JPH11186455A - Method for forming protruding electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability in a method for forming a protruding electrode including a process for arranging resin in the neighborhood of forming position of the protruding electrode. SOLUTION: A method for forming protruding electrode includes a mask mounting process for mounting a resin mask 44 in which is positioning opening 46 is formed at a forming position of a protruding electrode 52 on a package 32 having a pad part 40 at which the protruding electrode 52 is formed, paste arranging process for arranging paste 48 at the pad part 40 through this resin mask 44, protruding electrode arranging process for arranging a solder ball 50 on the paste 48 by using the resin mask 44 as a positioning reference, and heating process for connecting the protruding electrode 52 with the pad part 40 by operating a heating process while maintaining the mounting state of the resin mask 44.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a bump electrode, and more particularly to a method of forming a bump electrode including a step of arranging a resin in the vicinity of a formation position of a bump electrode. 2. Description of the Related Art Generally, as a method of forming a bump electrode on a semiconductor device and a circuit board, a method using plating, a method using solder paste, a method using solder balls, and the like are known. Further, a method using a solder ball is used in forming a projection electrode having a thickness of several hundred μm.

On the other hand, with the recent miniaturization of circuit elements, protruding electrodes tend to be miniaturized, and the formation pitch tends to be narrower. Further, in order to reduce the cost, it is necessary to simplify the method of forming the protruding electrodes. Therefore, there is a demand for a method for easily and reliably forming miniaturized bump electrodes.

[0003]

2. Description of the Related Art A conventional method for forming a bump electrode using solder as a bump electrode will be described below with reference to FIGS. FIG. 17 shows a semiconductor device in an initial state before the method of forming a bump electrode is performed. The semiconductor device in this state is a so-called LGA (Land Grid Arra).
y) The structure is such that only a plurality of pad portions 10 are arranged on the mounting side surface of the package 2.

In FIG. 1, a package 2 has a multilayer structure made of a ceramic or resin material, and has a cavity 12 formed therein. The semiconductor chip 4 is mounted in the cavity 12 and
It is configured such that a part of the internal wiring pattern 6 is exposed. The internal wiring pattern 6 is electrically connected to the pad section 10 by an internal wiring (not shown) formed in the package 2. The semiconductor chip 4 and the internal wiring pattern 6 are connected by wires 8. Therefore, the semiconductor chip 4 is configured to be electrically connected to the pad portion 10 via the wires 8, the internal wiring patterns 6, and the internal wires.

In the semiconductor device having the above structure, the protruding electrodes 2 are provided.
18, first, as shown in FIG. 18, a metal mask 14 is formed on the surface of the package 2 on which the pad portions 10 are formed.
Is mounted (mask mounting step). This metal mask 14
Is the position where the pad portion 10 is formed (that is,
(A position where is formed), a positioning opening 16 is formed.

As described above, the metal mask 1 is attached to the package 2.
After mounting 4, paste 18 (flux or the like) is arranged in positioning opening 16 formed in metal mask 14 as shown in FIG. 19 (paste arrangement step). As a method of disposing the paste 18 in the positioning opening 16, for example, a screen printing method can be applied. Further, by loading the paste 18 into the positioning opening 16, the paste 18 is arranged above the pad portion 10.

[0007] Subsequently, as shown in FIG. 20, a solder ball 20 is mounted on the pad portion 10 (projection electrode disposing step). At this time, the solder balls 20 are attached to the metal mask 14.
The solder ball 20 is mounted in a state where it is positioned by the positioning opening 16 formed in the pad portion 10.
It can be mounted in a state where it is positioned with high accuracy. In this mounting state, the paste 18 has a predetermined viscosity and thus functions as an adhesive, so that the solder balls 20 are temporarily fixed on the pad portion 10 by the paste 18.

[0008] As described above, the solder ball 20 is connected to the pad portion 1.
When the metal mask 14 is mounted on the package 2, the metal mask 14 is subsequently removed from the package 2 as shown in FIG. Next, the solder ball 20 is melted and bonded to the pad portion 10 by, for example, passing the package 2 through a reflow furnace and performing heat treatment, thereby forming the protruding electrode 22 as shown in FIG. Conventionally, the semiconductor device 24 having the protruding electrode 22 has been manufactured by performing the above-described processing.

FIG. 23 to FIG. 26 show a BGA (Ball
3 shows a method of forming a protruding electrode in a semiconductor device of a (Grid Array) type. FIGS. 23 and 24 show the semiconductor device before the formation of the bump electrode. The semiconductor device in this state has a so-called LGA structure, and the substrate 26
The structure is such that only a plurality of pad portions 10 are provided on the mounting side surfaces of A and 26B. Incidentally, in FIG.
Is an insulating film, which is provided to insulate and protect the substrate 26A except for the position where the pad portion 10 of the substrate 26A is provided.

In FIG. 23, the substrate 26A on which the pad portions 10 are provided has a structure using a so-called printed wiring board, and in FIG. 24, the substrate 26B has a structure using a single-sided copper-clad tape. The resin package 3, the semiconductor chip 4, the wires 8, and the bonding pads 29 are provided on the opposite sides of the mounting side surfaces of the substrates 26A and 26B. The semiconductor chip 4 is bonded to the substrates 26A, 26B by the die pad 5.
To the bonding pad 2 by wire 8
9 is connected. The bonding pad 29 is shown in FIG.
The configuration shown in FIG. 3 uses a through-hole electrode 28 and the like, and the configuration shown in FIG. The resin package 3 has a function of protecting the semiconductor chip 4, the wires 8, the bonding pads 29, and the like by sealing them.

FIG. 25 shows a state in which solder balls 20 for forming bump electrodes are arranged on the semiconductor device shown in FIG. In this state, the solder balls 20 are temporarily fixed to the pad portions 10 by the solder paste 18 (or flux) (projection electrode disposing step). Solder ball 2
When 0 is temporarily fixed to the pad section 10, a heating step is subsequently performed. FIG. 26 shows a state in which the heating step has been completed. By performing the heating step, the solder paste 18 is vaporized, and the solder balls 20 are melted to form the protruding electrodes 22.

