JP2002368044A - Method for assembling electronic component with solder ball and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form solder balls of uniform height in a ball forming process without increasing steps. SOLUTION: Height of solder balls is made uniform by mounting solder balls 1 on the electrodes (2a, 2b) of an electronic component and reducing or eliminating oxidation of solder balls at the time of thermally fusing the solder balls for bonding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for forming a solder ball to be used as an electrode of an electronic component. In particular, C4 (Co
ntrolled Collapse Chip Co
nection) or BGA (Ball Grid A)
The present invention relates to a method for forming a solder ball for uniformizing the size of a solder ball forming an electrode such as an electrode.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller, lighter and more sophisticated, there has been a demand for smaller and more sophisticated electronic components. Along with this, the electronic parts are also required to have a smaller area, a higher density of electrodes, a larger number of pins, and a smaller pitch. A BGA (Ball Grid Alla) in which solder balls are arranged on electrodes on the back surface of a device substrate for forming electronic components for reasons such as easiness and reliability of joining to satisfy these requirements.
y) Structures have been used. This structure is CSP (Chi
p Size Package), MCM (Multi
It is also used in semiconductor devices such as Chip Modules.

At present, the height of the solder balls is not uniform in many cases. If the height of the solder balls varies, when the electronic components having the solder balls are mounted on a circuit board or the like to be mounted, the solder balls and the substrate become inconsistent. An object that does not contact appears, and an open failure occurs.

For this purpose, Japanese Patent Laid-Open No. Hei 10-242631 discloses a method in which a ball formed on a back surface of a substrate of an electronic component in a process of forming a solder ball is made uniform by pressing a ball formed by a pressing device. No. 6,086,045.

[0005]

However, in these methods, one pressing step is added, and introduction of new pressing equipment, cost, and production time are further required. Further, there is a possibility that solder dust is generated at the time of pressing and adheres to the substrate or the pressing tool.

Further, when the solder pitch is narrow or when the pressing force is too strong, adjacent solder balls join together,
There is also a possibility that a short circuit may occur.

In order to solve such problems, there is a need for a method of forming solder balls having a uniform height in a ball forming step without increasing the number of steps.

[0008]

SUMMARY OF THE INVENTION In the solder ball forming process of the present invention, in order to solve such a problem, it is necessary to form a solder ball having a uniform height within a range where the influence of variation is not affected. When solder balls are mounted on the electrodes of
The height of the solder balls is made uniform by reducing and removing oxidation of the solder balls.

More specifically, the size of the solder ball is made uniform by controlling the oxygen concentration during reflow and the amount of flux applied to the solder ball to reduce or eliminate oxidation of the solder ball.

According to the present invention, a solder ball having a uniform height can be formed in the ball forming step without increasing the number of steps.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

In the present embodiment, by suppressing the oxidation of the solder ball when it is melted, the shape of the solder ball becomes uneven and individual heights are prevented from being different. Specifically, a flux is applied to at least one of the solder ball and the substrate electrode of the semiconductor element so as to sufficiently cover the surface of the solder ball when the solder ball is melted and suppress oxidation. Alternatively, the melting of the solder ball is performed in a reduced oxygen concentration state, in this embodiment, in an inert gas atmosphere state.

That is, by flowing an inert gas such as N ₂ , the concentration of oxygen in the atmosphere is reduced, and oxidation of the solder surface is prevented. As a result, the solder exhibits good wettability and fluidity, and enables the solder ball height to be uniform. Further, when a sufficient amount of flux is applied on the land, the flux is wet on the solder surface in the preheating step, and the oxide film on the solder surface can be removed. As a result, a solder ball having a uniform height can be formed.

An example of a method for manufacturing an electronic component according to the present embodiment will be specifically described.

