JP3215008B2 - Electronic circuit manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electronic circuit capable of soldering electronic parts such as lead parts and surface mount parts to a circuit board without using flux.

[0002]

2. Description of the Related Art In solder connection using a flux of an electronic component, in order to secure the reliability of a connection portion, a residue of the connection portion is generally used by using a cleaning agent mainly containing a chlorine-based or fluorine-based organic solvent. Have been removed by washing.
However, these cleaning agents have a problem of environmental pollution, and also have a problem that it is difficult to clean the residue at a fine connection portion such as a flip chip connection.

[0003] In order to solve these problems, flux-less solder supply, which can ensure reliability without cleaning,
Bonding methods and solder pastes have been developed.

First, as a technique related to a method of supplying and joining solder without flux, for example, Japanese Unexamined Patent Publication No.
No. 235061. This means that the oxide layer or organic contaminant layer on the surface layer of the solder and the part to be joined
This is a method of cleaning by irradiating an atom or ion beam, performing positioning in the air, heating and melting in a non-oxidizing atmosphere, and performing fluxless soldering.

In this fluxless joining method,
There is a problem that there is no means for preventing displacement during the process from mounting the electronic component on the circuit board to solder reflow.
In addition, since there is no flux action, the solder surface is thin but covered with oxide, which limits the exposure of a new surface of the solder and hinders the self-alignment action due to surface tension. The self-alignment is a phenomenon in which when electronic components are mounted on a circuit board, even if there is some deviation, the electronic components are self-aligned to a predetermined position by the surface tension of the solder. This makes it possible to realize a simple process that does not require a highly accurate alignment and mounting process in the fine connection portion.

On the other hand, as a technique related to a fluxless solder paste, for example, Japanese Unexamined Patent Publication No. Hei.
And JP-A-2-290693.

Japanese Patent Application Laid-Open No. Hei 2-25921 discloses a solder paste having a solder powder and a binder containing alcohol with respect to a solder paste used in a reducing atmosphere. In this solder paste, an activator,
Since no solids such as resin are used, residues can be eliminated. The boiling point of the alcohol used here exists in a boundary region between the solidus line and the liquidus line in the phase diagram of the solder powder (this is called a paste region). For this reason, when the solder is in a semi-molten state, the alcohol boils and evaporates, so that the problem of the scattering of the solder balls in the solder paste containing alcohol having a boiling point below the solidus line is solved. However, when the solder is melted and the connection is made, the surface of the solder is exposed without the liquid, so a reducing atmosphere such as hydrogen gas is required for oxidation prevention.

Japanese Patent Application Laid-Open No. Hei 2-290693 discloses an example in which connection is possible in an inert atmosphere.
This is a solder paste composed of alcohol having a boiling point higher than the melting point of the solder and solder fine particles. Solder connection is performed in a state where the connection portion surface is covered with alcohol. Therefore, at the time of connection, since the connection is cut off from the atmosphere, connection can be made even in an inert atmosphere, and there is an advantage that a special atmosphere such as a reducing atmosphere is not required unlike the above-described conventional technique.

However, the solder fine particles are produced during the manufacturing process.
Even if it is performed in a vacuum or in an inert atmosphere to suppress oxidation because it is made by melting by the atomizing method etc., the surface oxide film has a large variation of about several tens to several hundreds of nm, and this type of activator is used. In a solder connection using no solder paste, the oxide film is not broken only by the reducing power of the alcohol component, and it is difficult to obtain a stable and good connection. Furthermore, with the finer and narrower pitch of the solder connection,
In order to ensure printing accuracy, it is necessary to reduce the size of the solder fine particles in the solder paste, and the surface area of the solder is dramatically increased.

[0010]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional method of manufacturing an electronic circuit to be soldered without using a flux. An object of the present invention is to provide a method of manufacturing an electronic circuit that enables highly reliable solder bonding without using flux in a state where members to be connected such as a circuit board are temporarily fixed.

Another object of the present invention is to provide a method of manufacturing an electronic circuit which can eliminate a cleaning step by reducing or eliminating residues after connection and obtain highly reliable connection.

[0012]

In order to achieve the above object, at least one of the connection terminal of the electronic component and the electrode on the printed circuit board is preliminarily coated with solder, for example, by plating or welding a solder ball. Then, at least the surface of the solder is cleaned to remove an oxide film and / or an organic contaminant film formed on the surface (these are referred to as foreign substances). An organic material is supplied so as to cover it, and the electronic component is temporarily fixed at a predetermined position on the printed circuit board, and then the solder is heated and melted, and the connection surface is covered with the organic material to block the outside air. , To complete the connection.