[0012]

However, in the above-mentioned conventional method of forming a bump electrode, after the metal mask 14 shown in FIG. 21 is removed and the solder ball 20 shown in FIG. After the solder balls 20 were provided, the solder balls 20 were fixed only to the paste 18, and the solder balls 20 could not be held sufficiently.

Further, even after the heat treatment shown in FIGS. 22 and 26 is performed, the protrusion electrode 22 is held only by the bonding force between the protrusion electrode 22 and the pad portion 10. Even after formation, the protruding electrode 2
2 could not be sufficiently retained. For this reason, during the process of forming the protruding electrode 22 or the semiconductor device 24.
There is a possibility that the solder balls 20 or the protruding electrodes 22 may be detached from the package 2 during the transportation after the shipment, and that sufficient reliability cannot be obtained in the arrangement of the solder balls 20 or the protruding electrodes 22. There was a point.

The present invention has been made in view of the above points, and an object of the present invention is to provide a method for forming a projecting electrode capable of forming the projecting electrode with high reliability.

[0015]

The above objects can be attained by taking the following means. Claim 1
In the method for forming a protruding electrode described above, a mask mounting step of mounting a resin mask having a positioning opening formed at a position where the protruding electrode is formed on a substrate having a pad portion on which the protruding electrode is formed; A paste disposing step of disposing a paste on the pad portion, a protruding electrode disposing step of disposing a protruding electrode on the paste using the resin mask as a reference for positioning, and a state in which the resin mask is mounted. And a heating step of bonding the protruding electrode to the pad portion by performing a heat treatment while maintaining the above conditions.

According to a second aspect of the present invention, in the method of forming a bump electrode according to the first aspect, the resin mask is formed of a thermoplastic resin. According to a third aspect of the present invention, in the method of forming a bump electrode according to the first or second aspect, the bump electrode is made of solder.

According to a fourth aspect of the present invention, in the method of forming a bump electrode according to the third aspect, the melting point (Tm) of the resin mask is higher than the melting point (Tb) of the solder (Tm ≧ Tm). Tb). Further, in the method of forming a bump electrode according to claim 5, a mask mounting step of mounting a metal mask having a positioning opening at a position where the bump electrode is formed on a substrate having a pad portion on which the bump electrode is formed. A paste disposing step of disposing a paste on the pad portion via the metal mask; a projecting electrode disposing step of disposing a projecting electrode on the paste using the metal mask as a reference for positioning; After removing the mask, a heating step of bonding the protruding electrode to the pad portion by performing a heat treatment, and a resin plate that is performed after the heating step is completed and has an opening at a position where the protruding electrode is formed. And a step of disposing a resin plate on the substrate.

According to a sixth aspect of the present invention, in the method of forming a bump electrode according to the fifth aspect, the resin plate is formed of a thermoplastic resin. According to a seventh aspect of the present invention, in the method of forming a bump electrode according to the fifth or sixth aspect, the bump electrode is a solder.

In the invention according to claim 8, in the method for forming a bump electrode according to claim 7, the melting point (Tm) of the resin plate is higher than the melting point (Tb) of the solder (Tm ≧ Tm). Tb). Further, in the method of forming a bump electrode according to claim 9, a mask mounting step of mounting a metal mask having a positioning opening formed at a formation position of the bump electrode on a substrate having a pad portion on which the bump electrode is formed. A paste disposing step of disposing a paste on the pad portion via the metal mask; a projecting electrode disposing step of disposing a projecting electrode on the paste using the metal mask as a reference for positioning; A heating step of bonding the protruding electrode to the pad portion by performing a heat treatment after removing the mask, and a resin having fluidity, which is performed after completion of the heating step and has a fluidity except for a position where the protruding electrode is formed. And disposing a resin on the substrate.

According to a tenth aspect of the present invention, in the method of the ninth aspect, the resin is formed of a thermoplastic resin. According to an eleventh aspect of the present invention, in the method for forming a bump electrode according to the ninth or tenth aspect, the bump electrode is a solder.

According to a twelfth aspect of the present invention, in the method for forming a bump electrode according to the eleventh aspect, the melting point (Tm) of the resin is higher than the melting point (Tb) of the solder (Tm ≧ Tb). ). Also,
In the method for forming a bump electrode according to the invention of claim 13,
A protruding electrode is disposed at a position where the protruding electrode is provided through the opening on a substrate in which a protruding electrode protecting resin mask having an opening in advance at the position where the protruding electrode is disposed is provided at least in the protruding electrode formation region. And a heating step of bonding the projection electrode to a pad provided at a location where the projection electrode is provided by performing a heat treatment.

According to a fourteenth aspect of the present invention, in the projection electrode forming method according to the thirteenth aspect, the resin mask for protecting the bump electrode is provided with a mask mounting step before the bump electrode arranging step. It is characterized by being formed.

According to a fifteenth aspect of the present invention, in the method for forming a bump electrode according to the thirteenth or fourteenth aspect, a paste is applied to the bump electrodes provided. It is. Claim 16
According to the present invention, in the method for forming a bump electrode according to claim 13 or 14, the method further comprises a step of applying a paste to the bump electrode arrangement position before the bump electrode arrangement step. It is.

According to a seventeenth aspect of the present invention, in the method for forming a bump electrode according to any one of the thirteenth to sixteenth aspects, the resin mask for protecting the bump electrode has a softening point softened in the heating step. Characterized by comprising a resin having Each of the above means operates as follows.

According to the first aspect of the present invention, in the mask mounting step, the resin mask having the positioning openings formed at the positions where the protruding electrodes are formed is mounted on the substrate having the pad portions on which the protruding electrodes are formed. Is done. Therefore, in a state where the resin mask is mounted, portions other than the pad portion on the substrate are covered (masked) by the resin mask.