First, a flux is applied to one or both of a substrate electrode and a solder ball of an electronic component (a flux applying step), and the solder ball is mounted on the substrate electrode of the electronic component (a solder ball mounting step). The electronic components are put into a reflow oven or heating furnace, heated from room temperature to the temperature range where the flux is activated, and the heating state is maintained for a certain period of time (preheating step). After heating to a temperature (main heating step), the substrate is cooled by any one of cooling at room temperature, cooling, and fan cooling (cooling step) to form solder balls on the substrate electrodes of the electronic component.

Here, it should be noted that in order to suppress oxidation, flux was applied or solder balls were heated and melted in an inert gas atmosphere for reducing the oxygen concentration. Although both may be performed, the efficiency of quality and productivity is further improved by performing both.

FIGS. 1 and 2 illustrate the principle of uniformity of solder balls in the present invention.

FIG. 1 shows an embodiment in which the oxygen concentration is reduced, and FIG. 2 shows an embodiment in which a flux is applied.

FIG. 1A shows an example of a comparative example, in which a solder ball 1 is mounted on a substrate electrode 2 of an electronic component 3 via a flux 5 and heating and cooling are performed in the atmosphere. After mounting the ball (I), the solder ball is heated to melt the solder ball (II). At this time, an oxide film 7 is formed on the surface of the solder ball 1 by oxygen in the atmosphere. When cooling the solder balls, the oxide film 7
Is a layered film, and during the process of solidification shrinkage (III) of the solder ball, the overall stress due to the difference in solidification temperature between the oxide film and the solder material in the oxide film and the variation in the thickness of the oxide film The balance becomes uneven, and as a result, FIG.
As shown by III, the surface becomes a bumpy solder ball, and the height of each solder ball 1a, 1b becomes uneven.

On the other hand, as in the embodiment shown in FIG. 1B, the solder ball 1 is mounted on the substrate electrode 2 of the electronic component 3 via the flux 5 to reduce the oxygen concentration. Heating in an inert gas atmosphere such as N ₂ gas,
This shows a state in which cooling is performed. After the balls are mounted (I), the solder balls are heated to melt the solder balls (II). At this time, the oxide film 7 is hardly formed on the surface of the solder ball 1, and even if it is formed, a thin film is formed. When the solder ball cools, it is possible to eliminate the adverse effect of the oxide film as described above, and unnecessary stress does not act on the solder ball, and as a result, as shown in III of FIG. As described above, the solder exhibits good wettability and fluidity, and enables uniform height.

By melting the solder balls with the oxygen concentration reduced in this way, the quality of the shape of the solder balls can be maintained, and the height of each ball can be kept uniform. As a result, the solder ball can provide a high-quality electronic component.

Next, the principle of improving the quality and quality of solder balls by supplying flux will be described.

FIG. 2A shows an example of a comparative example, in which a solder ball 1 is mounted on a substrate electrode 2 of an electronic component 3 via a small amount of flux 5 and heating and cooling are performed in the atmosphere. After mounting the ball (I), the solder ball is heated to melt the solder ball (II). On this occasion,
In the comparative example, since the amount of applied flux is small, oxidation of the solder ball cannot be suppressed, and an oxide film 7 is formed on the surface of the solder ball 1 by oxygen in the atmosphere. When the solder ball is cooled, the oxide film 7 forms a layered film. During the course of the solidification shrinkage (III) of the solder ball, the solidification temperature of the oxide film and the solder material in the oxide film is reduced. Due to the difference and the variation in the thickness of the oxide film, the overall stress balance becomes non-uniform. As a result, as shown by III in FIG. 1A, the surface becomes a bumpy solder ball, and the solder balls 1a and 1b The height will be uneven.

On the other hand, as in the present embodiment shown in FIG. 2B, the solder ball 1 is mounted on the substrate electrode 2 of the electronic component 3 via a large amount of flux 5, and heating and cooling are performed in the atmosphere. This is a state in which solder balls are mounted (I), and then the solder balls are heated to melt the solder balls (II). At this time, due to the flux acting on the surface of the solder ball 1, the oxide film 7 is hardly formed, and even if formed, a thin film is formed. When the solder ball cools, it is possible to eliminate the adverse effect of the oxide film as described above, and no unnecessary stress acts on the solder ball. As a result, FIG.
As shown in III of (B), the solder exhibits good wettability and fluidity, and enables uniform height.

