JP2000340702A - Solder ball transfer sheet and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce and provide a low-cost solder ball transfer sheet that can transfer a highly reliable copper core solder solder ball onto a semiconductor device at a time and can form solder balls of various structures. I do. SOLUTION: A solder ball transfer sheet 1 in which a conductor terminal 3 composed of two or more layers is formed on a base resin 2, wherein a step of forming the base resin 2 on a metal plate 6,
A step of forming the plating mask 8 on the metal plate 6, a step of forming the solder layer 5 of the conductor terminal on the metal plate 6 by electrolytic plating or electroless plating, a step of removing the plating mask 8, and a step of removing the formed solder layer 5. Forming the metal layer 4 of the conductor terminal 3 by etching the metal plate 6 using the as an etching mask.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder ball transfer sheet mounted on a semiconductor device requiring a solder ball mounting step by transferring solder balls at once, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the demand for higher functionality and lighter, thinner and smaller electronic devices, high-density integration and high-density mounting of electronic components have been progressing. Semiconductor packages have been increasingly miniaturized and have more pins than ever before.

[0003] With the miniaturization of semiconductor devices, the size of a conventional device using a lead frame has reached its limit in miniaturization. Recently, a semiconductor device mounted on a circuit board has been described as: BGA (Ball Gr
id Array) and CSP (Chip Scale)
A new device method of area mounting type, such as "Package", has been proposed. The BGA mounts a semiconductor chip on a semiconductor mounting substrate (interposer), and uses a wire bonding method, TAB (Tape Automa).
The semiconductor chip and the interposer are electrically connected by the ted bonding method, etc., resin-sealed by the transfer molding method, etc., and the solder balls are mounted on the outer surface of the interposer (the surface on which the semiconductor chip is not mounted) in a grid array arrangement. Semiconductor device. Pads for mounting solder balls are formed in a grid array on the outer surface of the interposer.

As a method for mounting solder balls, there is a method in which ready-made solder balls are arranged at predetermined positions (on pads) on the outer surface of the interposer, and are mounted by reflow. To align the solder balls, a jig having holes in the same arrangement as the pad arrangement on the outer surface of the interposer is used. The hole of the jig is smaller than the diameter of the solder ball. The solder ball is placed on one side of the jig and sucked from the opposite side of the hole, whereby the solder ball is aligned with the hole. With the solder balls aligned with the holes in the jig, the aligned solder balls and the pads on the outer surface of the interposer are opposed to each other, aligned correctly, and arranged on the pads.
The solder balls are mounted on the pads on the outer surface of the interposer by reflow.

In this method of aligning solder balls,
In particular, when the solder balls become very small, due to the effects of dirt, dust and static electricity on the solder balls, suction errors or extra solder ball adhesion may occur, or multiple solder balls may be adsorbed in a single hole in a grape shape. In some cases, it is difficult to securely mount the solder balls.

Therefore, a solder ball transfer method in which the solder balls are mounted by transferring the solder balls at once, instead of aligning and mounting the solder balls, is considered. This is to mount bumps for flip chip connection of semiconductor chips by batch transfer,
This is an application of a transfer bump sheet. That is, by aligning the solder ball transfer sheet with the solder balls formed on the sheet-like base and the pads on the outer surface of the interposer, and applying heat and pressure, the solder balls on the solder ball transfer sheet side are transferred to the pads on the outer surface of the interposer. That is, they are collectively transferred.

Conventionally known transfer bump sheets are formed by forming solder bumps on a base metal serving as a base of the transfer bump sheet. In the manufacturing process, a plating mask is formed on a base metal, a solder bump is formed by electrolytic plating, and then the plating mask is removed. In this method, the bumps are formed to a desired size only by soldering, so that the manufacturing time and the manufacturing cost are increased. Further, in the electrolytic plating, it is difficult to make the current distribution in the plating tank completely uniform, so that the formed bumps vary in size. Variations in the size of the bumps become more pronounced as the plating time increases, and it is difficult to solve the problem by forming the bumps only with solder. In addition, in order to obtain the moisture resistance reliability of the bump connection part, there is a method of employing a bump having a metal core like a copper core solder bump, instead of using only a solder for the bump. Additional time and manufacturing costs are incurred. Therefore, it is difficult to use a conventionally known transfer bump sheet as it is for a solder ball transfer sheet.

