KR101032085B1 - Template for forming solder bump and method for manufacturing the template - Google Patents

Abstract

The present invention relates to a template used to form solder bumps in a semiconductor manufacturing process and a method of manufacturing the same, comprising a panel made of an alloy material containing silicon, and a plurality of housings that can accommodate solder balls on one side of the panel. It is possible to provide a template for forming a solder bump including a groove and a manufacturing method thereof.

According to the present invention, it is possible to provide a template for solder bump formation with improved workability. In addition, since the template can be customized in consideration of thermal expansion of the substrate during the reflow process, solder bumps can be formed at an accurate position.

Description

TEMPLATE FOR FORMING SOLDER BUMP AND METHOD FOR MANUFACTURING THE TEMPLATE}

The present invention relates to a template for forming solder bumps in a semiconductor manufacturing process and a method of manufacturing the same.

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 devices 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 fine terminals 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 the 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 is to arrange a solder ball to form a solder bump on the template, and then close the template to the substrate and heat the solder ball to the electrode side of the substrate. . To this end, a plurality of receiving grooves must be formed in a position corresponding to the electrodes of the substrate in advance so that the solder balls can be accommodated in the receiving 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 likely to be worn by contact with the substrate due to repeated use, so that a template of glass material having a relatively high hardness is used. Therefore, the receiving groove is formed on one surface of the glass template to accommodate the solder ball.

However, when manufacturing a template using a glass material as in the prior art, the manufacturing process is difficult, and the manufacturing cost increases. In particular, in recent years, since the substrate on which the solder bumps are formed is gradually larger in area and mass production is required, the conventional template has a problem in terms of processability and cost.

In addition, during the reflow process to form solder bumps on the substrate, the template and the substrate are heated to a high temperature. At this time, the template made of a glass material has a constant low coefficient of thermal expansion due to the properties of the material. Therefore, since the substrate is made of a material having a weak thermal deformation, it is difficult to form solder bumps at the correct position when expansion occurs during the reflow process.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a solder bump forming template and a method for manufacturing the same, which are excellent in workability and easy to mass production and large-scale production.

In addition, it is an object of the present invention to provide a template and a method for manufacturing the same that can form a solder bump in the correct position in response to this even if the substrate is expanded by heat during the reflow process.

An object of the present invention can be achieved by a panel formed of an alloy material including silicon, and a solder bump forming template including a plurality of receiving grooves for accommodating solder balls on one surface of the panel.

Here, the panel may be made of an alloy material including the silicon and aluminum.

In addition, the panel may adjust the thermal expansion coefficient according to the content ratio of the silicon contained in the alloy.

Further, the panel is more preferably configured to have a thermal expansion coefficient corresponding to the thermal expansion coefficient of the substrate on which the solder bumps are formed.

In this case, the panel may have a thermal expansion coefficient of 15 ppm or less.

Meanwhile, an object of the present invention is a solder bump including a panel manufacturing step of manufacturing a plate-shaped panel made of an alloy material including silicon, and a receiving groove forming step of forming a receiving groove in which solder balls are accommodated on one surface of the panel. It can also be achieved by a method for producing a template for forming.

In this case, the alloy used in the panel manufacturing step may be manufactured to include the silicon and aluminum.

Therefore, in the panel manufacturing step, it is preferable to adjust the thermal expansion coefficient of the panel by adjusting the content ratio of the silicon, more preferably the panel has a thermal expansion coefficient corresponding to the thermal expansion coefficient of the substrate on which the solder bumps are formed. It can be manufactured to have.

In this case, the panel manufacturing step may be formed so that the thermal expansion coefficient of the panel is less than 15ppm.

The receiving groove forming step may include a photosensitive film applying step of applying a photosensitive film to one surface of the panel, a pattern forming step of forming a pattern on the photosensitive film so as to correspond to a position where the solder ball is accommodated, and the photosensitive pattern. It may comprise a receiving groove forming step of forming a receiving groove by etching the substrate.

Alternatively, the receiving groove forming step may be configured to include a barrier film applying step of coating a barrier film on one surface of the panel, and a laser etching step of etching the receiving groove by irradiating a laser to the portion to which the barrier film is applied. .

According to the present invention, it is possible to provide a template for solder bump formation with improved workability.

In addition, since the template can be customized in consideration of thermal expansion of the substrate during the reflow process, solder bumps can be formed at an accurate position.

