JP2002305213A - Solder foil, semiconductor device, and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new solder and its manufacturing method, and an electronic apparatus using the solder, and to provide its manufacturing method. SOLUTION: A solder foil which is made by rolling material containing particles of Cu or the like as metallic particles and particles of Sn as solder particles, and the electronic apparatus, where components are connected with one another by that solder foil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder and a method for manufacturing a solder, or an electronic apparatus, an electronic apparatus, an electronic apparatus, and a method for manufacturing an electronic apparatus using a solder connection. In particular, Sn-A
The present invention relates to a technique which is effective when applied to a solder connection which requires a high-temperature side temperature hierarchical connection to g-Cu based Pb-free solder or the like.

[0002]

2. Description of the Related Art Pb-rich Pb-5Sn (melting point: 314 to 310 ° C.), Pb-10S
n (melting point: 302 to 275 ° C), etc., is soldered at a temperature of about 330 ° C. Then, without melting this soldered part, it is connected with a low-temperature solder Sn-37Pb eutectic (melting point: 183 ° C) Temperature hierarchy connection was possible. These solders were flexible and rich in deformability, so that easily breakable Si chips and the like could be bonded to substrates having different coefficients of thermal expansion. Such a temperature hierarchical connection is applied to a semiconductor device of a type in which a chip is die-bonded, or a semiconductor device such as a BGA or a CSP in which a chip is flip-chip connected. That is, it means that the solder used inside the semiconductor device and the solder connecting the semiconductor device itself to the substrate are connected in a temperature hierarchy.

[0003]

At present, lead-free is being promoted in all fields.

[0004] Pb-free solder is mainly composed of Sn-Ag eutectic (melting point: 221 ° C), Sn-Ag-Cu eutectic (melting point: 221-217 ° C), Sn-C
u It becomes eutectic (melting point: 227 ° C), but it is desirable that the soldering temperature for surface mounting is low due to the heat resistance of components.
Because of the necessity of ensuring wettability to ensure reliability, even if a furnace with excellent soaking control is used, the Sn-Ag-Cu eutectic system that can be used at the lowest temperature is possible in consideration of temperature variations within the substrate. 235-2
The actual situation is around 45 ° C. Therefore, as a layer solder that can withstand this soldering temperature,
It must be 250 ° C or higher. At present, there is no Pb-free solder for the high temperature side that can be used in combination with these solders. The most probable composition is Sn-5Sb (melting point: 240-232 ° C), but it is not suitable for temperature classes because it melts.

Also, Au-20Sn (melting point: 280 ° C.) is known as a high-temperature solder, but its use is limited to a narrow range due to its high cost and high cost. In particular, when connecting a Si chip to a material with a different coefficient of thermal expansion or connecting a large chip, Au
-20Sn solder is not used because it is hard and has a high possibility of breaking the Si chip.

An object of the present invention is to provide an electronic device (electronic device) and a method of manufacturing the electronic device by completely novel solder connection. Another object of the present invention is to provide a solder connection in a temperature hierarchical connection required in a method of manufacturing an electronic device, particularly a solder connection on a high temperature side. Another object of the present invention is to provide a completely novel solder and a method for manufacturing the same.

[0007]

Means for Solving the Problems In order to achieve the above object, among the inventions disclosed in the present application, typical ones will be briefly described as follows. This is a solder foil formed by rolling a solder material containing metal particles and solder particles. This is a solder foil formed by rolling a solder material containing metal particles having a plating layer such as Sn.
This is a method for producing a solder foil by rolling a solder material containing metal particles and solder particles. This is a method for producing a solder foil for rolling a solder material containing metal particles having a plating layer such as Sn. An electronic device having a first electronic component, a second electronic component, and a third electronic component, wherein the first electronic component and the second electronic component include metal particles and solder particles. The second electronic component and the third electronic component are connected using a first solder which is a solder foil formed by rolling a material containing the second solder, the second solder having a melting point different from that of the first solder. Are connected by using In the above electronic device, at a connecting portion between the first electronic component and the second electronic component, metal particles are linked by a compound formed by the metal and solder particles. An electronic device having a first electronic component and a second electronic component, wherein the first electronic component and the second electronic component are connected by a solder connection, and the solder connection is a metal connection. It has a Sn portion filling between the particles and the metal particles. In the electronic device described above, the metal particles are bonded to the metal by a compound formed by Sn. In the above-mentioned solder foil or electronic device, for example, the metal particles are Cu particles, and the solder particles are Sn particles.

[0008]

Embodiments of the present invention will be described below. When metal balls such as Cu and Sn-based solder balls are mixed and rolled at about 50%, Cu particles come into contact with each other,
For n, a composite solder that has entered the gap is obtained. When this foil is sandwiched between the chip and the substrate and pressurized and reflowed, the composite solder part is connected between the Cu balls with a Cu-Sn compound, and the compound between the composite solder part and the chip and the substrate is a compound of the Cu ball and the chip electrode, The formation of a compound between the Cu ball and the substrate terminal results in a lead-free temperature hierarchical structure that ensures bonding strength even at a high temperature of 280 ° C. Thereby, in the lead-free solder, a connection method having a temperature hierarchy can be provided. Considering the temperature hierarchy connection, the solder on the high-temperature side that has already been connected has sufficient strength to withstand the post-soldering process, even if part of the solder melts but the rest does not melt. it can. We are conducting research on solder materials in which metal balls (Cu, Ag, Au, surface-treated Al, Zn-Al based solder, etc.) and solder balls are dispersed and mixed. If connected by this solder material, for example, Sn-Ag-Cu
Even after passing through a reflow furnace (max 250 ° C) using a series of solders, the Sn portion in the connection portion is melted, but the intermetallic compound with a high melting point (Cu6Sn5) is used between Cu balls, between Cu balls and chips, and between Cu balls and substrates. ), The connection is maintained at the set temperature of the reflow furnace (max. 250 ° C.), and sufficient connection strength can be secured. That is, it is possible to realize the temperature hierarchical connection to the Sn-Ag-Cu solder.
The effect of this intermetallic compound formation is not limited to Cu-Sn,
The same applies to Au-Sn, a compound such as i-Sn (Ni3Sn4) and Ag-Sn (Ag3Sn). The same applies to solder instead of Sn. Although there is a difference in the alloy layer growth rate, the melting point of the alloy layer formed by diffusion is high, and once formed, it does not melt at 280 ° C.

The connection by the solder material is completely made of Cu
Since the comrades are not restrained, even if used for die bond connection, for example, there is some degree of freedom in the up and down, left and right, mechanical properties in the intermediate stage between Cu and solder can be expected,
In the temperature cycle test, high reliability can be expected due to thermal fatigue resistance by Sn and prevention of crack growth by Cu particles (balls).

However, in the composite paste in which the Cu ball and the solder ball are mixed, the Sn-based solder originally has a property that the wet spread is small on Cu, and there are many portions where Cu must be wetted, The ball is not necessarily completely wet, and furthermore, since Cu and the solder ball are initially restrained in a cross-linked state, even if the solder melts, that part remains as a space, so it becomes a void It is clear that the probability is high as our research progresses. For this reason, this paste method inevitably results in a process in which the number of voids increases, and is unsuitable for some connection applications. The void may be removed when the electronic component is mounted. However, for example, die bonding of a Si chip, power module bonding, or the like has a form in which the surfaces are connected to each other, so that the void is difficult to be structurally removed. The remaining voids cause problems such as generation of cracks due to the voids and inhibition of necessary heat diffusion.

Therefore, we put this solder material in a mold having a shape easily rollable in advance, and uniformly compressed the whole under vacuum, in a reducing atmosphere or in an inert atmosphere, and changed the Sn-based solder ball into a metal ball. A plastic molded body was formed by filling the gap with solder (Sn-based solder after plastic deformation), and then using a solder foil obtained by rolling this.

For example, when this composite molded body is rolled into a die-bonding solder foil such as a Si chip, Cu-C
It was confirmed that the metal balls such as u contacted by compression and easily formed an intermetallic compound at the time of die bonding, the whole was organically connected with a high melting point metal, and the strength was secured even at 280 ° C. . As a matter of course, at the connection portion, the gap is compressed and buried in a vacuum,
Connection with few voids is possible. When using a low-temperature hot press in nitrogen, it was confirmed that when the particle size of the Cu ball and the Sn-based solder ball was large (about 40 μm), the Sn-based solder exhibited a void filling rate of 97% or more. In addition, by applying Sn plating of an appropriate film thickness on the foil surface, oxidation can be prevented even for a material that is significantly oxidized.

The Cu foil leads were joined together with this solder, and the lap joints bonded together were subjected to a shear tensile test at 270 ° C. at a tensile speed of 50 mm / min. As a result, a value of about 0.3 kgf / mm ² was obtained. As a result, it was confirmed that the strength at a high temperature was sufficiently secured.

This method is to fill the space inside the solder material with metal balls in advance, and accordingly, the void is small, and it is expected that the void ratio will be the same level as or less than that of the conventional solder foil. (Large voids are difficult to form.) Therefore, in the solder according to the present method, a lead-free material (does not actively contain lead) suitable for, for example, die bonding of silicon, power module bonding, etc., for which voiding was an important issue due to its large area, is obtained. That is, a high-reliability high-temperature lead-free material suitable for temperature hierarchical connection and the like can be provided.

Furthermore, in the paste method, it is difficult to achieve fluxlessness due to easy oxidation, but this can be solved. That is, in the field where the flux residue is disliked, it is necessary to wash the flux after the connection by the paste method.

In addition, a hard and strong solder having a desirable melting point, for example, Au-20Sn, Au- (50-55) Sn (melting point: 309)
370 ° C), Au-12Ge (melting point: 356 ° C), etc., by using these as metal balls and dispersing and mixing soft, elastic rubber particles together with soft solder balls such as Sn and In. Since the solidus temperature of the solder used for metal balls has a temperature of about 280 ° C or higher, it has a high-temperature connection strength and is soft between particles against deformation.
Sn, In or rubber can alleviate, and a new effect that complements the weak points of these solders can be expected.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for describing the embodiments of the present invention, components having the same functions are denoted by the same reference numerals, and their repeated description will be omitted.

FIG. 1 shows an outline of a manufacturing process of a composite metal made of a composite ball (metal ball, solder ball).
Is a state in which a Cu ball 2 as a metal ball and a Sn ball 3 as a solder ball are placed in a carbon jig 1 of a vacuum hot press. Sn and Cu
Is transformed into a "sea-island structure." (c) is a model in which the composite ball mass is further rolled by the roll 5 to produce a solder foil.

