KR101208003B1 - A method for forming solder bump - Google Patents

Abstract

The present invention relates to a template manufacturing method used to form solder bumps in a semiconductor manufacturing process. And forming a solder bump by heating the base layer after filling the receiving groove with the solder, and forming a coating layer on the base layer on which the coating layer is formed.

According to the present invention, even though the solder bumps are repeatedly formed using one template, the size and position of the solder bumps are continuously maintained, thereby improving the accuracy of the product.

Description

Solder Bump Formation Method {A METHOD FOR FORMING SOLDER BUMP}

The present invention relates to a template manufacturing method used for forming solder bumps in a semiconductor manufacturing process.

It is necessary to make an electrical connection between the pair of substrates for data or signal transmission. In particular, in order to connect a semiconductor in which unit elements are integrated at a high density to a substrate, a technology capable of precisely connecting at precise positions with respect to the size and pitch of a minute terminal is required.

As such, the most common connection technology for interconnecting fine terminals between a pair of substrates is connection by a connector. Flexible printed circuit (FPC) is widely used as a connector, and has the advantage of being easy to connect and detachable repeatedly than other technologies. However, since the three-dimensional space occupied by the connector is an obstacle to miniaturization of electronic products, and the pitch between terminals of FPC, which is widely used at present, is about 0.3 mm, it is difficult to connect a terminal having a finer pitch than this.

There is also a method using an anisotropic conductive film (ACF) as a connection method other than the connector. When the ACF is attached to the terminal portion of one substrate and the terminal of the other substrate is overlapped and pressed, a conductive film is interposed between two opposing electrodes, thereby making an electrical connection. By hardening after pressurizing, ACF can also ensure connection strength, and even if pitch between terminals is about 0.1 mm, it can connect. However, since the conductive particles are connected to the terminal, the resistance value of the connecting portion is high, and after curing the film, it is difficult to separate the two substrates, which is substantially impossible to repair.

On the other hand, the board-to-board connection by solder bump is a method of forming a solder bump in the terminal of one board | substrate, and superimposing the terminal part of another board | substrate here, and connecting it by a reflow process. Solder bump refers to hemispherical protrusions mainly composed of tin and lead, which have better connection resistance than ACF, and are particularly advantageous for the connection of surface mount technology (SMT) components. This is an expanding trend.

At this time, several methods for forming solder bumps are known. The method using a template includes arranging a solder for forming solder bumps on the template, and then attaching and heating the template to the substrate so that the solder on the template is transferred to the electrode side of the substrate. To this end, a plurality of accommodating grooves must be formed in the template corresponding to the electrodes of the substrate in advance, so that solders are accommodated in the accommodating grooves, respectively. At this time, the plurality of receiving grooves formed in the template should be formed in the correct position corresponding to the electrode of the substrate, and can be formed with a pitch of several hundred μm or less, so precise processing is necessary.

On the other hand, the template is worn out by contact with the substrate or the like with repeated use. The shape accuracy of the template determines the precision of the solder bumps, which in turn determines the final quality of the substrate on which the solder bumps are formed. Therefore, if the template is excessively worn out, it must be replaced with a new template to obtain a substrate of the desired quality. However, the manufacture of the template is expensive because it requires precision processing processes such as etching or laser patterning. Therefore, there is a need for a technology that can enhance the strength of the template to improve the durability.

The present invention is to provide a method for manufacturing a template that can accurately form the size and location of the solder bumps even if the number of times of use is repeated to solve the above problems.

In order to achieve the above object, the present invention provides a base layer having a plurality of receiving grooves formed on one surface of the plate, forming a coating layer on one surface formed with a plurality of receiving grooves of the base layer, and solder to the receiving grooves. After filling the base layer is heated to form a solder bump, it may provide a template manufacturing method comprising the step of forming a coating layer again on the base layer on which the coating layer is formed.

Here, the coating layer formed on one surface of the receiving groove is made of a durable material, it is further preferably made of a material having a high wear resistance or heat resistance.

Specifically, the coating layer may be composed of one of silicon carbide (SiC), silicon nitride (SiN), or titanium oxide film (TiON).

Meanwhile, it is preferable to remove the coating layer formed on the base layer before forming the coating layer again. In this case, the coating layer formed on the base layer may be removed using a wet etching.

On the other hand, after the process of forming the solder bumps a plurality of times it is preferable to form a coating layer on the base again.

Furthermore, the process of forming the solder bumps may be performed a plurality of times, and after removing the coating layer formed on the base layer, the process of forming the coating layer again may be repeatedly performed.

According to the present invention, even though the solder bumps are repeatedly formed using one template, the size and position of the solder bumps are continuously maintained, thereby improving the accuracy of the product.

In addition, it is possible to drastically increase the number of times of use of one template to reduce manufacturing costs.

Hereinafter, a method for manufacturing a solder bump forming template according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of a template for solder bumps according to a preferred embodiment of the present invention, Figure 2 is a cross-sectional view showing a cross section of FIG.