In this embodiment, the solder balls are melted in the atmosphere. However, it is more effective to heat and cool in an atmosphere having an oxygen concentration reduced (inert gas atmosphere such as N ₂ gas).

When a sufficient amount of flux is applied to the land as described above, the flux is wet on the solder surface, and the oxide film on the solder surface can be removed. As a result, a solder ball having a uniform height can be formed.

FIG. 3 is a cross-sectional view of an electronic component on which solder balls are formed in the present embodiment. An electrode formed on the semiconductor element 4 and an electrode formed on the surface of the intermediate substrate 3 having electrodes on both sides are formed of a metal material such as gold or aluminum,
Joined by conductive adhesive. Here, the bonding of the metal material is performed by vibration, heating, pressurizing, or the like, and the bonding of the conductive adhesive is performed by heating, pressurizing, or the like. In the present embodiment, a gold bump 10 is formed on the electrode formed on the semiconductor element 4, a conductive paste (not shown) is transferred to the tip of the gold bump 10, and the gold paste is applied to the electrode 2 b formed on the surface of the intermediate substrate 3. Joining while performing pressure and heating. Then, the space formed between the semiconductor element and the intermediate substrate is sealed with the insulating resin 11. At this time, the gold bump 10 and the electrode 2
b is firmly joined by pressing, and the insulating resin is melted and hardened to join the intermediate substrate 3 and the semiconductor element 4.

The solder ball 1 is mounted on the electrode 2a provided on the back surface of the substrate 3. The electrode 2a is formed on the surface of the intermediate substrate by vapor deposition, sputtering, plating, or the like.

As described above, the electronic component of the present embodiment is configured such that the electrodes of the semiconductor element are connected to the solder balls via the intermediate substrate having the electrodes on both surfaces (the electrodes on both surfaces are electrically connected in the substrate). Electrically joined. The substrate 3 is made of a ceramic, an organic material (such as an epoxy resin), a composite material, or the like. The substrate electrodes 2a and 2b are made of gold, copper, tungsten, or the like (when a material having poor wettability with solder is used for the electrode, It is desirable to deposit a gold thin film on the electrode surface).

The solder balls are of Sn-Pb type, Sn-Ag
System, Sn-Ag-Cu system, Sn-Ag-Bi system, Sn-
An Ag-Bi-In-based, Sn-Zn-Bi-based solder or the like is used.

When the distance from the surface of the substrate to the top of the solder ball (hereinafter referred to as height) is defined as h, the height H
Can be made uniform by the forming process of the present invention.
The intermediate substrate is the same as the substrate 3 shown in FIGS.

Next, an example of a method of forming a solder ball in the electronic component of this embodiment shown in FIG. 3 will be described with reference to FIG. In this embodiment, the transfer method is used as the flux application, but it is also possible to directly apply and print. However, transfer is preferred from the viewpoint of easily stabilizing the film thickness of the flux.

First, a flux 5 formed of a uniform thick film on a flat transfer tray 9 is transferred to the tip of a transfer pin 6 as a transfer jig (step A). In this embodiment, the flux 5
Before the transfer, the squeegee is kept on the transfer plate 9 with a constant thickness of 1/5 to 2/3 of the diameter of the solder ball beforehand. Also,
It is desirable to use the same shape and size as the tip of the transfer pin 6 as the substrate back surface electrode 2a.

The flux 5 transferred to the transfer pins 6 is pressed against the electrode (back-side electrode) 2a of the intermediate substrate and pulled up to transfer a flux having a constant film thickness on the electrode (step B). Thereafter, the solder ball 1 is mounted on the electrode 2a to which the flux 5 is attached (Step C). Here, when mounting the solder balls, as shown in the drawing, necessary solder balls are collectively sucked by a suction nozzle 12 or the like, and then mounted on the electrodes 2a or individually.