Subsequently, in the paste disposing step, the paste is disposed on the pad portion via the resin mask, so that the bump electrodes can be temporarily fixed on the pace. Subsequently, by performing the protruding electrode arrangement step,
Protruding electrodes are provided on the paste. At this time, since the resin mask can be used as a reference for positioning, it is possible to mount the projecting electrode in a state where it is accurately positioned on the pad portion.

In the subsequent heating step, the protruding electrode is joined to the pad portion by performing a heat treatment while maintaining the state in which the resin mask is mounted. Therefore, even after the protruding electrodes are provided on the paste, the resin mask maintains the state of being mounted on the substrate, so that the protruding electrodes can be held by the resin mask. The resin mask is not removed from the substrate, and remains mounted on the substrate even after the semiconductor device is manufactured and shipped.

Thus, in the step of forming the protruding electrodes after the resin mask is mounted and during the transportation after shipping, the protruding electrodes can be prevented from separating from the substrate, and the reliability of the semiconductor device can be improved. it can. Further, when mounting the semiconductor device having the above configuration, the resin mask functions as a so-called underfill resin, so that a stress generated due to a difference in thermal expansion between the semiconductor device and the mounting board during mounting is applied to the protruding electrodes. Even if it does, the projection electrode can be reliably prevented from being damaged or peeled off.

[0029] Further, claim 2, claim 6, and claim 1
According to the invention described in Item 0, since the resin mask, the resin plate, and the resin having fluidity are formed of the thermoplastic resin, the thermoplastic resin is subjected to the heat treatment again after being heat-molded in the heating step. Melts. Therefore, the resin mask, the resin plate, and the resin having fluidity are melted by the heat applied at the time of mounting, and are filled without gaps between the semiconductor device and the mounting substrate. Thereby, the function as the underfill resin can be reliably achieved.

Further, claim 3, claim 7, and claim 1
According to the invention described in the first aspect, since the solder is used as the protruding electrode, the solder is melted at a relatively low temperature, so that the resin mask can be prevented from being damaged by heat due to the melting of the solder. According to the fourth, eighth, and twelfth aspects of the present invention, the melting point (Tm) of the resin mask, the resin plate, and the resin having fluidity is higher than the melting point (Tb) of the solder. With the setting (Tm ≧ Tb), the resin mask can be prevented from melting before the solder melts, and the connection between the solder and the pad portion can be reliably performed.

According to the fifth aspect of the present invention, a protruding electrode is formed by using a metal mask in the same manner as in the conventional method of forming a protruding electrode, and then the metal mask is removed and a heating step is performed. By performing the resin plate disposing step, a resin plate having an opening at a position where the protruding electrode is formed can be disposed on the substrate.

Further, since the bump electrodes are held by the resin plate, the reliability of the semiconductor device can be improved. When the semiconductor device having the above configuration is mounted, the resin plate functions as a so-called underfill resin, so that stress generated due to a difference in thermal expansion between the semiconductor device and the mounting substrate during mounting is applied to the protruding electrodes. Even if it does, the projection electrode can be reliably prevented from being damaged or peeled off.

According to the ninth aspect of the present invention, a protruding electrode is formed using a metal mask in the same manner as in the conventional method of forming a protruding electrode, and after removing the metal mask,
The protruding electrode can be formed by performing a resin disposing step and disposing a resin having fluidity on the substrate except for the position where the protruding electrode is formed.

Further, since the bump electrodes are held by the resin plate, the reliability of the semiconductor device can be improved. When the semiconductor device having the above configuration is mounted, the resin functions as a so-called underfill resin, so that during the mounting, a stress generated due to a difference in thermal expansion between the semiconductor device and the mounting substrate is applied to the projection electrode. However, it is possible to reliably prevent the protruding electrode from being damaged or peeled off.

Further, since a resin having fluidity is used as the resin, there is no need to previously form an opening or the like in the resin mask or the resin plate as in the first or second aspect of the present invention. Therefore, the cost and the number of steps can be reduced. According to the thirteenth aspect of the present invention, in the step of disposing the protruding electrodes, the protruding electrodes are disposed on the substrate. The substrate has a pad portion at a position where the projecting electrode is formed, and a resin mask for protecting the projecting electrode having an opening at a position where the projecting electrode is arranged at least in a region where the projecting electrode is arranged. Have been.

In the step of disposing the protruding electrode, the protruding electrode is disposed on the pad portion through the opening. On this occasion,
The protruding electrode protecting resin mask can be used for positioning the protruding electrodes. In the subsequent heating step, the protruding electrodes are joined to the pad portions. As a result, the projecting electrode is in a state where its joint is protected by the resin mask for protecting the projecting electrode, and even if a certain stress (mechanical or thermal stress) is applied to the projecting electrode in the subsequent use environment, it is compared with the conventional structure. Can be reinforced.

According to the fourteenth aspect of the present invention, the step of arranging the resin mask is performed before the step of arranging the projecting electrodes, so that the position at which the projecting electrodes are arranged on the substrate before the step of arranging the projecting electrodes. And a resin mask for protecting a protruding electrode having an opening is provided. Therefore, the pad portion can be protected by the protruding electrode protecting resin mask.

According to the present invention, before the heating step is performed, the projecting electrode is temporarily fixed to the pad portion by the paste, and the projecting electrode is dropped from the pad portion. Can be prevented. In the heating step, the paste (flux) is present at the contact portion between the bump electrode and the pad portion, so that the pad portion and the bump electrode can be smoothly and reliably joined.

Further, according to the seventeenth aspect of the present invention, the resin mask for protecting the protruding electrode is made of a resin having a softening point softened in the heating step. The resin mask for protecting the protruding electrodes softens and flows. As a result, the protruding electrode protecting resin mask fills the opening and comes into close contact with the protruding electrode, and the reformed protruding electrode protecting resin mask (resin) functions as a so-called underfill resin. For this reason, even if stress generated due to a difference in thermal expansion between the semiconductor device and the mounting substrate during mounting is applied to the protruding electrodes, it is possible to reliably prevent the protruding electrodes from being damaged or peeled off.