In a further preferred method of manufacturing an electronic circuit according to the present invention, when the organic material is supplied so as to cover the connection portion before the solder heating step, when the electronic component is positioned on the substrate, the organic material is adjacent to each other. Independent for each connection,
To supply the organic material so as not to be continuous. Usually, the supply of the organic material is performed by a coating method. To realize such a coating state, the height h of the solder previously supplied to at least one of the connection terminal of the electronic component and the electrode on the printed circuit board is used. The organic material is supplied so as to have a thickness of 2/3 or less. Thereby, the coating film of the organic material can be formed independently and discontinuously for each connection terminal.

Here, the meaning that the organic material is applied independently so as not to be continuous at each adjacent connection portion means not only the state where the organic material is completely applied independently at each connection portion but also the substrate. Even if a thin film is formed at the root of the connection terminal of the electrode or the electronic component and is partially continuous, the main part of each adjacent connection part does not have a continuous layer structure and is separated and independent from each other The case where it is applied in a state is also included.

The cleaning treatment of the solder surface and / or the surface of the part to be connected as a pretreatment step for supplying the organic material is performed, for example, by an etching method using physical means of irradiating an ion beam or the like, or a chemical method such as an acid. A surface cleaning treatment method using mechanical means such as polishing or grinding is used.

The above object can also be achieved by the following manufacturing method. First, a solder paste is supplied to at least one of the connection terminal of the electronic component and the electrode on the printed circuit board. As a solder paste, an oxide film and / or an organic contaminant film (referred to as foreign substances) formed on the surface of the solder powder is subjected to a surface cleaning treatment by physical or chemical etching as a pre-treatment step of the solder powder in advance. Removed and used by mixing and preparing the solder powder and the organic material.

Next, the electronic component is mounted at a predetermined position on the printed circuit board, and is positioned while being temporarily fixed using the adhesiveness of the solder paste. Thereafter, the connection is heated to a temperature equal to or higher than the solder melting point, whereby the solder is melted in a state where the surface of the connection is covered with the organic material in the solder paste, and the connection is completed.

Here, practical solder materials and organic materials used in the electronic circuit manufacturing method of the present invention will be described. First, the solder material is not particularly limited, and various well-known materials can be used. Examples of practically used solders include, for example, Sn and Pb, Sn and Ag, Sn and In, Sn and Bi, Au and Sn, Au and G
e and a solder alloy composed of a mixture thereof.

As the organic material, a material containing no flux and having a boiling point equal to or higher than the melting point of the solder is used, and is evaporated without leaving any residue after the heating step. Specifically, for example, hydrocarbons, ketones, esters, aldehydes, alcohols, and the like may be used as long as the boiling point is equal to or higher than the melting point (liquidus temperature) of the solder material used.

In particular, an organic material having at least one or more hydroxyl groups capable of reducing and removing the surface oxides of the solder and the member to be connected is desirable, and typical examples thereof include alcohols. Table 1 shows typical examples of alcohols. The effectiveness of these alcohols has been confirmed in Examples described later.

[0021]

[Table 1]

As described above, in practicing the present invention, the combination of a solder material and an organic material is appropriately selected, and the melting point of the solder material (liquidus line) is selected from organic materials having various boiling points. An organic material having a temperature equal to or higher than the temperature may be used.

The atmosphere in which the solder is heated and melted and connected to the solder may be air, but preferably, for example, H
e, Ar, inert gas atmosphere such as N ₂ is preferable.

[0024]

[Function] By supplying an organic material to a connection portion or supplying and positioning a solder by a solder paste prepared by mixing a solder powder and an organic material, the process from the mounting of the electronic component to the completion of the connection is completed. The component can be prevented from being displaced by the temporary fixing action utilizing the adhesiveness of the organic material against the vibration.

By covering the connection portion with the organic material until the connection is completed in the heating step, oxidation of the solder and / or the connected portion can be prevented, and a good joining without flux can be obtained.

Further, when an organic material having at least one or more hydroxyl groups is used, it is possible to prevent oxidation of the solder and the surface of the connected portion, and at the same time, it is possible to remove the oxide by a reducing action, thereby improving Connection can be obtained.

