JP2018047500A - Bi-BASED SOLDER ALLOY AND METHOD FOR PRODUCING THE SAME, AND ELECTRONIC COMPONENT AND ELECTRONIC COMPONENT-MOUNTED SUBSTRATE COMPRISING THE SOLDER ALLOY - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Bi-based solder alloy that is substantially free of Pb, Zn, Al, Sb, has excellent wettability and joining reliability, and is also suitable for mounting a semiconductor element on a joining object member having one of Ni layer, Ni/Au layer, and Ni/Pd/Au layer on its surface.SOLUTION: A Bi-based solder alloy contains Ag, Sn and In, with the Bi content of 70 mass% or more. The Ag content is 0.6 mass% or more and 18 mass% or less, the Sn content is 0.1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less relative to the Ag content, and the Bi-based solder alloy contains a particle containing an intermetallic compound of Ag, Sn and In, with the balance being Bi, excluding inevitable elements in production.SELECTED DRAWING: None

Description

  The present invention relates to a Bi-based solder alloy, a manufacturing method thereof, an electronic component using the solder alloy, and an electronic component mounting substrate, and more particularly, substantially free of Pb, Zn, Al, and Sb, and machined. Bi base suitable for mounting of semiconductor elements on a member to be joined having a Ni layer, Ni / Au layer, or Ni / Pd / Au layer on the surface. The present invention relates to a solder alloy, a manufacturing method thereof, an electronic component using the solder alloy, and an electronic component mounting substrate.

  When manufacturing an electronic component mounting substrate, first, a semiconductor element such as a semiconductor chip is bonded (die bonding) to a member to be bonded such as a lead frame via a first solder alloy, and then an electronic component is manufactured. The second solder alloy supplied on a substrate such as a printed circuit board is different from the first solder alloy and has a solidus temperature lower than that of the first solder alloy, and is melted (reflowed). Then, after mounting the electronic component on a substrate such as a printed circuit board, or mounting the semiconductor element on the substrate that is a member to be bonded via the first solder alloy, the second solder is applied to other portions of the substrate. It is common practice to reflow the alloy and mount other semiconductor elements and electronic components. As described above, the solder used when manufacturing the electronic component mounting board is roughly classified into a high temperature (about 260 ° C. to 400 ° C.) and a medium / low temperature (about 140 ° C. to 230 ° C.) depending on the use limit temperature. .

  Conventionally, a Sn-37 mass% Pb eutectic solder alloy (melting point 183 ° C.) is widely used as a low-temperature solder alloy for mounting electronic components on a substrate, and reflow is performed at 220 to 230 ° C. during mounting. It was done. On the other hand, when mounting a semiconductor element such as a semiconductor chip on a member to be joined such as a lead frame inside an electronic component, it is melted again at the reflow temperature (220 to 230 ° C.) when mounting the electronic component on the substrate, resulting in poor connection. In order to prevent generation of Pb-5 mass% Sn (solidus temperature 305 ° C.) as a high temperature solder alloy having a solidus temperature higher than the reflow temperature when mounting electronic components on a substrate. ), Pb-3 mass% Sn (solidus temperature 315 ° C.) and the like have been used.

  However, products that use lead (Pb) -containing solder alloys have been pointed out that after disposal, Pb flows out of the product, penetrates into the soil, accumulates in crops, etc., and can cause health damage to humans. In recent years, lead-free solder alloys that do not contain Pb have been actively developed because it has been pointed out that the outflow of Pb from discarded products due to acid rain has been pointed out.

As an alternative to Pb-containing solder alloys for medium and low temperatures, lead-free solder alloys that do not contain Pb, such as Sn—Ag—Cu, have been put into practical use.
However, since the melting point of a lead-free solder alloy such as Sn—Ag—Cu is about 220 ° C. which is higher than that of a conventional Pb—Sn eutectic solder alloy, the reflow temperature during mounting is around 250 ° C. For this reason, the lead-free solder alloy used for joining inside the electronic component has a high temperature that does not cause a problem in the joining reliability and the like inside the electronic component even after the cycle of holding at a reflow temperature of 250 ° C. for 10 seconds is repeated about 5 times. There is a need for lead-free solder alloys. Electronic parts have been miniaturized and used in various devices, and in particular, development of lead-free solder alloys with excellent long-term bonding reliability is also required.

  In other words, high-temperature lead-free solder alloys used for joining inside electronic components include reflow when mounting electronic components on a substrate, in addition to properties such as heat dissipation, stress relaxation, thermal fatigue resistance, and electrical conductivity. In order to prevent poor connection due to remelting at a temperature (250 ° C.), it is necessary to have a solidus temperature of 255 ° C. or higher after joining.

  In addition, when the liquidus temperature of a high-temperature lead-free solder alloy used for joining inside an electronic component is 400 ° C. or higher, it is necessary to increase the working temperature during die bonding to 400 ° C. or higher. In some cases, adverse effects such as changes in the characteristics of the semiconductor elements and acceleration of surface oxidation of the members to be joined may occur. Therefore, the liquidus temperature needs to be 400 ° C. or lower, and it is required to be 350 ° C. or lower in consideration of an actual production process.

  As a lead-free solder alloy having a melting point of 255 ° C. to 350 ° C., an Au—Sn solder alloy, a Bi—Ag solder alloy, and the like have been proposed. The Au—Sn solder alloy has a composition containing 20% by mass of Sn and has a melting point of 280 ° C., and has been put to practical use without the problem of remelting at the time of mounting. The actual situation is that it is not applied to general-purpose products.

  Patent Document 1 contains Bi in an amount of 0.03 mass% to 0.70 mass%, Zn is contained in an amount of 0.2 mass% to 14.0 mass%, and has a melting point of 265 ° C. or higher. Solder alloys have been proposed.

  Patent Document 2 includes Bi of 90% by mass or more, Sn of 1 to 5% by mass, and at least one element selected from Sb and / or Ag each containing 0.5 to 5% by mass. A solder alloy having a high bonding strength has been proposed.

WO2011 / 158668 WO2012 / 002173 Publication

Conventionally, the island part of a member to be joined to a semiconductor element such as a lead frame to which a solder alloy is applied has often been bare Cu, which is a raw material, or has been previously plated with Ag. However, in recent years, materials have become smaller and high corrosion resistance has been required for devices such as in-vehicle devices, and Ni plating having excellent corrosion resistance is often applied instead of Ag plating. Ni is basically inferior in solder wettability in many cases. Therefore, a very thin Au plating or Pd plating may be applied to the surface of Ni.
However, when a Bi-based solder alloy is used as a solder alloy for joining a semiconductor element to a member to be joined that has been subjected to Ni plating, Ni reacts with Bi as a main component, and Bi ₃ Ni which is brittle at the joint interface An alloy layer may be formed. When such a fragile Bi ₃ Ni alloy layer is formed, the bonding reliability may be deteriorated. In particular, when the surface of the member to be bonded is a Ni layer, the bonding reliability is significantly deteriorated. Even when the solder alloys described in Patent Document 1 and Patent Document 2 are used, there are cases where sufficient bonding reliability cannot be obtained due to the state of the bonding surface.

  In view of the problems of the prior art, the object of the present invention is substantially free of Pb, Zn, Al, and Sb, has improved bondability and excellent bonding reliability, and in particular, has a Ni layer, Ni / Au on the surface. Bi-base solder alloy suitable for mounting a semiconductor element on a member to be joined having any one of a layer and a Ni / Pd / Au layer, a manufacturing method thereof, and an electronic component and an electronic using the solder alloy It is to provide a component mounting board.

  As a result of intensive studies to solve the above problems, the present inventors further mixed a predetermined amount of Sn and In in the conventional Bi-Ag solder alloy to form an alloy. It is found that the formed particles containing an intermetallic compound of Ag, Sn and In have an effect of suppressing the reaction of Bi and Ni, and the particles containing an intermetallic compound of Ag, Sn and In are dispersed. In bonding, it has been found that a Bi-based solder alloy having good wettability and no joint failure, excellent stress relaxation and high joint reliability can be obtained, and is applied to the island portion of the lead frame to which the solder alloy is applied. Even when any one of Ni plating, Ni / Au plating, and Ni / Pd / Au plating is applied, the bonding strength after the bonding of the Bi-based solder alloy is not lowered and the bonding reliability is improved. It found that can produce electronic components, thereby completing the present invention. In addition, the present inventors further suppress the coarsening of particles containing an intermetallic compound of Ag and Sn by adding a predetermined amount of Ge or Te to the Bi-Ag-Sn-In solder alloy. Even if the lead frame island where the solder alloy is applied is found to be effective, and even if any of Ni plating, Ni / Au plating, and Ni / Pd / Au plating is applied, the bonding reliability is further improved The inventors have found that an excellent electronic component can be manufactured, and have completed the present invention. In addition, the present inventors further improve wettability by adding a predetermined amount of one or more metals selected from Cu, Ni, Pd, and Au to the Bi-Ag-Sn-In solder alloy. It has been found that an electronic component having improved bonding reliability can be manufactured, and the present invention has been completed.