In the figure, 10 to 40 μm Cu ball and 10 to 40 μm
And the Sn balls were blended such that the Cu balls accounted for 50 to 60% by volume. For Cu balls, add more fine particles,
Close-packed formulation (eg, Shigeo Miwa; Introduction to Powder Engineering, P39,
(1981/2/5, Nikkan Kogyo Shimbun), it is possible to increase the contact between Cu balls. With close packing, the theoretical volume ratio of Cu is about 74% and solder is 26%.
In addition, it is possible to make fine grains of 10 μm or less, and the network of the alloy layer becomes fine, and it is suitable for high density and fine connection. As an example, 3 ~ 8μm Cu ball and 10 ~
For 40 μm Sn balls, 3-10 μm Cu balls and 10-4
In the case of 0 μm Sn balls, or in the case of 5 to 15 μm Cu balls and 10 to 40 μm Sn balls, the solder filling density of the foil is reduced, but good connection is obtained. Note that Cu
For the diameter (size) of balls and Sn balls,
It is needless to say that not all the particles are included in the disclosed size, and a ball larger or smaller than the disclosed size may be included in a range that does not affect the effect of the invention. . These balls are mixed in nitrogen and placed in a pressure vessel made of a carbon jig as shown in FIG. After evacuating,
If pressure is applied uniformly from the surroundings over time, only Sn plastically deforms and fills the gap between the Cu balls.
Although the melting point of Sn is 232 ° C., it can be fluidized even at room temperature over time. When it is not possible to make the fluid flow to every corner at room temperature, it becomes possible easily by raising the temperature slightly (100 to 150 ° C.). In this process, Cu and Sn
The more the reaction does not occur, the more the degree of freedom is increased because there is no constraint at the interface, and Sn is more likely to deform (flow). Then, the composite ball lump formed by the vacuum hot press or the like is further rolled by the roll 5 to obtain a solder foil. By rolling, more Cu
There is no gap between the balls, and as a result, a solder foil with few voids can be formed. In this case, since the above-mentioned composite ball lump is intended for producing a solder foil having a thickness of 150 μm (± 10 μm), it is desirable that the composite ball lump is previously formed in a mold having a shape close thereto, since the rolling ratio can be reduced. Increasing the rolling ratio increases the contact area between Cu,
The constraint due to the increased contact area increases. Therefore, considering flexibility to respond to deformations such as temperature cycles,
It is desirable to reduce the contact area, and the final rolling rate is
20% or less is preferable. Further, the rolling ratio is more preferably 15 to 20%.

In the case where Cu or the like is exposed in the formed solder foil, it is preferable to prevent the oxidation of Cu in the exposed portion by further plating Sn to a thickness of 0.5 to 2 μm.

It is preferable that the Cu ball and the solder ball are spherical in terms of ease of production, easy dispersion at the time of blending, ease of handling, and the like, but they need not necessarily be spherical. Cu balls with severe irregularities on the surface, rods, needles,
It may be fibrous, angular, or dendritic, or a combination of these, as long as the Cus are intertwined after joining. However, if the degree of freedom is too low due to excessive restraint between Cu due to the above compression, cushioning will be lost at the time of soldering, and if connection failures are likely to occur, Cu balls have more irregularities on the surface than ball-shaped It is preferably a bar, a needle, a fiber, a square, a dendrite, or a combination thereof. And
As shown in FIG. 2, in addition to Cu2 and Sn3 balls, metallized heat-resistant soft elastic material (electroless Ni plating-
Au plating or electroless Ni plating-solder plating) Plastic balls (rubber) 6 can be dispersed to lower the Young's modulus to ensure cushioning. 2A shows the state before rolling, and FIG. 2B shows the state after rolling. Resin ball diameter is ideally 10
μm or less, preferably 1 μm level. For example, 0.5-5
μm is desirable. Even if the compounding amount is several percent by volume, it is effective. In the present specification, two terms of “particle” and “ball” are used for “metal” and “solder”.
As can be seen from the above description, they are used with almost the same meaning. To make a distinction, "particle" is used in a rather broad sense that encompasses "ball."

Next, a case where Al is used as an example of another metal ball will be described.

High melting point metals are generally hard, but pure Al is a low cost and soft metal. Pure Al (99.99%) is soft (Hv17), but usually hard to wet with Sn. Therefore, Ni-Au
Preferably, plating or Ni-Sn plating is performed. The Au surface may be thinly coated with Au by sputtering or the like.
It is difficult to make fine particles of soft pure Al due to safety issues such as explosion, but it is manufactured in an inert atmosphere and immediately Ni-A
By applying u plating, safety can be ensured by preventing Al from coming into contact with the atmosphere. It should be noted that the Al particles can be removed by plating even if a small amount of oxide film is formed, so there is no problem.
Furthermore, since the oxide film of Al is easily broken even in the rolling process,
Is not affected much by connection.
The metallization on the Al surface is not limited to these, but it is necessary that after the solder foil is produced, the solder is wetted with respect to Cu, Ni, etc., and the bonding strength is ensured at a high temperature. Therefore, metallization on Al particles between Ni particles between Al particles and Ni-plated Cu plate and between Al particles and Ni plating on Si chip
It is necessary to link with Sn compound formation.

In obtaining a composite ball lump, Al is easily diffused in a vacuum and particularly at a high temperature. Therefore, a compound with Al can be formed by using a Sn solder containing Ag. In addition to Ag, a small amount of Zn in Sn to react easily with Al,
Alternatively, Cu, Ni, Sb, or the like may be added to form a solder for Al connection. When a small amount of Ag, Zn, Cu, Ni, Sb, etc. is put in Sn, metallization on the Al surface is unnecessary, and the merit in cost is great.

It is possible to wet the Al surface completely or in a mottled manner. This is related to the area of metallization and depends on whether the metallization is to be formed speckled or to be formed entirely. If it is mottled, it is easy to deform when stress is applied due to reduced restraint during deformation, and non-wet parts absorb energy as friction loss, making it a material with excellent deformability . Naturally, the bonding strength is secured.

Instead of making Al into a ball, 20 to 40 μm
It is also possible to apply a plating of Sn, Ni-Sn, Au, or the like to the Al wire of the order, and cut and cut it into a granular shape or a rod shape. In addition, ball-shaped Al particles can be mass-produced at low cost by an atomizing method or the like in nitrogen.

Next, the Au ball will be described.

In obtaining a composite ball lump, the Sn-based solder is easily wetted with respect to the Au ball, so that there is no need for metallizing for a short-time connection. However, when the soldering time is long, Sn is remarkably diffused, and the formation of a brittle Au-Sn compound remains uneasy. For this reason, in order to obtain a soft structure, In plating with little Au diffusion is also effective, and Ni, Ni-Au or the like may be used as a barrier. By making the barrier layer as thin as possible, Au
The ball is easily deformed. Other structures may be used as long as the metallized structure can suppress the growth of the alloy layer with Au. By controlling the temperature until rolling, diffusion can be suppressed. When bonding is performed in a short time by die bonding, since the alloy layer formed at the grain boundary is thin, the effect of Au flexibility can be greatly expected without providing a barrier. A combination of Au balls and In solder balls is also possible.

Next, the Ag ball will be described.

The Ag ball is similar to the Cu ball, but the mechanical properties of the Ag3Sn compound are not bad, so that it is possible to connect the Ag particles with the compound by a normal process. It is also possible to use it mixed in Cu etc.

Next, a case where an alloy material is used as the metal ball will be described.

Typical examples of the alloy system include a Zn-Al system and an Au-Sn system. The melting point of Zn-Al-based solder is mainly in the range of 330-370 ° C. Can be used for metal balls. As a typical example of Zn-Al system, Zn-Al-M
g, Zn-Al-Mg-Ga, Zn-Al-Ge, Zn-Al-Mg-Ge, and those containing any one or more of Sn, In, Ag, Cu, Au, Ni, etc. including.

However, it has been pointed out that a Zn-Al-based material is highly oxidized and the rigidity of the solder is high, so that when Si is bonded, there is a possibility of cracking the Si chip (see Shimizu et al. Zn-Ai-Mg-Ga alloy for Pb-free solder "Ma
te99, 1999-2) These problems must be solved simply by using the composite ball as a metal ball.

Therefore, since it is necessary to solve these problems, in order to reduce the rigidity of the solder, a heat-resistant plastic ball plated with Ni-solder or Au is used.
Disperse uniformly with Sn ball and Zn-Al-based ball,
The Young's modulus was reduced. When 10 to 50% of the total Sn balls are mixed, molten Sn enters between Zn-Al based solders.
In this case, the Zn-Al balls are joined together in a part, but in the other part, a precipitated low-temperature soft Sn-Zn phase and insoluble Sn are present. The deformation is shared by the Sn, Sn-Zn phase and the rubber of the plastic ball.

When a connection is actually made using this solder foil, for example, even in the case of die bonding, the Sn can absorb deformation by leaving a part of the Sn layer thereafter.
The combined action of the plastic ball and the Sn layer can be expected to further reduce the rigidity. In this case, Zn
-Since the solidus temperature of the Al-based solder is 280 ° C or higher, there is no problem in strength at high temperatures.

It is desirable that the diameter of the plastic ball is smaller than that of the Zn-Al-based ball and the plastic ball is uniformly dispersed.
If a plastic ball of 1 μm level having soft elasticity is deformed when deformed, the effect of thermal shock relaxation and mechanical shock relaxation is great. There is a commercially available heat-resistant plastic ball. Since the plastic balls enter almost uniformly between the balls of the Zn-Al-based solder, the dispersion does not significantly deteriorate by a short melting at the time of connection. Since this heat-resistant resin has a thermal decomposition temperature of about 300 ° C., a material having higher heat resistance is desirable, but there is no problem in the case of a die bond having a short time.

As described above, when molding by hot pressing in a vacuum, plastic flow is achieved by uniformly compressing at a temperature at which Sn on a Sn-plated plastic ball does not melt (melting point of Sn: 232 ° C.). At this time, the Zn-Al ball does not deform much. The space is uniformly filled with plastic balls, Sn, etc. by uniform compression and rolled to about 150 μm to produce a solder foil. When used in die bonding, it can be wound in a roll and supplied in a continuous process.

Since Zn-Al is easily oxidized, it is preferable to apply Cu-substituted Sn plating to the surface in consideration of storage. The Sn and Cu dissolve in the Zn-Al-based solder at the time of die bonding, for example. By the presence of Sn on the surface, for example,
Connection to Ni-Au plating on Cu electrodes becomes easy. The Si chip side can be similarly easily joined to, for example, Ti-Ni-Au metallization. At high temperatures above 200 ° C, Ni
Since the growth rate of the alloy layer of Ni and Sn (Ni3Sn4) is higher than that of Cu-Sn, there is no possibility that bonding cannot be performed due to insufficient compound formation.