[0008]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies in view of the above problems of the structure and manufacturing method of the conventional transfer bump sheet. The purpose of the present invention is to provide a solder ball transfer sheet capable of transferring a high-cost copper core solder ball at a low cost as well as providing a solder ball transfer sheet capable of forming solder balls of various structures. .

[0009]

That is, the present invention relates to a solder ball transfer sheet which is mounted on a semiconductor device which requires a solder ball mounting step by collectively transferring solder balls. A solder ball transfer sheet, characterized in that conductor terminals composed of two or more layers are formed on a base resin serving as a base of the sheet, and a step of forming the base resin on a metal plate surface, a plating mask. A step of forming a metal plate, a step of forming a solder layer to be a part of a conductor terminal on the metal plate by electrolytic plating or electroless plating, a step of removing a plating mask, and a step of removing the metal by using the formed solder layer as an etching mask. A solder ball, comprising a step of forming a metal layer of a conductor terminal by etching a plate. A copy sheet method of manufacturing.

[0010] The solder ball transfer sheet of the present invention is based on one in which the conductor terminals are formed of two layers of a metal layer and a solder layer in order from the base resin side, and preferably, the conductor terminals are sequentially formed from the base resin side. It has a three-layer structure of a solder layer, a metal layer, and a solder layer, or a structure in which an adhesive metal layer is provided between a base resin and a solder layer in contact with the base resin. Furthermore, it is preferable to form a solder coating on the surface of the conductor terminal by electrolytic plating or electroless plating.

The metal layer of the conductor terminal (which becomes the core of the solder ball) may be any metal or alloy that can be etched, but generally, a metal plate such as a copper plate is used. By using copper, the electrical resistance can be significantly reduced, and furthermore, it can be expected that the reliability of the solder ball joint at the moisture resistance is improved. The method for manufacturing a solder ball transfer sheet of the present invention can be applied to metals or alloys other than copper, as long as they can be etched and are suitable for a solder ball core.

The solder used for the solder layer may be any solder that can be electroplated or electrolessly plated, and includes, for example, a Sn-Pb eutectic solder. Furthermore, development has been progressing rapidly in recent years.
So-called lead-free solders such as Sn-Sb, Sn-Cu, Sn-Ag, etc. can also be used as long as they can be plated.

The method for manufacturing a solder ball transfer sheet according to the present invention can be any of several methods depending on the contents and order of the steps. The first manufacturing method uses a base resin on one side of a metal plate. Forming, forming a plating mask on the other surface of the metal plate, forming a solder layer to be a part of the conductor terminal on the metal plate by electrolytic plating or electroless plating, and removing the plating mask. ,and,
The method is characterized by comprising a step of forming a metal layer of a conductor terminal by etching a metal plate using the formed solder layer as an etching mask, and performing each step in this order.

In a second method of manufacturing a solder ball transfer sheet according to the present invention, a step of forming plating masks on both surfaces of a metal plate, a solder to be a part of a conductor terminal on the metal plate by electrolytic plating or electroless plating. A step of forming a layer, a step of forming a base resin on one surface of a metal plate on which a solder layer is formed, a step of removing a plating mask, and a step of etching the metal plate using the formed solder layer as an etching mask to form a conductor. The method comprises the steps of forming a metal layer of a terminal, wherein each step is performed in this order.

In a third method of manufacturing a solder ball transfer sheet according to the present invention, there is provided a step of forming a plating mask on one side of a metal plate, and forming a portion of a conductor terminal on both sides of the metal plate by electrolytic plating or electroless plating. Forming the solder layer, forming the base resin on the surface of the metal plate on which the solder layer is not formed with the plating mask, removing the plating mask, and etching the formed solder layer The method comprises the steps of forming a metal layer of a conductor terminal by etching a metal plate as a mask, and performing each step in this order.