Further, since the resin mask for protecting the projecting electrode is softened in the heating step and then re-formed, the size of the opening of the resin mask for protecting the projecting electrode before the heating step is determined by the size of the projecting electrode. Therefore, the protrusion electrode can be set to a large value, and the process of disposing the protruding electrodes can be easily performed.

[0041]

Embodiments of the present invention will now be described with reference to the drawings. 1 to 6 show a method of forming a bump electrode according to one embodiment of the present invention. 1 shows a semiconductor device before a bump electrode is formed, FIG. 2 shows a mask mounting step in a bump electrode forming method, FIG. 3 shows a paste disposing step, and FIG. FIG. 5 shows an electrode disposing step, and FIG. 5 shows a heating step. FIG. 6 shows a state where the completed semiconductor device 30 is mounted. Hereinafter, regarding the method of forming the bump electrode,
The description will be made in the order of the formation process.

FIG. 1 shows a semiconductor device in an initial state before the method of forming a bump electrode is performed. The semiconductor device in this state is a so-called LGA (Land Grid Array)
The structure is such that only a plurality of pad portions 40 are provided on the mounting side surface of the package 32 (substrate). In the figure, a package 32 has a multilayer structure made of a ceramic or resin material, and has a cavity portion 42 formed therein. The semiconductor chip 34 is mounted on the cavity 42 and a part of the internal wiring pattern 36 is exposed.

The internal wiring pattern 36 is electrically connected to the pad section 40 by an internal wiring (not shown) formed in the package 32. The semiconductor chip 34 and the internal wiring pattern 36 are connected by wires 38. Therefore, the semiconductor chip 34 is
8, the internal wiring pattern 36, and the pad section 40 are electrically connected via the internal wiring. still,
The configuration described above is equivalent to a conventional semiconductor device in an initial state.

The protruding electrode 5 is provided on the semiconductor device having the above structure.
2, a resin mask 44 is first formed on the surface of the package 32 on which the pad portions 40 are formed.
Is mounted (mask mounting step). The resin mask 44 is made of a thermoplastic resin (for example, a polyimide resin).
A positioning opening 46 is formed in advance at the position where the pad portion 40 is formed (that is, the position where the protruding electrode 52 will be formed later). In a state where the resin mask 44 is mounted, a portion other than the formation position of the pad portion 40 on the package 32 is covered (masked) by the resin mask 44.

The resin mask 44 is in a state of being cured at room temperature, so that the accuracy of forming the opening 46 is maintained high. Furthermore, the thickness (t) of the resin mask 44 is set to be about half the thickness (R) of the solder ball 50 (see FIG. 4) described later (t =
R / 2). When the resin mask 44 is mounted on the package 32 as described above, subsequently, as shown in FIG. 3, a paste 48 (flux or the like) is disposed in the positioning opening 46 formed in the resin mask 44 (see FIG. 3). Paste disposing step). The paste 48 is used for temporarily fixing the solder balls 50 to the package 32 in a later-described projection electrode disposing step, which will be described later, and for improving the bonding between the solder balls 50 and the pad portions 40 in a heating step. It is arranged in.

As a method for disposing the paste 48 in the positioning opening 46, for example, a filling method using a dispenser, a screen printing method, or the like can be applied. In addition, by loading the paste 48 into the positioning opening 46, the paste 48 is arranged above the pad portion 40. Subsequently, as shown in FIG. 4, the solder balls 50 are mounted on the pad portions 40 (projection electrode arranging step). At this time, solder balls 5
0 is mounted in a state of being positioned by a positioning opening 46 formed in the resin mask 44. That is, the resin mask 44 is the same as the conventional metal mask 14 (see FIG. 20).
It has the same function as.

As described above, since the solder balls 50 are positioned by the positioning openings 46 formed in the resin mask 44, the solder balls 50 can be mounted on the pad portions 40 with high precision. it can.
In addition, since the paste 48 has a predetermined viscosity and also functions as an adhesive, the solder ball 50 is temporarily fixed on the pad portion 40 by the paste 48 in the mounted state shown in FIG. In addition, the solder balls 50 are used for the resin mask 4.
4 and is securely mounted on the package 32.

When the solder ball 50 is mounted on the pad portion 40, subsequently, the package 32 is subjected to a heat treatment while the resin mask 44 is maintained (heating step). In this heating step, the package 32 on which the resin mask 44 is mounted is passed through, for example, a reflow furnace to perform a heating process. During this heat treatment, the solder balls 50
Is held by the resin mask 44, so that the solder ball 50 does not separate from the package 32.

By performing the above-described heating step, the solder balls 50 are melted and bonded to the pad portions 40, thereby forming the protruding electrodes 52 as shown in FIG. Also,
The resin mask 44 made of a thermoplastic resin is also melted, and the positioning opening 46 is filled with the melted resin (hereinafter, the resin mask 44 in this state is referred to as an underfill resin 54A). By performing the above series of processes, the semiconductor device 30 having the protruding electrodes 52 and the underfill resin 54A shown in FIG. 5 is formed.

At this time, in this embodiment, the melting point Tm of the resin mask 44 is set to be higher than the melting point Tb of the solder to be the protruding electrodes 52 (Tm ≧ Tb). This allows
The resin mask 44 can be prevented from melting before the solder melts, and the connection between the protruding electrode 52 and the pad portion 40 can be reliably performed. Further, since the solder is melted at a relatively low temperature as described above, it is possible to prevent the resin mask 44 (the underfill resin 54A) from being damaged by heat due to the melting of the solder.

As described above, in the method of forming the protruding electrode 52 according to the present embodiment, the resin mask 44 is not removed from the package 32 after the mask mounting step, so that the semiconductor device 30 is manufactured and shipped. Thereafter, the state of being mounted on the package 32 is maintained. For this reason, the protruding electrodes 5 after the resin mask 44 is attached
In the formation process of 2, the transportation after shipping, and the like, it is possible to prevent the solder balls 50 and the protruding electrodes 52 from being detached from the package 32, thereby improving the reliability of the semiconductor device 30.