In some cases, a composite ball block may be composed of a Zn—Al-based solder ball and a plastic ball.

The solidus temperature of Zn-Al based solder was 280.
Hierarchical connection in which a large amount of Sn and In is added is possible up to a level that secures the ° C level. When a large amount of Sn, In, etc. is added, a low phase such as a eutectic of Zn-Sn is partially formed,
Since the bonding strength is borne by the Zn-Al-based solid phase serving as the skeleton, there is no problem in strength at high temperatures.

By the way, S in which Zn-Al based solder is replaced by Cu
When n-plating is performed, by raising the temperature to a temperature equal to or higher than the liquidus temperature of the Zn-Al-based solder, Sn easily spreads and spreads, and dissolves in the Zn-Al-based solder while forming a solid solution of thin Cu. If Sn is large (5% or more), it cannot be dissolved in Zn-Al and a low-temperature Sn-Zn phase precipitates at the grain boundaries. By intentionally dispersing and precipitating a large number of Sn phases, the deformation can be shared by the Sn-Zn phase and the bonding strength can be shared by the Zn-Al-based solid phase. Therefore, by subjecting the Zn-Al-based solder ball to Sn plating and intentionally leaving an Sn phase that cannot be dissolved in the ball, deformation can be absorbed by the Sn layer, and the rigidity of the Zn-Al can be reduced. That is, the rigidity of the solder at the connected portion can be reduced, and connection failures are reduced.

FIG. 3 shows a method of forming a metallized W-Cu plating (Al may be Ni plating) 14 on an Al 2 O 3 substrate 13 by using the above-mentioned solder foil 11.
An example of die bonding the Si chip 8 will be described. A typical example of the solder foil 11 is a combination of a metal ball of Cu and a solder of Sn. Cu is relatively soft, actively reacts with Sn, and the intermetallic compound (Cu6Sn5) has excellent mechanical properties. In the event that compound growth is remarkable and its adverse effects appear, it is possible to add a small amount of Cu or the like to Sn to suppress the alloy layer growth rate. Or
It is possible to suppress the alloy layer growth by applying a thin Ni plating such as Ni or Ni-Au on Cu. Here, it is important to reliably connect the Cu balls with an intermetallic compound at the time of short-time soldering, and it is desired to activate the reaction. Than that
In connection between Sn and the chip and between Sn and the substrate, it is important to improve the wettability and wet spreadability of Sn. For this reason, the effect of improving fluidity by adding trace amounts of Cu and Bi to Sn and improving wettability by reducing surface tension can be expected. On the other hand, the effect of adding a small amount of Ni, Ag, Zn or the like can be expected to improve the strength with the interface. In addition, Sn-Sb instead of Sn is used to improve the melting point of Sn.
By setting the content to (5 to 10%), the Sb concentration in the solder increases due to the formation of the Cu-Sn compound and the Ni-Sn compound, and the melting point of the solder can be improved to 246 ° C.

As another typical example, a pure Al ball that is softer than Cu has excellent deformability with respect to a temperature cycle. The challenge is the reaction between Al balls and metallization of chips and substrates. By applying Ni plating or Ni-Au flash plating on the Al surface, the bonding strength of Sn is similarly secured between Al balls, between Al balls and Ni-plated chips, and between Ni-plated substrates. The intermetallic compound between Ni and Sn is usually Ni3S
n4, which is faster than the growth rate of Cu-Sn at 200 ° C or higher, so there is no fear of insufficient reaction. Where Cu and Ni are simultaneously present, a mixed alloy layer of (NiCu) 3Sn4 may be formed partially. So that the solder can react directly to the Al ball
By adding a small amount of Ag, Ni, Zn, Ti, etc. into Sn, Al
Connection between the balls is also possible depending on the connection conditions.

The same can be applied to Au balls. Since Au is flexible and easily forms a compound with Sn, it is an effective composition except for cost. However, since a compound in a system containing a large amount of Sn has a low melting point, it is necessary to use a compound of AuSn and AuSn2 having a composition ratio of Sn of 55% or less in order to have a melting point of 280 ° C. or more. For this reason, it is necessary to increase the soldering temperature and reduce the Sn at the joints. For example, Cr-Ni-
By providing Sn, formation of Au-Sn and AuSn becomes easy. In consideration of cost reduction and the like, it is possible to mix Cu, Al, Ag balls and the like into the Au balls.

The Ag ball is also a promising candidate, and the formation of a high melting point Ag3Sn compound enables a connection connection that does not melt even at 280 ° C.

Next, an example of application to a hard Zn-Al-based ball having a low melting point will be described. In terms of melting point and brittleness, the Zn-Al system generally settles in the range of Al: 3 to 5%.
Add g, Ge, Ga, etc., and lower the solidus temperature mainly by adding Sn and In. And to ensure wettability and strength, Cu, A
In some cases, g, Ni, etc. may be added. Their melting points are 280-360
° C level. For example, in the case of Zn-4Al-2Mg-1Ag-10Sn, when Sn balls are mixed as solder balls, even if both are melted, Sn is partially dissolved in the Zn-Al-based balls, and most of the remaining Remains Sn. Also, in this case,
The same effect can be expected because extra Sn, In, etc. that cannot be dissolved in the solder can be well dispersed in the state of particles and isolated and dispersed in the solder. Thickening the Sn-plating on the Zn-Al-based ball is also one solution for isolating and dispersing Sn.

In the case of a Zn-Al-based ball, since the whole is melted at the time of soldering, there is a feature that the surface shape easily becomes a natural shape due to the action of surface tension or the like. Also, Zn-A
Since the surface oxidation of the l-system is severe, it is necessary to take measures to prevent oxidation, including the preheating process. When used as a foil, the surface is plated with Cu (0 to 0.2 μm) -Sn (1 μm) to provide an effect of preventing oxidation. The presence of Sn between the Zn-Al-based balls allows Sn to act as a buffer against deformation during temperature cycling. By mixing, the deformability and impact resistance can be further improved, the Young's modulus decreases, and the thermal fatigue resistance can be improved.

As an alloy system which is similarly hard and has a low melting point, there is an Au-Sn system and the like, but the same correspondence is possible.

On the used Al 2 O 3 substrate 13, an electrode which has been subjected to W (sintering) -Cu plating (3 μm) 38 (or W-Ni plating) is formed. Other examples of the ceramic substrate include mullite, glass ceramic, and ALN. If a flux is used at the time of connection, or if it can be used in an inert atmosphere or a reducing atmosphere from the preheating stage, the Cu electrode may be used as it is.

The size of the used Si chip 8 is 5 mm □, and the size of the solder foil 11 is 4 mm □ × t (thickness) 0.15. However, there is no restriction on chip size, and a large chip is also possible. The compound layer secures the strength at high temperature for the secondary reflow in the post-process and contributes mainly to the Sn-based solder for the subsequent thermal fatigue, and partially elastic at places where stress is severe. The joined parts provide the maximum effect, and the service life is improved compared to the case without the elastic joint (although some parts that can not withstand are broken). Therefore, there is no image that is strongly constrained by the compound layer, and some compounds may be formed in a network in the solder. By forming a compound at the bonding interface in the peripheral portion of the chip where a large strain or stress is applied, the connection is strong and the breakdown is less likely to occur. On the other hand, if the center of the solder foil at the same peripheral position has little network connection, the stress and strain applied to the outermost peripheral portion are applied to Sn at the center of the solder foil, so that the stress applied to the upper and lower interfaces can be reduced.

First, the Al 2 O 3 substrate 13 is fixed to a gantry by vacuum suction, and the Si chip 8 is also held by the resistance heating tool 7 as a mounting jig by vacuum suction 9. Then, the Si chip 8 is brought into contact with the Al2O3 substrate 13 via the solder foil 11 by lowering the resistance heating tool 7 or the like, and heating (max.
℃), pressurized (initial 2kgf) for 5 seconds. The thermocouple 16 for temperature measurement is embedded near the contact of the chip of the tool, and has a configuration capable of controlling the temperature.

When the temperature of the solder foil 11 reaches its melting point, Sn and the like of the solder foil are instantaneously melted, and pressure is applied to the joint between the metal balls, and the solder begins to melt. Therefore, in order to prevent crushing of the joining between the metal balls, when the set temperature is reached, the resistance heating tool 7 is used as a starting point when the solder foil 11 is pressed,
From that position, the amount of solder protruding from the chip is controlled by making it less than about 10% (max 20%) with respect to the solder foil thickness. Since the thickness of the solder foil affects the thermal fatigue life,
Generally, it is about 150 μm. The crushing amount is controlled by the solder thickness and the size of the solder foil relative to the chip size. However, this method is excellent in heat conduction because it contains half of Cu and is connected in a network, so that even at 200 to 250 μm, it is thermally superior to the conventional one.

The preheating 15 of the Al2O3 substrate 13 was set to about 100.degree. Preheating is also important in terms of reducing thermal shock, because a sudden rise or fall in temperature will cause a large stress on the joint.

In the case of die bonding using a resistance heating element, a mechanism is provided in which nitrogen 10 is locally blown from the surroundings in order to prevent oxidation of the solder foil 11 during connection. Further, it is preferable that nitrogen 10 is also blown around the resistance heating tool 7 for adsorbing the Si chip 8 so that the junction is always kept at the oxygen purity of the level of 50 to 100 ppm.

With this solder foil, die bonding of a Si chip or the like or bonding of a power module or the like can be performed at around 270 ° C. in a hydrogen furnace or an inert atmosphere furnace such as nitrogen. When a furnace is used, the maximum temperature can be from 260 ° C. to 350 ° C. for Sn, but conditions must be selected in consideration of the state of compound formation.

FIG. 4 shows a cross-sectional model of a typical bonded portion formed by die bonding using a resistance heating element and die bonding using a hydrogen furnace or an inert atmosphere furnace such as nitrogen. The top surface of the die-bonded chip is connected to the terminal of the substrate by wire bonding or the like, and the chip is sealed with a cap,
Seal with resin, and then connect a small chip component etc. around the board. (In this case, also connect a foil suitable for the terminal to the board, etc. It is also possible to connect the thermo-compressed parts simultaneously with a reflow furnace), and take external connection terminals (usually joined with solder such as Sn-3Ag-0.5Cu) from the back side of the board etc. By this, a module is completed.

