TW201704165A - Glass for covering semiconductor elements - Google Patents

Abstract

Provided is a glass for covering semiconductor elements, which is capable of suppressing warp of a semiconductor element if the semiconductor element is covered thereby. A glass for covering semiconductor elements, which is characterized by having a glass composition that contains, in mass%, 52-68% of ZnO, 5-30% of B2O3, 12.5-25% of SiO2 (excluding 12.5%), 0-3% of Al2O3 (excluding 3%) and 0-6% of RO (wherein R represents at least one element selected from among Mg, Ca, Sr and Ba) and does not substantially contain an alkali metal component and a lead component.

Description

Semiconductor component coated glass

The present invention relates to a glass which can be used as a coating for a semiconductor element including a P-N junction.

Generally, the surface of the semiconductor element including the P-N junction portion is covered with glass from the viewpoint of preventing contamination by the external atmosphere from the semiconductor element such as a ruthenium diode or a transistor. Thereby, stabilization of the surface of the semiconductor element can be achieved, and deterioration of temporal characteristics can be suppressed.

The characteristics required for the semiconductor element-coated glass include (1) coating at a low temperature (for example, 900 ° C or lower) in order to prevent deterioration of characteristics of the semiconductor element; and (2) not including adverse effects on the surface of the semiconductor element. Impurities such as alkaline components.

Conventionally, as the glass for semiconductor element coating, zinc-based glass such as ZnO-B ₂ O ₃ -SiO ₂ or PbO-SiO ₂ -Al ₂ O ₃ or PbO-SiO ₂ -Al ₂ O ₃ -B is known. _{In the} lead-based glass such as the O ₂ series, the lead-based glass such as PbO-SiO ₂ -Al ₂ O ₃ and PbO-SiO ₂ -Al ₂ O ₃ -B ₂ O ₃ is becoming practical. Mainstream (for example, refer to Patent Documents 1 to 4).

However, lead components such as PbO are environmentally harmful components, and thus their use in electrical and electronic equipment has been limited in recent years. The zinc-based glass such as the above-described ZnO-B ₂ O ₃ -SiO ₂ system also contains a small amount of lead component, and has environmental concerns. Therefore, the lead-free progress of various materials (for example, refer to Patent Document 5).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Special Fair No. 1-496653

[Patent Document 2] Japanese Patent Laid-Open No. 50-129181

[Patent Document 3] Japanese Patent Laid-Open No. SHO 48-43275

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2008-162881

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2012-051761

In the semiconductor element coating glass, in order to prevent the semiconductor element from being warped due to a difference in thermal expansion coefficient from the semiconductor element, it is necessary to make the thermal expansion coefficient of the semiconductor element coating glass and the semiconductor element (specifically, The substrate (such as a semiconductor wafer or the like) is adapted. However, in the case of the conventional semiconductor element-coated glass, even if the coefficient of thermal expansion is adapted to the thermal expansion coefficient of the semiconductor element, if the glass is actually applied to the semiconductor element and fired, there is also a wart of the semiconductor element. The situation of a big change.

In view of the above circumstances, an object of the present invention is to provide a semiconductor element coating glass which can suppress warpage of a semiconductor element when it is coated on a semiconductor element.

As a result of intensive studies, the present inventors have found that the above problems can be solved by a ZnO-B ₂ O ₃ -SiO ₂ -based glass having a specific composition, and are proposed in the form of the present invention.

In other words, the glass for coating a semiconductor element of the present invention is characterized in that it contains 52 to 68% of ZnO, 5 to 30% of B ₂ O ₃ , and 12.5 to 25% of SiO ₂ as a glass composition (wherein Does not contain 12.5%), 0 to 3% of Al ₂ O ₃ (excluding 3%) and 0 to 6% of RO (R is selected from at least one of Mg, Ca, Sr, and Ba), and It does not contain an alkali metal component or a lead component.