As shown in FIG. 6, when the semiconductor device 30 having the above structure is mounted on the mounting substrate 56, the underfill resin 54A (resin mask 44) is provided at a position of the package 32 facing the mounting substrate 56. Exists, so
Even if stress generated due to a difference in thermal expansion between the semiconductor device 30 and the mounting substrate 56 during mounting is applied to the protruding electrode 52,
The projection electrode 52 is reliably prevented from being damaged, and from being peeled off between the projection electrode 52 and the pad portion and between the projection electrode 52 and the connection pattern 58 (formed on the mounting board 56). be able to.

Next, a second embodiment of the present invention will be described. 7 and 8 are views for explaining a method of forming a bump electrode according to a second embodiment of the present invention. In the forming method according to the present embodiment, the metal mask 1 is formed in the same manner as the conventional method of forming the bump electrode described with reference to FIGS.
4, a heating step is carried out after removing the metal mask 14 and then a resin arranging step and a heating step are carried out to form the protruding electrodes 22. Is what you do.

FIG. 7 is a view showing a resin disposing step in the present embodiment. Except for resin 55 having fluidity (hereinafter referred to as
(Referred to as a liquid resin 55). In this embodiment, the liquid resin 55 is disposed in the package 2 using the nozzle 59. At this time, the liquid resin 55 uses a thermosetting resin, and the thickness of the liquid resin 55 on the package 2 is set to be approximately half the diameter of the solder ball 20.

When the liquid resin 55 is provided on the upper surface of the package 2 except for the position where the protruding electrodes 22 are formed by performing the above-described resin providing step, a heating step is subsequently performed. In this heating step, the package 2 provided with the liquid resin 55 is passed through, for example, a reflow furnace to melt the liquid resin 55 and remove the gap between the projecting electrode 22 and the liquid resin 55. It solidifies to form the underfill resin 54B. FIG. 8 is a view showing a semiconductor device 60 manufactured by using the forming method according to the present embodiment.

According to the forming method according to the present embodiment, the projecting electrode 22 can be formed by using the projecting electrode 22 as it is without changing the conventional process and equipment for forming the projecting electrode 22.
Further, even after the metal mask 14 is removed, the projection electrode 22 is held in the package 2 by the liquid resin 55 or the underfill resin 54B after the execution of the resin disposing step, so that the reliability of the semiconductor device 60 is improved. Can be improved.

As in the first embodiment, even if the stress generated due to the difference in thermal expansion between the semiconductor device 60 and the mounting substrate is applied to the projecting electrode by the underfill resin 54B during mounting, the projecting electrode 22 And the like can be reliably prevented from being damaged or peeled off. Further, since the liquid resin 55 having fluidity is used as the resin, the positioning openings 46 are previously formed in the resin mask 44 as in the first embodiment.
Need not be formed with high precision.

Next, a third embodiment of the present invention will be described. 9 to 11 are views for explaining a method of forming a bump electrode according to a third embodiment of the present invention. As in the second embodiment, the solder ball 20 is disposed using the metal mask 14 by applying the conventional method of forming a bump electrode, and then the metal mask 14 is removed. It is characterized in that the step of disposing a resin and the step of heating are performed to form the protruding electrodes 22.

FIG. 9 is a view showing a resin plate arranging step in this embodiment. The upper surface of the package 2 on which the protruding electrodes 22 are formed (the surface on which the pad portions 10 are formed) is provided. FIG. 10 shows a state in which a resin plate 62 having an opening 64 formed therein is provided at a position corresponding to the formation position, and FIG. 10 shows a state in which the resin plate 62 is provided in the package 2.

In this embodiment, since the resin plate 62 is used as described above, the liquid resin 55 is disposed on the package 2 using the nozzle 59 as in the second embodiment.
The resin plate 62 can be efficiently disposed on the package 2 in a short time. The resin plate 62 is made of a thermoplastic resin, and the thickness of the resin plate 62 is set to be approximately half the diameter of the solder ball 20.

By performing the above-described resin plate disposing step, when the resin plate 62 is disposed on the upper surface of the package 2,
Subsequently, a heating step is performed. In this heating step, the package 2 provided with the resin plate 62 is passed through, for example, a reflow furnace to melt the resin plate 62 and remove a gap between the resin plate 62 and the protruding electrode 22, thereby removing the underfill resin 54B. Form. FIG. 11 is a view showing a semiconductor device 70 manufactured by using the forming method according to the present embodiment.

According to the forming method according to the present embodiment, without changing the forming process and equipment of the conventional protruding electrode 22,
Since the protruding electrode 22 can be formed by using it as it is, the protruding electrode 22 can be formed at low cost. Further, after the resin plate disposing step is performed, the bump electrodes 22 are held in the package 2 by the resin plate 62 or the underfill resin 54C, so that the reliability of the semiconductor device 70 can be improved.

As in the first embodiment, even if the stress generated due to the difference in thermal expansion between the semiconductor device 70 and the mounting substrate is applied to the bump electrode by the underfill resin 54C during mounting, the bump electrode 22 And the like can be reliably prevented from being damaged or peeled off.

Next, a fourth embodiment of the present invention will be described. 12 to 16 are views for explaining a method of forming a bump electrode according to a fourth embodiment of the present invention. The description of the method for forming the bump electrode according to the present embodiment will be described with reference to BGA (BallGri
d Array) type semiconductor device will be described as an example.
Therefore, in FIGS. 12 to 16, the same components as those shown in FIGS. 23 to 26 are denoted by the same reference numerals and description thereof is omitted. Also, the same components as those of the first to third embodiments described with reference to FIGS. 1 to 11 are denoted by the same reference numerals and description thereof is omitted.