In addition, before supplying the organic material so as to cover the connection portion, and in the case of the solder paste, before mixing the solder powder and the organic material, the solder (including the solder powder) is used.
Surface cleaning process that removes foreign substances (oxide film and organic contaminant film) on the surface of the connection and the connected part, the surface condition can be made uniform regardless of the solder supply or solder powder manufacturing process, and more stable Fluxless solder connection can be realized.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. Here, as an example, mounting of an electronic component on a ceramic wiring circuit board (hereinafter, abbreviated as a ceramic substrate) using Sn ₃ Ag solder will be described.

The melting point of the Sn ₃ Ag solder is 222 ° C., and as the organic material to be used, it is necessary to use one having a boiling point equal to or higher than the melting point of the solder from among the examples shown in Table 1, and more preferably a heating atmosphere. It is necessary to select a material having an appropriate boiling point in consideration of the difference in the evaporation rate of the organic material. Specifically, since the evaporation rate in He is higher than that in Ar and N ₂ , an organic material having a boiling point 20 to 30 ° C. higher than that of Ar and N ₂ is required to maintain the same state of the organic material at the same temperature. As a result of examination, it was clarified that it was necessary to use it.

The example shown here is an example of C4 (Controlled Collapse Chip Connection) using fine solder bumps, and the solder spreads over the metallization on the substrate,
Further, it is a condition of good connection that sphere banding and self-alignment occur due to the surface tension of the molten solder. It is preferable that these series of connection processes be performed in as short a time as possible. This is because it is effective for improving the productivity by shortening the tact time and improving the number of repairs by reducing the diffusion amount between solder and metallization.

Embodiment 1 FIG. 1 is a manufacturing process diagram showing an embodiment of the present invention in which an electronic component (LSI chip) 5 is mounted on a ceramic substrate 1 and connected by solder reflow.

FIGS. 1A and 1B are cross-sectional views showing a pretreatment step for cleaning the surface of each connection portion. That is, as shown in FIG. 1A, after a solder material 3 is previously formed on a connection terminal of an electronic component 5 by a known method such as solder plating or solder ball welding, the surface of the solder 3 is coated with argon. Irradiation of the atom beam 6 physically removes foreign substances such as an oxide film and an organic contaminant film present on the surface, and cleans the surface. FIG. 1B shows a similar method.
As shown in (1), foreign substances such as an oxide film and an organic contaminant film on the surface of the connection pattern 2 on the ceramic substrate 1 are also removed.

The surface cleaning method is not limited to such physical means, but may be other chemical means such as etching with an acid, or mechanical means such as polishing or grinding. As a result, the surface of the solder material 3 and the connection pattern 2 once cleaned is oxidized by storage in the air thereafter, but the thickness can be reduced and uniformity can be achieved. As a result, good connection can be stably performed.

FIG. 1C shows an example of a temperature profile in the solder reflow step. Normally, the reflow peak temperature is set to be about 20 to 30 ° C. higher than the melting point (liquidus temperature) of the solder in order to reliably melt the solder. The melting point of Sn ₃ Ag solder is 222 ° C., and in this case, the peak temperature is set to 250 ° C. The time during which the solder is melted, that is, the time during which the solder is maintained at or above the melting point, is generally about 1 to 2 minutes. This profile is not limited to the conditions shown here, but may be adjusted so as to be uniformly heated by the heat capacity of the connected sample.

FIGS. 1 (d) to 1 (g) show a connection process diagram by solder reflow after the cleaning process of each connection portion is completed.

Hereinafter, a specific description will be given in accordance with the manufacturing process sequence shown in the drawings. First, as shown in FIG. 1D, a liquid organic material 4 is supplied onto a ceramic substrate 1. As the organic material, those having a boiling point in Table 1 that is equal to or higher than the melting point of the solder (222 ° C.) are used. For reflow in an Ar or N ₂ atmosphere, 2-phenoxyethanol (boiling point: 245 ° C.) is suitable, and for reflow in a He atmosphere, triethylene glycol (boiling point: 285 ° C.) is suitable. In the present embodiment, these were used.

