JP2001044231A - Method of forming solder bumps and wiring board, semiconductor element, semiconductor package and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form solder bumps having a large volume, even with narrow pitches and provide a wiring board, a semiconductor element and a semiconductor package having high connection reliability. SOLUTION: A jig 10, having through-holes 12 for forming solder bumps at prescribed sites, is placed on the surface of a wiring board or a semiconductor element. A solder paste 27 is filled in the through-holes 12 for forming solder bumps by printing the solder paste 27 via a screen 23 for printing and/or a mask 24 for printing. After solder bumps 34 are formed by melting the filled solder paste, the jig 10 for forming solder bumps is removed from the wiring board or the semiconductor element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, a wiring board, a semiconductor package, a method of manufacturing the same,
And a method for forming a solder bump used in the manufacturing method.

[0002]

2. Description of the Related Art In recent years, various electronic parts have been reduced in weight and thickness.
Due to the increasing needs for miniaturization and the like, the demand for high-density mounting is increasing. So, to respond to this,
It has become common to form peripheral arrays into area arrays and use solder bumps for the area array terminals.

[0003] There are two methods for forming the solder bumps: a mounting method for mounting a molded ball, and a printing method for forming by solder paste printing. In order to ensure the connection reliability between the substrate and the mounted components (such as semiconductor elements), it is desirable that the solder bumps be large. However, conventional printing methods can only supply a small amount of solder paste,
A large solder bump cannot be formed at a narrow pitch. Therefore, a mounting method is usually used for forming the solder bumps.

However, the mounting method is a method of directly arranging and melting a formed ball at a predetermined position on a substrate and has a problem in productivity. Therefore, it is desired to realize a technique for forming a solder bump having a required ball height by a printing method.

[0005] The solder material (ie, solder paste) is supplied by printing by pressing a solder paste with a squeegee into a through-hole of a print mask that is brought into close contact with the surface of a wiring board, which is a member to be supplied. From the mask) to a desired location on the wiring board. That is, in the conventional printing method, as shown in FIG. 2, a mesh screen 23 having a metal mask 24 adhered to a lower surface is set on a screen frame 22, and a wiring substrate 21 which is a printing object is positioned below the screen frame. After that, the solder paste 27 placed on the screen 23 is dispensed with the squeegee 2.
6, the solder paste pattern 25 is transferred onto the surface of the wiring board 21 by being pressed into the through hole 28 of the metal mask 24. In FIG. 2, the height difference between the wiring board 21 and the screen frame 22 is larger than the actual height and the metal mask 24 is made thicker to make the drawing easier to see.

[0006]

In this conventional printing method, the thickness of the printing mask is limited in order to ensure good plate separation. When a thick printing mask is used, the amount of solder paste attached to the mask when removing the mask becomes unstable, and the size of the formed solder bumps becomes uneven. Has limitations. On the other hand, when forming solder bumps with a fine pitch, the opening diameter cannot be increased because the opening diameter is limited by the pitch. Therefore, since the capacity of the through hole into which the solder paste is pressed cannot be increased, the volume of the solder bump obtained after melting is limited. In the conventional printing method, it was not possible to form a solder bump having a height of 0.4 times or more the pitch width.

However, in order to improve connection reliability, it is necessary to form a large-volume solder bump even with a narrow pitch. Therefore, in the present invention, a method for forming a solder bump capable of forming such a solder bump, a semiconductor element including a large-volume solder bump even at a narrow pitch, a wiring board and a semiconductor package,
An object of the present invention is to provide a method for producing the same.

[0008]

According to the present invention, (1) a jig mounting step of mounting a solder bump forming jig having a solder bump forming through hole at a predetermined position on a surface of a wiring board; (2) a printing step of filling the solder paste into the solder bump forming through holes by printing the solder paste through a printing screen and / or a printing mask; and (3) melting the filled solder paste. hand,
A melting step of forming a solder bump on the surface of the wiring board; (4)
And a jig removing step of removing the solder bump forming jig from the surface of the wiring board in this order.

Further, when a solder bump for mounting a semiconductor element is formed on the surface of a wiring board by using the method for forming a solder bump of the present invention, a wiring board for mounting a semiconductor element can be manufactured. The printed wiring board,
By forming solder bumps for mounting the substrate, a semiconductor package having external connection terminals for mounting can be manufactured. Further, using the solder bump forming method of the present invention, forming a solder bump on the surface of the semiconductor element,
An inner bump can also be used. Therefore, the present invention provides a method of manufacturing a wiring board or a semiconductor package including a step of forming a solder bump by the solder bump forming method of the present invention.