  That is, the Bi-based solder alloy according to the present invention is a Bi-based solder alloy containing Ag, Sn, and In, substantially free of Pb, Zn, Al, and Sb and having a Bi content of 70% by mass or more. The Ag content is 0.6 mass% or more and 18 mass% or less, the Sn content is 0.1 mass% or more and 10 mass% or less, and the In content is 0.1 mass% or more and 2 mass% or less. In addition, the total content of Sn and In is 1/1 or less with respect to the Ag content, and the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In However, the remainder is characterized by being made of Bi except for elements inevitably included in production.

  The Bi-based solder alloy according to the present invention contains Ag, Sn, and In, and further contains at least one of Cu, Ni, Pd, and Au, and substantially contains Pb, Zn, Al, and Sb. It is a Bi-based solder alloy with a Bi content of 70% by mass or more and an Ag content of 0.6% by mass to 18% by mass and a Sn content of 0.1% by mass to 10%. Mass% or less, the total content of Sn and In is 1/1 or less with respect to the Ag content, the In content is 0.1 mass% or more and 2 mass% or less, and the Bi group The solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and one or more of Cu, Ni, Pd, and Au are added in a total amount of 0.001% by mass to 3.0% by mass. It is contained in the following range, and the balance is made of Bi except for elements inevitably included in production. It is characterized in.

  In addition, the Bi-based solder alloy according to the present invention contains Ag, Sn, In, and Ge, does not substantially contain Pb, Zn, Al, and Sb, and has a Bi content of 70% by mass or more. An alloy having an Ag content of 0.6 mass% to 18 mass%, an Sn content of 0.1 mass% to 10 mass%, and an In content of 0.1 mass% to 2 mass% %, And the total content of Sn and In is 1/1 or less with respect to the Ag content, the Ge content is 0.001 mass% or more and 3.0 mass% or less, and the Bi The base solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and the balance is made of Bi except for elements that are inevitably included in manufacturing.

  The Bi-based solder alloy according to the present invention contains Ag, Sn, In, and Ge, and further contains at least one of Cu, Ni, Pd, and Au, and is substantially Pb, Zn, Al, Bi-based solder alloy containing no Sb and having a Bi content of 70% by mass or more, the Ag content being 0.6% by mass or more and 18% by mass or less, and the Sn content being 0.1% by mass 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content, and the Ge content An amount of 0.001% by mass to 3.0% by mass, and the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and Cu, Ni, Pd, Au 1 or more of the total amount in the range of 0.001% by mass to 3.0% by mass Balance production, it is characterized by comprising a Bi except element contained inevitably.

  The Bi-based solder alloy according to the present invention contains Ag, Sn, In, and Te, does not substantially contain Pb, Zn, Al, and Sb, and has a Bi content of 70% by mass or more. An alloy having an Ag content of 0.6% by mass to 18% by mass, an Sn content of more than 0.1% by mass, and an In content of 0.1% by mass to 2%. Less than mass%, Te content is 0.001 mass% or more and 3.0 mass% or less, and the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and the balance is It is characterized by being made of Bi except for elements inevitably included in the production.

  The Bi-based solder alloy according to the present invention contains Ag, Sn, In, and Te, and further contains at least one of Cu, Ni, Pd, and Au, and substantially contains Pb, Zn, Al, Bi-based solder alloy containing no Sb and having a Bi content of 70% by mass or more, the Ag content being 0.6% by mass or more and 18% by mass or less, and the Sn content being 0.1% by mass 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content, and the Te content An amount of 0.001% by mass to 3.0% by mass, and the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and Cu, Ni, Pd, Au 1 or more of the total amount in the range of 0.001% by mass to 3.0% by mass Balance production, it is characterized by comprising a Bi except element contained inevitably.

  Further, in the Bi-based solder alloy of the present invention, the particle size is 80 μm with respect to 100% by volume of the total volume of the particles including the intermetallic compound of Ag, Sn, and In formed in the Bi-based solder alloy. Preferably, less than 97% by volume of particles are present.

  Further, in the Bi-based solder alloy of the present invention used for electronic parts that contain Te and Ge and are further reduced in size, the intermetallic compound of Ag, Sn, and In formed in the Bi-based solder alloy It is preferable that 97% by volume or more of particles having a particle diameter of less than 50 μm are present with respect to 100% by volume of the total volume of the particles including.

  In addition, the Bi-based solder alloy of the present invention is preferably used for joining with a member to be joined having a Ni layer, a Ni / Au layer, or a Ni / Pd / Au layer formed on the surface.

  Moreover, the manufacturing method of the Bi group solder alloy by this invention contains Ag, Sn, and In, does not contain Pb, Zn, Al, Sb substantially, Bi content rate is 70 mass% or more Bi group. Solder alloy, Ag content is 0.6 mass% or more and 18 mass% or less, Sn content is more than 0.1 mass% and 10 mass% or less, and In content is 0.1 mass% or more After pouring a molten metal of the Bi-based solder alloy having a content of 2% by mass or less and a total content of Sn and In being 1/1 or less with respect to the Ag content, By cooling and solidifying at a cooling rate of sec or more, particles having a particle size of less than 80 μm including an intermetallic compound of Ag, Sn, and In are formed in the Bi-based solder alloy.

  In addition, the Bi-based solder alloy manufacturing method according to the present invention contains Ag, Sn, and In, and further contains at least one of Cu, Ni, Pd, and Au, and is substantially Pb, Zn, Al. , A Bi-based solder alloy that does not contain Sb and has a Bi content of 70% by mass or more, an Ag content of 0.6% by mass to 18% by mass, and a Sn content of 0.1% by mass % To 10% by mass, the In content is 0.1% to 2% by mass, and the total content of Sn and In is 1/1 or less with respect to the Ag content, and One or more of Cu, Ni, Pd, and Au are contained in a total amount in the range of 0.001% by mass to 3.0% by mass, and the balance is made of Bi except for elements that are inevitably included in production. After pouring the molten metal of the Bi-based solder alloy into the mold, the temperature is increased up to 255 ° C. at 3 ° C./sec. By cooling and solidifying at the above cooling rate, particles having a particle size of less than 80 μm containing an intermetallic compound of Ag, Sn, and In, the total volume of the whole particle containing the intermetallic compound of Ag, Sn, and In It is characterized by being formed in the Bi-based solder alloy by 97% by volume or more with respect to 100% by volume.

  Moreover, the manufacturing method of the Bi group solder alloy by this invention contains Ag, Sn, In, and Ge, does not contain Pb, Zn, Al, and Sb substantially, and the content rate of Bi is 70 mass% or more. Bi-based solder alloy, Ag content is 0.6 mass% or more and 18 mass% or less, Sn content is 0.1 mass% or more and 10 mass% or less, and In content is 0.1 mass% 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content, and the Ge content is 0.001 mass% or more and 3.0 mass% or less, and the balance In the manufacturing process, the molten Bi-based solder alloy composed of Bi except for elements inevitably included is poured into a mold, and then cooled to 255 ° C. at a cooling rate of 3 ° C./sec or more to be solidified. Particles having a particle size of less than 50 μm containing an intermetallic compound of Sn and In The total volume of 100 vol% of the total particles comprising an intermetallic compound with said Ag and Sn and In, is characterized by the formation in 97% or more by volume the Bi based solder the alloy.

  The method for producing a Bi-based solder alloy according to the present invention contains Ag, Sn, In, and Ge, and further contains at least one of Cu, Ni, Pd, and Au, and is substantially Pb, Zn. A Bi-based solder alloy that does not contain Al, Sb, and has a Bi content of 70% by mass or more, an Ag content of 0.6% by mass or more and 18% by mass or less, and a Sn content of 0.8%. 1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content, The Ge content is in the range of 0.001% to 3.0% by mass, and one or more of Cu, Ni, Pd, and Au in a total amount of 0.001% to 3.0% by mass. The Bi group solder is composed of Bi except for the elements that are inevitably contained in the production. After pouring the molten alloy into the mold, the alloy is cooled to a temperature of 255 ° C. at a cooling rate of 3 ° C./sec or more and solidified, whereby particles having a particle size of less than 50 μm containing an intermetallic compound of Ag, Sn, and In are obtained. It is characterized in that it is formed in the Bi-based solder alloy by 97% by volume or more with respect to the total volume of 100% by volume of the whole particles containing an intermetallic compound of Ag, Sn, and In.

  Moreover, the manufacturing method of the Bi group solder alloy by this invention contains Ag, Sn, In, and Te, does not contain Pb, Zn, Al, Sb substantially, and the content rate of Bi is 70 mass% or more. Bi-based solder alloy, Ag content is 0.6 mass% or more and 18 mass% or less, Sn content is 0.1 mass% or more and 10 mass% or less, and In content is 0.1 mass% 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the content of Ag, and the Te content is 0.001 mass% or more and 3.0 mass% or less, and the balance In the manufacturing process, the molten Bi-based solder alloy composed of Bi except for elements inevitably included is poured into a mold, and then cooled to 255 ° C. at a cooling rate of 3 ° C./sec or more to be solidified. Particles having a particle size of less than 50 μm containing an intermetallic compound of Sn and In The total volume of 100 vol% of the total particles comprising an intermetallic compound with said Ag and Sn and In, is characterized by the formation in 97% or more by volume the Bi based solder the alloy.