On the other hand, as another method, a part of a solder ball is directly immersed in a flux 5 formed of a uniform thick film on a flat transfer plate 9 and is lifted and transferred (step D) to form an intermediate substrate. This is a method of mounting on the electrode 2a (step E). Here, for the transfer and mounting of the solder balls, necessary solder balls are collectively sucked by the suction nozzle 12 or the like as shown in the figure, and then mounted on the electrode 2a or individually mounted.

In addition to these methods, (1) flux is applied to a part or the whole surface of the solder surface and the electrode,
As long as it has a function of temporarily fixing the solder ball on the electrode by the adhesive force of the flux, and (2) a function of keeping the amount of applied flux constant, any method may be used for the flux application / ball mounting step. .

Next, the electronic component on which the balls are mounted is put into a reflow furnace or a heating furnace, and the temperature is controlled by a temperature profile as shown in FIG. This profile is
Heating, preheating, preheating, reflow,
It consists of five processes of cooling. In the first heating process, moisture in the flux is evaporated, and in the next preheating process, the flux is activated and a temperature range lower than the solder melting temperature is selected and maintained for a certain time. Then, it is heated again to a temperature higher than the melting point of the solder, and cooled. The profile shown in FIG. 5 is an example, and does not necessarily require five processes. For example, the preheating step can be omitted.

As an example, the preheat (about 13
0-160 [° C], 0-120 [S] retention) III) Reflow (220-250 ° C when using Sn-Pb solder (melting point: 183 ° C), 20 ° C or more higher than the melting point for lead-free solder ), Cooling (cooling such as atmospheric room temperature, water cooling, and fan cooling).

As shown in FIG. 6, when an electronic component produced by the solder ball forming process of the present invention is mounted on the board electrode 13a of the circuit board 13, the connection has a small variation in solder ball height as shown in FIG. An electronic component mounting board having high accuracy and high connection strength can be obtained.

[0040]

EXAMPLES Examples of the present embodiment will be described below in detail based on experimental examples.

Example 1 Semiconductor device (length: width: thickness;
11 mm × 11 mm × 0.4 mm) and a CSP, which is an example of an electronic component composed of a ceramic substrate (length: width: thickness; 13 mm × 13 mm × 0.4 mm), have a diameter of 0.3 mm on the substrate back surface electrode of the ceramic substrate. Was mounted with a spherical Sn-37Pb eutectic solder ball. A circular tungsten electrode having a distance between adjacent centers of 0.5 mm and a diameter of 0.3 mm is formed on the back surface of the substrate, and the surface of the electrode is plated with Au. The flux uses Deltalux (made by Senju Kogyo) and the opening is 2
A rectangular metal mask (thickness: 0.20 mm) of 0 mm × 50 mm was fixedly arranged on the transfer plate, and after flux was put on the mask, a metal squeegee tilted perpendicular to the transfer plate was placed in the length of the transfer plate. By reciprocating in the direction, a flux layer having a thickness of 0.20 mm is formed on the transfer dish. Then, a transfer pin (tip shape: a circle having a diameter of 0.3 mm) is pressed against the surface of the transfer dish coated with the flux, then lifted up, moved onto the back electrode of the ceramic substrate for CSP, and transferred to the surface of the transfer pin. Is pressed until it contacts, and the flux is transferred. Thereafter, the required number of solder balls are collectively adsorbed by the suction nozzle, the solder balls are mounted on the back electrode of the ceramic substrate for CSP, the suction nozzle is broken in vacuum, and the solder ball is pressed against the back electrode.