As described above, even when the thermal expansion coefficient of the glass and the semiconductor element has been adapted, if the glass is actually applied to the semiconductor element and fired, the warpage of the semiconductor element may become large. The reason for this is considered to be an abnormal expansion of the glass at a high temperature (specifically, above the glass transition point). The inventors conducted research and found that the reason for the abnormal expansion at a high temperature is the Al ₂ O ₃ component contained in the glass. Therefore, in the glass for semiconductor element coating of the present invention, the content of Al ₂ O ₃ is reduced to 3% or less as much as possible, whereby the above-described abnormal expansion can be reduced and the warpage of the semiconductor element can be suppressed.

Further, since the semiconductor element coating glass of the present invention does not substantially contain an alkali metal component, it is possible to suppress adverse effects on the surface of the semiconductor element. Moreover, since the lead component is not substantially contained, the load on the environment is small. Here, "substantially not contained" means that the corresponding component is not intentionally added as a glass component, and does not mean that impurities which are inevitably mixed are completely excluded. Objectively, it means that the content of the corresponding component containing impurities is less than 0.1% by mass.

The semiconductor element coating glass of the present invention preferably further contains, in mass%, 0 to 5% of Ta ₂ O ₅ , 0 to 5% of MnO ₂ , 0 to 5% of Nb ₂ O ₅ and 0 to 3%. CeO ₂ .

The glass for coating a semiconductor element of the present invention preferably has a thermal expansion coefficient of 20 to 60 × 10 ^-7 / ° C at a temperature ranging from 30 to 300 °C.

According to the above configuration, it is possible to adapt to the thermal expansion coefficient of the semiconductor element. As a result, it is possible to suppress problems such as warpage of the semiconductor element having a difference in thermal expansion coefficient or occurrence of cracks in the glass for covering the semiconductor element.

The glass powder for coating a semiconductor element of the present invention is characterized by comprising the above-described glass for covering a semiconductor element.

By coating the glass powder for semiconductor elements of the present invention, it is possible to easily coat the surface of the semiconductor element.

The semiconductor element coating material of the present invention is characterized by containing 100 parts by mass of the above-mentioned glass element for coating a semiconductor element, and is selected from the group consisting of ZnO and αZnO. B ₂ O ₃ and 2ZnO. At least one inorganic powder of SiO ₂ is 0.01 to 5 parts by mass.

According to the above configuration, precipitation of crystals in the glass can be promoted, and low thermal expansion can be achieved. Thereby, it becomes easy to match the thermal expansion coefficient of a semiconductor element.

According to the present invention, it is possible to provide a semiconductor element coating glass which can suppress warpage of a semiconductor element when it is coated on a semiconductor element.

The semiconductor element coating glass of the present invention is characterized in that it contains 52 to 68% of ZnO, 5 to 30% of B ₂ O ₃ , and 12.5 to 25% of SiO ₂ as a glass composition (excluding 12.5%), 0 to 3% of Al ₂ O ₃ (excluding 3% thereof) and 0 to 6% of RO (R is selected from at least one of Mg, Ca, Sr and Ba), and is substantially not Contains alkali metal components and lead components. The reason for specifying the content of each component as described above will be described below. In addition, in the description of the content of each component below, "%" means "% by mass" unless otherwise specified.

ZnO is a component that stabilizes glass. The content of ZnO is preferably from 52 to 68%, particularly preferably from 57 to 64%. When the content of ZnO is too small, the devitrification property at the time of melting becomes strong, and it becomes difficult to obtain a homogeneous glass. On the other hand, when the content of ZnO is too large, the acid resistance tends to decrease.

The B ₂ O ₃ -based glass has a network former and is a component that improves fluidity. The content of B ₂ O ₃ is preferably from 5 to 30%, particularly preferably from 15 to 25%. When the content of B ₂ O ₃ is too small, the crystallinity becomes strong and the fluidity is impaired, and the uniform coating on the surface of the semiconductor element tends to be difficult. On the other hand, when the content of B ₂ O ₃ is too large, the coefficient of thermal expansion becomes large, or the chemical durability tends to decrease.

The mesh structure of the SiO ₂ -based glass forms a component and has an effect of lowering the coefficient of thermal expansion. Moreover, there is also an effect of improving chemical durability such as acid resistance. The content of SiO ₂ is preferably from 12.5 to 25% (excluding 12.5%), from 13 to 24%, and particularly preferably from 14 to 22%. If the content of SiO ₂ is too small, the chemical durability tends to be poor. Further, the coefficient of thermal expansion becomes large, and the matching with the semiconductor element tends to be difficult. On the other hand, when the content of SiO ₂ is too large, crystallinity becomes strong and fluidity is impaired, and uniform coating on the surface of the semiconductor element tends to be difficult.