Further, some of the lead-free solders having a new composition which have been developed in recent years can be etched similarly to metal layers such as copper. A fourth method for manufacturing a solder ball transfer sheet according to the present invention uses this etchable solder. Solder that becomes one part of a conductor terminal on both surfaces (entire surface) of a metal plate by electrolytic plating or electroless plating. Forming a layer, forming a base resin on one surface of the metal plate on which the solder layer is formed, forming an etching mask on the other surface of the metal plate on which the solder layer is formed, It is characterized by comprising a step of forming a conductor terminal by etching a solder layer and a step of removing an etching mask.

Further, it is preferable to add a step of forming a solder coating on the surface of the conductor terminal formed by the first to fourth manufacturing methods by electrolytic plating or electroless plating. The solder ball transfer sheet of the present invention is manufactured by any one of the first to fourth methods.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 is a view for explaining a method for manufacturing a solder ball transfer sheet according to a first embodiment of the present invention. FIG. 1E shows a solder ball transfer sheet obtained by the first manufacturing method. It is sectional drawing which shows the structure of a sheet. Solder ball transfer sheet 1 includes base resin 2 and conductor terminals 3
, And the conductor terminal 3 includes a metal layer 4 and a solder layer 5.

In the first manufacturing method, first, the base resin 2
And a two-layer sheet composed of a metal plate 6 is prepared (a).
The two-layer sheet can be obtained by laminating the metal plate 6 on the base resin 2 by applying heat and pressure. There is also a method in which a resin varnish is uniformly applied on the metal plate 6 and then dried.
Next, a plating mask 8 is formed on the metal plate 6 (b), and subsequently, the metal plate 6 is formed by electrolytic plating or electroless plating.
A solder layer 5 constituting a part of the conductor terminal 3 is formed thereon (c). Thereafter, the plating mask 8 is peeled off (d), and the metal plate 6 is etched using the formed solder layer 5 as an etching mask to form a metal layer 4 constituting a part of the conductor terminal 3 (e). The solder ball transfer sheet 1 of the present invention is obtained.

FIG. 2 is a view for explaining a transfer method in which the solder balls 12 are collectively transferred to the semiconductor device 10 using the solder ball transfer sheet 1 obtained by the first manufacturing method. First, the solder ball transfer sheet 1 is placed at a predetermined position on a substrate receiving table 22 of a bonding apparatus, and the semiconductor device 10 is placed on a heating and pressing tool 20 having suction holes 21.
To adsorb. The semiconductor device 10 is obtained by mounting the semiconductor chip 15 on the interposer 13, connecting the wiring of the interposer 13 and the electrode of the semiconductor chip 15 by a method such as wire bonding, and then molding with a sealing resin 16. is there. On the interposer 13, pads 11 for mounting the solder balls 12 (hereinafter, pads 11 of the semiconductor device 10) are formed.

Next, the positioning marks formed in advance on the solder ball transfer sheet 1 and the semiconductor device 10 are read by an image recognition device, and the conductor terminals 3 of the solder ball transfer sheet 1 and the pads 11 of the semiconductor device 10 are read. Are opposed to each other and accurately positioned (a). Subsequently, the heating / pressing tool 20 is lowered, and the semiconductor device 10 is pressed in parallel to the solder ball transfer sheet 1 at a predetermined temperature and pressure (b). When the solder layer 5 reaches the melting temperature, a part of the solder layer 5 wraps around the side of the metal layer 4,
The surface tension changes to a balanced shape (c). After heating and pressing for a predetermined time, the heating and pressing tool 20 is raised, and the semiconductor device 10 and the solder ball transfer sheet 1 are removed from the heating and pressing tool 20. After the solder layer 5 is solidified, the base resin 2 is removed to obtain the semiconductor device 10 in which the solder balls 12 are collectively transferred (d).