Next, as shown in FIG. 1E, an electronic component 5 to which the solder material 3 has been supplied in advance is mounted on the connection pattern 2 of the ceramic substrate 1 to which the organic material 4 has been supplied.
Position each connection. In this positioning, the center of the solder 3 and the center of the connection pattern 2 are usually made to coincide with each other. However, in this figure, in order to confirm the self-alignment effect, the centers of the respective connection parts are intentionally shifted slightly. It shows the state where it was turned on. Thereby, the electronic component 5 is temporarily fixed on the ceramic substrate 1 due to the viscosity and the surface tension of the organic material 4, and it is possible to prevent the displacement from occurring due to the vibration at the time of conveyance up to the reflow connection.

Thereafter, heating is performed according to a reflow profile as shown in FIG. Until the solder 3 is melted and the connection is completed, as shown in FIG.
Covers the connection portion. Thereby, the solder 3
In addition, in the present embodiment, since alcohols are used, oxides on the solder surface are removed by a reducing action, so that the solder material 3 wets the connection pattern 2 and self-alignment is performed in a short time. And a good connection can be obtained.

After the connection is completed, the organic material 4 is completely evaporated during the cooling step, as shown in FIG. This makes it possible to obtain a clean joint having no residue and eliminate the necessity of cleaning in a later step. Through the above steps, the LSI chip was mounted on the ceramic substrate,
The desired highly reliable electronic circuit could be easily manufactured.

Next, the embodiments shown in FIG. 2 and FIG. 3 explain in more detail the behavior of the solder connection portion when the electronic component is connected by solder reflow. The reason why a highly reliable solder connection can be easily achieved by self-alignment in a state where the connection portion is shielded from the outside air without being displaced by temporarily fixing with an organic material will be described.

<Embodiment 2> That is, FIG. 2 illustrates an example in which an electronic circuit is manufactured using other organic materials not having a hydroxyl group in a molecule as an organic material and not shown in Table 1. It is. Examples of the organic material used here include tridecane CH ₃ (CH ₂ ) ₁₁ CH ₃ (boiling point: 234 ° C.), when reflowing in an Ar or N ₂ atmosphere.
-Methylnaphthalene C ₁₁ H ₁₀ : [31] (CH ₃ ) (boiling point 23
For example, hexadecane CH ₃ (CH ₂ ) ₁₄ CH ₃ (boiling point: 287 ° C.) is used for reflow in a He atmosphere such as 4 ° C.). The atmosphere during the solder reflow process is not necessarily required to be an inert gas atmosphere because the connection portion is covered with the organic material, and can be carried out even in the air. Here, an inert gas atmosphere was selected here because the amount of the product due to (i.e., the amount of residue after reflow increases).

In the following, the order of the steps will be described with reference to the drawings. First, as shown in FIG. 2 (a), the surface of the solder material 3 previously formed on the electronic component 5 has foreign matter 7 such as an oxide film or an organic contaminant film. Exists. Since the thickness of the solder material 3 is generally melted once in the manufacturing process, the thickness is as thick as several tens to hundreds of nm, and the thickness varies greatly depending on the location.

Therefore, as shown in FIG. 2B, a processing method similar to that of the first embodiment is used (corresponding to FIGS. 1A and 1B).
By cleaning the surface of the connection part, the
The oxide film and the organic contaminant film 7 attached to the surface of the solder material 3 formed on the terminal and the connection pattern 2 on the ceramic substrate 1 are made thin and uniform.

Thereafter, as shown in FIG. 2C, the electronic component 5 is positioned and mounted on the ceramic substrate 1 to which the organic material 8 having no hydroxyl group has been supplied, and the connection portion is covered with the organic material 8. At the same time, during the process from the mounting of the electronic component 5 to the reflow heating, it is made to withstand vibration (corresponding to FIGS. 1D to 1E). In this positioning, it is usual that the centers of the solder 3 and the connection pattern 2 coincide with each other. In this figure, as in the case of the first embodiment, the self-alignment effect is to be confirmed. This shows a state where the center of the connection portion is slightly shifted and positioned.

Thereafter, in a heating step, as shown in FIG. 2D, the solder 3 melts and spreads over the connection pattern 2 on the ceramic substrate 1, and further, as shown in FIG. The connection is covered with the organic material 8 having no hydroxyl group until the connection is completed as shown in FIG. 2 (f), and the connection is cut off from the heating atmosphere. This can prevent oxidation of the connection portions (solder 3 and connection pattern 2) and promote solder wetting [FIG.
(Equivalent to (f))].

