particularly excellent.

  As the organic resin, the same ones as described above can be used.

The semi-solid composition includes a diluent, a curing accelerator, a silane coupling agent, a coupling agent such as a titanate coupling agent, a pigment, a dye, an antifoaming agent, and an interface as long as the object of the present invention is not impaired. An activator, nm-size filler (for example, 1 to 100 nm filler), a composite filler in which a metal is coated on the surface of an organic filler, and the like may be added.
In particular, when the organic resin is solid or semi-solid, or when it is liquid but has a high viscosity, it is preferable to use a diluent (solvent). Examples of such a diluent include reactive diluents such as phenyl glycidyl ether, butyl glycidyl ether, neopentyl glycol diglycidyl ether, ethylhexyl glycidyl ether, propylene glycol diglycidyl ether, butyl cellosolve, methyl cellosolve, butyl carbyl Examples include non-reactive diluents such as tall acetate and butyl carbitol, and plasticizers represented by tricresyl phosphate, diphtyl phthalate, dioctyl phthalate, and the like. These may be used alone or in combination.
These diluents are preferably used in an amount suitable for the viscosity suitable for dropping the metal-containing paste.

Moreover, when the said organic resin is an epoxy resin especially, it is preferable to use together the reactive diluent which has an epoxy group as the diluent. Thereby, workability | operativity of a metal containing paste can be improved.
Examples of the reactive diluent include n-butyl diglycidyl ether, versatic acid diglycidyl ester, ethylhexyl glycidyl ether, and the like. These may be used alone or in combination.

  The metal-containing paste of the present invention can be obtained, for example, by premixing a semisolid composition as described above, kneading using a roll, and degassing under vacuum.

  The ultraviolet reflectance [A] at 280 nm of the metal-containing paste is not particularly limited, but is preferably 50% or more, particularly preferably 60 to 95%. When the ultraviolet reflectance is within the above range, the weather resistance is particularly excellent.

  The ultraviolet reflectance [B] after irradiating the metal-containing paste with ultraviolet rays of 280 nm for 250 hours is not particularly limited, but is preferably 80% or more of the ultraviolet reflectance [A], particularly 90% or more. It is preferable. When the ultraviolet reflectance is within the above range, the long-term reliability is particularly excellent.

  The viscosity of the metal-containing paste is not particularly limited, but is preferably 5 to 100 [Pa · s], particularly preferably 10 to 50 [Pa · s]. When the viscosity is within the above range, workability is particularly excellent.

  Such a metal-containing paste can be used, for example, to join a semiconductor element such as an IC or LSI and a semiconductor support member such as a lead frame or a substrate.

Next, a semiconductor device will be described.
FIG. 1 is a cross-sectional view showing an example of a semiconductor device of the present invention.
The semiconductor device 1 includes a substrate 2, a metal-containing paste 3, and a bluish white LED chip 4.
The substrate 2 and the blue-white LED chip 4 are joined via the metal-containing paste 3.
The blue-white LED chip 4 and the substrate 2 are connected by a wire 5.

  As the substrate 2, for example, a lead frame such as a 42 alloy lead frame, a copper lead frame, a glass epoxy substrate (a substrate made of glass fiber reinforced epoxy resin), a BT substrate (a BT resin made of cyanate monomer and its oligomer and bismaleimide) is used. Organic substrate such as a substrate).

As a method for bonding the blue-white LED chip 4 and the substrate 2 using the metal-containing paste 3, for example, the metal-containing paste 3 is applied on the substrate 2 by a dispensing method, a screen printing method, a stamping method, or the like. There is a method in which the white LED chip 4 is pressure-bonded and then heated and cured using a heating device such as an oven or a heat block.
Furthermore, after a wire bonding step, the semiconductor device can be completed by sealing by a normal method.

Since the semiconductor device 1 of the present invention uses the metal-containing paste 3 having excellent adhesion and weather resistance, the semiconductor device 1 has excellent weather resistance and excellent connection reliability.
In addition, since the semiconductor device 1 uses the metal-containing paste 3 that is excellent in ultraviolet ray resistance, the semiconductor device 1 is also excellent in long-term reliability. The reason for excellent long-term reliability is as follows. This is because the metal-containing paste 3 can prevent deterioration of the metal-containing paste 3 because it is excellent in reflectivity with respect to light having a wavelength in the vicinity of ultraviolet rays emitted from the blue-white LED chip 4. Furthermore, since the metal-containing paste 3 is excellent in reflectivity with respect to light having a wavelength in the vicinity of ultraviolet rays emitted from the blue-white LED chip 4, it is possible to prevent a decrease in luminance of the blue-white LED chip 4. .

  In the present embodiment, the blue-white LED chip 4 is used as a semiconductor element. However, the present invention is not limited to this, and a semiconductor element such as an IC or LSI can also be used.