Thereafter, the CSP substrate on which the solder balls were mounted was put into a reflow furnace, and a nitrogen gas was applied under the conditions of a main heating peak of 230 ° C., no preheating, and an oxygen concentration of 100 ppm or less as shown in the temperature profile of FIG. Reflow heating was performed in an atmosphere. The resulting CSP with solder balls was obtained using an optical microscope with a three-dimensional position measurement function.
The position where the apex of the solder ball and the back surface of the substrate were focused was measured, and the difference was defined as the height of the solder ball. 10 in 1 part
As a result of measuring the solder balls at the points, as shown in the example of FIG.
03 mm.

Usually, the apex position 20 of the solder ball is
(Ie, 1/2 of the width t of the spherical solder ball as shown in FIG. 10) and the land center position 21 (ie, 1/2 of the width W of the mounting position of the solder ball on the board electrode of the circuit board shown in FIG. 10). The solder ball is mounted on the board with almost no horizontal deviation Z from
If the displacement Z is within 1/2 of W, the same solder balls could be mounted by self-alignment.

As another demonstration example, S having a diameter of 0.3 [mm]
Example 1 was also obtained when n-37Pb solder was formed on a land having a diameter of 0.3 [mm] by the same method as in Example 1.
The same effect was obtained. In this case, when the reflow peak temperature is in the range of 230 to 250 ° C., the oxygen concentration during reflow is 100
ppm or less, a preheat time of 80 S or less, and a flux film thickness of 200 μm, the variation in height can be suppressed,
A solder ball of 228 ± 3 μm was formed.

(Example 2) In Example 2, the thickness of the flux mask, that is, the thickness of the flux to be transferred was set to 150 [μm], and nitrogen gas was used as an inert gas during reflow heating of the solder balls. As a comparative example, heating was performed in air instead of nitrogen gas.
That is, the effect of reflow heating in an inert gas atmosphere was verified without considering the effect of flux.

[0046]

[Table 1]

Table 1 shows the reflow atmosphere in the atmosphere and nitrogen gas, and the preheat time is 0 to 160 seconds.
[S], 30 [S], 80 [S], 120 [S], 16
The height of the solder ball at 10 points was measured every 0 [S].

The average of the measured values of the heights of the solder balls is indicated by “AVE.”, The maximum height is indicated by “Max”, and the minimum height is indicated by “Min”.

As is clear from Table 1, the reflow heating in the nitrogen gas can reduce the variation in the height of the solder ball without being affected by the pre-heating time, and furthermore, the maximum and minimum heights of the solder ball can be reduced. Width and variations can be reduced. FIG. 11 shows the result, and the above description is clear from this figure.

(Embodiment 3) In Embodiment 3, the thickness of the flux is changed. First, the case where the flux is transferred to the substrate will be considered. The other conditions are the same as in the first embodiment. FIG. 12 shows 0.08 [mm], 0.1 [mm],
The flux having a thickness of 0.15 [mm] and 0.2 [mm] is transferred to the transfer pin, and the flux is transferred to the electrode of the substrate. And 0.3 [mm], 0.4 [mm], 0.5
A spherical solder ball having a diameter of [mm] is mounted on the electrode, and then the solder ball and the substrate are joined by reflow heating, and the quality of the joint at that time is shown. “◎” indicates that the height variation is very small (specifically, height error within ± 5 [μm]) and the bonding strength is good, and ““ ”indicates that the height variation is small (specifically, high (Error within ± 15 [μm]) The bonding strength is good. “×” indicates an unstable state with a large variation in height (specifically, a height error of ± 15 [μm] or more).

As is clear from the above experimental results, the thickness of the flux by transfer is 2/5 of the diameter of the solder ball.
Or more, in other words h _f ≧ 2 / 5d (of flux height h _f, of the solder ball diameter d) is required.

[0052] In the case of transferring the direct flux in the solder balls in the same manner as is, 1/6 or more of the solder ball diameter, that is, h _f ≧ 1 / 6d (of flux height h _f, the diameter d of the solder ball) is required is there. Here, when the flux is directly transferred to the solder ball, the effect can be produced with a small amount as compared with the pin transfer.

From the viewpoint of economy, it is preferable to set the flux height to a half or less of the diameter of the solder ball.