Further, according to the present invention, there is provided a wiring board or a semiconductor having a solder bump formed by melting a solder paste and having a height of 0.4 to 0.9 times the pitch width. An element and a semiconductor package are provided. Solder bumps having such a height cannot be obtained by a conventional printing method, but are only possible in the present invention.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The solder bump forming method of the present invention is to fill a solder bump forming through-hole of a solder bump forming jig by printing, but a conventional printing machine is used for printing. Can be. In addition, as a printing screen used for printing, a net or the like, which is usually used in screen printing, made of fine wire such as stainless steel can be used. As the printing mask, for example, a metal mask made of a metal such as stainless steel can be used. The printing may be performed only through the printing screen, may be performed only through the printing mask, may be performed through a printing screen adhered to the printing mask, and may not be used. Can also be printed.

In the present invention, since a jig for forming a solder bump is used, the solder bump can be formed at a predetermined position even when printing is performed only through a net-shaped printing screen without using a printing mask. it can. When a printing mask is not used, it is not necessary to position the printing mask and the solder bump forming jig.

Further, when the solder bump forming jig has an opening other than the solder bump forming through hole, the solder paste can be efficiently supplied only to the solder bump forming through hole. It is preferable to use a mask. When a printing mask is used, its opening pattern is not particularly limited as long as it does not cover the solder bump forming through-hole of the solder bump forming jig. For example, a printing mask having exactly the same pattern as the opening pattern of the solder bump forming jig may be used, and the opening diameter of the printing mask may be slightly larger in order to suppress variations in the amount of paste filling due to misalignment. Is also good.

Further, the solder paste is directly supplied to the through holes of the solder bump forming jig without using any of the printing mask and the printing screen, and the surface of the solder bump forming jig is directly rubbed off with a squeegee or the like. You may do so. In this way, the amount of the solder paste to be melted can be kept constant without providing a separate cutting step.

The jig for forming a solder bump used in the present invention can be manufactured by forming a through-hole in a metal plate, and can be easily manufactured by the same process as the manufacturing process of a conventional printing mask. is there. In the present invention,
It is only necessary to place the solder bump forming jig on the surface of the printing object at the time of printing, and conventional printing equipment can be used, so that the present invention can be introduced at low cost.

When a semiconductor package is manufactured, an IC (integrated circuit) is provided on the surface of the wiring board on which the solder paste is supplied.
However, the conventional printing method could not form a solder bump due to the presence of a protrusion due to resin sealing or the like. However, in the present invention, the flatness of the printed surface is maintained by providing a retracting concave portion or a retracting through hole in the solder bump forming jig at a portion corresponding to the convex portion on the surface of the wiring board, so that printing is performed. The formation of solder bumps is possible. When the evacuation through-hole is provided in the solder bump forming jig, the opening of the evacuation through-hole is formed by using a printing mask having a pattern that covers an area other than the above-described solder bump forming through-hole. It is desirable to cover.

The material for the solder bump forming jig used in the present invention is not particularly limited as long as it can withstand the reflow process. However, in order to ensure good plate separation and volume accuracy of the obtained solder bump, At least the inner wall of the through hole for forming a solder bump is desirably made of a material having poor solder wettability, such as stainless steel, a stainless alloy, titanium, a titanium alloy, and / or silicon nitride, and the jig is easily manufactured. Therefore, it is preferable that the entire jig is made of these materials. The thickness of the solder bump forming jig can be appropriately determined according to the volume of the electrode to be formed and the opening area of the solder bump forming through hole, since it is removed after the solder paste is melted, The solder paste may have a problem in plate releasability, for example, may be as thick as 0.2 mm or more.

The solder bump forming through-holes 12
Although it may be a cylindrical shape whose cross section is shown in FIG.
In order to further increase the volume, the shape may be a prism such as a quadrangular prism or a hexagonal prism, and the corner may be a curved surface as shown in a cross section in FIG. 5B so that the solder paste is filled without voids. That is, the through hole for forming a solder bump can be a columnar space having a shape in which a cross section parallel to the surface of the wiring board is surrounded by a plurality of line segments. It is desirable to be connected via a curve.