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

1 is a cross-sectional view showing a cross section of a template for forming solder bumps according to a preferred embodiment of the present invention.

As shown in FIG. 1, the solder bump forming template 100 is formed on a panel 110 having a plate shape and a plurality of accommodation grooves formed on one surface of the panel 110 to accommodate solder balls ( 120).

In this case, the panel 110 is preferably made of an alloy material. In general, alloys are easier to handle and have better processability than glass materials. Therefore, when the panel 110 is made of an alloy, handling and workability may be improved, so that the panel 110 may be easily processed even when the size of the panel 110 is increased, and productivity may be improved.

In addition, the alloy can change the properties of the material according to the type and proportion of the components contained. Therefore, even if the type of the substrate on which the solder bumps are formed is diversified, it is possible to manufacture to form an alloy corresponding thereto. Furthermore, it is also possible to improve the properties required by adding various additives and the like in the manufacture of the alloy.

Therefore, the template 100 according to the present embodiment preferably includes a panel 110 formed of an alloy material, and forms a plurality of receiving grooves 120 by processing one surface of the panel 110.

Meanwhile, a process of forming solder bumps using the template 100 is as follows. First of all, the solder ball is put in a required position among the receiving grooves 120 of the template 100, and then heated while being in close contact with the template 100. At this time, as the template 100 is heated, melting of the solder ball, which is a solid state, is started. At this time, the solder ball forms a solder bump while being transferred to the substrate using viscosity.

Here, a process of heating the template to about 200 ° C. or more may be performed to melt the solder ball. In this case, the template 100 may be deformed while being exposed to high temperature for a predetermined time or more. At this time, if the thermal deformation of the template 100 is severely generated, there is a fear that the solder bumps are formed at the wrong position on the substrate while the position of the receiving groove is changed.

Therefore, in the present invention, the panel 100 corresponding to the body of the template may be made of an alloy containing silicon so that the template 100 may have a coefficient of thermal expansion of a predetermined value or less.

Here, silicon refers to silicon corresponding to element number 14, and the silicon has a low coefficient of thermal expansion of about 3 ppm (part per million meter) or less. Therefore, when the panel 110 of the template 100 is configured using an alloy including a predetermined amount or more of silicon, deformation caused by high temperature may be reduced compared to other materials.

However, when the panel 110 is formed using only silicon, the workability may be deteriorated due to the properties of silicon. Therefore, in the present invention, it is preferable to configure the panel 110 made of another metal and alloy so as to improve the properties of the silicon.

Specifically, in the present embodiment, the alloy constituting the panel 110 may use an alloy using silicon and aluminum. The alloy containing silicon and aluminum has a lower coefficient of thermal expansion, superior alloy castability, and excellent flowability and fillability of the molten metal compared to other alloy materials. Accordingly, the panel 110 of a material having improved thermal workability while having less heat deformation can be obtained.

In addition, the alloy including silicon and aluminum may not only obtain high strength by adding other elements, but also may be excellent in wear resistance, thereby preventing the shape from being changed due to contact with the substrate during repeated use of the template 100.

As such, although the panel 110 is manufactured using an alloy including silicon and aluminum, the present invention is not limited thereto. In addition, among the alloys containing silicon, it is obvious that other alloys may be used to improve workability.

Meanwhile, in the case of the present invention, the panel of the template 100 is made of an alloy including two or more components. Therefore, it is possible to adjust the coefficient of thermal expansion by adjusting the type of components or the content ratio of the components of the alloy.

In the case of focusing on the alloy material used in the present embodiment, the thermal expansion coefficient of silicon is about 3 ppm or less, whereas aluminum has a thermal expansion coefficient of about 20 ppm. Therefore, an alloy having a relatively low thermal expansion coefficient can be obtained by increasing the content ratio of silicon, and an alloy having a relatively high thermal expansion coefficient can be obtained by lowering the content ratio of silicon.

However, when a large amount of silicon is contained, macro segregation of the process silicon and coarsening of primary silicon particles may reduce the mechanical properties of the cast product. Therefore, it is desirable to refine the process silicon by adding sodium (Na), strontium (Sr), or the like, or to refine the primary silicon by adding phosphorus (P) or the like to improve the properties of the alloy.

As such, according to the present invention, it is possible to selectively manufacture the thermal expansion coefficient of the template 100 to have a specific value within the range of approximately 3 ppm to 20 ppm. However, when the thermal expansion coefficient is too high, the formation position of the solder bumps may be inaccurate, and the thermal expansion coefficient will need to be limited to have a value within 15 ppm and more preferably within 10 ppm.