The Cu ball 2 and the Cu ball and the metallization 44 on the chip side (for example, Cr-Ni-Au; Au is very thin,
The formation of an alloy layer between u-Sn-Ni) and the metallized 42 on the Cu ball and the substrate side (eg, Ni plating on Ag-Pd conductor; formation of an alloy layer between Cu-Sn-Ni) The layers are firmly formed and ensure a connected state. There are various combinations of metallization on the chip side, but Cu or Ni reacts with solder Sn
Is the majority. Au may be used mainly for oxidation prevention in the surface layer, but it dissolves in Sn below 0.1 μm level,
It does not participate in alloy layer formation. On the other hand, the substrate side also has various bases similarly, but the reaction layer with Sn is Ni or Cu like the chip.
It is. As a special case, there is a thick film conductor such as Ag, Ag-Pt, Ag-Pd, and Au-Pd. In the case of power bonding, voids are of the utmost importance since the presence of voids greatly affects the characteristics of die bonding in terms of heat conduction. In the case of the solder paste, since the gas amount is large due to the reaction of the flux, the volatilization of the solvent, etc., the solder paste is applied to a joint structure in which the gas easily escapes, for example, a thin terminal, a die bond of a small Si chip, and the like. Therefore, in the die bonding of medium and large Si chips, it is common to use a die bonding by a resistance heating element using a solder foil without flux in an inert atmosphere, or a die bonding by an inert atmosphere furnace such as a hydrogen furnace or nitrogen. is there. The voids built into the solder foil made in the present invention are Cu
Although there is a tendency for the particle size to increase as the particle size decreases, the structure is finely dispersed below the particle size, so that there is no image of a large void so far, and it is expected that the influence on the characteristics is small. When Cu particles and Sn particles having a particle size of 3 to 8 μm were used, the solder filling rate in the foil was about 80% (void rate 20%). When this foil is sandwiched between Sn-plated Cu plates and pressure-bonded with a die bonder in a nitrogen atmosphere, Cu6S
It was found that the intermetallic compound of n5 was formed, and the excess Sn was absorbed into the micro space (void) inside the solder, and a good joint was obtained. Even in the cross-section observation results,
It was confirmed that the filling rate after joining was improved compared to the filling rate of the foil before joining. From this, it was found that the problem of voids, which was a conventional problem, does not become a significant problem in the present method. When the Cu particle diameter is reduced to the level of 3 μm or less, the soldering temperature becomes
If the connection is made at a high temperature of 0 ° C or higher, or if the holding time at a high temperature is long, the reaction with Sn is active, so the shape of the Cu particles collapses and Cu
-Sn compounds may be linked, but the properties such as high-temperature strength remain unchanged. Particularly when it is desired to suppress the reaction, chemical Ni / Au plating (the compound is difficult to be formed thick even at a high temperature) or the like can be applied, or Ag particles or the like can be used. When the Cu particles are coarse at the 30 μm level, the void fraction is 3%
It is the following, and since it is a dispersed void, it can be said that the void does not affect the characteristics.

By the way, the solder foil produced in the steps shown in the above embodiment can be wound around a reel and continuously supplied including a cutting step. Therefore, when used for connection of a sealing portion and a terminal connection portion of a component requiring a temperature hierarchy, it is possible to use a material that matches the shape by punching, laser processing, or the like. Then, by heating and pressurizing the sealing portion and the terminal connection portion of the component under a nitrogen atmosphere with a pulse-type pressurizing heat tool, the connection can be performed without flux. In order to prevent oxidation during preheating and ensure wettability, a Sn-plated solder foil is preferable. For connection of components having a coarse pitch and a small number of terminals, placement of solder foil, positioning of component terminals, pressure connection by resistance heating electrodes by pulse current, and the like are easy and easy.

FIG. 5A shows a state in which the solder foil 39 as shown in FIG. 5C is provided between the chip 8 and the relay substrate 36 by a resistance heating body by pulse heating in a nitrogen atmosphere without using a flux. And then die bond, then Au wire wire bond
At 35, connect the terminal on the chip and the terminal on the relay board 36,
This is a cross section of a BGA / CSP type chip carrier in which a foil is placed between a cap 23 made of Ni-plated Al or the like and a relay substrate 36 and sealed without flux with a resistance heating element in a nitrogen atmosphere. The solder foil can also be temporarily fixed to the object to be joined and joined. The relay board 36 secures an electrical connection between the upper and lower sides, that is, an electrical connection between the chip 8 and an external connection terminal by a through hole (not shown). This structure is a typical example of a normal module structure. Although not shown, chip parts such as a resistor and a capacitor may be mounted on the relay board 36. In the case of a high-output chip, it is preferable to use an AlN relay substrate having excellent thermal conductivity in terms of heat radiation efficiency. The solder composition of the external connection terminals of this module is Sn-3Ag-0.5Cu. When the terminal pitch is wide, it is supplied by a ball, and when the pitch is narrow, it is formed by a paste. In some cases, the Cu terminal or the Ni-Au plated terminal may remain. The module is then mounted on a printed circuit board,
It is reflow-connected at a maximum temperature of 240 ° C with Sn-3Ag-0.5Cu solder (melting point: 217-221 ° C) paste at the same time as other components. It can be connected on a printed circuit board with high reliability. That is, the connection in the module mounting and the connection on the printed board can realize a temperature hierarchical connection. Although the form of the external connection terminal is various, in any case, the use of the solder foil can realize the temperature hierarchical connection for the connection between the external connection terminal and the printed circuit board. In this structure, the semiconductor chip is die-bonded on the board from the solder foil, the terminals of the semiconductor chip and the terminals on the board are connected by wire bonding, and solder balls are formed on the back of the board as external connection terminals. Needless to say, the present invention can be applied to a so-called BGA type semiconductor device. In this case, a resin mold is applied to the chip mounting surface. In order to further improve the wettability of the outer peripheral portion of the connection portion, a good joint can be formed by performing reflow in a nitrogen furnace or a hydrogen furnace after connecting with a resistance heating body by pulse heating.

FIG. 5 (b) shows the structure of FIG. 5 (a) in which a Ni-plated Al fin 23 in a nitrogen atmosphere is connected to a relay substrate.
This is an example in which foil is placed on 43 and fluxless sealing is performed with a resistance heating element.

FIG. 5 (b) left shows a solder foil 24 made of Cu balls and Sn balls and cut out by punching, and FIG. 5 (b) right shows a resistance pressing body 41 by pulse heating in a nitrogen atmosphere. 40 is a cross-section of a model in which a 40 (BB ′ cross-section in the left figure) and a Ni-plated Al fin 23 are heated and sealed in a terminal portion (Ni-Au flash 42) on the relay board. After connection in the right state in FIG. 5B, the shape of the joint 24 in FIG. 5A is obtained. As shown in FIG. 5 (C), the solder foil used was the same as described above.

A fluxless reflow connection in a furnace for reducing hydrogen or the like is also possible. In addition, in the case of a rosin-based flux that can ensure long-term insulation, there is no problem of corrosion, so that reflow connection without washing can be used depending on the product.

By the way, the problem of reflow is that when using a metal ball having a high melting point, in order to facilitate diffusion connection on both sides of the solder foil, it is important to make a state where the solder foil is in contact with the side to be connected. Therefore, it is preferable that the contact be made under pressure. Therefore, it is preferable to adopt a process having a tacking step or a pressing step. For example, it is preferable to fix and supply the lead and the electrode of the component in advance by pressing or the like. In the case of the Zn-Al system, there is no need to worry because it is a type in which everything melts.

FIG. 6 shows an example applied to a power module connection. In many cases, the size of the Si chip 8 is of the order of 10 mm □. For this reason, soft Pb-rich high-temperature solder has conventionally been used. Sn-3.5Ag when Pb-free
(221 ° C), Sn-0.7Cu (227 ° C) or Sn-5Sb (235 ° C). Considering that there is a problem of environmental load on Sb, there is no actual situation other than Sn-3.5Ag and Sn-0.7Cu. Z
Since the n-Al system is hard, there is a high possibility that the Si chip will be cracked as it is.

In this case, the Pb-5Sn-based solder has been used since the reliability of even the conventional Sn-5Sb or the like cannot be ensured due to high heat generation rather than high-temperature solder for hierarchical connection. Since there is no Pb-free soft solder that can replace high Pb solder, the present invention is an alternative. The condition where the temperature reaches 230 ° C rarely occurs in cars, but it is specified as a required specification. Furthermore, it is also required to withstand 260 ° C. reflow. This composite solder dissolves Sn during reflow at 260 ° C., but has high-temperature strength because the intermetallic compound is connected by a network. In addition,
In vehicles where there is a chance to be exposed to high temperatures of 220 ° C, Sn- (5 ~
7) By using% Sb solder (melting point: 236-243 ° C) ball, the reaction between Sn and Cu ball, the reaction between Sn and substrate terminal (Cu, Ni), the Sb concentration becomes 10% or more, The minimum temperature can be raised to a 245 ° C level above Sn (232 ° C). Therefore, there is no need to worry about partial melting even at 220 ° C. The shear strength of this method at 280 ° C is 1 N / mm2 (0.1 kgf
/ Mm ² ) or more. On the other hand, Sn-Ag-Cu solder
Unlike Sn-Pb eutectic, it is said that it has high strength, high rigidity, and poor deformability, which has an adverse effect on elements, components, and the like. For this reason, flexible Sn-In, Sn-Cu-In, Sn-
By using (0-1) Ag-Cu, Sn- (0-1) Ag-Cu-In type solder, even if the melting point of the solder falls slightly to the 200 ° C level, the solder itself can respond to deformation. Therefore, it can be expected to be applied as a hierarchical solder for mounting of portable equipment and the like that require impact resistance. Naturally, the strength required at the time of secondary soldering ensures high-temperature strength through compound connection with Cu that has developed in a network, especially at the outermost periphery of chips and components that are subjected to maximum stress and strain. In the part, it is desirable to form a network in which formation of a compound with the Cu ball prevents breakage near the interface and breaks inside the solder.

Therefore, here, a solder foil of Cu ball and Sn ball is used. 10-30μm soft Cu ball and 10-30μm
Are mixed in a weight ratio of about 1: 1 and Sn is plastically flowed between Cu balls in a vacuum or a reducing atmosphere, and further rolled to produce a solder foil. Or 3 ~ 8μm soft C
Even if u ball and 3-8 μm Sn ball are mixed at a weight ratio of about 1: 1 and Sn is plastically flowed between Cu balls in a vacuum or reducing atmosphere, and further rolled to produce a solder foil, Good. The foil is cut to the required size, and between the Ni-plated Cu lead 51 and the Si chip, between the Si chip 8 and the Ni-plated Cu disk (or Mo disk) 48, the Cu disk The solder foil was mounted between 48 and the alumina insulating substrate 50 on which the Ni plating 49 was applied on the W metallization, and between the alumina insulating substrate 50 and the Cu base plate 49 on which the electric Ni plating 46 was applied. A reflow connection was made in a lump in a hydrogen furnace at ℃. Thereby, between Cu balls, between Cu balls and Cu leads,
Bonding between Cu and Ni intermetallic compounds such as between Cu balls and chips, between Cu balls and Ni-plated Cu plates, between Cu balls and Ni-plated alumina insulating substrates, and between Cu balls and Ni-plated Cu bases. Connections made with this are already connected by a high-temperature resistant intermetallic compound (Cu6Sn5 for Cu, Ni3Sn4 for Ni), so the strength is maintained at 260 ° C (260 ° C to 280 ° C is possible). There is no problem in the reflow in the post-process. The joint was subjected to a temperature cycle test and a power cycle test, and it was confirmed that the joint had a life equivalent to that of the conventional high-Pb solder.