Further, as shown in FIG. 6A, the through hole for forming a solder bump may be formed in a columnar shape having no change in the shape of a cross section parallel to the surface of the wiring board. 6B, a taper may be provided as shown in FIG. That is, the inner diameter of the cross section of the through hole for forming the solder bump parallel to the surface of the wiring board may be made larger as it is closer to the opening on the wiring board side.

In the solder bump forming method of the present invention, when the solder paste is melted, a jig having a flat surface on the jig side (flattening jig) is placed on the jig for forming the solder bump. Is desirably placed. In this case, even if the substrate has warpage or unevenness, the height of the solder bumps after melting can be made uniform, so that connection reliability can be improved, which is preferable.

In the solder bump forming method of the present invention, as shown in FIG.
By changing the inner diameter of the solder bumps, solder bumps of different volumes can be formed. In the example shown in FIG. 7, among the through holes 12 for forming solder bumps in the rectangular area A corresponding to one semiconductor package, four through holes 1 located at four corners are formed.
Only 2a is larger than the other through holes 12b. In this way, large-volume solder bumps can be formed at the four corners of the component mounting area. Note that even when the solder bumps having different volumes are formed on one substrate as described above, if the heights need to be uniform, the flattening jig may be used as described above.

The method of manufacturing a wiring board according to the present invention is not particularly limited in terms of other steps as long as it includes a step of forming a solder bump by the method of forming a solder bump according to the present invention. Can be appropriately selected and applied.

The present invention can be applied to any of a printed board, a ceramic board and the like, and can be applied to a single-layer board or a multilayer board. The wiring board on which the solder bumps are formed according to the present invention is not particularly limited, but the present invention can form the solder bumps at a very narrow pitch with high accuracy, so that high-precision and high-density mounting is possible. Manufacture of required semiconductor element mounting substrates,
It is particularly suitable for semiconductor packages, such as chip size packaging, which require formation of high-density external connection terminals, and semiconductor elements mounted on the semiconductor package.

The method of manufacturing a semiconductor package is not particularly limited as long as it includes a step of forming a solder bump by the method of forming a solder bump of the present invention. Can be selected and applied. For example, after mounting a semiconductor element at a predetermined position on a wiring board and connecting the terminals by wire bonding, the entire element and the connection portion are resin-sealed. A semiconductor package can be obtained by forming solder bumps by a method and performing processing such as cutting as necessary.

The method of manufacturing a semiconductor device is not particularly limited as long as it includes a step of forming a solder bump by the method of forming a solder bump of the present invention. Can be appropriately selected and applied.

[0026]

Next, the present invention will be described by taking as an example a case where a semiconductor package is manufactured by forming solder bumps on a wiring board or a semiconductor element on which a semiconductor element is mounted.
The present invention is not limited to this.

<Embodiment 1> First, the following (1) to (4)
By the above process, solder bumps were formed on the surface of the wiring board. In this embodiment, a substrate made of glass epoxy resin is provided as a substrate on which solder bumps are formed.
C with 40 device mounting areas of 200 mm pitch 200 pins
A substrate for SP (Chip Size Package) was used. FIG.
As shown in FIG. 1A, a solder bump forming pad 31 and a solder resist pattern 32 are formed on the surface of the CSP substrate 30 in advance.

(1) Jig placement step First, a small amount of flux is placed (or applied) on several surfaces of the solder resist 32 on the surface of the CSP substrate 30 on which the solder bumps are formed (FIG. 1). (B)). This is for fixing the solder bump forming jig 10 on the substrate. The solder bump forming jig 10 withstands solder reflow conditions, and the solder bump forming jig 10 can be easily removed in the jig removing step (cleaning step). Other adhesives may be used as long as they can be easily washed and removed. Also, the amount
It is enough that the solder bump forming jig 10 can be fixed, and the solder bump forming jig 10 and the solder resist 32 are sufficient.
Jig for solder bump formation
From the viewpoint of avoiding the movement of 0 and facilitating cleaning, it is desirable that the amount is not too large. In this embodiment, as the flux for fixing the jig, RMA (Rosi
n mildly activated) Flux “Deltalux 52
3 "(manufactured by Senju Metal Co., Ltd.).