  The method for producing a Bi-based solder alloy according to the present invention contains Ag, Sn, In, and Te, and further contains at least one of Cu, Ni, Pd, and Au, and is substantially Pb, Zn. A Bi-based solder alloy that does not contain Al, Sb, and has a Bi content of 70% by mass or more, an Ag content of 0.6% by mass or more and 18% by mass or less, and a Sn content of 0.8%. 1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content, Te content is 0.001% to 3.0% by mass, and one or more of Cu, Ni, Pd and Au in a total amount of 0.001% to 3.0% by mass The Bi group solder is composed of Bi except for the elements that are inevitably contained in the production. After pouring the molten alloy into the mold, the alloy is cooled to a temperature of 255 ° C. at a cooling rate of 3 ° C./sec or more and solidified, whereby particles having a particle size of less than 50 μm containing an intermetallic compound of Ag, Sn, and In are obtained. It is characterized in that it is formed in the Bi-based solder alloy by 97% by volume or more with respect to the total volume of 100% by volume of the whole particles containing an intermetallic compound of Ag, Sn, and In.

  An electronic component according to the present invention includes a member to be bonded, a Bi-based solder alloy according to any one of the present invention, and a semiconductor element mounted on the member to be bonded via the Bi-based solder alloy. It is characterized by that.

  An electronic component mounting board according to the present invention is manufactured using any of the Bi-based solder alloys of the present invention.

The Bi-based solder alloy of the present invention does not substantially contain Pb, Zn, Al, and Sb, and contains fine particles containing an intermetallic compound of Ag, Sn, and In in the Bi-based solder alloy. It is possible to improve the bondability at the time of soldering and suppress the occurrence of bonding failure. Furthermore, it is possible to obtain a Bi-based solder alloy having excellent stress relaxation properties and high bonding reliability. It can be suitably used for die bonding or the like for mounting the semiconductor element. In particular, even when any of the Ni layer, Ni / Au layer, and Ni / Pd / Au layer is formed on the island portion of the lead frame to which the Bi-based solder alloy is applied, after the Bi-based solder alloy is joined Thus, it is possible to form an electronic component having good bondability without reducing the bonding strength. This is considered to be because the fine particles containing the intermetallic compound of Ag, Sn, and In suppress the diffusion of Ni and make it difficult to form a fragile Bi—Ni alloy. In addition to the above Ag, Sn, and In as an additive element, the addition of elements such as Ge and Te can suppress the coarsening of particles including intermetallic compounds, and increase the bonding reliability. Can do. Furthermore, the wettability of the Bi-based solder alloy can be improved by containing at least one element of Cu, Ni, Pd, and Au.
Further, as in the method for producing a Bi-based solder alloy according to the present invention, the molten Ag of the Bi-based solder alloy is poured into a mold and then cooled to 255 ° C. at a cooling rate of 3 ° C./sec or more and solidified. Fine particles containing an intermetallic compound of Sn, Sn, and In can be more easily formed.
Furthermore, the electronic component mounting board using the Bi-based solder alloy of the present invention provides an electronic component mounting board with high mechanical strength without causing a change in characteristics or member oxidation of a semiconductor element such as a semiconductor chip. can do.

It is sectional drawing which shows an example of the semiconductor package using the Bi group solder alloy of this invention.

Hereinafter, the Bi-based solder alloy technology of the present invention in which Bi contains a predetermined amount of Ag, Sn, and In, and fine particles including an intermetallic compound of Ag, Sn, and In are formed in the solder alloy. explain.
The Bi-based solder alloy of the present invention is a Bi-based solder alloy containing Ag, Sn, and In, substantially free of Pb, Zn, Al, and Sb and having a Bi content of 70% by mass or more. , Ag content is 0.6 mass% or more and 18 mass% or less, Sn content is more than 0.1 mass%, 10 mass% or less, In content is 0.1 mass% or more and 2 mass% or less, And the particle | grains which contain the intermetallic compound of Ag, Sn, and In are formed in Bi group solder alloy, and the remainder consists of Bi except the element inevitably contained on manufacture.
Further, the Bi-based solder alloy according to another embodiment of the present invention contains Ag, Sn, and In, and further contains at least one of Cu, Ni, Pd, and Au, and is substantially Pb, Zn. A Bi-based solder alloy that does not contain Al, Sb, and has a Bi content of 70% by mass or more, an Ag content of 0.6% by mass or more and 18% by mass or less, and a Sn content of 0.8%. 1 mass% or more and 10 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the content of Ag, and the content of In is 0.1 mass% or more and 2 mass% or less, In addition, the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and one or more of Cu, Ni, Pd, and Au is added in a total amount of 0.001% by mass or more 3 From Bi except for elements that are contained in the range of 0.0 mass% or less and the remainder is inevitably included in the production. That.
Further, the Bi-based solder alloy according to still another embodiment of the present invention contains Ag, Sn, In, and Ge, substantially does not contain Pb, Zn, Al, and Sb, and has a Bi content of 70 mass. % Bi-based solder alloy, Ag content is 0.6 mass% or more and 18 mass% or less, Sn content is 0.1 mass% or more and 10 mass% or less, and In content is 0.00. 1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content, and the Ge content is 0.001 mass% or more and 3.0 mass%. In the following, particles containing an intermetallic compound of Ag, Sn, and In are contained in a Bi-based solder alloy, and the balance is made of Bi except for elements that are inevitably included in production.
Further, the Bi-based solder alloy of still another embodiment of the present invention contains Ag, Sn, In, and Ge, and further contains one or more of Cu, Ni, Pd, and Au, It is a Bi-based solder alloy that does not contain Pb, Zn, Al, and Sb, and has a Bi content of 70% by mass or more, and the Ag content is 0.6% by mass or more and 18% by mass or less, and the Sn content 0.1 mass% or more and 10 mass% or less, In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content The Ge content is 0.001% by mass to 3.0% by mass, and the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and Cu, One or more of Ni, Pd, and Au in a total amount of 0.001% by mass to 3.0% by mass Contained in circumference, balance production, consisting of Bi except element contained inevitably.
Further, the Bi-based solder alloy of still another embodiment of the present invention contains Ag, Sn, In, and Te, substantially does not contain Pb, Zn, Al, and Sb, and the Bi content is 70 mass. % Bi-based solder alloy, Ag content is 0.6 mass% or more and 18 mass% or less, Sn content is more than 0.1 mass% and 10 mass% or less, and In content is 0%. Particles containing an intermetallic compound of Ag, Sn, and In in a Bi-based solder alloy with a Te content of 0.001 mass% to 3.0 mass%, and a Te content of 1 mass% to 2 mass% It is contained, and the balance is made of Bi except for elements which are inevitably included in production.
Further, the Bi-based solder alloy according to yet another embodiment of the present invention contains Ag, Sn, In, and Te, and further contains one or more of Cu, Ni, Pd, and Au, and substantially includes It is a Bi-based solder alloy that does not contain Pb, Zn, Al, and Sb, and has a Bi content of 70% by mass or more, and the Ag content is 0.6% by mass or more and 18% by mass or less, and the Sn content 0.1 mass% or more and 10 mass% or less, In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content The Te content is 0.001% by mass to 3.0% by mass, and the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and Cu, One or more of Ni, Pd, and Au in a total amount of 0.001% by mass to 3.0% by mass Contained in circumference, balance production, consisting of Bi except element contained inevitably.
As described above, the Bi-based solder alloy of the present invention is composed of particles containing an intermetallic compound of Ag, Sn, and In and a parent phase of a Bi-based solder alloy containing Bi as the main component. It is a feature.

The parent phase of the Bi-based solder alloy of the present invention has an appropriate melting point as a high-temperature solder alloy. For this reason, when mounting an electronic component on a substrate after mounting a semiconductor element on a member to be bonded and manufacturing the electronic component, or after mounting the semiconductor element on a substrate that is a member to be bonded, Without remelting during reflow when mounting other semiconductor elements or electronic components, the Bi-based solder joint state inside the electronic component can be kept as it was at the initial bonding, and the bonding reliability Excellent in properties.
Hereinafter, each element used in the Bi-based solder alloy of the present invention, the intermetallic compound to be formed, the manufacturing method of the Bi-based solder alloy, the electronic component using the obtained Bi-based solder alloy, and the electronic component mounting substrate will be described in detail. explain.

1. Bi
The Bi-based solder alloy of the present invention is mainly composed of Bi, which belongs to the group Va element of the periodic table, and has a trigonal crystal (rhombohedral crystal) with very low crystal structure and is very fragile. In addition, the main component here means that it is a component that is contained most in the solder alloy by mass ratio.
Since the melting point of Bi is 271 ° C., the main component of Bi is that it does not remelt at a temperature of about 200 ° C., which is required for a high-temperature lead-free solder alloy, and can be soldered at a temperature of 350 ° C. or less. A possible solder alloy can be made relatively easily.

  In the Bi-based solder alloy of the present invention, the Bi content is a value determined according to the content of additive elements such as Ag, Sn, and In, but is 70% by mass or more with respect to the total amount of the Bi-based solder alloy. There must be. If the content of Bi is less than 70% by mass, the increase in the liquidus of the Bi-based solder alloy matrix of the present invention may increase, and it may not melt sufficiently during soldering, resulting in an undissolved residue, This is not preferable because it may adversely affect bonding failure and bonding reliability.