As described above, the amount of the applied flux when the solder ball is immersed in the flux layer and transferred is set in a flux bath having a uniform thickness of １ ／ to 以下 of the solder ball diameter. It is preferable to immerse and transfer the ball. If the diameter is less than 1/6 of the solder ball diameter, it is difficult for the flux to suppress the oxidation of the entire solder ball, and if it is more than 1/2, the flux adheres to the solder ball suction jig, and the suction hole is formed by the flux. There is a possibility that the solder ball may not be able to be sucked due to the blockage or the solder ball may not be opened due to the adhesive force of the flux.

Further, a pin having the same diameter as the solder ball in the amount of flux applied by the transfer pin is immersed in a flux bath having a thickness equal to or more than ５ to ／ of the solder ball diameter. It is more preferable to make contact with the back electrode of the semiconductor element.

As described above, according to the size of the solder ball,
By using an appropriate amount of flux, it is possible to suppress the oxidation of the solder ball and reduce the variation in the height of the solder ball.

Example 4 In Example 4, the case where the diameter of the solder ball, the distance between the back electrodes of the substrate, and the size were changed was verified, and the diameter of the spherical eutectic solder ball was 0.50 m.
m, the distance between the centers of adjacent back electrodes on the ceramic substrate of the CSP is 0.8 mm, and the diameter of the electrodes is 0.5
0 mm, and the thickness of the metal mask for flux transfer is 0.
The thickness was changed to 25 mm, and the same solder ball forming treatment as in Example 1 was performed. Other conditions are the same as in the first embodiment. In addition,
When viewed from above, the solder balls were mounted such that the distance in the substrate surface direction between the ball apex position and the land center position was within 0.2 mm. As a result, as shown in FIG. 9B, the height of the solder balls at ten points is 0.377 ± 0.00.
It was uniformed to 2 μm.

Comparative Example 1 Comparative Example 1 is an example in which the thickness of the metal mask is reduced and the amount of flux transferred is reduced. The thickness of the metal mask for forming the flux is changed to 0.080 mm, and the same solder as in Example 1 is used. After performing flux transfer and ball mounting processing, air reflow heating processing was performed. FIG. 9A shows the result obtained by the same height measuring method as in Example 1. Solder ball height is 0.263 ±
It varied to 0.009 mm.

Next, a similar experiment was conducted by changing the size of the solder ball.

(Comparative Example 2) After changing the thickness of the metal mask for flux transfer to 0.10 mm and performing the same solder flux transfer and ball mounting processes as in Example 4, the temperature profile shown in FIG. 223 degrees, preheating 13
The reflow heating was performed in the air atmosphere under the conditions of 0 to 150 degrees and a heating time of 70 S). FIG. 9B shows the result obtained by the same measurement method as in Example 4. The height of the solder balls at 10 points varied from 0.381 ± 0.007 mm.

(Embodiment 5) Another embodiment will be described.

Sn-Pb having a diameter of 0.1 to 1.0 mm
Shaped eutectic solder balls, and preheat (preheat) 15
0 ± 10 degrees, 0-120S, the main heating maximum temperature is 2
20 to 250 ° C. In addition, the diameter is 0.1 to 1.0 mm
And the maximum heating temperature is 30 ° C. or more higher than the melting point of the solder ball.

[0063]

Conventionally, a method of flattening a mechanically formed ball by pressing has been generally used for equalizing the height of a solder ball. However, according to the present invention, a short process can be performed without increasing the number of processes. Solder balls having a uniform height can be easily formed in a short time, and the rate of occurrence of open defects can be reduced when a chip with solder balls formed by this process is mounted on a substrate. At the same time, the solder diameter and the center position can be made uniform, and short-circuit defects can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state of the present embodiment and a comparative example in a ball solder forming process.

FIG. 2 is a diagram showing a state of the present embodiment and a comparative example in a ball solder forming process.