Meanwhile, when the template 100 is heated in a reflow process, heat may be transferred to a substrate in contact with the template 100. That is, the substrate may also undergo thermal deformation by heating. Therefore, in order to form solder bumps at the correct position of the substrate, it is desirable to consider the extent to which the substrate is expanded by heat, that is, the coefficient of thermal expansion of the substrate.

However, in recent years, since the material forming the substrate is gradually diversified, it may be difficult to prepare a template in consideration of the thermal expansion coefficient of the various substrate materials when using a conventional glass material. In contrast, according to the present invention, by adjusting the ratio of the components included in the alloy, that is, in the present embodiment it is possible to adjust to have a corresponding coefficient of thermal expansion for each substrate by controlling the content of silicon and aluminum Do.

That is, in consideration of the degree of heat transfer to the substrate and the thermal expansion coefficient of the substrate material when the template 100 is heated, a template having a thermal expansion coefficient corresponding thereto may be provided.

Hereinafter, a method of manufacturing the above-described template will be described with reference to the drawings.

2 is a flow chart of a method for manufacturing a solder bump forming template according to the present embodiment, Figure 3 is a schematic diagram showing a step of forming a receiving groove according to the present embodiment.

The solder bump forming template 100 in Figure 2 is a panel manufacturing step (S100) for manufacturing the panel 110 constituting the body and the receiving groove forming step of forming a receiving groove for receiving the solder ball on one surface of the panel ( It may be formed by a manufacturing method including S200.

The panel manufacturing step (S100) forms a plate-shaped panel 110 using an alloy material containing silicon. Here, after the alloy is first manufactured, the panel 110 may be manufactured using the alloy. Or it is also possible to manufacture a plate-shaped alloy panel by one process by injection molding etc. using a metal mold | die.

Here, the alloy may comprise at least two or more components, including silicon. At this time, the components included are preferably composed of a component that can improve the processability of the alloy. In this embodiment, an alloy including silicon and aluminum is used as an example, but the present invention is not limited thereto.

On the other hand, as described above, the alloy can control the coefficient of thermal expansion of the panel 110 by adjusting the content ratio of the constituents. That is, the higher the content of silicon having a lower thermal expansion coefficient, the lower the thermal expansion coefficient of the alloy constituting the panel 110.

Therefore, in the present embodiment, a preferable coefficient of thermal expansion of the panel 110 may be set in consideration of the coefficient of thermal expansion of the substrate to be used and the amount of heat transferred to the substrate. In addition, the alloy 110 may be manufactured by adjusting the content ratio of the components so that the panel 110 has the set thermal expansion coefficient.

In the present embodiment, the coefficient of thermal expansion of the panel 110 is preferably equal to or smaller than the coefficient of thermal expansion of the substrate. Heat is transferred to the substrate through the template 100 during the reflow process. If the template 100 and the substrate have the same thermal expansion coefficient, the template 100 may have the same or larger deformation as compared with the substrate. to be.

As described above, the panel 110 manufactured in the panel manufacturing step (S100) can set the thermal expansion coefficient by adjusting the content ratio of the alloy, so that even if the thermal deformation occurs in the substrate in the reflow process, the corresponding size Is also generated in the template 100, it is possible to form a solder bump accurately in the intended position.

After performing the panel manufacturing step (S100), it is possible to perform the receiving groove forming step (S200) for forming the receiving groove 120 on one surface of the panel 110.

As shown in Figures 2 and 3, the receiving groove forming step (S200) is a photosensitive film applying step (S211) for applying the photosensitive film 200 to one surface of the panel 110 manufactured in the panel manufacturing step (S100). A pattern forming step of forming a pattern in the photosensitive film 200 so as to correspond to a position where the solder ball is accommodated (S212), and etching the panel 110 according to the photosensitive pattern to form an accommodating groove 120. It may be made by including the step (S213).

This is to apply a photo lithography process, and to use the property that the property is changed when the photosensitive film is exposed to light.

Specifically, the photosensitive film 200 may be applied to one surface of the panel 110 on which the accommodation groove 120 is to be formed. The photosensitive film 200 may be exposed to correspond to the pattern on which the receiving groove 120 is to be formed using a mask, and the developer may be applied to the surface of the photosensitive film 200 to form a photosensitive pattern. As such, when the photoresist coating step S211 and the pattern forming step S212 are performed, a position where the receiving groove 120 is formed in the panel 110 may be exposed to the outside at the portion where the pattern is formed.