2. Ag
A solder alloy containing Ag in Bi is conventionally known as a high-temperature solder alloy that does not contain lead and has a solidus temperature higher than the upper limit of 250 ° C. when the electronic component is mounted on a substrate. For example, Bi-2.5 mass% Ag solder alloy is a eutectic type alloy, the solidus temperature is 262 ° C., which is about 9 ° C. lower than the melting point 271 ° C. of pure Bi, but more than 250 ° C. Yes.

  Moreover, by including Ag in Bi, the brittleness of Bi can be improved and the stress relaxation property can be improved. However, it is difficult to say that the wettability with a member to be joined such as a lead frame is sufficient. In particular, when the member to be joined has a Ni layer, wetting and spreading to the member to be joined was very bad. Moreover, when the member to be joined has a Ni layer, Ni reacts with Bi to form a fragile Bi—Ni alloy. For this reason, in the conventional Bi-Ag solder, it was easy to generate | occur | produce the malfunction at the time of joining generation | occurrence | production at the time of joining, and subsequent reliability test.

  Therefore, the present inventors diligently studied further additive elements and their blending amounts in order to improve the above-mentioned problems without impairing the advantages of the Bi-Ag solder alloy. As a result, when Sn and In are contained at a predetermined ratio with respect to Ag, the stress relaxation property of the Bi-based solder alloy matrix is improved, the wettability is improved, the joining property is good, and the joining failure does not occur. The present inventors have found that the bonding reliability can be improved.

The Bi-based solder alloy of the present invention contains Ag, Sn, and In to contain a predetermined amount, so that Ag, Sn, and In improve the brittleness of Bi, and forms an Ag-Sn-In intermetallic compound. By dispersing the particles in the Bi-based solder alloy, the Bi-based solder alloy is effectively dispersed and strengthened to improve the fragility of Bi more effectively, and the reaction between Bi and Ni is also inhibited. It is thought that formation of Ni alloy can be suppressed. The Ag—Sn—In intermetallic compound will be described in detail later.
The content of Ag is 0.6 mass% or more and 18 mass% or less. When the Ag content is less than 0.6% by mass, the Ag—Sn—In intermetallic compound is not sufficiently generated, and the brittle mechanical characteristics of Bi become dominant, resulting in poor stress relaxation and bonding reliability. In addition to the improvement in performance, the elongation rate is insufficient and the machinability is inferior, and the continuous supply by the apparatus cannot be ensured, resulting in inferior productivity.
Further, when the Ag content exceeds 18% by mass, the liquidus becomes 390 ° C. or higher, and the Bi-based solder alloy is sufficiently dissolved at the time of joining with a joining target member for mounting a semiconductor element such as a semiconductor chip. However, it is not preferable because unsuccessful melting occurs and bonding failure occurs. In the present invention, the more preferable Ag content is 5.0% by mass or more and 15% by mass or less.

3. Sn and In
In the Bi-based solder alloy of the present invention, Sn and In are elements that form an Ag—Sn—In intermetallic compound when combined with Ag. Moreover, there exists an effect which improves the bondability with a joining object member by reacting with the metal of a joining object member.
Further, the conventional Bi—Ag solder alloy has greatly reduced the bonding reliability by forming a Bi ₃ Ni alloy which is a fragile Bi—Ni alloy when Ni is present in the members to be bonded. On the other hand, when the Bi—Ag—Sn—In alloy is used like the Bi-based solder alloy of the present invention, the formation of the Bi—Ni alloy can be suppressed. This is because the above-described Ag—Sn—In intermetallic compound formed in the Bi-based solder alloy of the present invention is finely dispersed in the Bi-based solder alloy and inhibits the reaction between Bi and Ni. It is considered that the Ni—Sn—In layer formed by reacting Ni with In and Ni can suppress the diffusion of Ni into the Bi-based solder alloy. Furthermore, by dispersing particles of an alloy composition rich in flexibility formed from Ag, Sn, and In in the Bi-based solder alloy, a Bi-based solder alloy having excellent stress relaxation and high joint reliability can be obtained. In addition, since the reactivity with the bonding interface is good, wettability is good and no bonding failure occurs at the time of bonding. Therefore, the bonding target member using the Bi-based solder alloy of the present invention and a semiconductor element are used. In the electronic component, the long-term connection reliability is greatly improved, and the same reliability as that of the conventionally used Pb—Sn solder can be obtained.
The contents of Sn and In are preferably set to an amount necessary for reacting with a member to be bonded and improving wettability and bondability, and an amount necessary for forming an Ag-Sn-In intermetallic compound. . When Sn or In is contained in an amount more than necessary, excess Sn or In reacts with Bi to form an alloy with a melting point of around 100 ° C., and when other electronic components are mounted on a substrate at a reflow temperature of 250 ° C. Since it may melt out, it is not preferable. Therefore, it is necessary to keep the ratio of the content of Sn and In appropriately to the content of Ag so as not to generate surplus Sn and In.
The compounding ratio of Sn and In to Ag for forming a reaction layer with the substrate and an alloy composed of Ag-Sn-In in a well-balanced manner is a result of tests conducted by varying the compounding amounts of Ag, Sn, and In. It was found that the total amount of Sn and In needs to be 1/90 or more and 1/1 or less with respect to the Ag content. By making the total amount of Sn and In with respect to the Ag content within this range, a reaction layer with the substrate is formed without excessive Sn and In forming a brittle alloy with Bi, and good Can be obtained. The total amount of Sn and In is more preferably 17/60 or more and 1/2 or less with respect to the Ag content.
Moreover, Sn content is 0.1 mass% or more and 10 mass% or less, and In content is 0.1 mass% or more and 2 mass% or less, and it is favorable, without generating excess Sn and In. It was confirmed that a joining state was achieved.

4). Ag-Sn-In intermetallic compound By producing a Bi-based solder alloy with the compounding ratio of the present invention, particles containing Ag, Sn and In intermetallic compounds essential to the present invention are formed in the Bi-based solder alloy. be able to. In order to efficiently exhibit the above effect, it is preferable to make the particles containing the intermetallic compound fine. Further, it has been confirmed that the melting point of the Ag—Sn—In intermetallic compound within the scope of the present invention is high, and the particles containing the Ag—Sn—In intermetallic compound may not melt even at the time of soldering. For this reason, it is preferable to form fine particles when a raw material for the solder is produced by melting various raw materials.
In addition, as electronic components are miniaturized, it is also required to reduce the thickness of the joint. For this reason, it is preferable that the particle | grains containing an Ag-Sn-In intermetallic compound have a particle size of less than 80 micrometers. Further, the particles having a particle size of less than 80 μm are preferably 97% by volume or more, more preferably 98% by volume or more, and particularly preferably 99% by volume or more with respect to 100% by volume of the total particle volume. preferable. When the particle size is 80 μm or more exceeds 3% by volume, the brittleness is not improved, and bonding reliability may be insufficient or handling may be unfavorable. This is because the variation in the particle size of the formed particles becomes large, the difference in the degree of vulnerability improvement is caused by the difference in particle size, and the increase in the number can sufficiently relax the stress due to the difference in behavior. This is considered to be because it becomes impossible to cause destruction and, as a result, Bi's vulnerability may not be sufficiently improved.
In addition, in this invention, the particle size of the particle | grains containing an Ag-Sn-In intermetallic compound observes each specimen with a 200 times optical microscope, and counts the number of the particle | grains containing all the intermetallic compounds in a visual field. At the same time, the cross-sectional diameter of each particle is measured, and the measured value is multiplied by 1.12. In the present invention, based on the particle size calculated in this way, the volume when all intermetallic compound particles are assumed to be true spheres is calculated, and the proportion of particles having a particle size of less than 80 μm in all the particles. Is calculated by volume%. This calculation method will be described in detail later.

  In addition, although the particle | grains containing the Ag-Sn-In intermetallic compound formed in the Bi group solder alloy of this invention mainly point out the intermetallic compound formed from Ag, Sn, and In, other of this invention In the Bi-based solder alloy of the embodiment, an intermetallic compound in which Ge, Te, Cu, Ni, Pd, and Au are mixed is also included.