FIG. 12 shows the semiconductor device in an initial state before the bump electrodes 22 are provided. 23 is different from the conventional structure shown in FIG. 23 in that a resin mask 44 (hereinafter, referred to as a resin mask 44) for protecting a protruding electrode having a positioning opening 46 is provided at a position where the protruding electrode 22 is disposed. Where you are. The resin mask 44 is made of a thermoplastic resin (for example, a polyimide resin) and is in a cured state at room temperature.
In the heating step described later, those having a softening point to be softened are selected. The thickness of the resin mask 44 is about half the diameter of the solder ball 20 described later.

The resin mask 44 having the above structure is formed by performing a resin mask disposing step before the projecting electrode disposing step. In this manner, the resin mask 44 is formed before the step of providing the protruding electrodes, and the pad portion 10 of the substrate 26A is
The pad portion 10 is located at the bottom of the positioning opening 46 by covering the area other than the formation position with the resin mask 44. For this reason, the pad portion 10 is
4, the pad portion 10 can be prevented from being damaged as compared with the configuration in which the pad portion 10 is exposed.

In this embodiment, first, a projection electrode arranging step is performed on a semiconductor device in an initial state. FIG. 13 is a diagram for explaining the protruding electrode disposing step. In the protruding electrode disposing step, the solder balls 20 are disposed on the pad parts 10 through the positioning openings 46 formed in the resin mask 44. As shown in FIG. 13, the solder balls 20 are carried onto the semiconductor device while being held by suction at the mounter 66. Further, as will be described later in detail, a base and 65 are provided at the lower end of each solder ball 20 in a state where the solder ball 20 is transported onto the semiconductor device.

After the solder ball 20 and the pad portion 10 have been positioned, the mounter 66 moves downward toward the semiconductor device, whereby the solder ball 20 is placed on the pad portion 10 through the positioning opening 46. It is arranged in.
At this time, the positioning openings 4 formed in the resin mask 44 are formed.
6 can be used for positioning the solder ball 20, so that the solder ball 20 can be bonded to the pad portion 10 with high positional accuracy.

Here, referring to FIG.
(Hereinafter referred to as a solder ball transfer step) until transfer to the semiconductor device will be described in detail. In the solder ball transfer step, first, as shown in FIG. 16A, the solder balls 20 are arranged and arranged on a jig 67. The jig 67
A concave portion 68 corresponding to the position where the pad portion 10 is formed is formed, and the spherical solder balls 20 are brought into an aligned state corresponding to the position where the pad portion 10 is formed by engaging with the concave portion 68.

Subsequently, as shown in FIG. 16B, the solder balls 20 are sucked into the mounter 66 while maintaining the above-mentioned alignment. The mounter 66 is configured to be movable by a moving mechanism (not shown). An internal suction pipe 72 is formed in the mounter 66, and the internal suction pipe 72 branches to form a suction opening 69 at the lower end of each branch pipe.

The opening position of the suction opening 69 is configured to correspond to the position where the pad portion 10 is formed. The other end of the internal suction pipe 72 is connected to a vacuum pump (not shown). Therefore, by performing the suction process using the mounter 66, the solder balls 20 are held (transferred) to the mounter 66 while maintaining the above-described alignment.

The mounter 66 holding the solder balls 20 as described above moves onto the paste tank 71 filled with the paste 65 and then moves downward, and as shown in FIG. Paste 65 into a predetermined area
Immerse it in. Subsequently, the mounter 66 moves upward, and as a result, as shown in FIG.
The paste 65 is provided in a predetermined region at the lower end of the zero. Thereafter, the mounter 66 moves to the upper part of the semiconductor device, and the state shown in FIG. 13 is obtained.

In this embodiment, the paste 65 is provided on the solder ball 20 in the process of transferring the solder ball 20 by the mounter 66. However, as in the first embodiment, a screen printing method or the like is used. Using resin mask 4
It is also possible to apply a method of printing a paste in the positioning opening 46 of No. 4 and thereafter mounting the solder ball 20 on the pad 10.

FIG. 14 is an enlarged view showing a state in which the solder balls 20 are provided in the semiconductor device in the initial state. As shown in the drawing, the solder 20 is temporarily fixed by the paste 65 via the positioning opening 46 of the resin mask 44. Therefore, before the heating step is performed, it is possible to prevent the solder balls 20 from falling off from the pad portions 10. In the heating step described later, the paste (flux) is present at the contact portion between the solder ball 20 and the pad portion 10 so that the bonding between the pad portion 10 and the solder ball 20 can be performed smoothly and reliably. Becomes possible.

When the above-described projecting electrode arrangement step is completed,
Subsequently, a heating step is performed. In this heating step, the semiconductor device having the solder balls 20 mounted on the pad portions 10 is subjected to a heat treatment by a reflow furnace or the like. By performing this heating step, the solder ball 20 melts and the pad portion 1
0 to form a protruding electrode 22. As described above, since the resin mask 44 is made of a resin having a softening point that softens in the heating step, the solder balls 20
When joining the pad portion 10 with the resin mask 44, the resin mask 44 softens and flows. Thus, as shown in FIG. 15, the resin mask 44 fills the positioning opening 46 and the projection electrode 22
And a close contact state.

As described above, the resin mask 44 that has been melted and then re-formed functions as a so-called underfill resin (hereinafter, the re-formed resin mask 44 is referred to as an underfill resin and 54D). Therefore, even if a stress generated due to a difference in thermal expansion between the semiconductor device and the mounting board during mounting is applied to the projection electrode, this stress is prevented or absorbed by the underfill resin and 54D, and the projection electrode 22 is damaged. And peeling can be reliably prevented.

Since the resin mask 44 is re-formed after being softened in the heating step as described above, the size of the positioning opening 46 before the heating step is larger than the size of the solder ball 20. It can be set to be large (it can be made large in the range where positioning can be performed). Therefore, in the above-described step of disposing the protruding electrodes, the process of disposing the solder balls 20 on the pad portions 10 can be easily performed.