Further, by dispersing the rubber of the Sn-plated plastic ball, the Young's modulus can be reduced, so that the thermal shock resistance can be further improved and a larger Si chip can be joined. In addition, mounting can also be carried out by a method in which nitrogen is blown by a pulse heating type die bonder and pressure bonding is performed at a maximum temperature of 350 ° C. for 5 seconds (5 to 10 seconds is also possible). In addition, it is possible to secure the wetness of the outer peripheral portion and secure the connection of the bonding interface by temporarily attaching by the pulse heating method and ensuring the contact at the interface, and then reflowing at once in a hydrogen furnace. . Since it is desirable to form a smooth fillet in the peripheral portion of the chip, it is also possible to provide a layer of only Sn on the peripheral portion of the solder foil.

Instead of the Cu ball, a Zn-Al system (Zn-Al-Mg,
(Sn-Al-Ge, Zn-Al-Mg-Ge, Zn-Al-Mg-Ga, etc.) As a result of the use, similarly, the temperature cycle resistance and the impact resistance can be reduced, and high reliability can be ensured. Only Zn-Al solder is hard (about
Hv120-160), the rigidity is high, so large Si chips may be easily broken. Therefore, the presence of a soft low-temperature Sn layer and an In layer partially around the ball, and the dispersion of rubber around the ball have the effect of deforming, lowering rigidity and reducing reliability. Can be improved.

Also, by mixing Ni-plated or Ni-Au-plated particles into low thermal expansion fillers (SiO2, AlN, Invar, etc.), the thermal expansion coefficient approaches that of Si, etc., and the acting stress is reduced, resulting in a longer life. Can be expected.

FIG. 7 shows an example in which a high-frequency RF (Radio Frequency) module used for signal processing used in a cellular phone or the like is mounted on a printed circuit board.

In this type of form, a method is generally used in which the back surface of the element is die-bonded to a relay substrate having excellent thermal conductivity, and the wire is spread over the terminal portion of the relay substrate by wire bonding. In many cases, chip parts such as R, C, etc. are arranged around several chips to form an MCM (multi-chip module). Conventional HICs (Hybrid ICs) and power MOSICs are typical examples. Metal core such as Si thin film substrate, AlN substrate with low thermal expansion coefficient and high thermal conductivity, glass ceramic substrate with low thermal expansion coefficient, Al2O3 substrate with thermal expansion coefficient close to GaAs, Invar with high heat resistance and improved thermal conductivity as module substrate material There are organic substrates and the like.

FIG. 7A shows an example in which a Si chip 8 is mounted on a Si module substrate 29. Since R, C, and the like can be formed on the Si module substrate 29 by a thin film, higher-density mounting is possible. Only the Si chip 8 is mainly flip-chip mounted. Mounting on printed circuit board 22 is QFP-LSI type and soft Cu
This is performed via the system lead 20. The connection between the lead 20 and the Si substrate 29 is performed by pressing and heating using the cut solder foil 17 of the present invention. Thereafter, protection and reinforcement are finally performed with a soft resin 19 such as silicone. Sn-3A solder bump 18 of Si chip
g (melting point: 221 ° C.) and connected to the relay board 29. The printed circuit board 22 is connected by Sn-Ag-Cu-based Pb-free solder 21. Even if the solder bumps 18 are re-melted during reflow of the Sn-Ag-Cu-based Pb-free solder 21, the solder bumps 18 hardly change due to the weight of the Si chip 8 in mounting on the printed circuit board 22.
In addition, there is no stress load due to the Si-Si connection, and there is no problem in reliability. After the mounting on the printed circuit board 22, the Si
The chip 8 can be coated with a silicone gel 12 or the like for protection.

As another method, when the solder bumps 18 of the Si chip 8 are made of Au ball bumps and the terminals formed on the relay board 29 are plated with Sn, an Au-Sn bond can be obtained by thermocompression bonding. Can be mounted on the printed circuit board 22
It does not melt at a reflow temperature of 250 ° C, so
A temperature hierarchy connection is possible, and the junction is sufficiently resistant to reflow.

The connection by the solder foil 17 is made of Cu, as described above.
Bonding is maintained by an intermetallic compound formed between metal balls such as
Strength can be ensured even at a reflow temperature of 0 ° C. This makes it possible to realize a lead-free connection with a temperature hierarchy, which has been a major issue so far.

When a thick film substrate such as an AlN substrate, a glass ceramic substrate, or an Al2O3 substrate is used in place of the Si substrate, mounting of chip components such as R and C is necessary for producing a functional element. On the other hand, there is a method of forming R and C by laser trimming with a thick film paste. In the case of R and C using a thick film paste, a mounting method similar to that of the above-mentioned Si substrate is possible.

FIG. 7B shows a case where a GaAs chip 8 is insulated and sealed with a module using an Al 2 O 3 module substrate 29 having excellent thermal conductivity and mechanical properties in a case of Al fins 23. G
Since aAs and Al2O3 have similar thermal expansion coefficients, there is no problem in flip chip mounting in reliability. If the terminal area of these chip parts is 0.6 mm or more, solder thickness t: 0.05
Temporarily attached to an element or chip component with a small number of terminals as a foil of ~ 0.10, or temporarily attached to the terminal on the substrate side, individually by pressure connection in a nitrogen atmosphere with a resistance heating element, or in a reducing atmosphere or inert Connection by atmosphere reflow is possible. It is also possible to use a foil having a solder thickness t of 0.15 to 0.25. Although not shown here for high output,
As the chip mounting method, use the foil of the present invention (chip back surface 8),
In general, a die bonding method and a terminal wire bonding method are used.

In the case of Al fin connection, a foil having a shape surrounding the fin is used, and pressure connection is performed with a resistance heating element in a nitrogen atmosphere. FIG. 7 (c) shows an example of terminal connection on the left side and an example of Al fin 23 on the right side. At this time, the solder foil may be temporarily attached to either the substrate or the fin in advance. In the case of Al, the terminal portion is plated with Ni or the like.

FIG. 7D shows a model of a setup to be mounted on a C organic substrate 32 such as Invar. The heat-generating chip is an organic substrate made of metal core polyimide, etc.
If a build-up board or the like that supports high-density mounting is used, it is possible to directly mount a GaAs chip. In the case of a high heat generation chip, a dummy terminal can be provided to directly conduct heat to the metal.

As an embodiment for the device of the present invention, RF
Although the module was taken up, the same applies to SAW (surface acoustic wave) element structure, PA (high frequency power amplifier) module, other modules and elements used as bandpass filters for various mobile communication devices. Can be applied. The product field is not limited to mobile phones and notebook computers, but includes a module mounted product that can be used for new home appliances and the like in the digital age.

FIG. 8 shows a more specific application to RF module mounting. FIG. 8A is a cross-sectional view of the module, and FIG. 8B is a plan view model in which the member 23 is seen through the upper surface. The actual structure is about □ 2mm that generates radio waves
Several MOSFET elements of chip 8 are mounted face-up in order to support multi-band, and high frequency circuits that efficiently generate radio waves are formed by R, C chip parts 52 etc. in the periphery . Chip components have also been miniaturized, 1005 and the like have been used, and the modules have a vertical and horizontal dimension of about 7 × 14 and are mounted at high density. Here, only the functional aspect of solder is taken into consideration, and an example of a model in which one element and one chip component are mounted is shown as a representative. Note that the chip 8 and the chip component 52 are soldered to the Al2O3 substrate 13 as described later. The terminals of the chip 8 are connected to the electrodes of the Al2O3 substrate 13 by wire bonding, and are further electrically connected to the thick-film electrodes 60 serving as external connection portions on the back surface of the substrate via the through-holes 59 and the thick-film conductors 61. . The chip component 52 is connected to the electrode of the substrate 13 by soldering,
59, it is electrically connected to the thick film electrode 60 serving as an external connection portion on the back surface of the substrate via the wiring 61. Although not shown, the electrode 62 of the substrate connected to the chip or chip component and the through hole 59 are electrically connected by wiring. The member (Al fin) 23 that covers the entire module and the Al2O3 substrate 13 are joined by caulking or the like. In addition, this module is mounted on a printed circuit board or the like by solder connection with a thick film electrode 60 serving as an external connection portion, and requires temperature hierarchical connection.

FIG. 9 is a flowchart showing four processes on the assumption of die bonding of a Si (or GaAs) chip using a solder foil in the structure shown in FIG.
Processes (1) and (2) use a conventional Ag paste for workability of small R and C chip components such as 1005, and (1) is fluxless with a clean substrate surface. This is a method in which die bonding is performed using a solder foil in a short time in a nitrogen atmosphere, followed by wire bonding, and thereafter, chip components are connected with an Ag paste. (2) is a method of connecting chip components with Ag paste first.If a furnace is used to cure the resin, the surface of the substrate may be stained, which may affect wire bonding in the subsequent process. Wire bonding. In (3), the bonding principle is the same as that of the solder foil in order to secure the temperature hierarchy on the high-temperature side as well, but for small chip components, a mixed paste of metal balls and solder balls, which has excellent workability, is used. Supply method,
It can be printed or dispensed. After reflow cleaning, high output Si chips are required to be voided as much as possible. Die bonding of solder foil suitable for voiding is performed, and finally wire bonding is performed. In addition, if die bonding and wire bonding are performed first in the step (3), the flux cleaning step can be omitted. (4) is a method in which die bonding and wire bonding are performed first, and there are two concepts in a later process. One is a method of connecting chip components one by one in a post-process without flux in a nitrogen atmosphere. This method has the disadvantage of being time consuming. Therefore, the other is a method shown in (4), in which a chip component is temporarily attached to a chip component by using a flux, and later connected collectively by reflow. Specifically, after die bonding and wire bonding, for example, it is composed of Cu ball and Sn ball,
Cut the composite solder foil with approximately 1μm of Sn plating on the surface (in most cases, chip components are pre-coated with Ni plating, in which case Sn plating is unnecessary) to approximately the electrode dimensions. Temporarily fixed to the electrode part by pressurizing and heating (or flux may be used), and temporarily fix the temporarily fixed part to the W-Ni-Au plating electrode part on the Al2O3 substrate to the extent that the solder is plastically deformed by thermocompression bonding Preferably. In addition, each individual part is pulsed under a nitrogen atmosphere with a resistance heater.
When pressed at 300 to 350 ° C. for 5 seconds, the intermetallic compound is surely formed and connected, and it is needless to say that the strength is maintained even at a high temperature of 260 ° C. or higher. And reflow furnace (max27
(0-320 ° C.), the pressed portions are connected by the connection of the alloy layers for both Cu and Ni. This connection need not be perfect, and if connected somewhere, there is no problem at high temperatures, even if the strength is low.