5. Ge, Te
Since the particles containing the Ag—Sn—In intermetallic compound have a solder thickness of 30 μm or more and 200 μm or less at the time of joining, it is desirable in terms of connection reliability, so that the particle size is less than 80 μm as described above. Is preferred. Furthermore, when used for joining smaller and thinner electronic components, in order to improve connection reliability, the particle size of the particles containing the Ag—Sn—In intermetallic compound is more preferably less than 50 μm. .
However, in the Bi-Ag-Sn-In alloy, when the Ag-Sn-In intermetallic compound is sufficiently generated and the effect of improving the strength of the Bi-based solder alloy is exhibited, the formation of the Ag-Sn-In intermetallic compound and Since growth also occurs, it is difficult to control the particle size to less than 50 μm.
Therefore, as a result of intensive studies, the present inventors have found that when Ge or Te is contained in a Bi—Ag—Sn—In alloy, Ge or Te forms an Ag—Sn—In intermetallic compound. It has been found that by being a nucleus, generation is prioritized over the growth of Ag—Sn—In intermetallic compound particles, and coarsening is suppressed.
This is because Ge and Te have a higher melting point than the Ag-Sn-In intermetallic compound, and thus become the primary crystal component that precipitates first when the molten Bi-Ag-Sn-In alloy solidifies, and precipitates later. It is considered that each crystal grain is finely precipitated by becoming the starting point of the Ag—Sn—In intermetallic compound or matrix crystal grains to be formed, and the coarsening of the solidified structure as a whole can be suppressed. As a result, the structure of the Bi-based solder alloy becomes a fine solidified structure as compared with the case where neither Ge nor Te is contained, and it is difficult for cracks to occur, and the connection reliability can be improved.
Content of Ge or Te is 0.001 mass% or more and 3.0 mass% or less. When the content of Ge or Te exceeds 3.0% by mass, the primary crystal component becomes coarse and the effect of making the crystal grains fine is inferior, and the wettability during melting may be reduced. Moreover, when content of Ge or Te is less than 0.001 mass%, the effect which refines | miniaturizes a solidification structure | tissue may not fully be acquired. The content of Ge or Te is more preferably 0.03% by mass or more and 0.8% by mass or less.

6). Cu, Ni, Pd, Au
In addition to the above as an additive element, the Bi-based solder alloy according to another aspect of the present invention further includes any one of Cu, Ni, Pd, and Au in order to improve the wettability of the solder alloy and increase the bonding strength after bonding. Or one or more. Cu, Ni, Pd, and Au move preferentially to the bonding interface as compared to Bi, Ag, Sn, and Ge, and form an initial reaction layer with a metal element at the bonding interface such as Ni, thereby wetting the solder alloy. It is considered that the bonding strength after bonding can be improved.
The total content of Cu, Ni, Pd, and Au is 0.001 mass% or more and 3.0 mass% or less. When the total content of Cu, Ni, Pd, and Au exceeds 3.0% by mass, intermetallic compounds formed at the bonding interface are generated as coarse primary crystals, and intermetallic compounds are partially formed. By growing, the reaction at the bonding interface becomes non-uniform and the wettability at the time of melting may be lowered, which is not preferable. Further, if the total content of Cu, Ni, Pd, and Au is less than 0.001% by mass, an intermetallic compound may not be sufficiently formed at the bonding interface, and an improvement in wettability may not be obtained. . The total content of Cu, Ni, Pd, and Au in the Bi-based solder alloy according to another aspect of the present invention is more preferably 0.03% by mass or more and 0.8% by mass or less.

7). Production of Bi-based solder alloy The production method of the Bi-based solder alloy of the present invention is not particularly limited, and can be produced by a known method that has been conventionally used, using each of the components described above.
The shape of the solder product is not particularly limited, and may be used as a solder paste by mixing with a flux containing an appropriate rosin or the like in addition to a wire, a ribbon shape, a ball shape, or the like.
An example of the manufacturing method is shown below.
The raw material should be shot or finely processed to reduce compositional variation in the Bi-based solder alloy after melting, and should have a fine shape with a diameter of 5 mm or less, more preferably 3 mm or less. Is preferred.

  In order to suppress the oxidation of the raw material, the raw material having such a shape is put in an atmosphere of nitrogen or an inert gas, and then heated and melted at 500 to 600 ° C., preferably 500 to 550 ° C. Stirring is started when the metal begins to melt, and stirring is continued sufficiently so that local variations in composition do not occur. The stirring time varies depending on the apparatus and the amount of raw materials, but is preferably 1 to 5 minutes.

Thereafter, for example, a molten Bi-based solder alloy melted at a temperature of 500 ° C. or higher is cast into a cylindrical graphite mold having an inner diameter of 30 mm or less and a thickness of about 10 mm. When casting, a material having good heat conductivity, for example, a chill metal made of Cu, is adhered to the outside of the mold, or preferably a chill metal with cooling water flowing in a hollow structure is adhered to the mold. After pouring the molten metal, it is rapidly cooled and solidified at a cooling rate of 3 ° C./sec or higher, more preferably 20 ° C./sec or higher, to about 255 ° C. By such a method, it is possible to stably produce an ingot of a Bi-based solder alloy in which the particle size of most of the precipitated particles is less than 80 μm.
Moreover, when manufacturing using a continuous casting method, it is preferable to improve cooling efficiency by reducing the cross-sectional area of the ingot formed by continuous casting. For example, it is preferable to use a die having an inner diameter of 30 mm or less. Further, it is more preferable to cool the die at a cooling rate of 50 ° C./sec or more by covering the die with a water cooling jacket.

  Using the Bi-based solder alloy of the present invention thus obtained, when mounting an electronic component obtained by mounting a semiconductor element on a member to be joined such as a lead frame on a substrate via another solder alloy, Using the Bi-based solder alloy of the invention, after mounting a semiconductor element on a substrate that is a member to be joined, re-flow at each reflow temperature when mounting another semiconductor element or electronic component on another part of the substrate. Since it does not melt, it is possible to obtain a highly reliable electronic component that does not deteriorate from the initial joined state when the solder joint is soldered.

8). The electronic component and the electronic component mounting board Figure 1 shows a schematic cross section of a semiconductor package, which is an example of an electronic component using a Bi based solder alloy of the present invention. In the case of such a semiconductor package, the Bi-based solder alloy 3 of the present invention is supplied to the center surface of the island portion 4 of the lead frame, and the Bi-based solder alloy 3 is melted, and then the semiconductor chip 1 is mounted thereon. Then, by cooling and solidifying, soldering (die bonding) is performed. Next, the electrode 2 on the semiconductor chip 1 and the lead portion 5 of the lead frame are connected by the bonding wire 6, and then the other portions except for the external connection terminal portion of the lead portion 5 of the lead frame are molded resin 7. A covered semiconductor package can be obtained.

  The island portion 4 of the lead frame to which the solder alloy 3 of the present invention is applied may be subjected to Ag plating together with the joint surface of the lead portion 5 of the lead frame to be joined by the bonding wire 6 or the like. Therefore, only the island part 4 of the lead frame may not be subjected to the Ag plating process. In that case, the island portion 4 of the lead frame is formed only of Cu which is a material of the lead frame. In addition, for in-vehicle use, in order to protect the joint surface of the lead portion 5 of the lead frame joined by the bonding wire 6 and improve the joining reliability, instead of Ag plating, a Ni layer, a Ni / Au layer, or Ni / A plating process for forming a Pd / Au layer may be performed. In the case of a fine lead frame used in recent years, the same is applied to the island portion 4 of the lead frame from the viewpoint of improving workability. A plating process may be performed.

By the way, Cu and Ni have a slower reaction rate with other elements than Ag, so that wetting spread deteriorates. Since the Pb-based solder alloy has high reactivity with other elements, even when the bonding surface is Cu or Ni, the bonding is maintained by spreading by a certain amount, especially in a member to be bonded having Ni plating, depending on the Ni layer. Due to the anticorrosion effect, the growth of the reaction layer at the bonding interface between the Pb-based solder alloy and the member to be bonded was suppressed, and long-term reliability could be increased. However, Pb-free solder alloys often have inferior wettability compared to Pb-based solder alloys, and when the joint surface is Cu or Ni, the wettability cannot be sufficiently spread and sufficient bondability is obtained. There were often no cases. In particular, in the case of a Bi-based solder alloy, Bi may react with Ni to form a fragile Bi—Ni alloy, so that it is difficult to use it for joining with a member to be joined having a Ni layer. It was.
However, as in the Bi-based solder alloy of the present invention, if Ag, Sn, and In are contained at an appropriate blending ratio, the Ag—Sn—In intermetallic compound is dispersed in the Bi-based solder alloy, and Ni and Bi. And the wettability can be improved by the reaction of Sn and In. Further, as in a Bi-based solder alloy according to another aspect of the present invention, if a predetermined amount of either Ge or Te is contained, the coarsening of particles containing an Ag—Sn—In intermetallic compound can be suppressed. Reliability can be further increased. Further, the Bi-based solder alloy according to another embodiment of the present invention can further improve wettability by containing Cu, Ni, Pd, and Au. Therefore, according to the Bi-based solder alloy of the present invention, the conventional Bi-based solder alloy has a Ni layer, a Ni / Au layer, or a Ni / Pd / Au layer, which has not been able to obtain sufficient jointability. It can join firmly also to a member to be joined, and can have sufficient joining reliability.
That is, according to the method for manufacturing an electronic component of the present invention, the wettability of a Bi-based solder alloy is improved, and a Ni layer, a Ni / Au layer, a Ni / Pd / Au layer on the surface of a copper material, which has been difficult in the past. Even if a Bi-based solder alloy is used, mounting of a semiconductor element or the like on a member to be bonded such as a lead frame on which any of the above is plated can be performed without causing a problem of deterioration in bonding reliability.
For example, an electronic component in which a semiconductor element such as a semiconductor chip is soldered to a member to be joined is often reheated at a reflow temperature up to 250 ° C. when mounted on a substrate. Since the solidus temperature is 255 ° C. or higher, the solder joint in the electronic component does not remelt. In addition, by setting the melting point to 320 ° C. or lower, the initial bonding temperature can be made relatively low and no change in semiconductor chip characteristics or member oxidation occurs, so that the characteristics of the mounting substrate including the solder joints are not deteriorated. , Mechanical strength can be maintained.

