KR20100126030A - A method for manufacturing a template for forming solder bump - Google Patents

Abstract

PURPOSE: A method for manufacturing a template for forming a solder bump is provided to reduce manufacturing costs by forming a protective layer using molybdenum which is inexpensive and has excellent anti-corrosive properties. CONSTITUTION: A protective film is formed by using molybdenum on the top of a substrate(S1). A pattern in formed on the protective film to correspond with the position of a groove(S2). The groove is formed by etching the substrate according to the pattern(S3). The protective film is removed from the substrate(S4).

Description

Manufacturing method of solder bump forming template {A METHOD FOR MANUFACTURING A TEMPLATE FOR FORMING SOLDER BUMP}

The present invention relates to a method for manufacturing a template used to form 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 electroconductive particle connects with a terminal, the resistance of a connection part is high, and after hardening a film, it is difficult to separate two board | substrates, and it has a disadvantage that a repair is practically impossible.

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.

In general, the receiving groove is formed by etching one surface of the substrate. At this time, the receiving groove should be formed at the correct position corresponding to the electrode of the substrate, so that only the position of the receiving groove on the substrate can be etched in a state where a protective film is applied to the other portion of the substrate. However, there is a problem in that the cost of manufacturing a template for the bar that is conventionally used as a component of the protective film is expensive.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a template for forming solder bumps using a material which is inexpensive and capable of performing the function of a protective film in order to solve the above problems.

In order to achieve the above object, the present invention forms a protective film using molybdenum on the substrate, to form a pattern on the protective film to correspond to the position where the receiving groove is to be formed, and etching the substrate according to the pattern to accommodate the receiving groove Forming and removing the protective film from the substrate may provide a method for manufacturing a solder bump forming template.

At this time, the thickness of the protective film may be configured to 1000 ~ 2000 kPa.

On the other hand, it is preferable to form the pattern by etching the protective film by a photolithography process.

Here, the protective film may be etched using a solution of hydrochloric acid (HCl) and hydrogen peroxide (H ₂ O ₂ ), and a solution of sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ), and water may be mixed. It is possible to etch the said protective film by using.

In addition to this, it is also possible to form the pattern on the protective film by a laser patterning process, or to form the pattern according to the protective film by using an imprinting process or the like.

Further, in the step of wetting the substrate, it is possible to proceed with wet etching using hydrofluoric acid.

According to the present invention, the protective film is formed by using molybdenum which is inexpensive and has good corrosion resistance, and thus the manufacturing cost can be reduced. Furthermore, it is environmentally friendly compared to other heavy metals used for the protective film, and thus can solve the problem of environmental pollution due to repeated use.

Hereinafter, a method of manufacturing a template for forming solder bumps according to the present embodiment will be described with reference to the accompanying drawings.

1 is a flowchart illustrating a method for manufacturing a solder bump forming template according to the present embodiment.

In order to manufacture the template for forming the solder bumps, the substrate 10 may be prepared first. Here, the substrate 10 forms a body of a template for forming solder bumps, and a plurality of receiving grooves 10a may be formed on one surface of the substrate 10 by the manufacturing process.

The substrate 10 may be configured using glass or a wafer. In addition, the substrate 10 may be configured in various ways using a separate film lamination structure or powder molding.

In the present embodiment, the substrate 10 is formed using glass, and among these, glass made of alkali-free glass can be used. Since alkali free glass is excellent in heat resistance, chemical resistance, and high mechanical strength, it is suitable as a board | substrate material of a template for solder bump formation.

On the other hand, the protective film 11 may be formed on one surface of the prepared substrate 10. (S1) At this time, the protective film is coated on one surface of the substrate as shown in the cross-sectional shape shown in FIG.

In general, the protective film formed on the substrate 10 is composed of a heavy metal compound containing chromium (Cr). However, since chromium (Cr) is expensive, the manufacturing cost of the solder bump forming template may be increased. In addition, the protective film is to selectively protect the substrate 10 during the etching process, and is removed when the etching process is completed. At this time, the chromium (Cr) component to be removed is an element that has a harmful effect on the environment, and if it is continuously used, it will not only cause environmental pollution, but also requires a high cost to deal with it. .

Therefore, in the present invention, as the material capable of replacing the chromium (Cr), it is possible to configure the protective film 11 of the substrate 10 by using molybdenum (Mo). Molybdenum (Mo) is a silver gray metal belonging to Group 6 of the Periodic Table of the Elements, and is suitable for use as a protective film 11 for protecting a portion of a substrate which is excellent in heat resistance and corrosion resistance and is not etched by an etching solution during an etching process. In addition, the alloy of molybdenum (Mo) and the molybdenum (Mo) metal itself can maintain the strength even at a high temperature above the melting point of most other metals or alloys, and further excellent wear resistance. Therefore, even when the substrate 10 is etched by using means other than the etchant, the portions not etched can be effectively protected.

The cost of molybdenum (Mo) is significantly lower than that of chromium (Cr). Therefore, compared with the case where a protective film is formed using chromium (Cr), it is possible to manufacture the template for solder bump formation at low cost. In addition, molybdenum (Mo) has a lesser impact on environmental pollution than chromium (Cr), and various clean dissolving technologies capable of recovering molybdenum (Mo) using hydrogen peroxide (H ₂ O ₂ ) in recent years. It is being developed so, it is possible to provide an environmentally friendly manufacturing process compared to the case of forming a protective film using chromium (Cr).

As such, the protective film 10 made of molybdenum (Mo) may be easily formed by a process such as sputtering. In this embodiment, a protective film was formed by depositing molybdenum (Mo) on the substrate 10 to a thickness of 1000 ~ 2000Å.