In the solder ball transfer sheet 1 according to the first embodiment, since the solder coating is not formed on the side surfaces of the metal layer 4 constituting the conductor terminals 3, when the solder layer 5 reaches the melting temperature, Part of the solder layer 5 is a metal layer 4
It is necessary to go around the side of the. When the applied pressure is small or when the wettability of the solder to the metal layer 4 is poor, it does not go around the side surface of the metal layer 4, but this is achieved by optimizing the pressure and temperature, improving the wettability, or This can be easily solved by optimizing the amount of solder in the layer 5. Conversely, if they are properly adjusted, it is possible to prevent a part of the solder layer 5 from going around the side surface of the metal layer 4.

Since the metal layer 4 occupying most of the conductor terminals 3 is formed by etching a metal plate 6 having a uniform thickness, the thickness of the metal layer 4 of each conductor terminal 3 is very uniform. is there. When the solder layer 5 is formed by electroless plating, the thickness of the solder layer 5 becomes very uniform. Therefore, the thickness of the conductor terminal 3 is very uniform, and no transfer error of the solder ball due to the thickness variation of the conductor terminal 3 occurs. On the other hand, when the solder layer 5 is formed by electrolytic plating, the thickness of the solder layer 5 varies somewhat, but can be ignored compared to the conventional technique of forming solder balls only by electrolytic plating. About as small.

When the solder ball transfer sheet 1 according to the first embodiment is used, as can be seen from FIG. 2D, the core of the solder ball 12 is attached to the end face (the lower face in the figure) of the transferred solder ball 12. Metal layer 4 is exposed.
If the amount of solder in the solder layer 5 is small, it may be difficult to join the semiconductor device 10 to the substrate when mounting the semiconductor device 10 on a substrate. This can be easily solved by adjusting the amount of solder so that the solder goes around the exposed surface of the metal layer 4 during mounting.

FIG. 3 is a view for explaining a method of manufacturing a solder ball transfer sheet according to a second embodiment of the present invention. FIG. 3 (f) shows a solder ball transfer sheet obtained by the second manufacturing method. It is sectional drawing which shows the structure of a sheet. The solder ball transfer sheet 31 is composed of a base resin 32 and conductor terminals 33, and the conductor terminals 33 are characterized by being composed of three layers of a metal layer 34, a solder layer 35 and a second solder layer 39. is there.

In the second manufacturing method, first, plating masks 38 are formed on both sides of a metal plate 36 (a). At this time, it is important that the plating masks 38 on the front and back of the metal plate 36 be accurately positioned. Next, the conductor terminals 33 are provided on both surfaces of the metal plate 36 by electrolytic plating or electroless plating.
Solder layer 35 and second solder layer 3 constituting a part of
9 is formed (b), and then the base resin 32 is laminated on the surface of the metal plate 36 on which the second solder layer 39 is formed (c). Alternatively, there is a method in which a resin varnish is uniformly applied to the surface of the metal plate 36 on which the second solder layer 39 is formed, and then dried. Thereafter, the plating mask 38 on the side not in contact with the base resin 32 is peeled off (d), and the metal plate 36 is etched by using the formed solder layer 35 as an etching mask to form a metal layer constituting a part of the conductor terminal 33. 3
4 is formed (e). Finally, the plating mask 38 in contact with the base resin 32 is removed (f) to obtain the solder ball transfer sheet 31 of the present invention.

When the adhesion between the conductor terminal 33 and the base resin 32 is low, the step (f) of removing the plating mask 38 is omitted, and the adhesion between the base resin 32 and the remaining plating mask 38 is reduced. Secure the base resin 3
2 can prevent the conductor terminal 33 from peeling off.
Alternatively, both or one of the second solder layer 39 and the base resin 32 may be subjected to a surface treatment to improve the adhesion. Furthermore, if a bonding metal layer having high adhesion to the base resin 32 is formed on the surface of the second solder layer 39 and the base resin 32 is formed on the bonding metal layer, the adhesion can be improved. . The adhesive metal layer includes, for example, nickel, and can be formed by electrolytic plating or electroless plating. In this case, the configuration of the conductor terminal 33 has a four-layer structure of an adhesive metal layer, a second solder layer 39, a metal layer 34, and a solder layer 35 in this order from the base resin 32 side.