After the connection is completed, as shown in FIG. 2 (g), the organic material 8 evaporates during the heating step so that no residue remains, so that cleaning after bonding can be eliminated [FIG. 1 (g)]. Equivalent to].

<Embodiment 3> FIG. 3 is a manufacturing process diagram illustrating an example in which an electronic circuit is manufactured using the organic material having a hydroxyl group shown in Embodiment 1. Note that this example is basically the same as FIG. 2 except that the organic material is different. 2 and FIG. 3 are solder reflow process diagrams [FIG.
(Step (e) = Steps (d) to (e) in FIG. 3), it is clear that, in this embodiment, the oxide film 7 which has remained slightly thin even after the surface cleaning treatment is replaced with It is characteristic that the organic material 4 having a hydroxyl group is completely removed by a reducing action. Hereinafter, description will be made in accordance with the process sequence shown in the drawings.

FIGS. 3 (a) and 3 (b) correspond to FIGS.
FIG. 3B shows a step of thinning and uniforming the oxide film and / or the organic contaminant film 7 on the surface of the solder 3 and the connection pattern 2 which are to be connected similarly to FIG.

Here, as shown in FIG. 3C, the connecting portion is covered with an organic material 4 having a hydroxyl group. As a result, in the heating step, which is the solder reflow step, FIG.
As shown in (d) and (e), the connection portion is not only prevented from being oxidized but also because the oxide is reduced and removed, so that the wettability is good and the self-alignment property is remarkably different from the case of the second embodiment. improves.

Then, as shown in FIG. 3 (f), the cleaning step can be omitted because it is completely evaporated and no residue is left.

<Embodiment 4> FIG. 4 is a process chart showing a method of supplying an organic material independently and non-continuously for each connection terminal in the method of manufacturing an electronic circuit of the present invention. FIG.
As shown in FIGS. 1A and 1B, as in the first embodiment shown in FIG. 1, first, a cleaning treatment for removing the solder 3 and the oxide film or organic contaminant film 7 on the surface of the connection pattern is performed.

Next, in this embodiment, the amount of the organic material supplied to the connection portion is smaller than that in the embodiment 1 shown in FIG. It is desirable to use an organic material having a higher boiling point. When reflowing in an Ar or N ₂ atmosphere,
When triethylene glycol (boiling point 285 ° C.) or tetraethylene glycol (boiling point 314 ° C.) reflows in a He atmosphere, tetraethylene glycol (boiling point 314 ° C.) or pentaethylene glycol (boiling point 370 ° C.) is preferable. .

As shown in FIG. 4C, the liquid organic material 4 is supplied on the ceramic substrate 1 thinner than in the first embodiment. At this time, the thickness of the organic material 4 is set to ２ or less of the height of the solder material 3 supplied to the electronic component 5 in advance.

Thus, as shown in FIG. 4D, when the electronic component 5 is mounted on the connection pattern 2 of the ceramic substrate 1, the organic material 4 becomes wet by the action of the wetting and the surface tension. Can be independent and not continuous. When positioning the electronic component, the center of the solder 3 and the center of the connection pattern 2 are usually made to coincide with each other. In this figure, the self-alignment effect is confirmed as in the case of the first embodiment. In this case, the center of each connecting part is slightly deviated and positioned.

Thereafter, similarly to the first embodiment, heating is performed according to a reflow profile as shown in FIG. Until the solder is melted and the connection is completed, the connection portion is covered with the organic material 4 as shown in FIG. Thereby, the oxidation of the solder is prevented, and furthermore, in this embodiment, since the alcohol having a hydroxyl group is used, the oxide on the solder surface is removed by reduction, thereby removing the solder.
Good wettability of the solder material 3 with respect to the connection pattern 2, self-alignment occurs in a short time, and good connection can be obtained.

At this stage, the connection is completed. Thereafter, as shown in FIG. 4F, during the cooling step, the organic material 4 is completely evaporated. This makes it possible to obtain a clean joint having no residue and eliminate the necessity of cleaning in a later step.

Although not shown here, after the connection is completed, the organic material can be positively evaporated and removed by lowering the atmospheric pressure (evacuating or the like), and the time required for the manufacturing process can be shortened.

Further, by selecting an organic material which is solid at room temperature, the fixing force of the mounted component is stronger, and during the period from the step of positioning the component on the substrate to the reflow step,
A more reliable process for vibration is obtained.