Although the small chip component does not become as high in temperature as the element, if it is used for a long time and the Ag paste deteriorates, the reliability of the component of the present invention is improved by using the solder of the present invention. Can be secured. The problem is that it takes time to securely fix each small chip component by thermocompression bonding.

FIG. 8C shows an example in which the above-described module is connected to the printed circuit board 22 by soldering. In addition to the module, an electronic component 52 and a BGA type semiconductor device are connected by soldering. In the semiconductor device, the semiconductor chip 8 is connected to the relay substrate 4
3 is connected in a face-up state by the aforementioned solder foil, and the terminals of the semiconductor chip 8 and the terminals of the relay board 43 are connected by wire bonding 35,
The periphery thereof is resin-sealed with a resin 58. The solder ball bumps 21 are formed below the relay board 43. For example, Sn-2.5Ag-0.5
Cu solder is used. The solder ball 30 is preferably Sn- (1 to 2.5) Ag-0.5Cu, for example, Sn-1.0A
g-0.5Cu may be used. An electronic component is also soldered to the back surface, which is an example of so-called double-sided mounting.

As a mode of mounting, first, for example, Sn-3Ag-0.5Cu solder (melting point: 217
Print the paste. And first, electronic components
In order to perform solder connection from the mounting surface side of 54, this is realized by mounting the electronic component 54 and performing reflow connection at a maximum of 240 ° C.
Next, electronic components, modules, and semiconductor devices are mounted, and ma
Realizes double-sided mounting by reflow connection at x240 ° C.
In this way, reflow the light parts with heat resistance first,
It is common to later connect heavy parts that do not have heat resistance. When reflow connection is performed later, it is ideal that the solder on the first connection side is not melted again.

As described above, also in this case, the bonding of the solder foil itself used for connection in the module is secured at the reflow temperature during mounting on the printed circuit board, so that the module or the semiconductor device can be mounted on the printed circuit board with high reliability. Can be connected. That is, the temperature hierarchical connection between the connection in the semiconductor device or the module and the connection on the printed board can be realized. Although both sides of the printed circuit board were connected by the same solder, small-sized electronic parts such as 1005 as the electronic parts 54, even when the solder was melted in the reflow connection of the electronic parts, modules, and semiconductor devices, did not change. Because of its light weight, the action of surface tension is greater than gravity, and it does not fall. Therefore, when the worst case is considered, no problem occurs even if the intermetallic compound with the terminal of the substrate is not formed and the connection is made only by Sn. For a small component mounted in a module, a combination using a solder paste containing a mixture of Cu and Sn is more desirable than a method of temporarily fixing a solder foil containing a mixture of Cu and Sn in consideration of productivity.

Next, an example of application of a high-output chip such as a motor driver IC to a resin package will be described. FIG. 10A is a plan view in which the lead frame 65 and the heat diffusion plate 64 are adhered and caulked, and there are two caulking points 63. FIG. 10B is a sectional view of the package, and FIG. 10C is an enlarged view of a part thereof. Heat from 3W level heating chip 8 is solder 47
Through the heat diffusion plate (Cu-based low expansion composite material) 64 of the header. The lead material is made of, for example, a 42Alloy-based material.

FIG. 11 shows a process chart of the package. First, a lead frame and a heat diffusion plate (heat sink) are caulked and joined. Then, the semiconductor chip 8 is die-bonded via the solder (foil) 47 onto the caulked and bonded heat diffusion plate 64. The semiconductor chip 8 connected by die bonding is wire-bonded with the lead 56 and the gold wire 35 as shown in the figure. Then, it is resin-molded, and after cutting the dam 57, Sn-based solder plating is performed. Then, lead cutting and molding are performed, and the thermal diffusion plate is cut to complete.
The electrodes on the back of the Si chip 8 are Cr-Ni-Au, Cr-Cu-Au, Ti-Pt
Any commonly used metallization such as -Au, Ti-Ni-Au can be used. Au with high melting point of Au-Sn
It suffices if a compound on the rich side is formed. Die bonding of the chip was performed by blowing nitrogen and using a pulsed resistance heater at an initial pressure of 2 kgf at 350 ° C. for 5 seconds. The solder thickness control is set at a position 10 μm below the initial pressurization position (70 μm film thickness), and the system is mechanically secured to improve the thermal fatigue resistance. In addition to the above, initial pressure 1
Kgf was performed at 350 ° C. for 5 to 10 seconds. The control of the solder thickness was the same even if it was set at a position 10 μm below the position at the time of the initial pressurization (150 μm film thickness). Because of high output chip,
It is important to reduce the void fraction, and the target of 5% or less was achieved. Since the solder contains Cu balls in a state of being uniformly dispersed, structurally large voids are hardly generated. Even with severe thermal fatigue, the Sn, Sn-based solder itself has excellent thermal fatigue resistance and excellent deformability.
Further, since an intermetallic compound is formed on the network between the Cu particles and between the Cu particles and the electrode, the strength is secured even at a high temperature of 260 ° C. or higher. If the Cu particles are too strongly bonded (Cu
(There are many alloy layer formation surfaces between particles and the like), and there is no degree of freedom due to restraint, and a strong elastic body bond is formed, which is not good for elements and the like. There is a modest binding. In particular, in the peripheral portion of the chip, the conventional solder breaks down near the joint interface where stress is concentrated, and hardly breaks down inside the solder. In this method, the interface between the bonding interface and the Cu ball hardly undergoes interface destruction, and it is possible to form a network that can be destroyed inside the solder. After die bonding and wire bonding, resin molding was performed, dam 57 was cut, and the lead was Sn
-Bi, Sn-Ag, Sn-Cu based Pb-free solder plating 2 ~ 8μm
Will be applied. Further, lead cutting is performed, and unnecessary portions of the heat diffusion plate are cut to complete.

FIG. 12 shows an example applied to a general plastic package. Tab 66 with 42Alloy backside Si chip
It is adhered on the upper side with solder foil 67 (conductive paste 67). The element is connected to a lead 56 through a wire bond 35 and molded with a resin 58. Thereafter, the lead is plated with Sn-Bi based plating corresponding to the Pb-free. In the past, Sn-37Pb eutectic solder with a melting point of 183 ° C could be used for mounting on a printed circuit board, so reflow connection was possible at a maximum of 220 ° C. When it becomes Pb-free, Sn-3Ag-0.5Cu (melting point: 217-22
(1 ° C), the reflow connection will be performed, so the maximum temperature will be 240 ° C and the maximum temperature will be about 20 ° C higher. For this reason, Si chips
If a conventional heat-resistant conductive paste or adhesive is used to connect the 8 and 42Alloy tabs 66, it is expected that the adhesive strength at high temperatures will be reduced and affect the reliability thereafter. Therefore, by using the solder foil instead of the conductive paste, the strength at a high temperature of max 270 to 350 ° C is ensured.
b Hierarchical connection with free solder is possible. This plastic package application can be applied to any plastic package structure that connects a Si chip and a tab. Gull Wing type, Flat type, J-Lead type, Butt-Leed type in structure. There is a Leadless type.

FIG. 13 shows an example of a model structure before a composite solder foil is formed. 3 ~ 15μm level Sn plated Cu
Metal fiber 69 (for high temperature molding and rolling, C
(Surface treatment such as Ni / Au may be applied to suppress the reaction between u and Sn) .Lay them in a row and mix solder balls such as Sn and metal balls such as Sn-plated Cu appropriately.
(Approximately 50%) is mixed, molded and rolled to produce a foil processed to a level of 150 to 250 μm. Heat-resistant plastic balls plated with Sn for further lowering the Young's modulus, or low thermal expansion silica or invar plated with Cu / Sn as a part of the metal balls may be added. At the stage of molding and rolling, the soft solder balls enter the gaps between the metal balls and the metal fibers to form a "sea-island structure" sea shape. The metal fiber diameter is not limited to the above-mentioned 3 to 15 μm, but becomes a nucleus at the center of the foil, and the metal ball plays a major role at the joint interface with the object to be joined. By directing the metal fibers in that direction in continuous rolling or the like, work becomes easier. In addition,
Instead of metal fibers, thinner wires, copper (or Cu / solder) plated carbon fibers that can be reduced in expansion, other ceramic, glass, invar, etc., Ni / Au, Ni / solder, Cu (or Cu / solder) plating is also possible.

FIG. 13 shows an example in which metal fibers serving as the core of the foil are arranged in a line. FIG. 14 shows an example in which the metal fibers are arranged in a cloth (the angle is free) and the structure is stable. A mixture of solder balls such as Sn and metal balls such as Sn-plated Cu in an appropriate mixture (about 50%) is inserted into the gap of the cloth, and the application is possible as in FIG. .

FIG. 15 is a cross section of the foil when the wire mesh fiber 71 is used, and the cross section of the wire mesh extending in the depth direction is indicated by a cross 70. FIG. 15A shows a foil formed of a wire mesh and solder. There is a limit to the fineness of the wire mesh, the current minimum mesh size of commercial products is 325, and the particle size passing through is 44 μm
Therefore, since the diameter of the wire forming the net is large, the contact area at the bonding interface is small (compound formation area), and there is a problem in securing strength at high temperatures. Therefore, solder balls such as Sn and metal balls 2 such as Sn-plated Cu are provided between the wire meshes 70 and 71.
Fig. 15 (b) shows a cross section of a foil produced by filling a mixture obtained by mixing (1) and (2) in an appropriate composition (about 50%). The solder 72 has a structure in which it enters the gap. If high temperature strength is required, use Cu
Add a large amount of balls, focus on compound formation at the interface with the workpiece, and if the thermal fatigue of the joint is important, add a large amount of solder to emphasize the thermal fatigue resistance of the solder. Control is possible. The metal balls to be filled are not limited to balls, but fibers and the like described below are effective. The mixing ratio of the metal ball and the solder also depends on the shape of the metal,
There is a possibility that it greatly differs depending on the contact state and the like.