  That is, the electronic component mounting board of the present invention is obtained by mounting an electronic component using the Bi-based solder alloy of the present invention at a reflow work peak temperature of 250 ° C. In addition, as a board | substrate for electronic component mounting, a conventionally well-known board | substrate can be used and although a ceramic substrate is common, a resin-made printed board and Si board | substrate can also be used.

  EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

1. Measurement method and evaluation method The following measurement methods and evaluation methods were used for the Bi-based solder alloys of the examples and comparative examples.
(1) Observation method of Ag—Sn—In intermetallic compound and calculation method of particle diameter and volume ratio Wire-shaped Bi-based solder alloy having a diameter of 0.75 mmφ is embedded in a resin, and cross-sectional polishing is performed. The evaluation sample with the exposed cross section of the Bi-based solder alloy is immersed in a nitric acid aqueous solution (nitric acid concentration 20%) for 5 seconds and etched.
In the sample for evaluation after etching, the matrix phase of the Bi-based solder alloy looks corroded and black, while the precipitated particles containing the Ag—Sn—In intermetallic compound appear white. The sheath distribution state can be easily determined. Therefore, each evaluation sample is observed with a 200 × optical microscope, and the cross-sectional diameter of the precipitated particles in the field of view is measured. The cross-sectional diameter is obtained from an average value of the longest diameter of the measured particles and the shortest diameter perpendicular to the longest diameter. Moreover, since the cross-sectional diameter is an arbitrary cross-section of the particle and is measured to be smaller than the actual particle size, a value obtained by multiplying the obtained measured value by 1.12 was regarded as the particle size of the particle. In accordance with the above method, the particle diameters of all the observed particles are calculated, and the volume when each particle is assumed to be a true sphere is calculated using the calculated particle diameter. From the calculated volume of each particle, the ratio of particles having a particle size of less than 80 μm is calculated in volume%. Since samples 22 to 73 containing any element of Ge and Te of the present invention described later are samples for the purpose of particle refinement, the ratio of particles having a particle size of less than 50 μm is calculated by volume%. To do.

(2) Method for evaluating wettability A Cu lead frame having a Ni plating layer is supplied to a die bonder, and the processing area is filled with a nitrogen atmosphere, then heated to 370 ° C., and then Ag-Sn-In of (1) above The same 0.75 mmφ Bi-based solder alloy as the cross-sectional observation in the intermetallic compound observation method is set on the Ni plating layer. After the Bi-base solder alloy is sufficiently melted, a 1 mm square silicon dummy chip having Au deposited on the solder joint surface is placed on the Bi-base solder alloy and joined to a Cu lead frame with Ni plating. Thereafter, the sample is transferred to an area that is not heated in a nitrogen atmosphere and cooled to obtain a sample for evaluation. The supply amount of the Bi-based solder alloy is adjusted so that the thickness after bonding the silicon dummy chip is 50 μm.
For solder wettability evaluation, the sample for evaluation is observed from the top, and it is confirmed that there is no protrusion of the Bi-based solder alloy from any side of the silicon dummy chip. Is evaluated as “excellent” when the protrusion is confirmed to be almost uniform from each side of the silicon dummy chip.

(3) Evaluation Method of Bonding Reliability Similar to the method for preparing the wettability evaluation sample in (2) above, a silicon dummy chip is bonded to a Cu lead frame with Ni plating using a Bi-based solder alloy. Thereafter, three molds made of epoxy resin are prepared under the same conditions as samples for evaluating the bonding reliability. In the bonding reliability test, each sample is first subjected to a reflow process of holding at 250 ° C. for 10 seconds, and then a temperature cycle test of −50 ° C./150° C. is performed for 300 cycles, 500 cycles, and 700 cycles. Then, after filling each sample with resin, cross-section polishing is performed, and cross-section observation of the solder joint is performed.
In the joint reliability evaluation, a case where cracks are not confirmed at the Bi-base solder alloy or the solder joint interface is evaluated as “good”, and a case where joint failure or cracks are confirmed as “bad”. .

(4) Evaluation method of heat resistance A part of the sample molded in the above embodiment is mounted on a substrate, and heat treatment at 250 ° C. for 10 seconds is performed five times. Then, after filling each sample with resin, cross-section polishing is performed to check the silicon dummy chip and the joint after mounting, and to check for defects such as cracks and voids. A case where no conspicuous voids or defects are observed and there is no trace of remelting is evaluated as “good”, and a case where voids or defects are observed is evaluated as “bad”.

2. Production of Bi-based solder alloy First, Bi, Ag, Sn, In, Ge, Te, Cu, Ni, Pd, and Au (purity of each element: 99.99% by mass or more) were prepared as raw materials. The raw material was basically shot-shaped raw material of 3mmφ or less. However, if the raw material is large flakes or bulk, cut and pulverize it to make it smaller than 3mm, and cause segregation during melting. As much as possible, it was made uniform with no variation in composition in the solder alloy after melting.
Next, a predetermined amount of raw material corresponding to the composition of the target Bi-based solder alloy was weighed into a graphite crucible for a high-frequency melting furnace.
Next, the crucible containing the raw material was put into a high-frequency melting furnace, and nitrogen was flowed at a flow rate of 0.7 L / min or more per 1 kg of the raw material in order to suppress oxidation, so that the high-frequency melting area was a nitrogen atmosphere. With the high frequency melting area in a sufficiently nitrogen atmosphere, the inside of the high frequency melting furnace was heated to 500 ° C. at a rate of 5 ° C./sec to heat and melt the raw material. When the raw material started to melt, stirring was performed for 3 minutes using a stirring bar so that local variations in composition did not occur. After confirming that the raw metal was sufficiently melted and did not melt, the high frequency power supply was turned off, the crucible was quickly taken out, and the molten metal in the crucible was poured into the solder mother alloy mold.
As the mold, a cylindrical graphite mold having an inner diameter of 30 mm and a thickness of about 10 mm is used, and a cooling metal made of Cu having a hollow structure capable of passing cooling water is adhered to the outside of the mold. The structure. After pouring the molten metal into the mold, a chilled metal with cooling water was brought into close contact therewith, and rapidly cooled to about 255 ° C. at a cooling rate of 5 ° C./sec and solidified.
The obtained Bi-based solder mother alloy was extruded to form a wire-based Bi-based solder alloy having a diameter of 0.75 mm.

Using the obtained wire-based Bi-based solder alloy, the composition confirmation of each Bi-based solder alloy, the ratio measurement of the particles containing the above Ag-Sn-In intermetallic compound, the wettability evaluation, the bonding reliability evaluation went.
These results are shown in Tables 1 to 3. The results of the joint reliability evaluation are shown in the table with the largest number of cycles among the cycles determined as “good”. In addition, in the case of a sample determined to be “defective” in the least 300 cycles, it was described as “defective”.

3. Evaluation
Test 1
Samples 1 to 7 within the scope of the present invention have a particle size of less than 80.mu.m, as a result of cross-sectional observation as shown in Table 1, with 98.3 vol% or more of additives and intermetallic compound particles in the Bi-based solder alloy. It was confirmed that In addition, the wettability has been improved to a “good” level, and in the bonding reliability test, defects such as cracks have not been confirmed in the silicon dummy chip and the bonding portion up to 300 cycles, and it has been confirmed that the bonding property and vulnerability are improved. did it.
Furthermore, since Samples 8 to 15 contain Cu, Ni, Pd, and Au that improve wetting and spreading, Cu, Ni, Pd, Au, and the Ni surface undergo an interfacial reaction to further improve wetting and spreading. The evaluation result of sex was “excellent”. Further, since the wettability was improved and the interfacial bonding became stronger, defects such as cracks did not occur in the silicon dummy chip and the joint until 700 cycles of the temperature cycle test. However, when these elements were contained, it was confirmed that the volume ratio of intermetallic compound particles of less than 80 μm was slightly lower, 97.1 to 98.2%. This is thought to be due to the fact that additive elements such as Cu present in the solder alloy serve as a nucleus for the formation of intermetallic compound particles and promote growth.
Samples 1 to 15 within the scope of the present invention have a good heat resistance test in any sample, and the reflow temperature at 250 ° C. is good without the Bi-based solder alloy of the present invention melting out. It was confirmed that it was possible to maintain a proper bonding state, and that it was suitable as a high-temperature solder alloy.

On the other hand, it was confirmed that Samples 16 to 21, which are outside the scope of the present invention, were not sufficiently wetted and spread with respect to the lead frame with the wetted Ni surface, resulting in poor bonding reliability.
Sample 16 has too little content of Ag, and Sample 19 has too much content of Sn and In, so that the total content of Sn and In is 1 / of the Ag content. Although it is larger than 1 and the wettability is good, it is considered that excess Sn or In formed a low melting point phase, resulting in poor bonding reliability.
It is considered that the sample 17 had too much Ag content, so that the liquidus became too high, so that unmelted residue was generated at the time of solder joining, and wetting spread was not improved. Further, it is considered that the sample 18 was not able to sufficiently react with the Ni surface to be joined because the Sn and In contents were too small, and the wetting spread was not improved. Moreover, since the samples 20 and 21 have too much Cu and Ni content, Cu and Ni are formed as coarse primary crystal components, and it is considered that the wetting and spreading at the time of solder joining was hindered. In this way, it is considered that the sample with insufficient wetting spread did not improve the bonding reliability due to the inclusion of voids during bonding, cracking at the interface between the undissolved portion different from the surroundings and coarse primary crystal components, and so on. It is done. Moreover, the heat resistance test was "bad" in any sample 16-21 which is outside the scope of the present invention.