As an example of a preferable organic material of this type, among the organic materials shown in Table 1, 3-phenoxy-1,2
-Propanediol (melting point 55 ° C). 1D and 4C, the substrate and the organic material are heated to a temperature equal to or higher than the melting point of the organic material so that the organic material that is liquid at normal temperature is solid at room temperature. It can be supplied in the same manner as when supplying the material.

In the subsequent positioning step by mounting components, the electronic components are positioned while the substrate is continuously heated. Thereafter, when cooled to room temperature, the organic material solidifies and the electronic component is fixed on the substrate. In the reflow step, since the boiling point is equivalent to that of tetraethylene glycol, a good connection can be obtained as in the above-described embodiment.

Embodiment 5 This embodiment describes a method of manufacturing an electronic circuit by supplying a solder paste made of a solder powder and an organic material and containing no flux to a connection portion.

Hereinafter, description will be made with reference to the process chart of FIG. Connecting terminals 1 for electronic components on printed circuit board 11
In the case of surface mounting by soldering, the eutectic solder of Sn ₃₇ Pb (melting point: 183 ° C.)
Commonly used.

(1) Preparation of Solder Paste In this embodiment, first, the surface of the solder powder 9 is cleaned in the same manner as in Embodiment 1 so that the oxide film and organic contaminant film on the surface are thin and uniform. Process. The surface-cleaned solder powder 9 is mixed with ethylene glycol (boiling point 197 ° C.) or trimethylene glycol (boiling point 214 ° C.) selected from the organic materials 4 shown in Table 1 instead of the flux, A solder paste 12 can be made. The solder paste 12 thus created is
Since the organic material 4 has the characteristics as described in the previous embodiment, a good connection can be obtained, and there is no residue and the washing step can be omitted.

(2) Solder Connection Step A method of manufacturing an electronic circuit using the solder paste 12 will be described in accordance with the process sequence shown in FIG. In this example, an example is shown in which a surface-mounted component with a lead 10 is mounted as an electronic component.

First, as shown in FIG. 5A, the solder paste 1 is applied to the connection pattern 2 on the printed circuit board 11.
2 is supplied by screen or metal mask printing to supply the necessary amount of solder powder 9 for connection. Although the description is omitted here, it is desirable that the connection pattern 2 of the printed circuit board 11 be subjected to a surface cleaning treatment in advance in the same manner as in the first embodiment.

Next, as shown in FIG. 5B, the connection terminals 10 of the electronic components are positioned on the substrate 11 and mounted. At this time, the electronic component is fixed on the substrate 11 due to the wetting of the organic material 4 with the lead 10 and the surface tension and the viscosity of the solder paste 12, so that the displacement due to vibration during the process can be prevented.

Next, as shown in FIG. 5C, in the reflow step of heating and melting the solder, the solder paste 12
The organic material 4 therein remains so as to cover the joint until the joining is completed, and while maintaining the positioned state, the lead 10 of the solder 9 and the connection pattern are removed by the action of oxidation prevention and / or oxide removal. 2 to ensure wetting.

Thereafter, during the heating, as shown in FIG. 5D, the organic material 4 is removed by evaporation so that no residue remains.

Here, Sn ₃ Ag, S
Although n ₃₇ Pb has been described as an example, other organic materials having no melting point have no toxicity, good solderability, and good reflow atmosphere.
An organic material having a suitable boiling point may be selected from the relationship with the temperature profile. In addition, it goes without saying that the present invention can be applied to other various substrates and various components that cannot be described here.

[0070]

As described in detail above, the intended object has been achieved by the present invention. In other words, in the solder connection method that does not use flux, the temporary fixing of components on the board, ensuring the wetting of the solder at the connection part, shortening the self-alignment, and eliminating residue-free cleaning after solder connection Thus, a method of manufacturing an electronic circuit having a highly reliable solder connection process that enables the semiconductor device to be realized.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram illustrating one embodiment of a method for manufacturing an electronic circuit according to the present invention.

FIG. 2 is a manufacturing process diagram of a method for manufacturing an electronic circuit using an organic material having no hydroxyl group according to another embodiment.

FIG. 3 is a manufacturing process diagram of a method for manufacturing an electronic circuit using an organic material having a hydroxyl group according to another embodiment.

FIG. 4 is a manufacturing process diagram including a step of supplying an organic material independently for each connection terminal so as not to be continuous, according to another embodiment.