FIG. 4 is a view for explaining a transfer method of collectively transferring the solder balls 42 to the semiconductor device 10 using the solder ball transfer sheet 31 obtained by the second manufacturing method. The transfer method is the same as the case of using the solder ball transfer sheet according to the first embodiment, but the behavior of the solder layer at the time of transfer is different. That is, the solder ball transfer sheet 31 and the semiconductor device 10 are heated and pressed (b).
Thereby, when the solder layer 35 and the second solder layer 39 reach the melting temperature, a part of both the solder layers 35 and 39 goes around the side surface of the metal layer 34. Further, the solder ball 42 formed and transferred in this manner includes the metal layer 34.
Is wrapped inside the solder ball 42 and is not exposed on the surface.

FIG. 5 is a view for explaining a method of manufacturing a solder ball transfer sheet according to a third embodiment of the present invention. FIG. 5E shows a solder ball transfer sheet obtained by the third manufacturing method. It is sectional drawing which shows the structure of a sheet. The solder ball transfer sheet 51 is composed of a base resin 52 and a conductor terminal 53. The conductor terminal 53 is formed of a metal layer 54, a solder layer 55, and a second solder layer 59 connected to all the conductor terminals 53. It is characterized by being composed of three layers.

In the third manufacturing method, first, a plating mask 58 is formed on one surface of a metal plate 56 (a). Next, a solder layer 55 and a second solder layer 59 to be a part of the conductor terminal 53 are formed on both surfaces of the metal plate 56 by electrolytic plating or electroless plating (b). The base resin 52 is laminated on the surface on which the solder layer 59 is formed (c). Alternatively, there is a method in which a resin varnish is uniformly applied to the surface on which the second solder layer 59 is formed and then dried. Thereafter, the plating mask 58 is peeled off (d),
Using the formed solder layer 55 as an etching mask, the metal plate 56 is etched to form the metal layer 54 constituting the conductor terminal 53 (e), and the solder ball transfer sheet 51 of the present invention is obtained.

FIG. 6 is a view for explaining a transfer method in which the solder balls 62 are collectively transferred to the semiconductor device 10 using the solder ball transfer sheet 51 obtained by the third manufacturing method. The transfer method is the same as the case of using the solder ball transfer sheet according to the first embodiment, but the behavior of the solder layer at the time of transfer is different. That is, since the second solder layer 59 is connected to all the conductor terminals 53, the adjacent conductor terminals 53 appear to generate a bridge due to the second solder layer 59 at the time of transfer.
If the amount of solder in the solder layer 59 is properly adjusted, no bridge occurs. In addition, a solder resist is generally formed around the pads 11 of the semiconductor device 10, and the wettability of the solder is poor, so that the bridge is hardly generated.

It is easy to adjust the amount of solder (thickness) of the second solder layer 59. For example, the second solder layer 59
The method of making the solder amount (thickness) of the solder layer 55 smaller than the solder amount (thickness) of the solder layer 55 will be described. FIG. 5 (a)
In the above, when the plating mask 58 is formed on one surface of the metal plate 56, the plating mask is also formed on the entire surface on the opposite surface. Then, the solder layer 55 is formed for a predetermined time by electrolytic plating or electroless plating. At this time, the solder layer 55 has not been formed to the target thickness. The plating mask formed on the entire surface is peeled off, and the solder layer 55 is formed to a target thickness by electrolytic plating or electroless plating. Thus, the amount of solder (thickness) of the second solder layer 59 can be smaller than that of the solder layer 55. The amount of solder (thickness) of the second solder layer 59 can be adjusted by adjusting the time until the plating mask formed on the entire surface is removed. On the other hand, if the amount of solder (thickness) of the second solder layer 59 is desired to be larger than that of the solder layer 55, the metal plate 56
A plating mask is formed on the entire surface on which the solder layer 55 is to be formed, and then the solder layer 55 and the second
The solder layer 59 may be formed.