Next, the CSP substrate 30 and the solder bump forming jig 10 are aligned and pressed so that the pads 31 and the solder bump forming through holes 12 overlap, and the substrate 30 and the solder bump forming jig are pressed. Between the fixture 10 (ie, the thickness of the jig fixing flux 33 layer (not shown))
However, it was made as narrow as possible. In this state, the substrate 30
The jig 10 was placed in a dryer and dried by heating at 120 ° C. for 15 minutes, and then taken out of the dryer and returned to room temperature. Thus, the solder bump forming jig 10 was fixed on the surface of the substrate 30 (FIG. 1C).

The solder bump forming jig 10 used in the present embodiment has a length of 150.5 mm, a width of 66 mm,
It is made of a stainless steel plate (SUS) having a thickness of 0.2 mm, and as shown in FIG. 3A, includes 40 rectangular areas A each having a length and width of 14.5 mm. As shown in FIG. 3B, the rectangular area A has a rectangular opening 1
1, and around the opening 11, there are provided 200 solder bump formation through holes 12 each having a columnar space of 0.4 mm in inner diameter and arranged in two rows.

Pad 31 and through hole 1 for forming solder bump
2 and the CSP substrate 3
Protrusion (not shown) of a semiconductor element sealed with resin 0
Is located in the opening (evacuation through hole) 11 of the solder bump forming jig 10. In this embodiment, since the height of the convex portion of the element is lower than the thickness of the jig 10 of 0.2 mm, it is possible to prevent the convex portion from hindering printing. (2) Printing Step Next, the metal mask 24 is set on the automatic printing machine “NP-04AN2Z” (manufactured by Hitachi Techno Engineering Co., Ltd.), the solder paste 27 is supplied on the metal mask 24, and the solder bump is applied to the printing machine. The substrate 30 to which the forming jig 10 was attached was put in, and printing was performed (FIG. 1D). Thereby, the solder paste 27 was filled in the through holes 12 of the jig 10 and the through holes 28 of the metal mask 24 (FIG. 1).
(E)). In this embodiment, a 0.05 mm stainless steel plate (SUS) is used as the metal mask 24 at the solder bump formation position (that is, the position of the solder bump formation through hole 12 of the solder bump formation jig 10). The one provided with a circular opening having a diameter of 0.40 mm in a corresponding portion was used. The solder paste 27 includes Z
n: Pb = 63: 37 paste containing solder powder “O
Z7050-606F-53-10 "(Senju Metal Co., Ltd.)
Was used. In the printing press used in this embodiment, positioning and printing are automatically performed.

In this embodiment, the metal mask 24 is adhered to the entire surface of the solder bump forming jig 10 for printing. However, as in the conventional method shown in FIG. And the printing method is not particularly limited. The pattern of the metal mask 24 is also determined by the through-hole 11 for retreating the substrate convex portion of the jig 10 for forming a solder bump.
As long as it covers the solder bump forming through-hole 12 and does not cover the solder bump forming jig 1 as in this embodiment.
The pattern may not be the same as that of the through-holes 12 for forming the solder bumps.

According to this embodiment, a conventional printing machine can be used as it is, and the cost required for applying this embodiment can be kept low.

Subsequently, the printed substrate 30 is taken out of the printing machine (FIG. 1 (f)), and is scraped off with a stainless steel (SUS) doctor blade (not shown) to remove excess solder paste 27 (FIG. 1 (f)). FIG. 1 (g)). When the metal mask 24 is used, since the solder paste 27 may adhere to the metal mask 24 and be removed, the amount of the solder paste 27 may not be constant. It is desirable. However, when the filling amount is stable, or when it is not necessary to precisely control the amount of the paste 27, the sliding-off processing may be omitted. (3) Melting Step Next, the solder bump forming jig 10 and the wiring board 30 filled with the solder paste 27 are put into a nitrogen reflow apparatus “IAR-250CL” (manufactured by Nippon Heat Transfer Instruments Co., Ltd.). In an atmosphere having an oxygen concentration of 100 ppm, heating was performed at a peak temperature of 240 ° C., and the solder paste 27 was melted to form a solder bump 34 (FIG. 1H).

In this melting step, as shown in FIG. 4A, a flattening jig 40 (titanium plate having a length of 150 mm, a width of 66 mm and a thickness of 2.0 mm) is placed on the solder bump forming jig 10. When reflow was performed in a state where the solder bumps were placed, the upper ends of the solder bumps after melting could be flattened as shown in FIG. 4 (b), and the height was uniform as shown in FIG. 4 (c). A complete set of bump electrodes (solder bumps) 41 was obtained.