FIG. 16 shows an elongated metal fiber 73 to make paper.
Is a model in which a mixture of a solder ball 68 such as Sn and a metal ball 2 such as Sn-plated Cu in an appropriate combination (about 50%) is formed on both sides by flattening randomly. . FIG. 16A is a plan view, and FIG. 16B is a cross-sectional view.

FIG. 17 shows a strip metal fiber instead of a metal ball, or a carbon fiber which can be reduced in expansion, plated with Cu (or Cu / solder). , Ni / solder, Cu (or Cu / solder) plated strip fiber, etc. are possible. By using strip fibers, the amount of the solder can be greatly increased. It is also possible to mix a metal ball in the gap to reinforce the network by compound formation. Although it is constrained by the metal ball alone, it has a rigid structure, but by dispersing the strip-shaped fibers in this way, a structure with high deformability and elasticity can be expected, and good performance against die bonding or thermal fatigue can be obtained. I think it can be done. The length of the strip is desirably 1/10 or less if the thickness of the foil is 200 μm. As an example,
The diameter is preferably in the range of 1 to 5 μm and the length is in the range of 5 to 15 μm. Although the invention made by the inventor has been specifically described based on the embodiment, the present invention is not limited to the above embodiment, and various changes can be made without departing from the gist of the invention. Nor. Also,
Representative aspects disclosed in the above embodiment are as follows. This is a solder foil formed by rolling a solder material containing metal particles and solder particles. This is a solder foil formed by rolling a solder material containing metal particles having a plating layer such as Sn. This is a method for producing a solder foil by rolling a solder material containing metal particles and solder particles. This is a method for producing a solder foil for rolling a solder material containing metal particles having a plating layer such as Sn. In the above solder foil, for example, the metal particles are Cu particles, and the solder particles are Sn particles. A solder foil formed by applying pressure to a solder having Cu and Sn, wherein Cu is in a state of particles and Sn is in a state of filling between the Cu particles. When the solder foil is reflowed, at least a part of the surface of the Cu particles is covered with Cu6Sn5. The solder foil, wherein Cu particles and Sn after plastic deformation are Cu6 when the solder foil is reflowed.
It is bound by a compound containing Sn5. The solder foil, wherein the particle size of the Cu particles is 10 to 40 μm. The solder foil, wherein the particle size of the Cu particles is 3
〜１０10 μm. The solder foil,
The Cu particles have a Ni plating or Ni / Au plating layer on the surface. In the solder foil, at least a portion of the foil where Cu is exposed is subjected to Sn plating. The solder foil, wherein the thickness of the solder foil is 80 μm.
m to 150 μm. The solder foil, wherein the thickness of the solder foil is from 150 μm to 250 μm. The solder foil has plastic particles. The solder foil has another particle having a smaller coefficient of thermal expansion than the Cu.
The other particles of the solder foil having a smaller coefficient of thermal expansion than the Cu are particles of Invar, silica, alumina, AlN (aluminum nitride), and SiC. Invar (alloy) is obtained by alloying 34% to 36% of Ni (nickel) with Fe (iron) and has a small linear expansion coefficient. The solder foil further includes In particles. The solder foil is obtained by mixing Cu particles and Sn particles in a vacuum, a reducing atmosphere, or an inert atmosphere, and then applying pressure to form a foil. The solder foil,
The rolling ratio is 15% to 20%. The solder foil is formed by rolling a material containing metal fibers and solder particles. This is a solder foil formed by rolling a solder material containing Cu metal fibers and Sn particles. The solder foil, wherein the Cu metal fibers are strip-shaped in the solder material. This is a solder foil formed by rolling a solder material containing any of Al, Au, and Ag particles and Sn particles. Zn-Al alloy, Au-Sn alloy particles and Sn
This is a solder foil formed by rolling a solder material containing particles of the above. In addition, a single metal, an alloy, a metal ball containing a compound or a mixture of these, and a solder ball containing at least one of Sn and In were mixed with a solder ball to be wetted with solder, and the gap was filled and press-filled, followed by rolling. It is a solder foil characterized by the above. In addition, a metal ball containing a single metal, alloy, compound or a mixture thereof which is wettable by solder, and Sn, In
Mixed with a solder ball containing at least one of
This is a solder foil produced by placing in a mold that is easy to be rolled in advance to which uniform pressure is applied, press-fitting evenly without any gaps and embedding, and then rolling the composite. Further, in the solder foil described above, the solder, other than Sn, In, Ag, Bi, Cu,
It contains any one or more of Zn, Ni, Pd, Au, Sb and the like. Further, in the solder foil described above, the metal ball is Cu, Cu alloy, Cu6Sn5 compound, Ag, Ag-Sn compound, A
u, Au-Sn compound, Al, Al-Ag compound, Al-Au compound, Zn-
It is a ball containing an Al-based solder or a mixture thereof. Further, the solder foil according to the above, wherein the rolled foil, or the solder composite material is Sn-plated, or Sn-plated.
Is plated with at least one of Bi, In, Ag, Au, Cu, Ni, and Pd. Further, in the solder foil described above, if the metal ball containing the single metal, alloy, compound or a mixture thereof is not wet, the surface is plated with Ni, Ni-Au, Cu, Ag, Sn, Au, etc. Or a composite plating thereof, or a metallization that is wettable to solder such as a Sn-based plating. Further, the solder foil according to the above, wherein the single metal, alloy,
A solder foil having a particle size distribution in consideration of close packing of metal balls containing a compound or a mixture thereof. Also,
The solder foil according to the above, wherein metallized plastic balls whose surfaces are wetted with solder are dispersed in order to reduce the rigidity of the composite solder. Further, in the solder foil described above, in order to reduce the thermal expansion coefficient of the composite solder, a particle having a lower thermal expansion coefficient than a single metal, an alloy, a compound or a metal containing a mixture thereof, and wets the solder to the surface Metallization for or on top of
It is obtained by applying a solder plating such as Sn or In and dispersing it. Further, in the solder foil described above, as particles having a low coefficient of thermal expansion, invar, silica, alumina,
AlN, SiC and the like. Further, in the solder foil described above, as the plastic ball material, polyimide resin, heat-resistant epoxy resin, silicone resin,
Various polymer beads, denatured ones thereof, or a mixture thereof. Further, the solder foil described above is a band, a wire, a ball, or a lump. Further, in the solder foil described above, instead of the metal ball, a metal fiber or copper plated carbon, glass, using a fiber such as ceramic, or the metal ball dispersed and mixed in the metal fiber It is a thing using a thing. Further, in the solder foil described above, metal fibers or copper-plated carbon, glass, ceramic, or other fibers are stacked on the cloth instead of the metal balls, or the fibers of the cloth and the metal balls are dispersed. It is a thing using a thing. Further, the solder foil according to the above, wherein a metal fiber or a copper-plated carbon, glass, ceramic or other fiber formed into a net is used instead of the metal ball, or the metal ball is dispersed in the net. It was done. The solder foil as described above, wherein the fiber has a diameter of 1 to 20 μm, preferably 3 to 15 μm. Further, the solder foil described above, wherein a metal short fiber or a short fiber such as copper plated carbon, glass, or ceramic is used instead of the metal ball, or the metal ball is dispersed in the short fiber. Is used. Further, in the solder foil described above, the short fiber has a diameter of 1 to 10
μm, desirably 1 to 5 μm, aspect ratio (length / diameter):
2 to 5. An electronic device having a first electronic device, a second electronic device, and a third electronic device,
The first electronic device and the second electronic device are connected by the solder foil, and the second electronic device and the third electronic device are connected by a solder different from the first solder. is there. A semiconductor device comprising a semiconductor chip, a tab on which the semiconductor chip is arranged, and a lead serving as a connection terminal with the outside, wherein an electrode of the semiconductor chip and the lead are connected by wire bonding, The semiconductor chip and the tab are connected by the solder foil. An electronic device having a first electronic component, a second electronic component, and a third electronic component, wherein the first electronic component and the second electronic component include metal particles and solder particles. The second electronic component and the third electronic component are connected using a first solder which is a solder foil formed by rolling a material containing the second solder, the second solder having a melting point different from that of the first solder. Are connected by using A first electronic component, a second electronic component, an electronic device having a third electronic component, wherein the first electronic component and the second electronic component,
By applying pressure to a solder material having metal particles and solder particles, the metal is in a particle state, and the solder particles are filled with particles of the metal using a first solder. The second electronic component and the third electronic component are connected using a second solder having a melting point different from that of the first solder. In the electronic device, solder particles in the first solder are Sn. A first electronic device, a second electronic device, and an electronic device having a third electronic device, wherein the first electronic device and the second electronic device are metal particles having a Sn plating layer. Are connected using a first solder, which is a solder foil formed by rolling a solder material containing, the second electronic component and the third electronic component have a different melting point from the first solder. Are connected by using the solder of FIG. A first electronic component, a second electronic component, and an electronic device having a third electronic component, wherein the first electronic component and the second electronic component are metal particles having a Sn plating layer. By applying pressure to the metal, the metal is in the form of particles,
Sn is connected using a first solder that fills the metal particles, and the second electronic component and the third electronic component have a second melting point different from that of the first solder. Are connected by using the solder of FIG. In the electronic device, the metal particles in the first solder are Cu. In the electronic device, the metal particles in the first solder are particles of any of Al, Au, and Ag. In the electronic device, a melting point of the second solder is lower than a melting point of metal particles of the first solder. In the electronic device, when Sn contained in the first solder is melted, the Cu particles react with the Sn, and the Cu particles are bound by a compound containing Cu6Sn5. In the electronic device, the diameter of the metal particles is 10 to 40 μm. The electronic device, wherein the thickness of the first solder is from 80 μm to 150 μm.
μm. The electronic device, wherein the first solder further includes plastic particles. In the electronic device, the first solder further includes other particles having a smaller coefficient of thermal expansion than the particles of the metal. In the electronic device, the second solder is a Sn-Ag-Cu-based lead-free solder. An electronic device having a first electronic component and a second electronic component, wherein the first electronic component and the second electronic component are connected by a solder connection, and the solder connection is a metal connection. It has a Sn portion filling between the particles and the metal particles. In the electronic device, the metal particles are bonded to the metal by a compound formed by Sn. A semiconductor device comprising a semiconductor chip, a tab on which the semiconductor chip is arranged, and a lead serving as a connection terminal with the outside, wherein an electrode of the semiconductor chip and the lead are connected by wire bonding, The semiconductor chip and the tab are connected by using a solder foil in which metal particles and solder particles are mixed. A semiconductor device comprising a semiconductor chip, a tab on which the semiconductor chip is arranged, and a lead serving as a connection terminal with the outside, wherein an electrode of the semiconductor chip and the lead are connected by wire bonding, The semiconductor chip and the tab have metal particles and solder particles. By applying pressure to the solder material, the metal is in a state of particles, and the solder particles are in a state of filling between the particles of the metal. They are connected using the first solder. A semiconductor device comprising a semiconductor chip, a tab on which the semiconductor chip is arranged, and a lead serving as a connection terminal with the outside, wherein an electrode of the semiconductor chip and the lead are connected by wire bonding, The semiconductor chip and the tab are connected by a connecting portion having a Sn portion filling between metal particles. In the semiconductor device, the metal particles are bonded to the metal by a compound formed by Sn. A module comprising a substrate, a passive component mounted on the substrate, and a semiconductor chip, wherein the electrodes of the semiconductor chip and the electrodes of the substrate are connected by wires, and the surface of the semiconductor chip and the substrate which are not wire-bonded are connected to each other. The metal particles are connected by a connecting portion having a Sn portion filling the metal particles. In the module, the passive component and the substrate are also connected by a connection portion having a metal particle and a Sn portion filling a space between the metal particle. In the module, the substrate has a through-hole in a portion where the semiconductor chip is mounted, and the inside of the through-hole is also filled with metal particles and a solder filling between the metal particles. Things.