The base layer 100 is a plate-shaped structure, one surface of the plurality of receiving grooves 101 may be formed. Receiving groove 101 is for accommodating the solder (S) to form a solder bump (not shown), each receiving groove 101 is corresponding to the electrode located on a substrate such as a wafer or a semiconductor to be formed solder bump It may be formed at the point.

The base layer 100 may be made of a glass material or may be made of a wafer. In addition to this, it can be configured using various methods such as loading a film of a predetermined material, or forming a powder material.

Meanwhile, in the solder bump forming template according to the present invention, the coating layer 200 may be formed on one surface of the receiving groove 101. In general, one solder bump forming template may be used in a solder bump forming process a plurality of times. In this case, the template repeatedly performs a process of contacting the substrate on which the solder bump is formed in the state in which the solder S is filled in the receiving groove 101. For this reason, one surface of the template in which the receiving groove 101 is formed is easily worn due to repeated contact with other members. Therefore, in this embodiment, it is preferable to coat one surface of the template in which the receiving groove 101 is formed by using such a material having excellent wear resistance, heat resistance, durability, and the like.

However, the above-described coating layer 200 may also be scratched or worn by repeated contact with other members in a high temperature environment. In this case, the solder S may be filled in a portion where the scratch is formed to form unnecessary solder bumps on the substrate. Alternatively, the size of the accommodating groove 101 may increase gradually due to wear, which may increase the size of the solder bumps formed by the template or may cause an incorrect installation position.

Therefore, in the present invention, it is preferable to form the coating layer 200 again on the base layer 100 in which the coating layer is formed so as to prevent wear that may occur in the coating layer 200. That is, after the process of forming the solder bumps for a plurality of times, the process of coating the template again is continuously repeated.

In this way, it is possible to continuously and smoothly maintain the surface state of one surface of the template in contact with the substrate, so that it is possible to accurately maintain the size and position of the solder bumps formed by the template.

Hereinafter, a method of manufacturing the solder bump forming template of FIG. 1 will be described in detail.

3 is a flowchart illustrating a method of manufacturing a solder bump forming template according to a preferred embodiment of the present invention, and FIG. 4 is a schematic diagram illustrating each step of the manufacturing method according to FIG. 3.

First, the base layer 100 may be manufactured by forming a plurality of receiving grooves on one surface of the flat plate (see S10 of FIG. 3 and FIG. 4A). In this case, the base layer 100 may be manufactured by various methods. It is possible to.

In general, the base layer 100 may be manufactured using a flat plate made of glass or a wafer material. In addition, the base layer 100 may use a flat plate formed using a film material or a powder material.

At this time, the process of forming the base layer 100 is composed of a process of etching the receiving groove 101 which may include a solder on the plate. In this case, the etching of the plate may be performed by a wet etching method or a dry etching method. In addition, the receiving part may be configured by using laser irradiation or other molding methods.

However, in the case of forming the accommodating groove 101 through an etching process, a protective film may be formed in portions other than the accommodating groove 101 so that only a portion where the accommodating groove 101 is formed may be selectively etched. In this case, after the protective film is deposited on one surface on which the receiving groove 101 is formed, a predetermined pattern may be formed to correspond to the position where the receiving groove 101 is formed through a predetermined process. As a representative method, a pattern of the protective film may be formed using a photolithography process. In addition, the pattern may be formed on the protective film by a method such as laser patterning.

In this embodiment, a protective film was deposited on one surface of the glass plate, and a pattern was formed on the protective film by a photolithography process, and then the receiving groove 101 was formed by wet etching. However, the present invention is not limited by the contents of the process of forming the base layer 100, and the base layer 100 of the present invention may be configured using various template manufacturing methods known in the art.

As described above, when the base layer 100 is manufactured, a step of forming the coating layer 200 on one surface of the base layer 100 where the plurality of receiving grooves 101 are formed may be performed. (See 20 in FIG. 3 and FIG. 4B).

In this case, the material for forming the primary coating layer 200 is preferably composed of a non-conductor strong durability, heat resistance, wear resistance. Specifically, in the present invention, silicon carbide (SiC), silicon nitride (SiN) or titanium oxide film (TiON) may be used. Therefore, one surface of the base layer 100 on which the coating layer 200 is formed may have improved performance for wear and high temperature environments when solder bumps are formed, thereby improving durability.

Here, the method of forming the coating layer on the base layer 100 is made by a sputtering deposition method, etc. In addition, various CVD methods such as thermal CVD method, plasma CVD method, catalytic CVD method, etc. are deposited using this method. It is also possible.

However, when the coating layer 200 is formed as described above, the space in which the solder S may be filled may be substantially reduced. Therefore, in the step of manufacturing the base layer 100, it is preferable to manufacture the size of the cross section of the receiving groove 101 in consideration of the thickness of the coating layer 200. In this case, the thickness of the coating layer may be generally 1 μm or less.