When the adhesion between the second solder layer 59 and the base resin 52 is low, the second solder layer 59 or the base resin 52 may be subjected to a surface treatment to improve the adhesion. Further, if an adhesive metal layer having high adhesion to the base resin 52 is formed on the second solder layer 59 and the base resin 52 is formed on the adhesive metal layer, the adhesion can be improved. The adhesive metal layer is, for example, nickel, and can be formed by electrolytic plating or electroless plating. In this case, the configuration of the conductor terminal 53 is such that the adhesive metal layer, the second solder layer 5
9, a four-layer structure of a metal layer 54 and a solder layer 55.

FIG. 7 is a view for explaining a method of manufacturing a solder ball transfer sheet according to a fourth embodiment of the present invention. FIG. 7 (e) shows a solder ball transfer sheet obtained by the fourth manufacturing method. It is sectional drawing which shows the structure of a sheet. The solder ball transfer sheet 71 is composed of a base resin 72 and conductor terminals 73, and the conductor terminals 73 are composed of three layers of a metal layer 74, a solder layer 75, and a second solder layer 79. The configuration is the same as that of the solder ball transfer sheet 31 obtained by the second manufacturing method shown in FIG.

In the fourth manufacturing method, an etchable solder is used. First, two solder layers to be a part of the conductor terminal are formed on both surfaces (entire surface) of the metal plate 76 by electrolytic plating or electroless plating. (A). Next, a base resin 72 is formed on one surface of the metal plate 76 on which the solder layer is formed (b), and then an etching mask 77 is formed on the other surface (c). The order can be reversed. Further, the method of forming the base resin 72 may be a method of laminating a sheet-like base resin,
A method in which the resin varnish is uniformly applied and then dried may be used. Then, by etching the metal plate and the two solder layers via the etching mask 77,
A conductor terminal 73 including the metal layer 74, the solder layer 75, and the second solder layer 79 is formed (d). At this time, of course, an etching solution that can simultaneously etch the metal layer and the two solder layers is used. Finally, the etching mask 77 is removed (e) to obtain the solder ball transfer sheet 71 of the present invention.

When the adhesion between the conductor terminal 73 and the base resin 72 is low, a surface treatment is applied to both or one of the second solder layer 79 and the base resin 72, or the surface of the second solder layer 79 is Forming the adhesive metal layer is a second step.
And the third manufacturing method. The method of using the obtained solder ball transfer sheet 71 is the same as that of the solder ball transfer sheet 31 obtained by the second manufacturing method.

In each of the solder ball transfer sheets according to the first to fourth embodiments, no solder coating is formed on the side surfaces of the metal layers 4, 34, 54, and 74. By adjusting the amount of solder in the solder layer, optimizing the temperature and pressure during transfer, and improving the solder wettability of the metal layer, the solder is transferred to the side surfaces of the metal cores of the transferred solder balls 12, 42 and 62. Wrap around. However, the temperature and pressure at the time of transfer are limited, and when it is difficult to make the solder wrap around the side surface of the metal core of the solder ball after transfer, after the solder ball transfer sheet is prepared, the conductor terminals 3 and 33,
A solder coating may be formed on the surfaces (side surfaces) of the 53 and 73 by electrolytic plating or electroless plating. As a result, the solder is also formed on the side surfaces of the metal layer. Therefore, even if the temperature and pressure at the time of transfer are limited, the metal core of the solder ball after transfer has a shape surrounded by the solder layer.

As described above, in the solder ball transfer sheet according to the present invention, the metal layer serving as the core of the solder ball is formed by etching. Manufacturing time and manufacturing cost can be significantly reduced. Also, judging from the viewpoint of the size and reliability of the solder ball, by increasing the thickness of the metal plate as much as possible,
If the rate of the etching step can be increased, the manufacturing time and the manufacturing cost can be further reduced.

Since the metal layer is obtained from a metal plate having a uniform thickness by an etching process, a uniform metal layer having no thickness variation is obtained, and a solder layer formed by electroless plating is uniform without thickness variation. . In addition, although the solder layer formed by electrolytic plating has some thickness variation, the thickness variation is so small as to be negligible as compared with the conventional technique of forming solder balls only by electrolytic plating.