[0094]

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows. (1) It is possible to provide an electronic device and a method for manufacturing the electronic device by completely novel solder connection. (2) It is possible to provide a solder connection in a temperature hierarchical connection required in a method of manufacturing an electronic device, particularly a solder connection on a high temperature side. (3) A completely new solder and a method for manufacturing the same can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram of a manufacturing process of a composite metal made with a composite ball.

FIG. 2 is a diagram of a cross-sectional model before and after rolling in a state in which elastic plastic balls are dispersed.

FIG. 3 is a cross-sectional model diagram showing an example of a die bonding process.

FIG. 4 is a diagram of a cross-sectional model of a die-bond connection portion using a Cu and Sn-containing solder foil.

FIG. 5 is a diagram of a cross-sectional model for connecting an LSI and a cap to a substrate.

FIG. 6 is a diagram of a cross-sectional model of a power module.

FIG. 7 is a diagram of a cross-sectional model in which a module is mounted on a printed circuit board.

FIG. 8 is a model diagram of a cross section of an RF module mounted.

FIG. 9 is a flowchart showing a process of mounting an RF module.

FIG. 10 is a plan view and a cross-sectional model view of a high-output resin package.

FIG. 11 is a flowchart showing a process of a high-output resin package.

FIG. 12 is a cross-sectional model diagram of a plastic package.

FIG. 13 is a plan view and a cross-sectional view of a model blended using metal fibers.

FIG. 14 is a plan view of a model using crossed metal fibers.

FIG. 15 is a cross-sectional view of a model using a wire mesh fiber.

FIG. 16 is a plan view and a cross-sectional view in which elongated metal fibers are randomly placed and flattened.

FIG. 17 is a cross section of a model using strip metal and non-metal fiber.

[Explanation of symbols]

1. Carbon jig 2. Cu ball 3. Sn ball 4. Sn 5. Roll 6. Plastic ball 7. Resistance heating tool 8. Si chip 9. Vacuum suction hole 10. Nitrogen 11. Solder foil 12. Silicone gel 13 .Al2O3 substrate 14.W (sintered) -Cu plating electrode 15.Preheating heater 16.Nitrogen 17.Cu, Sn mixed foil 18.Bump 19.Soft resin 20.Lead 21.Solder ball bump 22.Printed circuit board
23. Al fin 24. Joint with fin 25. Joint with lead 26. Lead 27. Solder foil 28. Board terminal 29. Module board 30. Terminal 31. Cu 32. Organic board 33. Cu through-hole conductor 34.Ag-Pd conductor 35.Wire bond 36.AlN relay board 37.Connection terminal 38.Cr-Cu-Au 39.Die bond 40.Solder foil 41.Pressing body 42.Ni-Au plating metallization 43.Relay board 44 .Cr-Ni-Au metallization 45.Chemical Ni plating 46.Electric Ni plating 47.Solder 48.Cu disk 49.Cu base 50.Al2O3 insulating board 51.Cu lead 52.Chip parts 53.Cu pad 54.TQFP-LSI 55.Sn-Ag-Cu solder 56.Lead 57.Dam cut 58.Resin 59.Through hole 60.W-Ni-Au thick film electrode 61.W-Ni (or Ag-
Pd, Ag) Thick film conductor 62. Au plating electrode 63. Caulked portion 64. Heat diffusion plate (header) 65. Lead frame 66. Tab 67. Conductive paste 68. Solder 69. Fiber 70. Cu net (cross section) 71 .Cu net (longitudinal section) 72.Solder (sea) 73.Elongated fiber 74.Strip fiber

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 25/00 H01L 25/00 B H05K 3/34 512 H05K 3/34 512C (72) Inventor Toshiharu Ishida Kanagawa 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Japan Inside Hitachi, Ltd.Production Technology Research Institute (72) Inventor Tetsuya Nakatsuka 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd.Production Technology Research Laboratory (72) Inventor Okamoto Masahide 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi, Ltd. Production Technology Research Laboratories (72) Inventor Kazuma Miura 4-6, Kanda Surugadai, Chiyoda-ku, Tokyo Hitachi, Ltd. Manufacturing Technology Division, F-term (Reference) 5E319 AA03 AB01 AB05 AC01 BB01 CC33 GG20 5F047 AA00 AA03 AA11 AA14 BA05 BA17 BA19 BB0 3 BC00 CA02 FA52 FA62 5F067 AB03 BB12

Claims (24)

[Claims] 1. An electronic device having a first electronic component, a second electronic component, and a third electronic component, wherein the first electronic component and the second electronic component are metal particles. Are connected using a first solder, which is a solder foil formed by rolling a material containing solder particles, and the second electronic component and the third electronic component have different melting points from the first solder. An electronic device, wherein the electronic device is connected using a second solder. 2. An electronic device having a first electronic component, a second electronic component, and a third electronic component, wherein the first electronic component and the second electronic component are metal particles. By applying pressure to the solder material having solder particles, the metal is in the state of particles, and the solder particles are connected using the first solder that fills the space between the particles of the metal, An electronic device, wherein the second electronic component and the third electronic component are connected using a second solder having a melting point different from that of the first solder. 3. The electronic device according to claim 1, wherein the solder particles in the first solder are Sn. 4. An electronic device having a first electronic device, a second electronic device, and a third electronic device, wherein the first electronic device and the second electronic device are formed of a Sn plating layer. Are connected using a first solder which is a solder foil formed by rolling a solder material containing metal particles having the second electronic component and the third electronic component are different from the first solder An electronic device connected by using a second solder having a melting point. 5. An electronic device having a first electronic component, a second electronic component, and a third electronic component, wherein the first electronic component and the second electronic component are formed of an Sn plating layer. By applying pressure to the metal particles having the following formula, the metal is in a particle state, and the Sn is connected using a first solder that fills the space between the metal particles; and An electronic device, wherein the electronic component and the third electronic component are connected using a second solder having a melting point different from that of the first solder. 6. The electronic device according to claim 1, wherein metal particles in the first solder are Cu. 7. The electronic device according to claim 1, wherein the metal particles in the first solder are Al, Au, or Ag particles. Electronic device. 8. The electronic device according to claim 1, wherein a melting point of said second solder is lower than a melting point of metal particles of said first solder. Electronic device. 9. The electronic device according to claim 6, wherein when Sn contained in the first solder is melted, the Cu particles react with the Sn, and the Cu particles are bound by a compound containing Cu6Sn5. An electronic device characterized by being performed. 10. The electronic device according to claim 1, wherein said metal particles have a diameter of 10 to 40 μm.
An electronic device, wherein the electronic device is m. 11. The electronic device according to claim 1, wherein said first solder has a thickness of 80 μm to 150 μm. 12. The electronic device according to claim 1, wherein said first solder further comprises plastic particles. 13. The electronic device according to claim 1, wherein said first solder has another particle having a smaller coefficient of thermal expansion than said metal particle. Electronic device. 14. The electronic device according to claim 1, wherein the second solder is a Sn—Ag—Cu-based lead-free solder. 15. An electronic device having a first electronic component and a second electronic component, wherein the first electronic component and the second electronic component are connected by a solder connection. The portion is Sn particles filling between the metal particles
An electronic device having a portion. 16. The electronic device according to claim 15, wherein:
The electronic device according to claim 1, wherein the metal particles are linked to the metal by a compound formed by Sn. 17. A semiconductor comprising a semiconductor chip, a tab on which the semiconductor chip is arranged, and a lead serving as a connection terminal with the outside, wherein an electrode of the semiconductor chip and the lead are connected by wire bonding. A semiconductor device, wherein the semiconductor chip and the tab are connected by using a solder foil in which metal particles and solder particles are mixed. 18. A semiconductor comprising a semiconductor chip, a tab on which the semiconductor chip is arranged, and a lead serving as a connection terminal with the outside, wherein an electrode of the semiconductor chip and the lead are connected by wire bonding. An apparatus, wherein the semiconductor chip and the tab have metal particles and solder particles, and by applying pressure to a solder material, the metal is in a state of particles, and the solder particles are interposed between the particles of the metal. A semiconductor device, wherein the semiconductor device is connected using a first solder in a buried state. 19. A semiconductor comprising a semiconductor chip, a tab on which the semiconductor chip is arranged, and a lead serving as a connection terminal with the outside, wherein an electrode of the semiconductor chip and the lead are connected by wire bonding. The semiconductor device, wherein the semiconductor chip and the tab are connected by a connection having a metal particle and a Sn portion filling between the metal particles. 20. The semiconductor device according to claim 19, wherein said metal particles are linked to said metal by a compound formed by Sn. 21. A module comprising a substrate, a passive component mounted on the substrate, and a semiconductor chip, wherein the electrodes of the semiconductor chip and the electrodes of the substrate are connected by wires, and are not connected by wire bonding. The module is characterized in that the surface and the substrate are connected by a connecting portion having a Sn portion filling between the metal particles. 22. The module according to claim 21, wherein the passive component and the substrate are also connected by a connection portion having metal particles and a Sn portion filling between the metal particles. Features module. 23. The module according to claim 21, wherein the substrate has a through hole in a portion where the semiconductor chip is mounted, and the inside of the through hole also includes metal particles and metal particles. A module filled with solder filling between the modules. 24. The solder foil according to claim 21, wherein:
A solder foil, wherein the connection portion uses a solder foil formed by rolling a solder material containing particles formed by plating a Sn layer on Cu.