On the other hand, when the protective film 11 is formed as described above, the step of forming a pattern by removing a portion of the protective film 11 to correspond to the position of the receiving groove (10a) to accommodate the solder can be performed. That is, the pattern may be formed of a through hole formed in the protective film 11 to correspond to the size, shape and arrangement of the receiving groove 10a to be finally formed on the substrate 10.

FIG. 2 is a flowchart showing a procedure of forming a pattern on the protective film in this embodiment. Hereinafter, a step of forming a pattern on the protective film 11 will be described in detail with reference to FIG. 2.

In this embodiment, a pattern may be formed on the passivation layer 11 by using a photolithography process. Therefore, the photosensitive agent is apply | coated to the protective film 11, and a photosensitive agent layer is formed. Here, when the exposure is selectively made to the photosensitive layer, the photosensitive layer of the exposed portion may be modified.

Therefore, light is irradiated in the state which the mask in which the pattern was previously formed on the photosensitive agent layer is irradiated, and a photosensitive agent layer is selectively modified. Here, the photoresist may be selectively used as a positive photoresist and a negative Guam photoresist in response to the light, it is preferable that the pattern of the mask is formed correspondingly. In this case, while the photoresist is selectively denatured, the protective film 11 may be exposed in a predetermined pattern while some photoresist layers are removed. That is, only the protective film 11 at the position where the receiving groove is to be formed is exposed to the outside by the pattern formed in the photosensitive agent layer.

Thereafter, an etchant capable of etching the exposed protective film 11 may be added thereto to remove the protective film. Here, the etchant used in this step is preferably configured to etch molybdenum (Mo). To this end, it is also possible to use a mixture of hydrochloric acid (HCl) and hydrogen peroxide (H ₂ O ₂ ) 1: 1 as an etchant, and sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ) and water 1: 1. It is also possible to use the solution mixed with: 1 as an etchant. Of course, each component ratio of the above-described solution can be selectively adjusted by the user, it is also possible to etch the protective film 11 by using an etchant other than the above-described solution.

On the other hand, when the above-described step is carried out, this is terminated and the photoresist layer remaining in the protective film 11 is removed. Through this photolithography process, as shown in FIG. 4, a portion of the protective film 11 is etched to form a predetermined pattern on the protective film 11.

In this embodiment, the photolithography process is used to form the pattern of the protective film 11, but the present invention is not limited thereto. For example, a laser patterning process may be used to form a pattern by directly removing a portion of the protective film exposed to the laser by irradiating a laser having a fine cross-sectional diameter, and forming a pattern using a separate stamp or the like. It is also possible to form a pattern on the protective film using an imprinting process or the like. Furthermore, in addition to this, various other methods used for forming a fine pattern may be applied.

As such, when a pattern is formed in the passivation layer 11, the substrate 10 is exposed to the position of the pattern. As described above, the protective film 11 pattern has a shape corresponding to the shape of the receiving groove 10a at the position where the receiving groove 10a is formed, and the receiving groove 10a at the position where the substrate 10 is exposed. ) May be formed.

In this case, as shown in FIG. 5, the receiving groove 10a may be formed while the substrate 10 is etched by an etching process (S3). At this time, depending on the material of the substrate 10 and the shape of the receiving groove (10a) may proceed by a wet etching or dry etching method. In this embodiment, as an example, the glass substrate 10 made of an alkali-free glass material is used, and it is possible to perform wet etching using hydrofluoric acid (HF) as an etchant.

Thus, the exposed portion of the substrate 10 is etched by the etching process to form the receiving groove 10a. At this time, it is possible to precisely control the concentration and etching time of the etchant used in the etching process to form a receiving groove of the correct size and shape. In addition, the portion in which the accommodating groove 10a is not formed is protected by a maldibrene protective film having excellent corrosion resistance and chemical resistance, so that the etching selectivity in the portion adjacent to the etching portion can be maintained well.

When the substrate 10 is etched into a desired shape to form the receiving groove 10a, the etching is stopped and washed to remove the etchant. Then, by performing the step of removing the protective film 11 remaining on the substrate, it is possible to configure a solder bump template as shown in Fig. 6 (S4). Here, the step of removing the protective film may also be performed using a separate etching process.

Using such a process, it is possible to manufacture a template for forming solder bumps that can prevent environmental pollution at low cost. However, the above-described embodiment corresponds to an example according to the present invention, and the present invention may be modified and modified in various forms.

1 is a flowchart illustrating a method of manufacturing a template for forming solder bumps according to the present embodiment;

2 is a flowchart showing a procedure of forming a pattern on the protective film in this embodiment,

3 to 6 are cross-sectional views illustrating each step of FIG. 1.

Claims (8)

A protective film is formed on the substrate using molybdenum, A pattern is formed in the passivation layer so as to correspond to the position where the accommodation groove is to be formed. Etching the substrate according to the pattern to form a receiving groove, And removing the protective film from the substrate. The method of claim 1, The thickness of the protective film is a method for producing a solder bump forming template, characterized in that 1000 ~ 2000 1000. The method of claim 1, And forming said pattern by etching said protective film by a photolithography process. The method of claim 3, The protective film is etched by using a solution in which hydrochloric acid (HCl) and hydrogen peroxide (H ₂ O ₂ ) are mixed. The method of claim 3, The protective film is etched using a solution of sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ) and water. The method of claim 1, And forming the pattern on the protective film by a laser patterning process. The method of claim 1, Forming the pattern according to the protective film by an imprinting process, characterized in that the manufacturing method of the solder bump forming template. The method of claim 1, A method for producing a solder bump forming template, characterized in that the substrate is wet etched using hydrofluoric acid.

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