FIG. 5 is a manufacturing process diagram using a solder paste according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ceramic substrate, 2 ... Connection pattern, 3 ... Solder material, 4 ... Organic material which has a hydroxyl group, 5 ... Electronic component, 6 ... Argon atom beam, 7 ... Oxide film and / or organic contaminant film, 8 ... Hydroxyl group Organic materials not used, 9: solder powder, 10: lead of electronic parts, 11: substrate, 12: solder paste.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuko Takehara 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi, Ltd. Production Technology Research Laboratory (72) Ryohei Sato 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi Manufacturing Co., Ltd. (72) Inventor Mitsunori Tamura 1st Horiyamashita, Hadano-shi, Kanagawa Prefecture Hitachi, Ltd.General-purpose Computer Division (72) Inventor Yasuhiro Iwata 1st Horiyamashita, Hadano-shi, Kanagawa Hitachi, Ltd. (56) References JP-A-4-269896 (JP, A) JP-A-2-290693 (JP, A) JP-A-5-82954 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) H05K 3/34 507 H01L 21/60 311

Claims (12)

(57) [Claims] A step of supplying solder in advance to at least one of the connection pattern of the circuit board and the connection terminal of the electronic component; and mounting the electronic component on the circuit board without using flux. And a step of solder-connecting these two connection parts, wherein as a pre-treatment step of the step of solder connection, the surface of the part to be connected including solder is preliminarily cleaned to remove foreign matter. Adding a surface cleaning treatment step to remove, and a step of temporarily fixing the electronic component in a state where the electronic component is positioned by supplying an organic material having a boiling point higher than the melting point of the solder onto the circuit board, and Heating and melting the solder in a state where at least the connection portion surfaces of the positioned circuit board and the electronic component are covered with the organic material, and connecting the solder to the solder. The method of production. 2. A step of supplying solder in advance to at least one of the connection pattern of the circuit board and the connection terminal of the electronic component, and mounting the electronic component on the circuit board without using flux. And a step of solder-connecting these two connection parts, wherein as a pre-treatment step of the step of solder connection, the surface of the part to be connected including solder is preliminarily cleaned to remove foreign matter. Adding a surface cleaning treatment step to remove, and a step of temporarily fixing the electronic component in a state where the electronic component is positioned by supplying an organic material having a boiling point higher than the melting point of the solder onto the circuit board, and In a state in which the organic materials coated on the respective connection portions of the circuit board and the electronic component which are positioned are coated independently of each other with a predetermined space without being continuous, The method of manufacturing an electronic circuit comprising constituted by heat-melting to the step of solder connection. 3. The organic material is a solid organic material at room temperature.
2. The method for manufacturing an electronic circuit according to claim 1, wherein the method is configured. 4. The organic material is an organic material which is liquid at normal temperature.
The electronic circuit according to claim 1 or 2, wherein
Construction method. 5. The method according to claim 1 , wherein the organic material has a hydroxyl group in a molecule.
3. The electrode according to claim 1, which is made of an organic material.
A method for manufacturing a slave circuit. 6. The step of soldering the connection part,
After the solder connection is completed, the solder
Temperature below the melting point of the solder and above the melting point of the organic material
Area, so that no residue of organic material remains at the connection
3. The method according to claim 1, further comprising the step of:
3. The method for manufacturing an electronic circuit according to 1. 7. A solder connection by heating and melting the solder.
2. The process according to claim 1, wherein the process atmosphere is an inert gas atmosphere.
Or the method for manufacturing an electronic circuit according to 2. 8. An inert gas atmosphere comprising a He gas atmosphere.
The method for manufacturing an electronic circuit according to claim 7, wherein 9. The method according to claim 1, wherein the inert gas atmosphere is an N2 gas atmosphere.
The method for manufacturing an electronic circuit according to claim 7, wherein 10. An inert gas atmosphere comprising an Ar gas atmosphere.
8. The method for manufacturing an electronic circuit according to claim 7, wherein said method is performed. 11. A solder connection by heating and melting said solder.
Wherein the atmosphere of the step (c) is a reducing gas atmosphere.
3. The method for manufacturing an electronic circuit according to 1 or 2. 12. The method according to claim 12, wherein the reducing gas atmosphere is a gas containing H2.
12. The method for manufacturing an electronic circuit according to claim 11, wherein the electronic circuit is formed as an atmosphere.
Law.