Test 2
Samples 22 to 47 are samples that suppress the coarsening of particles of the Ag—Sn—In intermetallic compound by containing Te.
Samples 22 to 32 within the scope of the present invention have a particle size of 97.6 to 99.8% by volume of the additive and intermetallic compound particles in the Bi-based solder alloy by cross-sectional observation as shown in Table 2. It became less than 50 micrometers, and it was confirmed that coarsening is suppressed. In addition, the wettability has been improved to a “good” level, and in the bonding reliability test, defects such as cracks have not been confirmed in the silicon dummy chip and the bonding portion up to 500 cycles, and it has been confirmed that the bonding property and the vulnerability are improved. did it.
Further, since Samples 33 to 40 contain Cu, Ni, Pd, and Au that improve wetting and spreading, Cu, Ni, Pd, Au, and the Ni surface undergo an interfacial reaction to further improve wetting and spreading. The evaluation result of sex was “excellent”. Further, since the wettability was improved and the interfacial bonding became stronger, defects such as cracks did not occur in the silicon dummy chip and the joint until 700 cycles of the temperature cycle test. However, when these elements were contained, it was confirmed that the upper limit of the volume ratio of intermetallic compound particles of less than 50 μm was slightly lowered to 98.9%. This is considered to be because an additive element such as Cu existing in the solder alloy serves as a nucleus for the formation of intermetallic compound particles and promotes growth.
In addition, the samples 22 to 40 within the scope of the present invention have a good heat resistance test in all samples, and the reflow temperature at 250 ° C. is good without melting the Bi-based solder alloy of the present invention. It was confirmed that it was possible to maintain a proper bonding state, and that it was suitable as a high-temperature solder alloy.

On the other hand, it was confirmed that Samples 41 to 47, which are outside the scope of the present invention, were not sufficiently wetted and spread with respect to the lead frame with the wetted Ni surface, resulting in poor bonding reliability.
Sample 41 has too little content of Ag, and Sample 44 has too much content of Sn and In, so that the total content of Sn and In is 1 / of the Ag content. Although it is larger than 1 and the wettability is good, it is considered that excess Sn or In formed a low melting point phase, resulting in poor bonding reliability. Moreover, since the sample 42 has too much Ag content, a liquidus line became too high, the undissolved residue generate | occur | produced at the time of solder joining, and it is thought that wetting spread did not improve. Moreover, since the sample 43 has too little content of Sn and In, it is considered that the sample 43 could not sufficiently react with the Ni surface to be bonded, and the wetting spread was not improved. Moreover, since the sample 45 has too much content of Te, Te is produced | generated as a coarse primary-crystal component, and it is thought that the wetting spread at the time of solder joining was disturbed. Moreover, since the samples 46 and 47 have too much Cu and Pd content, Cu and Pd are formed as coarse primary crystal components, and it is considered that the wetting and spreading at the time of solder joining is hindered. In this way, it is considered that the sample with insufficient wetting spread did not improve the bonding reliability due to the inclusion of voids during bonding, cracking at the interface between the undissolved portion different from the surroundings and coarse primary crystal components, and so on. It is done. Further, the samples 41 to 47 which are outside the scope of the present invention were “bad” in the heat resistance test in any sample.

Test 3
Samples 48 to 73 are samples in which coarsening of particles of the Ag—Sn—In intermetallic compound is suppressed by containing Ge.
Samples 48 to 58 within the scope of the present invention have a particle size of 97.9 to 99.7% by volume of the additive and intermetallic compound particles in the Bi-based solder alloy, as shown in Table 3. It became less than 50 micrometers, and it was confirmed that coarsening is suppressed. In addition, the wettability has been improved to a “good” level, and in the bonding reliability test, defects such as cracks have not been confirmed in the silicon dummy chip and the bonding portion up to 500 cycles, and it has been confirmed that the bonding property and the vulnerability are improved. did it.
Furthermore, since samples 59 to 66 contain Cu, Ni, Pd, and Au that improve wetting and spreading, Cu, Ni, Pd, Au, and the Ni surface undergo an interfacial reaction to further improve wetting and spreading. The evaluation result of sex was “excellent”. Moreover, since the wettability was improved and the interfacial bonding became stronger, no cracks occurred in the silicon dummy chip and the joint until 700 cycles of the temperature cycle test. However, when these elements were contained, it was confirmed that the upper limit of the volume ratio of intermetallic compound particles of less than 50 μm was slightly lowered to 98.8%. This is considered to be because an additive element such as Cu existing in the solder alloy serves as a nucleus for the formation of intermetallic compound particles and promotes growth.
In addition, the samples 48 to 66 within the scope of the present invention have a good heat resistance test in any sample, and the reflow temperature at 250 ° C. does not melt the Bi-based solder alloy of the present invention. It was confirmed that it was possible to maintain a proper bonding state, and that it was suitable as a high-temperature solder alloy.

On the other hand, it was confirmed that the samples 67 to 73 which are outside the scope of the present invention were not sufficiently wetted and spread with respect to the lead frame with the wetted Ni surface, and the bonding reliability was inferior.
Sample 67 has too little Ag content, and sample 70 has too much Sn and In content, so the total content of Sn and In is 1 / of the Ag content. Although it is larger than 1 and the wettability is good, it is considered that excess Sn or In formed a low melting point phase, resulting in poor bonding reliability. Moreover, since the sample 68 has too much Ag content, a liquidus line became too high, the undissolved part generate | occur | produced at the time of solder joining, and it is thought that wetting spread was not improved. Further, it is considered that the sample 69 was not able to sufficiently react with the Ni surface to be joined because the Sn and In contents were too small, and the wetting spread was not improved. Moreover, since the sample 71 has too much Ge content, it is thought that Ge was produced | generated as a coarse primary-crystal component and disturbed the wetting spread at the time of solder joining. Moreover, since the samples 72 and 73 have too much Cu or Au content, Cu and Au are formed as coarse primary crystal components, and it is considered that wetting and spreading at the time of solder joining were hindered. In this way, it is considered that the sample with insufficient wetting spread did not improve the bonding reliability due to the inclusion of voids during bonding, cracking at the interface between the undissolved portion different from the surroundings and coarse primary crystal components, and so on. It is done. In addition, the samples 67 to 73 which are out of the scope of the present invention were “bad” in the heat resistance test in any sample.

  In addition, the measurement and evaluation in each of the above samples were performed using, as a matter of convenience, a Cu lead frame that is a bonding target member to be bonded to the Ni-based solder alloy, and having a Ni plating layer on the surface. Even when a Cu lead frame having a thin protective Au plating layer or Pd / Au plating layer on top is used, Ni or Bi diffuses in the Au plating layer or Pd plating layer at the time of soldering, and the same result is shown. I was able to confirm. In addition, it was confirmed that when a Cu lead frame having no Ni plating and having an exposed Cu surface was used, it showed better bondability than the Ni plated surface.

  As described above, the Bi-based solder alloy joint portion joined by the Bi-based solder alloy according to the present invention is subjected to reflow for mounting an electronic component in which a semiconductor element such as a semiconductor chip is mounted on a member to be joined to the substrate. In addition, after mounting a semiconductor element on a substrate that is a member to be joined, peeling and voids do not occur in other parts of the substrate even during reflow for mounting other semiconductor elements and electronic components. In addition, even in a member to be joined that has a Ni layer and deteriorates in wettability and joint reliability, there is no problem in the characteristics of the Bi-based solder alloy joint, so that it is possible to supply more reliable electronic components than in the past. It can be said.

  The Bi-based solder alloy of the present invention is a member to be joined by plating containing Ni, such as a Ni layer, a Ni / Au layer, or a Ni / Pd / Au layer, as an alternative to a high-temperature solder alloy such as Pb-5 mass% Sn. It can be suitably used as a solder paste containing a preform solder alloy for a frame substrate applied to the surface of the substrate or a Bi-based solder alloy of the present invention, and for joining semiconductor chips of semiconductor packages such as power devices and power modules. It can be particularly preferably used.

DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Electrode 3 Solder 4 Island part of lead frame 5 Lead part of lead frame 6 Bonding wire 7 Mold resin

Claims (17)

  A Bi-based solder alloy containing Ag, Sn, and In and having a Bi content of 70% by mass or more, wherein the Ag content is 0.6% by mass or more and 18% by mass or less, and the Sn content is 0.00. 1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content, A Bi-based solder comprising particles containing an intermetallic compound of Ag, Sn and In in the Bi-based solder alloy, the balance being made of Bi except for elements which are inevitably included in production. alloy.   A Bi-based solder alloy containing Ag, Sn, and In, further containing one or more of Cu, Ni, Pd, and Au, and having a Bi content of 70% by mass or more. 0.6 mass% or more and 18 mass% or less, Sn content is 0.1 mass% or more and 10 mass% or less, In content is 0.1 mass% or more and 2 mass% or less, and Sn and In The total content is 1/1 or less than the Ag content, and the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and Cu, Ni One or more of Pd and Au are contained in a total amount in the range of 0.001% by mass to 3.0% by mass, and the balance is made of Bi except for elements that are inevitably included in the production. Bi-based solder alloy.   A Bi-based solder alloy containing Ag, Sn, In, and Ge and having a Bi content of 70% by mass or more, wherein the Ag content is 0.6% by mass or more and 18% by mass or less, and the Sn content is 0.1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content Yes, the Ge content is 0.001 mass% or more and 3.0 mass% or less, and the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and the balance is in the manufacturing process. A Bi-based solder alloy comprising Bi except for elements inevitably contained.   A Bi-based solder alloy containing Ag, Sn, In, and Ge, further containing at least one of Cu, Ni, Pd, and Au, and having a Bi content of 70% by mass or more. The content is 0.6 mass% or more and 18 mass% or less, the Sn content is 0.1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and Sn The total content of In is 1/1 or less with respect to the content of Ag, the content of Ge is 0.001% by mass or more and 3.0% by mass or less, and Ag and Ag are contained in the Bi-based solder alloy. Contains particles containing an intermetallic compound of Sn and In, and contains at least one of Cu, Ni, Pd, and Au in a range of 0.001% by mass to 3.0% by mass in total. The Bi group is characterized in that the remainder consists of Bi except for elements inevitably included in production. I alloy.   A Bi-based solder alloy containing Ag, Sn, In, and Te and having a Bi content of 70% by mass or more, wherein the Ag content is 0.6% by mass or more and 18% by mass or less, and the Sn content is 0.1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content Yes, the Te content is 0.001 mass% or more and 3.0 mass% or less, and the Bi-based solder alloy contains particles containing an intermetallic compound of Ag, Sn, and In, and the balance is in the manufacturing process. A Bi-based solder alloy comprising Bi except for elements inevitably contained.   A Bi-based solder alloy containing Ag, Sn, In, and Te, further containing one or more of Cu, Ni, Pd, and Au, and having a Bi content of 70% by mass or more. The content is 0.6 mass% or more and 18 mass% or less, the Sn content is 0.1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and Sn The total content of In is 1/1 or less with respect to the content of Ag, the content of Te is 0.001% by mass or more and 3.0% by mass or less, and Ag is contained in the Bi-based solder alloy. Contains particles containing an intermetallic compound of Sn and In, and contains at least one of Cu, Ni, Pd, and Au in a range of 0.001% by mass to 3.0% by mass in total. The Bi group is characterized in that the remainder consists of Bi except for elements inevitably included in production. I alloy.   The presence of 97% by volume or more of particles having a particle diameter of less than 80 μm with respect to 100% by volume of the total volume of particles including the intermetallic compound of Ag, Sn, and In formed in the Bi-based solder alloy. The Bi-based solder alloy according to claim 1 or 2, characterized in that:   The presence of 97% by volume or more of particles having a particle size of less than 50 μm with respect to 100% by volume of the total volume of particles including the intermetallic compound of Ag, Sn, and In formed in the Bi-based solder alloy. The Bi-based solder alloy according to any one of claims 3 to 6, wherein   The Bi-based solder according to any one of claims 1 to 8, wherein the Bi-based solder is used for joining to a member to be joined having a Ni layer, a Ni / Au layer, or a Ni / Pd / Au layer formed on a surface thereof. alloy.   A Bi-based solder alloy containing Ag, Sn, and In and having a Bi content of 70% by mass or more, wherein the Ag content is 0.6% by mass or more and 18% by mass or less, and the Sn content is 0.00. 1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content, After flowing the molten metal of the Bi-based solder alloy into the mold, it is cooled to a temperature of 255 ° C. at a cooling rate of 3 ° C./sec or more and solidified, so that the particle size including an intermetallic compound of Ag, Sn, and In is less than 80 μm. A Bi-based solder alloy characterized in that particles are formed in the Bi-based solder alloy by 97% by volume or more with respect to a total volume of 100% by volume of the entire particle containing an intermetallic compound of Ag, Sn, and In. Manufacturing method.   A Bi-based solder alloy containing Ag, Sn, and In, further containing one or more of Cu, Ni, Pd, and Au, and having a Bi content of 70% by mass or more. 0.6 mass% or more and 18 mass% or less, Sn content is 0.1 mass% or more and 10 mass% or less, In content is 0.1 mass% or more and 2 mass% or less, and Sn and In The total amount of the content is 1/1 or less with respect to the content of Ag, and one or more of Cu, Ni, Pd, and Au is 0.001% by mass to 3.0% by mass in total The Bi-based solder alloy molten metal containing Bi, excluding elements inevitably contained in the production, is poured into a mold, and then cooled to 255 ° C. at a cooling rate of 3 ° C./sec or more. By solidifying, a particle size of 80 μm containing an intermetallic compound of Ag, Sn, and In Bi-based solder characterized in that full particles are formed in the Bi-based solder alloy in an amount of 97% by volume or more based on 100% by volume of the total volume of the particles including the intermetallic compound of Ag, Sn and In. Solder alloy manufacturing method.   A Bi-based solder alloy containing Ag, Sn, In, and Ge and having a Bi content of 70% by mass or more, wherein the Ag content is 0.6% by mass or more and 18% by mass or less, and the Sn content is 0.1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content Yes, after pouring the molten metal of the Bi-based solder alloy into the mold, the Ge content being 0.001 mass% or more and 3.0 mass% or less, and the balance is Bi except for elements inevitably contained in the production By cooling and solidifying to 255 ° C. at a cooling rate of 3 ° C./sec or more, particles having a particle size of less than 50 μm including an intermetallic compound of Ag, Sn, and In are obtained between the metal of Ag, Sn, and In. 97% by volume based on 100% by volume of the total volume of the particles including the compound Method for producing a Bi-based solder alloy, characterized in that to form on the Bi-based solder in alloys.   A Bi-based solder alloy containing Ag, Sn, In, and Ge, further containing at least one of Cu, Ni, Pd, and Au, and having a Bi content of 70% by mass or more. The content is 0.6 mass% or more and 18 mass% or less, the Sn content is 0.1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and Sn The total content of In is 1/1 or less with respect to the content of Ag, the Ge content is 0.001% by mass to 3.0% by mass, and Cu, Ni, Pd, and Au 1 to at least 3.0% by mass in the total amount, and the balance is made of Bi except for elements inevitably included in production. After pouring into the mold, it is cooled to 255 ° C at a cooling rate of 3 ° C / sec or more and solidified. The particles having a particle size of less than 50 μm containing the intermetallic compound of Ag, Sn, and In are 97 volumes with respect to the total volume of 100 volume% of the entire particles containing the intermetallic compound of Ag, Sn, and In. % Or more of the Bi-based solder alloy is formed in the Bi-based solder alloy.   A Bi-based solder alloy containing Ag, Sn, In, and Te and having a Bi content of 70% by mass or more, wherein the Ag content is 0.6% by mass or more and 18% by mass or less, and the Sn content is 0.1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and the total content of Sn and In is 1/1 or less with respect to the Ag content Yes, after pouring the molten metal of the Bi-based solder alloy into the mold, the content of Te being 0.001 mass% or more and 3.0 mass% or less, and the balance being made of Bi except for elements inevitably contained in production By cooling and solidifying to 255 ° C. at a cooling rate of 3 ° C./sec or more, particles having a particle size of less than 50 μm including an intermetallic compound of Ag, Sn, and In are obtained between the metal of Ag, Sn, and In. 97% by volume based on 100% by volume of the total volume of the particles including the compound Method for producing a Bi-based solder alloy, characterized in that to form on the Bi-based solder in alloys.   A Bi-based solder alloy containing Ag, Sn, In, and Te, further containing one or more of Cu, Ni, Pd, and Au, and having a Bi content of 70% by mass or more. The content is 0.6 mass% or more and 18 mass% or less, the Sn content is 0.1 mass% or more and 10 mass% or less, the In content is 0.1 mass% or more and 2 mass% or less, and Sn The total content of In is 1/1 or less with respect to the content of Ag, the Te content is 0.001% by mass to 3.0% by mass, and Cu, Ni, Pd, and Au 1 to at least 3.0% by mass in the total amount, and the balance is made of Bi except for elements inevitably included in production. After pouring into the mold, it is cooled to 255 ° C at a cooling rate of 3 ° C / sec or more and solidified. The particles having a particle size of less than 50 μm containing the intermetallic compound of Ag, Sn, and In are 97 volumes with respect to the total volume of 100 volume% of the entire particles containing the intermetallic compound of Ag, Sn, and In. % Or more of the Bi-based solder alloy is formed in the Bi-based solder alloy.   A member to be joined, the Bi-based solder alloy according to any one of claims 1 to 9, and a semiconductor element mounted on the member to be joined via the Bi-based solder alloy. Electronic components.   10. An electronic component mounting board manufactured using the Bi-based solder alloy according to claim 1.

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