[0041]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

Rolled copper plate 0.25 mm thick (metal plate 6)
Was laminated with a silicone-modified polyimide (base resin 2) to obtain a two-layer sheet composed of a copper plate and a resin layer. A dry film resist was laminated on the copper plate surface of the two-layer sheet, exposed and developed, and then Sn-Pb eutectic solder was electroplated to form a 20 μm-thick solder (solder layer 5). In addition, peel off the dry film,
Through a copper plate etching process, 4096 copper cylinders (metal layer 4) having a pitch of 0.5 mm and a diameter of 0.25 mm were formed, and a solder ball transfer sheet 1 according to the first embodiment of the present invention was produced.

Example 2 On both sides of a rolled copper plate (metal plate 36) having a thickness of 0.25 mm,
After laminating dry film resist, exposing and developing,
A 20 μm thick solder (solder layers 35 and 39) was formed on both sides by electroplating Sn—Pb eutectic solder. After laminating silicone-modified polyimide (base resin 32) on the copper plate on which the solder is formed, the base resin 3
The dry film on the side not in contact with No. 2 was peeled off, and after a copper plate etching step, the pitch was 0.5 mm and the diameter was 0.25.
4096 mm copper columns (metal layer 34) are formed, and the solder ball transfer sheet 31 according to the second embodiment of the present invention is formed.
Was prepared. The dry film in contact with the base resin did not peel off.

Example 3 One side of a 0.25 mm thick rolled copper plate (metal plate 56)
After laminating dry film resist, exposing and developing,
Electroplating of Sn-Pb eutectic solder allows solder having a thickness of 20 μm (solder layer 55) and a thickness of 10 μm
(The second solder layer 59, solder plating on the entire surface) was formed. Silicone-modified polyimide (base resin 52) was laminated on the entire surface of the copper plate that was solder-plated. Peel the dry film, through the copper plate etching process,
A copper cylinder with a pitch of 0.5 mm and a diameter of 0.25 mm (metal layer 5
4) were formed to form a solder ball transfer sheet 51 according to the third embodiment of the present invention.

The solder balls were transferred to the semiconductor device 10 using the solder ball transfer sheets prepared in Examples 1 to 3. The transfer conditions are as follows: the temperature of the heating / pressing tool 20: 150 ° C., the temperature of the substrate support 22: 250 ° C., the load: 6 kgf / 4096 balls, the heating and pressing time:
10 seconds. Ten samples were prepared for each example, and a transfer experiment was performed under the above conditions. As a result, it was confirmed that 4096 solder balls were completely transferred to the semiconductor device side in all the samples. The solder balls mounted on the semiconductor device have a pitch of 0.5 mm,
The diameter was 0.3 mm. The height of the solder ball was 0.26 mm in Example 1 and 0.27 mm in Examples 2 and 3.

[0046]

According to the present invention, a solder ball transfer sheet on which solder balls can be collectively mounted on a semiconductor device can be manufactured and provided at low cost, and productivity can be greatly improved. In addition, by using the solder ball transfer sheet of the present invention, not only can the solder balls be easily mounted on the semiconductor device, but also the transferred solder balls have a metal core so that the moisture resistance reliability is greatly improved. In addition, when copper is used for the metal layer (the core of the solder ball), the electric resistance can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a method for manufacturing a solder ball transfer sheet according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a transfer method of collectively transferring solder balls to a semiconductor device using the solder ball transfer sheet according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a method for manufacturing a solder ball transfer sheet according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a transfer method for collectively transferring solder balls to a semiconductor device using a solder ball transfer sheet according to a second embodiment of the present invention.

FIG. 5 is a sectional view illustrating a method for manufacturing a solder ball transfer sheet according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a transfer method for collectively transferring solder balls to a semiconductor device using a solder ball transfer sheet according to a third embodiment of the present invention.

FIG. 7 is a sectional view illustrating a method for manufacturing a solder ball transfer sheet according to a fourth embodiment of the present invention.