Although Al ₂ O ₃ has an effect of stabilizing the glass, on the other hand, it is a component which causes the abnormal expansion of the glass at a high temperature (specifically, the glass transition point or more). The content of Al ₂ O ₃ is preferably 0 to 3% (excluding 3%), 0 to 2.5%, 0 to 2%, and particularly preferably 0 to 1%. When the content of Al ₂ O ₃ is too large, there is a tendency that the warpage of the semiconductor element is increased after the glass of the present invention is applied to a semiconductor element and baked.

RO (R is at least one selected from the group consisting of Mg, Ca, Sr, and Ba) has an effect of improving the meltability. However, if the content is too large, the thermal expansion coefficient tends to increase. As a result, warping or cracking tends to occur when applied to a semiconductor element. Therefore, the content of RO is preferably 0 to 6%, 0 to 3%, and particularly preferably 0 to 1%, and most preferably substantially does not contain RO.

The semiconductor element coating glass of the present invention does not substantially contain an alkali metal component (Li ₂ O, Na ₂ O, K ₂ O, etc.) which adversely affects the surface of the semiconductor element. Further, the lead component (PbO or the like) which is an environmentally-charged substance is not substantially contained.

The glass for semiconductor element coating of the present invention may further contain Ta ₂ O ₅ , MnO ₂ , Nb ₂ O ₅ or CeO ₂ . By containing these components, there is an effect of reducing leakage current when coated on the surface of the semiconductor element.

The content of Ta ₂ O ₅ , MnO ₂ and Nb ₂ O ₅ is preferably from 0 to 5%, particularly preferably from 0.1 to 3%. If the content of these components is too large, the meltability tends to decrease. Further, the content of CeO ₂ is preferably from 0 to 3%, particularly preferably from 0.1 to 2%. When the content of CeO ₂ is too large, the crystallinity is too strong, and the fluidity tends to decrease when the semiconductor element is coated.

The glass for covering a semiconductor element of the present invention is preferably in a powder form (glass powder for coating a semiconductor element). Thereby, the coating of the surface of the semiconductor element can be easily performed using, for example, a paste method or an electrophoretic coating method. In this case, the average particle diameter D _{50 of the} glass powder is preferably 25 μm or less, and particularly preferably 15 μm or less. If the average particle diameter D _{50 of} the glass powder is too large, the paste tends to be difficult to be deformed. Moreover, electrophoretic coating also becomes difficult. In addition, the lower limit of the average particle diameter D ₅₀ of the glass powder is not particularly limited, and is actually 0.1 μm or more.

The semiconductor element coating material of the present invention comprises the above-described glass element for coating a semiconductor element. For example, the semiconductor element coating material of the present invention is a glass powder for coating a semiconductor element, and is selected from the group consisting of ZnO and αZnO. B ₂ O ₃ and 2ZnO. At least one inorganic powder of SiO ₂ is used as a nucleating agent. By adding these inorganic powders, the low-expansion crystals are easily precipitated at the time of firing. As a result, it can be easily adjusted to the desired coefficient of thermal expansion.

The content of the inorganic powder is preferably 0.01 to 5 parts by mass, and particularly preferably 0.1 to 3 parts by mass, per 100 parts by mass of the glass powder for coating a semiconductor element. When the content of the inorganic powder is too small, the amount of precipitated crystals at the time of baking is small, and it tends to be difficult to achieve a desired thermal expansion coefficient. On the other hand, when the content of the inorganic powder is too large, the amount of precipitated crystals at the time of baking becomes too large to impair the fluidity, and the coating on the surface of the semiconductor element tends to be difficult.

In addition, as the particle diameter of the inorganic powder is smaller, the particle size of the precipitated crystal becomes smaller, and the mechanical strength tends to increase. Therefore, the average particle diameter D _{50 of the} inorganic powder is preferably 5 μm or less, and particularly preferably 3 μm or less. The lower limit of the average particle diameter D ₅₀ of the inorganic powder is not particularly limited, and is actually 0.1 μm or more.