In the above-described second and third embodiments, after the protruding electrodes 22 shown in FIG. 22 are formed, a resin disposing step or a resin plate disposing step is performed.
After removing the metal mask 14 shown in FIG. 5, a resin disposing step or a resin plate disposing step may be performed. In this forming method, the solder balls 20 can be held in the package 2 even in the heating step, so that the reliability of the formed semiconductor device can be further improved. Further, in the heating step, the melting process of the solder balls 20 and the formation of the underfill resins 54B and 54C can be performed collectively, so that the process can be simplified.

[0079]

As described above, according to the present invention, the following various effects can be realized. According to the first aspect of the present invention, even after the protruding electrodes are provided on the paste, the resin mask remains mounted on the substrate, so that the protruding electrodes can be held by the resin mask. Therefore, it is possible to prevent the protruding electrode from being detached from the substrate in the step of forming the protruding electrode after the resin mask is mounted, during transportation after shipping, and the like, thereby improving the reliability of the semiconductor device.

Further, since the resin mask functions as an underfill resin at the time of mounting, even if a stress generated due to a difference in thermal expansion between the semiconductor device and the mounting substrate is applied to the projecting electrodes at the time of mounting, the projecting electrodes are not affected. Damage and peeling can be reliably prevented. Claim 2
According to the fourth and tenth aspects of the present invention, the thermoplastic resin is melted by performing the heat treatment again even after being heat-formed in the heating step. The plate and the resin having fluidity are melted and filled without gaps between the semiconductor device and the mounting substrate, so that the function as an underfill resin can be reliably achieved.

In addition, claims 3, 7, and 1
According to the invention described in the first aspect, since the solder is used as the protruding electrode, the solder is melted at a relatively low temperature, so that the resin mask can be prevented from being damaged by heat due to the melting of the solder. Further, according to the present invention, it is possible to prevent the resin mask from being melted before the protruding electrode is melted, and to reliably connect the protruding electrode to the pad portion. Can be performed.

According to the fifth aspect of the present invention, since the bump electrodes are held by the resin plate, the reliability of the semiconductor device can be improved. Further, at the time of mounting, since the resin plate functions as a so-called underfill resin, it is possible to reliably prevent the protruding electrode from being damaged or peeled off. According to the ninth aspect of the present invention, the bump electrode can be formed without changing the conventional forming process and equipment. Further, since the bump electrodes are held by the resin plate, the reliability of the semiconductor device can be improved.

Also, at the time of mounting, the resin functions as a so-called underfill resin. Therefore, even if a stress generated due to a difference in thermal expansion between the semiconductor device and the mounting substrate during the mounting is applied to the projecting electrode, Can reliably be prevented from being damaged or peeled off. According to the thirteenth aspect of the present invention, since the resin mask for protecting the projecting electrode can be used for positioning the projecting electrode in the projecting electrode arranging step, it is possible to improve the accuracy of the arrangement position of the projecting electrode. .

After the heating step, the joints of the projecting electrodes are protected by the resin mask for protecting the projecting electrodes, so that some stress (mechanical or thermal stress) is applied to the projecting electrodes in the subsequent use environment. Can be reinforced as compared with the conventional structure. According to the fourteenth aspect of the present invention, the pad portion can be protected by the protruding electrode protecting resin mask before the protruding electrode arranging step.

According to the present invention, before the heating step is performed, the bump electrode is temporarily fixed to the pad portion by the paste, and during the heating step, the bump electrode and the pad portion are fixed to each other. The presence of the paste (flux) at the contact portion allows smooth and reliable bonding between the pad portion and the protruding electrode.

Further, according to the present invention, in the heating step, the projecting electrode protecting resin mask fills the opening and comes into close contact with the projecting electrode. (Resin) functions as a so-called underfill resin. Therefore, even when a stress generated due to a difference in thermal expansion between the semiconductor device and the mounting substrate during mounting is applied to the bump electrode, the bump electrode can be reliably prevented from being damaged or peeled.

Further, since the resin mask for projecting electrode protection is re-formed after being softened in the heating step, the size of the opening of the resin mask for projecting electrode protection before the heating step depends on the size of the projecting electrode. Therefore, the protrusion electrode can be set to a large value, and the process of disposing the protruding electrodes can be easily performed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method of forming a bump electrode according to a first embodiment of the present invention, and is a diagram illustrating an initial state.

FIG. 2 is a view for explaining a method of forming a bump electrode according to a first embodiment of the present invention, and is a view showing a mask mounting step.

FIG. 3 is a diagram illustrating a method for forming a bump electrode according to a first embodiment of the present invention, and is a diagram illustrating a paste disposing step.

FIG. 4 is a view for explaining a method of forming a bump electrode according to a first embodiment of the present invention, and is a view showing a bump electrode arrangement step.

FIG. 5 is a view for explaining a method of forming a bump electrode according to the first embodiment of the present invention, and is a view showing a heating step.

6 is a diagram showing a state where the semiconductor device shown in FIG. 5 is mounted.

FIG. 7 is a view for explaining a method for forming a bump electrode according to a second embodiment of the present invention, and is a view showing a resin disposing step.

FIG. 8 is a diagram showing a semiconductor device manufactured by using the method for forming a bump electrode according to the second embodiment of the present invention.

FIG. 9 is a view for explaining a method of forming a bump electrode according to a third embodiment of the present invention, and is a view showing a resin plate disposing step (part 1).

FIG. 10 is a view for explaining a method of forming a bump electrode according to a third embodiment of the present invention, and is a view showing a resin plate disposing step (part 1).

FIG. 11 is a view showing a semiconductor device manufactured by using a method of forming a bump electrode according to a third embodiment of the present invention.

FIG. 12 is a view for explaining a method of forming a bump electrode according to a fourth embodiment of the present invention, and is a view showing a state where a mask mounting step is completed.

FIG. 13 is a view illustrating a method of forming a bump electrode according to a fourth embodiment of the present invention, and is a view showing a bump electrode disposing step.