On the other hand, when the primary coating layer 200 is formed on one surface of the base layer 100, it is possible to perform the step of forming a solder bump after filling the solder (S) in the receiving groove 101. (S30 of FIG. , (B) of FIG. 4)

At this time, the method of filling the solder (S) in the receiving groove 101 may use a variety of methods. In this embodiment, after spreading the solder on one surface formed with the receiving groove 101, using a bar-shaped member having a chisel-shaped end (bar) to push the solder (S) along the upper surface of the coating layer 200 Can be used. In this case, the bar-shaped member may fill the inside of the accommodating groove 101 with the solder S while pushing the solder S and remove the solder S unfolded at a position other than the accommodating groove 101. Of course, in addition to this, it is also possible to charge the solder by inserting a solder ball for each position of the receiving groove, but according to the present embodiment to reduce the time required to charge the solder (S) to improve the work speed desirable.

The base layer filled with the solder (S) is in close contact with the electrode and the receiving groove of the first substrate to correspond to the solder bump on the substrate. The solder may be transferred to the electrode side of the first substrate to form solder bumps.

However, in the case where the solder is filled in the base layer and the process of forming the solder bumps using the same is repeated, scratches, abrasion or surface oxidation are likely to occur. Of course, the coating layer 200 was formed on the surface of the base layer 100 as described above in order to improve durability in the above environment, but in this case, the coating layer 200 itself may be scratched or worn by repeated implementation. (See (d) of FIG. 4).

Therefore, in the present embodiment, when the solder bump forming step is repeated more than a predetermined number of times while the coating layer 200 is formed, it is determined that scratching or abrasion has occurred on the coating layer 200, and the coating is performed secondarily. desirable. (Refer to S50 of FIG. 3 and FIG. 4F) In this case, the number of times of use of one template can be significantly increased as compared with the case of forming a coating layer at once.

However, when the secondary coating layer 200 is formed, the space in which the solder S is filled may be gradually reduced. In addition, when the coating is performed again in a state where the scratches or abrasions generated in the previous process are not removed, the existing scratches or abrasions may be exposed on the newly formed coating layer. Therefore, in the present embodiment, when the coating layer is newly formed on the previously coated base layer, it is preferable to form the secondary coating layer after removing the previous primary coating layer (see S40 of FIG. 3 and FIG. 4E). In this case, it is possible to configure the surface of the receiving groove 101 of the correct size and at the same time so as not to reflect the previous scratch or wear when forming the coating layer again.

The method of removing the existing primary coating layer 200 may be made in various ways, and in this embodiment, an etching method using an etchant may be used. Therefore, by etching the one surface on which the primary coating layer 200 is formed for a predetermined time, the primary coating layer can be effectively removed.

In this step, the coating layer 200 may be completely removed according to the etching time, and the coating layer 200 may be removed at a level at which scratches or abrasion generated by the previous process are removed.

When the primary coating layer 200 is removed in this way, it is possible to form the secondary coating layer 200 through the same material and the same process for forming the primary coating layer. (S50 of Fig. 3, (f) of Fig. 4). In this case, the strength of the surface on which the solder is filled is improved compared to the conventional one, and the shape of the solder is filled in the receiving groove in which the second coating layer is formed, and the solder bump is transferred to the second substrate, thereby accurately forming the shape at the correct position of the second substrate. Can be used to produce a template that can form a solder bump.

As described above, the process of forming the solder bumps is performed a plurality of times, and after removing the coating layer formed on the base layer, the process of forming the coating layer again and again is repeated (that is, repeating the sections of S30 to S50). The solder bumps can then be recycled to the template.

1 is a perspective view of a template for solder bumps according to a preferred embodiment of the present invention,

2 is a cross-sectional view showing a cross section of FIG.

3 is a flow chart showing a procedure of a method for manufacturing a solder bump forming template according to a preferred embodiment of the present invention, and

4 is a schematic diagram illustrating each step of the manufacturing method according to FIG. 3.

Claims (8)

Forming a primary coating layer on the base layer on which the plurality of receiving grooves are formed, Filling the receiving groove with solder and transferring the solder bumps to the substrate a plurality of times; If a scratch or abrasion occurs in the primary coating layer, a part or all of the primary coating layer formed on the base layer is removed, Forming a second coating layer on the base layer again; The solder bump forming method comprising the step of transferring the solder bumps by filling a solder in the receiving groove in which the secondary coating layer is formed. delete The method of claim 1, The first coating layer and the second coating layer is a solder bump forming method, characterized in that consisting of one of silicon carbide (SiC), silicon nitride (SiN), or titanium oxide film (TiON). delete The method of claim 1, And the primary coating layer formed on the base layer is removed by wet etching. delete delete The method of claim 1, The thickness of the primary coating layer is a solder bump forming method, characterized in that each formed within 1㎛.

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