FIG. 3 is a sectional view of a CSP component as an example of the electronic component according to the embodiment of the present invention;

FIG. 4 is a diagram showing a method of forming a solder ball according to an embodiment of the present invention.

FIG. 5 is a diagram showing an example of a temperature profile of solder ball formation in one embodiment of the present invention.

FIG. 6 is a view showing an electronic component mounting board according to an embodiment of the present invention.

FIG. 7 is a diagram showing an example of a temperature profile for forming a solder ball according to an embodiment of the present invention.

FIG. 8 is a diagram showing an example of a temperature profile for forming a solder ball according to an embodiment of the present invention.

FIG. 9 is a view showing a measurement result of a solder ball height in the embodiment of the present invention.

FIG. 10 is a diagram showing a mounting positional relationship between a solder ball and an electrode (land) of a substrate according to an embodiment of the present invention.

FIG. 11 is a diagram showing a relationship between a solder heating time and a height of a solder ball according to the embodiment;

FIG. 12 is a diagram showing the relationship between the amount of applied flux and the height of a solder ball according to the embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solder ball 2 Electrode (2a, 2b) 3 Substrate (interposer etc.) 4 Semiconductor element (IC) 5 Flux 6 Transfer pin 7 Solder oxide film 9 Flux transfer dish 13 Circuit board

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) // B23K 101: 42 B23K 101: 42 (72) Inventor Hiroyuki Otani 1006 Kazuma Kazuma, Kadoma City, Osaka Matsushita Electric F-term (reference) in Sangyo Co., Ltd. 5E319 AA03 AB05 AC01 CC33 CD21 5F044 KK01 LL04

Claims (10)

[Claims] 1. A method of mounting a plurality of solder balls on electrodes of a substrate constituting an electronic component, melting the solder balls,
A method for assembling an electronic component, wherein, when joining the electrodes of the substrate and the solder balls, the solder balls are melted while suppressing oxidation of the solder balls. 2. A method of mounting a plurality of solder balls on electrodes of a substrate constituting an electronic component, melting the solder balls,
A method for assembling an electronic component, comprising: heating and melting a solder ball in a state where an oxygen concentration is reduced, when bonding an electrode of the substrate and a solder ball. 3. A flux is applied to one or both of an electrode and a solder ball of a substrate constituting an electronic component, and the solder ball is mounted on a substrate electrode of the semiconductor element. A method of assembling an electronic component in which a flux covers a solder ball and suppresses oxidation while melting the solder ball and joining the solder ball to the substrate electrode. 4. A state in which a flux is applied to one or both of an electrode and a solder ball of a substrate constituting an electronic component, and the solder ball is mounted on a substrate electrode of the semiconductor element, and then the oxygen concentration is reduced. A method of assembling an electronic component in which the flux covers the solder ball in the heating atmosphere to suppress the oxidation and melts the solder ball to bond the solder ball to the substrate electrode. 5. An oxygen concentration reduced to 10 when the oxygen concentration is reduced.
5. The method of assembling an electronic component according to claim 2, wherein the solder balls are heated and melted in an atmosphere of 0 PPM or less. 6. The electronic component assembly according to claim 2, wherein the solder balls are heated and melted in an atmosphere of an inert gas such as a nitrogen gas or an argon gas in an oxygen concentration reduced state. Method. 7. The method for assembling an electronic component according to claim 3, wherein the flux application amount is at least 1/6 of the height of the solder ball. 8. A semiconductor element having a bump for electrical connection, an intermediate substrate having electrodes on both sides, and one electrode joined to the other electrode of the intermediate substrate, one of which is connected to the bump; and An electronic component with solder balls, comprising: a plurality of solder balls formed by the method according to claim 1. 9. An electronic component mounting board, wherein the solder balls of the electronic component according to claim 8 are mounted on board electrodes of a circuit board. 10. The electronic component mounting board according to claim 9, wherein a vertex center position of the solder ball substantially coincides with an electrode center position of the board.