FIG. 14 is a diagram for explaining a method of forming a bump electrode according to a fourth embodiment of the present invention, and is an enlarged view showing the vicinity of a solder ball after a bump electrode arrangement step is completed.

FIG. 15 is a diagram illustrating a method for forming a bump electrode according to the first embodiment of the present invention, and is a diagram illustrating a state where a heating process is completed and a semiconductor device is completed.

FIG. 16 is a view for explaining details of a projection electrode disposing step in the fourth embodiment.

FIG. 17 is a diagram illustrating an example of a conventional method for forming a bump electrode, and is a diagram illustrating an initial state.

FIG. 18 is a view illustrating an example of a conventional method of forming a bump electrode, and is a view illustrating a mask mounting step.

FIG. 19 is a diagram illustrating an example of a conventional method for forming a bump electrode, and illustrating a paste disposing step.

FIG. 20 is a view illustrating an example of a conventional method of forming a bump electrode, and is a view illustrating a step of providing a bump electrode.

FIG. 21 is a view illustrating an example of a conventional method for forming a bump electrode, and is a view illustrating a state where a metal mask is removed.

FIG. 22 is a diagram showing a semiconductor device manufactured by using a conventional method for forming a bump electrode.

FIG. 23 is a diagram illustrating an example of a conventional method for forming a bump electrode, and is a diagram illustrating an initial state.

FIG. 24 is a diagram illustrating an example of a conventional method for forming a bump electrode, and is a diagram illustrating an initial state.

FIG. 25 is a view illustrating an example of a conventional method of forming a bump electrode, and is a view illustrating a state where solder balls are provided.

FIG. 26 is a view illustrating an example of a conventional method for forming a bump electrode, and is a view illustrating a state where a heat treatment is completed.

[Explanation of symbols]

2, 32 package 3 resin package 4, 34 semiconductor chip 8, 38 wire 10, 40 pad portion 18, 48 paste 20, 50 solder ball 22, 52 projecting electrode 23, 64 opening 26A, 26B substrate 27 insulating film 28 through hole Electrode 29 Bonding pad 30, 60, 70, 80 Semiconductor device 44 Resin mask 46 Positioning opening 37, 65 Paste 54A, 54B, 54C, 54D Underfill resin 55 Liquid resin 56 Mounting substrate 58 Wiring pattern 59 Nozzle 62 Resin plate 66 Mounter 67 Jig 69 Suction opening 71 Paste tank

Claims (17)

[Claims] A mask mounting step of mounting a resin mask having a positioning opening formed at a position where the bump electrode is formed on a substrate having a pad portion on which the bump electrode is formed; A paste disposing step of disposing a paste on the pad portion, a protruding electrode disposing step of disposing a protruding electrode on the paste with the resin mask as a reference, and maintaining a state in which the resin mask is mounted. A heating step of bonding the bump electrode to the pad portion by performing a heat treatment. 2. The method according to claim 1, wherein the resin mask is formed of a thermoplastic resin. 3. The method for forming a bump electrode according to claim 1, wherein the bump electrode is a solder. 4. The method of claim 3, wherein the melting point (Tm) of the resin mask is equal to the melting point (Tm) of the solder.
b) A method of forming a protruding electrode, which is higher than (b) (Tm ≧ Tb). 5. A mask mounting step of mounting a metal mask having a positioning opening formed at a position where the projecting electrode is formed on a substrate having a pad portion on which the projecting electrode is formed; A paste disposing step of disposing a paste on the pad portion; a protruding electrode disposing step of disposing a protruding electrode on the paste with the metal mask as a positioning reference; A heating step of bonding the projecting electrode to the pad portion by performing the heating step; and a resin plate which is performed after the heating step and has a resin plate having an opening at a position where the projecting electrode is formed, disposed on the substrate. And a disposing step. 6. The method according to claim 5, wherein the resin plate is formed of a thermoplastic resin. 7. The method for forming a bump electrode according to claim 5, wherein the bump electrode is a solder. 8. The method of claim 7, wherein the melting point (Tm) of the resin plate is a melting point (Tb) of the solder.
(Tm ≧ Tb). 9. A mask mounting step of mounting a metal mask having a positioning opening formed at a position where the bump electrode is formed on a substrate having a pad portion on which the bump electrode is formed; A paste disposing step of disposing a paste on the pad portion; a protruding electrode disposing step of disposing a protruding electrode on the paste with the metal mask as a positioning reference; and a heating process after removing the metal mask. A heating step of bonding the protruding electrode to the pad portion by performing the step; and a resin that is performed after the heating step and has a fluid resin disposed on the substrate except for a position where the protruding electrode is formed. And a disposing step. 10. The method according to claim 9, wherein the resin is formed of a thermoplastic resin. 11. The method for forming a bump electrode according to claim 9, wherein the bump electrode is a solder. 12. The method according to claim 11, wherein the melting point (Tm) of the resin is higher than the melting point (Tb) of the solder (Tm ≧ Tb). Forming method. 13. A substrate provided with a resin mask for protecting a protruding electrode having an opening at a position where the protruding electrode is provided in advance at least in a region where a protruding electrode is formed. A projection electrode arranging step of arranging a projection electrode on the projection, and a heating step of performing a heat treatment to join the projection electrode to a pad portion provided at the projection electrode arranging position. Method of forming electrodes. 14. The projection electrode forming method according to claim 13, wherein the projection electrode protecting resin mask is formed by performing a mask mounting step before the projection electrode arranging step. Method of forming electrodes. 15. The method of forming a bump electrode according to claim 13, wherein a paste is applied to the bump electrode provided. 16. The method for forming a bump electrode according to claim 13, further comprising a step of applying a paste to the bump electrode placement position before the bump electrode arrangement step. Formation method. 17. The method for forming a bump electrode according to claim 13, wherein the bump electrode protecting resin mask is made of a resin having a softening point that softens in the heating step. A method for forming a bump electrode.