In addition, the panel 110 may be etched to form a receiving groove by a portion where the pattern is formed. In this embodiment, the panel 110 may be etched by using a wet etching method. Here, the solvent used for the wet etching may use a potassium hydroxide (KOH) solution or the like mainly used to etch silicon.

Accordingly, the receiving groove 120 may be formed while etching the position of the panel 110 exposed by the photosensitive pattern. The solder bump forming template 100 may be manufactured by removing the photosensitive film 200 applied to the remaining portion (S214).

Here, the method may include a process of protecting the panel from the developer when the photosensitive pattern is formed, and applying a separate barrier film (not shown) between the panel 110 and the photosensitive film 200 to precisely form the receiving groove. In this case, the barrier film protects the substrate from the developer when the photosensitive pattern is formed, and is for precision molding of the receiving groove 120. The material of the barrier film may include silicon nitride and silicon oxide. However, in this case, a step of forming a pattern on the barrier layer may be additionally required before performing the etching step (S213).

On the other hand, the template manufacturing method according to the present invention may perform the receiving groove forming step (S200) different from the above.

4 is a flow chart showing the steps of the template manufacturing method according to another embodiment, Figure 5 is a schematic diagram schematically showing the receiving groove forming step of FIG.

As shown in FIG. 4, in the receiving groove forming step S200, a barrier film applying step S221 for applying the barrier film 300 to one surface of the panel and a portion of the barrier film 300 coated with the laser are applied. Irradiation may include a laser etching step (S222) of etching the receiving groove 120. That is, one surface of the panel 110 is directly etched along a predetermined pattern using a laser to form the receiving groove 120.

In this case, when the barrier layer 300 directly etches the panel 110 using the laser, the barrier layer 300 helps to obtain a precise shape by preventing the portion adjacent to the preset pattern from being recessed during the laser etching. In this case, the barrier layer 300 used may be formed of a metal such as chromium (Cr) or chromium oxide and a metal oxide.

Therefore, according to the present exemplary embodiment, the template 100 is manufactured by directly irradiating a laser toward the barrier film 300 to form the receiving groove 120 directly, and then removing the barrier film 300 (S214). It is possible to.

1 is a cross-sectional view showing a cross section of a template for forming solder bumps according to a preferred embodiment of the present invention;

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

3 is a schematic diagram schematically showing the receiving groove forming step of FIG.

4 is a flow chart showing another step of manufacturing the template for solder bump molding of Figure 1,

FIG. 5 is a schematic diagram schematically illustrating a receiving groove forming step of FIG. 4.

Description of the Related Art [0002]

100: template 110: panel

120: receiving groove 200: photosensitive film

300: barrier film S100: panel manufacturing step

S200: receiving groove forming step

Claims (12)

A panel panel composed of an alloy material including silicon and aluminum, and having a thermal expansion coefficient of 15 ppm or less; And The solder bump forming template comprising a; a plurality of receiving grooves that can accommodate the solder ball on one surface of the panel. According to the first, The panel has a thermal expansion coefficient corresponding to the thermal expansion coefficient of the substrate on which the solder bump is formed, the solder bump forming template. A panel manufacturing step of manufacturing a plate-shaped panel composed of an alloy material including silicon and aluminum, and having a thermal expansion coefficient of 15 ppm or less; And, And a receiving groove forming step of forming a receiving groove in which solder balls are accommodated on one surface of the panel. The method of claim 3, The panel manufacturing step is a solder bump forming template, characterized in that for manufacturing the panel has a thermal expansion coefficient corresponding to the thermal expansion coefficient of the substrate on which the solder bump is formed. The method of claim 3, The receiving groove forming step A photoresist coating step of applying a photoresist film to one surface of the panel; A photosensitive pattern forming step of forming a photosensitive pattern on the photosensitive film so as to correspond to a position where the solder ball is accommodated; And, And etching to form the receiving groove by etching the panel according to the photosensitive pattern. The method of claim 3, The receiving groove forming step A barrier film applying step of coating a barrier film on one surface of the panel; And And a laser etching step of etching the receiving groove by irradiating the laser to the portion to which the barrier film is applied. delete delete delete delete delete delete

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