Hereinafter, although the metal containing paste and semiconductor device of this invention are demonstrated in detail based on an Example, this invention is not limited to this. First, the Example and comparative example of a metal containing paste are demonstrated.
Example 1
80% by weight (34.5% by volume) of alicyclic epoxy resin (manufactured by Daicel Chemical Industries, Celoxide 2021, viscosity 0.3 Pa · s at room temperature) as an organic resin, and 4-methylhexahydrophthalic anhydride as a curing agent 80% by weight (34.4% by volume) of acid (manufactured by Shin Nippon Rika Co., Ltd., Ricacid MH-700), 0.2% by weight (0.1% by volume) of 2-methylimidazole, and stearin as the first metal powder Flaked aluminum powder A surface-treated with acid (average particle size 10 μm, ionic impurities 10 ppm or less) 33% by weight (6.0% by volume) and flaky silver powder (average particle size) as the second metal powder 3 μm, maximum particle diameter of 40 μm) and 525 wt% (25.0 vol%) were kneaded with a three roll at room temperature for 20 minutes to obtain a metal containing paste. The metal-containing paste was defoamed in a vacuum chamber and subjected to various evaluations.
The volume ratio of the first metal powder to the second metal powder was 19:81.

(Example 2)
It carried out similarly to Example 1 except having changed the ratio of the 1st metal powder and the 2nd metal powder as follows.
The first metal powder was 11% by weight (2.0% by volume), and the second metal powder was 609% by weight (29.0% by volume).
The volume ratio of the first metal powder to the second metal powder was 6:94.

(Example 3)
It carried out similarly to Example 1 except having changed the ratio of the 1st metal powder and the 2nd metal powder as follows.
The first metal powder was 60% by weight (11% by volume), and the second metal powder was 380% by weight (20% by volume).
The volume ratio of the first metal powder to the second metal powder was 35:65.

Example 4
It carried out similarly to Example 1 except having used the following as 1st metal powder.
As the first metal powder, flaky aluminum B (average particle size of 3 μm, ionic impurities of 10 ppm or less) surface-treated with stearic acid was used.

(Example 5)
It carried out like Example 1 except having used the following as the 1st metal powder.
As the first metal powder, flaky aluminum C (average particle size 30 μm, ionic impurities 10 ppm or less) surface-treated with stearic acid was used.

(Example 6)
It carried out like Example 1 except having used the following as the 1st metal powder.
As the first metal powder, spherical aluminum D (average particle size 10 μm, ionic impurities 10 ppm or less) surface-treated with stearic acid was used.

(Example 7)
It carried out like Example 1 except having used the following as the 1st metal powder.
As the first metal powder, spherical aluminum E (average particle diameter: 10 μm, ionic impurities: 10 ppm or less) not subjected to surface treatment was used.

(Example 8)
The following was performed as in Example 1 except that the following were used as the organic resin, and the contents of the first metal powder and the second metal powder were as follows.
As the organic resin, radically polymerizable oligomer (acryl-modified hydrogenated polybutadiene, number average molecular weight: about 2250, Nippon Soda Co., Ltd., TEAI-1000) 50% by weight (32.1% by volume) and radically polymerizable monomer (1 .6-hexanediol) 50% by weight (30.3% by volume) and radical polymerization catalyst [1.1-bis (t-butylperoxy) -2-methylcyclohexane, rapid heating test decomposition temperature: 109 ° C., Japan 1% by weight (0.6% by volume) of Perhexa 3M] manufactured by Yushi Co., Ltd., 8% by weight (2.0% by volume) of the first metal powder and 608% by weight (35% of the second metal powder) 0.0 vol%).
The volume ratio of the first metal powder to the second metal powder was 5:95.

(Comparative Example 1)
It carried out similarly to Example 1 except having changed the ratio of the 1st metal powder and the 2nd metal powder as follows.
The first metal powder was 6% by weight (1.0% by volume), and the second metal powder was 630% by weight (30.0% by volume).
The volume ratio of the first metal powder to the second metal powder was 3:97.

(Comparative Example 2)
It carried out similarly to Example 1 except having changed the ratio of the 1st metal powder and the 2nd metal powder as follows.
The first metal powder was 81% by weight (15% by volume), and the second metal powder was 336% by weight (16% by volume).
The volume ratio of the first metal powder to the second metal powder was 48:52.

The following evaluation was performed about the metal containing paste obtained by each Example and the comparative example. The evaluation items are shown below together with the contents. The obtained results are shown in Table 1.
1. UV reflectance [A]
The metal-containing paste obtained in each Example and Comparative Example was applied on a glass plate and cured at 175 ° C. for 1 hour. Thereafter, the ultraviolet reflectance [A] of the cured product surface of the metal-containing paste was measured using an ultraviolet spectrophotometer (measured at 240 to 800 nm).