The coefficient of thermal expansion (30 to 300 ° C) of the glass for semiconductor element coating of the present invention (or a material for coating a semiconductor element) is based on the thermal expansion coefficient of the semiconductor element, for example, 20 × 10 ^-7 to 60 × 10 ^-7 / ° C, 30 It is appropriately adjusted within the range of ×10 ^-7 to 50×10 ^-7 /°C, 30×10 ^-7 to 45×10 ^-7 /°C, and further 31×10 ^-7 to 40×10 ^-7 /°C.

The semiconductor element coating glass of the present invention can be formed into a batch by, for example, mixing raw material powders of the respective oxide components, and is melted at about 1500 ° C for about 1 hour to be vitrified, then formed, and then pulverized as needed. And graded to get.

[Examples]

Hereinafter, the present invention will be described based on examples, but the present invention is not limited to the examples.

Table 1 shows Examples 1 to 4 and Comparative Examples 1 and 2 of the present invention.

Each sample was produced in the following manner. First, a raw material powder was prepared so as to have a glass composition in the table, and a batch was prepared and melted at 1500 ° C for 1 hour to be vitrified. Then, the molten glass was formed into a film shape, and then pulverized by a ball mill and classified using a 350-mesh sieve to obtain a glass powder having an average particle diameter D ₅₀ of 12 μm. Then, the inorganic powder described in the table is added to the obtained glass powder to obtain a semiconductor element coating material. Further, the amount of the inorganic powder added is expressed in an amount of 100 parts by mass based on the glass powder. The thermal expansion coefficient was measured in a temperature range of 30 to 300 ° C using a thermal expansion measuring device (dwellometer) for the obtained semiconductor element coating material. The results are shown in Table 1.

The semiconductor element coating material was dispersed in an organic solvent, adhered to the surface of a 3 inch wafer by electrophoresis, and fired at 700 to 800 ° C to form a sintered layer having a film thickness of 15 μm. After the formation of the sintered layer, the wafer was confirmed to have a slight warpage. With the following The way to evaluate the size of the warp.

The tantalum wafer after the formation of the sintered layer is placed on the flat plate so that the convex surface becomes the lower side. When the oriented flat portion of the crucible wafer was pressed against the flat plate, the distance from the end portion on the opposite side to the orientation flat portion to the flat plate was measured and evaluated in the form of the warpage.

As is clear from Table 1, the semiconductor element coating materials of Examples 1 to 4 have a thermal expansion coefficient of 32 × 10 ^-7 to 36 × 10 ^-7 / ° C and a warpage of 250 μm or less. On the other hand, the warpage of the tantalum wafer of the semiconductor element coating materials of Comparative Examples 1 and 2 was as large as 500 μm or more.

Claims (5)

A glass for coating a semiconductor element, characterized in that, as a glass composition, 52 to 68% of ZnO, 5 to 30% of B ₂ O ₃ , and 12.5 to 25% of SiO ₂ (excluding 12.5) are contained by mass%. %), 0 to 3% of Al ₂ O ₃ (excluding 3% thereof) and 0 to 6% of RO (R is selected from at least one of Mg, Ca, Sr and Ba), and does not substantially contain Alkali metal component, lead component. The semiconductor element coating glass according to claim 1 further comprising, in mass%, 0 to 5% of Ta ₂ O ₅ , 0 to 5% of MnO ₂ , 0 to 5% of Nb ₂ O ₅ and 0 to 3 % of CeO ₂ . The semiconductor element coated glass of claim 1 or 2 has a thermal expansion coefficient of 20 to 60 × 10 ^-7 / ° C at a temperature ranging from 30 to 300 °C. A glass powder for coating a semiconductor element, comprising the glass for coating a semiconductor element according to any one of claims 1 to 3. A semiconductor element coating material comprising 100 parts by mass of a glass powder for coating a semiconductor element according to claim 4, and selected from the group consisting of ZnO and αZnO. B ₂ O ₃ and 2ZnO. At least one inorganic powder of SiO ₂ is 0.01 to 5 parts by mass.