[Explanation of symbols]

 1,31,51,71 Solder ball transfer sheet 2,32,52,72 Base resin 3,33,53,73 Conductor terminal 4,34,54,74 Metal layer 5,35,55,75 Solder layer 6,36 , 56, 76 Metal plate 8, 38, 58 Plating mask 10 Semiconductor device 11 Pad 12, 42, 62 Solder ball 13 Interposer 15 Semiconductor chip 16 Sealing resin 20 Heating / pressing tool 21 Suction hole 22 Substrate support 39, 59, 79 Second solder layer 77 Etching mask

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi August Shuto 2-5-8 Higashishinagawa, Shinagawa-ku, Tokyo Sumitomo Bakelite Co., Ltd.

Claims (14)

[Claims] 1. A solder ball transfer sheet to be mounted on a semiconductor device requiring a solder ball mounting step by collectively transferring solder balls, wherein the solder ball transfer sheet is mounted on a base resin serving as a base of the solder ball transfer sheet. 2. A solder ball transfer sheet, wherein a conductor terminal comprising two or more layers is formed. 2. The solder ball transfer sheet according to claim 1, wherein the conductor terminals are composed of two layers, and a metal layer and a solder layer are formed in this order from the base resin side. 3. The solder ball transfer sheet according to claim 1, wherein the conductor terminals are formed of three layers, and are formed in the order of a solder layer, a metal layer, and a solder layer from the base resin side. 4. The solder ball transfer sheet according to claim 3, wherein an adhesive metal layer is provided between the base resin and the solder layer forming the conductor terminal. 5. The solder ball transfer sheet according to claim 1, wherein a solder coating is formed on the surface of the conductor terminal by electrolytic plating or electroless plating. 6. The solder ball transfer sheet according to claim 2, wherein the metal layer is copper. 7. A step of forming a base resin on one side of the metal plate, a step of forming a plating mask on the other side of the metal plate, and a portion of the conductor terminal on the metal plate by electrolytic plating or electroless plating. A step of forming a solder layer to be formed, a step of removing a plating mask, and a step of forming a metal layer of a conductor terminal by etching a metal plate using the formed solder layer as an etching mask. A method for producing a solder ball transfer sheet. 8. A step of forming a plating mask on both sides of the metal plate, a step of forming a solder layer to be a part of a conductor terminal on the metal plate by electrolytic plating or electroless plating, A step of forming a base resin on one surface, a step of removing a plating mask, and a step of forming a metal layer of a conductor terminal by etching a metal plate using the formed solder layer as an etching mask. A method for producing a solder ball transfer sheet, wherein the method is performed in this order. 9. A step of forming a plating mask on one side of a metal plate, a step of forming a solder layer to be a part of a conductor terminal on both sides of the metal plate by electrolytic plating or electroless plating, and a metal plate having a solder layer formed thereon. Forming a base resin on the side where the plating mask is not formed, removing the plating mask, and forming a metal layer of the conductor terminal by etching the metal plate using the formed solder layer as an etching mask A method of manufacturing a solder ball transfer sheet, wherein the steps are performed in this order. 10. A step of forming a solder layer to be a part of a conductor terminal on both sides (entire surface) of a metal plate by electrolytic plating or electroless plating, and forming a base resin on one surface of the metal plate on which the solder layer is formed. Forming an etching mask on the other surface of the metal plate on which the solder layer is formed,
A method for manufacturing a solder ball transfer sheet, comprising: a step of forming conductor terminals by etching a metal plate and two solder layers; and a step of removing an etching mask. 11. A method for forming an adhesive metal layer on a surface of a solder layer on which a base resin is formed by electrolytic plating or electroless plating before the step of forming a base resin. A method for producing a solder ball transfer sheet according to any one of claims 8 to 10. 12. The method according to claim 7, wherein after forming the conductor terminal, a solder coating is formed on the surface of the conductor terminal by electrolytic plating or electroless plating. Manufacturing method of solder ball transfer sheet. 13. The method according to claim 13, wherein the metal layer is copper.
A method for manufacturing a solder ball transfer sheet according to any one of claims 7 to 12. 14. A solder ball transfer sheet mounted on a semiconductor device requiring a solder ball mounting step by batch-transferring solder balls, according to claim 7, wherein A solder ball transfer sheet produced by the method.