2. UV reflectance [B] after 250 hours UV irradiation
The metal-containing paste obtained in each Example and Comparative Example was applied on a glass plate, cured at 175 ° C. for 1 hour, and then irradiated with ultraviolet rays at room temperature for 250 hours. Thereafter, the ultraviolet reflectance [B] of the cured product surface of the metal-containing paste was measured using an ultraviolet spectrophotometer (measured at 240 to 800 nm). Each code is as follows.
A: The ultraviolet reflectance [B] exceeds 90% of the ultraviolet reflectance [A].
○: The ultraviolet reflectance [B] is 80% to 90% of the ultraviolet reflectance [A].
Δ: The ultraviolet reflectance [B] is 70% to less than 80% of the ultraviolet reflectance [A].
X: The ultraviolet reflectance [B] is less than 70% of the ultraviolet reflectance [A].

3. Conductivity (resistance value)
Using the metal-containing paste obtained in each example and comparative example, a 42 mm 2 mm × 2 mm chip was mounted on a lead frame and cured at 175 ° C. for 1 hour. Thereafter, the resistance value in the vertical direction was measured with a tester.

4). Workability As for workability, workability when discharging a metal-containing paste from a dispenser was evaluated. Each code is as follows.
A: There is no problem in both the discharge speed and spread of the metal-containing paste.
○: The discharge speed of the metal-containing paste is a little slow, but there is no problem with spreading.
Δ: There is no problem in the discharge speed of the metal-containing paste, but the spread is insufficient.
X: The metal-containing paste cannot be discharged.

5). Adhesiveness Adhesiveness was evaluated by the shear strength after bonding a silicon chip and a silver-plated copper frame with the metal-containing paste obtained in each of Examples and Comparative Examples.

As is apparent from Table 1, Examples 1 to 8 had high shear strength and excellent ultraviolet reflectance after irradiation for 250 hours. Thereby, it was shown that it is excellent in both adhesive strength and weather resistance.
Moreover, Examples 1-8 were especially excellent in ultraviolet-ray reflectivity, and when used for the LED chip, it was shown that it is excellent in a brightness | luminance.
Moreover, Examples 1-4 and 6-8 were excellent also in workability | operativity.
In addition, Examples 1, 2, 4, 6 and 8 also showed a low resistance value and excellent conductivity.

Next, examples of semiconductor devices and comparative examples will be described.
(Examples 1A-8A)
A 2 mm × 2 mm 42 alloy chip was mounted on the lead frame through the metal-containing paste obtained in Examples 1 to 8, and the metal-containing paste was cured at 175 ° C. for 1 hour to obtain a semiconductor device.

(Comparative Examples 1A and 2A)
A 2 mm × 2 mm 42 alloy chip was mounted on the lead frame through the metal-containing paste obtained in Comparative Examples 1 and 2, and the metal-containing paste was cured at 175 ° C. for 1 hour to obtain a semiconductor device.

Each of the semiconductor devices obtained in Examples 1A to 8A operates normally and is irradiated with ultraviolet rays, and is subjected to a normal temperature energization test (forward current 30 mA), high temperature and high humidity in an environment of 60 ° C. and 95% RH. In the standing test, the number of defectives was small even after 250 hours.
On the other hand, all of the semiconductor devices obtained in Comparative Examples 1A and 2A operated normally, but the number of defects generated was large after 250 hours in the high temperature and high humidity standing test described above.

It is sectional drawing which shows an example of the semiconductor device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Board | substrate 3 Metal containing paste 4 Blue white LED chip 5 Wire

Claims (12)

A semi-solid composition comprising an organic resin, a first metal powder containing aluminum as a main component, and a second metal powder containing a metal different from aluminum as a main component in a volume ratio of 5:95 to 40:60 A metal-containing paste composed of objects,
UV reflectance [A] at 280 nm is 50% or more,
The metal-containing paste is characterized in that the ultraviolet reflectance [B] after irradiation for 280 nm ultraviolet rays for 250 hours is 80% or more of the ultraviolet reflectance [A] .   2. The metal-containing paste according to claim 1, wherein the content of the first metal powder is 1 to 30% by volume of the whole semi-solid composition.   The metal-containing paste according to claim 1 or 2, wherein the metal constituting the second metal powder mainly contains silver.   The metal-containing paste according to any one of claims 1 to 3, wherein the content of the first metal powder and the second metal powder is 20 to 70% by volume of the whole semi-solid composition.   The metal-containing paste according to any one of claims 1 to 4, wherein an average particle diameter of the first metal powder is larger than an average particle diameter of the second metal powder.   The metal-containing paste according to any one of claims 1 to 5, wherein the first metal powder mainly includes a plate-like metal powder.   The metal-containing paste according to claim 1, wherein the organic resin includes an epoxy resin.   The metal-containing paste according to claim 7, wherein the epoxy resin does not have an aromatic ring.   The metal-containing paste according to any one of claims 1 to 8, wherein the organic resin contains a radical polymerizable material. The metal-containing paste according to any one of claims 1 to 9 , which is used for bonding semiconductor members. Via a metal-containing paste according to any one of claims 1 to 10, a semiconductor device which is characterized in that the semiconductor member, and the support member are joined. The semiconductor device according to claim 11 , wherein the semiconductor member is an LED chip.

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