(4) Jig Removal Step After the molten solder has solidified, the wiring board 30 on which the solder bump forming jig 10 is fixed is taken out of the reflow device, and the hydrocarbon-based cleaning liquid “FX70” (trade name) is used. (Made by Tosoh Corporation). Thereby, the solder bump 3
The jig 10 for forming solder bumps was peeled off from the wiring board 30 on which 4 was formed (FIG. 1 (i)). Further, the wiring board 3
0 and the solder bump forming jig 10 were separately subjected to ultrasonic cleaning for 5 minutes to remove the residual flux.

By cutting the wiring board on which the solder bumps were formed as described above for each predetermined package area A, 40 semiconductor packages were obtained from one board 30. Table 1 shows the heights of the solder bumps measured using three packages in the substrate as samples. In Table 1, σ represents a standard deviation. Each value in Table 1 is a total of the heights of all 200 solder bumps included in each sample package.

[0038]

[Table 1]

The height of the solder bumps formed according to the present embodiment is 0.243 mm on average for all the samples, and 0.218 mm at the lowest. Solder bumps of 2 mm or more could be formed.

In this embodiment, the semiconductor package is manufactured using the wiring board 30 on which the semiconductor element is mounted. However, if the wiring board on which the element is not mounted is used, the wiring for mounting the semiconductor element is performed in the same process. A substrate can be manufactured. In this case, since the printed surface of the wiring substrate, which is the printing substrate, is flat, it is not necessary to provide the evacuation through-hole 11 in the solder bump forming jig 10. However, if there is any convex portion, a retreat through hole or a concave portion may be provided.

Example 2 A. Formation of Solder Bump First, a solder bump was formed on the surface of a semiconductor element by the following steps (1) to (4). In this embodiment,
ICs (Integrated
Circuit) chip (T made by Hitachi Hokkai Semiconductor Co., Ltd.)
(EG chip) and mounted on a test substrate to confirm the IC function. The IC chip 81 used in this embodiment is shown in FIG.
As shown in (a), a solder resist layer 82 and an electrode pad 83 are provided on the surface. This IC chip 81 is 2.0 mm in length and width and 0.3 mm in thickness. As shown in FIG. 11, the outer periphery of the surface is 0.09 mm in length and width, which has been subjected to a Cr—Cu—Au surface treatment. The electrode pad 83 is 0.15
48 positions are arranged at a pitch of mm. A region other than the pad 83 on the surface of the chip 81 is covered with a solder resist 82.

(1) Jig Placing Step First, a small amount of flux (the same “Deltalux 5” as that used in Example 1) was applied to several places on the surface of the solder resist layer 82.
23 ”) is placed (or applied) (FIG. 8B), and the chip 81 and the solder bump forming jig 85 are attached to the pad 83.
And the through holes 86 for forming solder bumps are aligned and pressed so that the gap between the chip 81 and the jig 85 (that is, the thickness of the jig fixing flux 84 layer (not shown)) is as small as possible. I made it narrow. In this state, the chip 81 and the jig 85 are put into a drier and
After drying by heating for a minute, it was taken out of the dryer and returned to room temperature. As a result, the jig 85 was fixed to the surface of the chip 81 (FIG. 8C).

The solder bump forming jig 85 used in the present embodiment is 2.0 mm long and horizontal and 70 μm thick.
As shown in FIG. 12, through holes 86 each having a length of 0.12 mm and a width of 0.12 mm are formed in the outer peripheral portion.
Forty-eight are provided at a pitch of 15 mm.

(2) Printing Step Next, the solder paste 87 is applied to the solder bump forming jig 8.
5 and pressed into the through-hole 86 with a doctor blade 88 made of stainless steel (SUS), and furthermore, the doctor blade 88 was moved so as to be slid off the surface of the jig 85 to remove the excess solder paste 87 (FIG. 8). (D)).
Thus, the solder paste 87 was filled in the through-hole 86 for forming a solder bump of the jig 85 for forming a solder bump (FIG. 8E). The solder paste 87 has Z
n: Pb = 63: 37 paste containing solder powder “O
Z63-381F9-10.5 "(manufactured by Senju Metal Co., Ltd.)
Was used.

(3) Melting Step Next, the flattening jig 90 is placed on the surface of the solder bump forming jig 85 filled with the solder paste 87, and the flattening jig and the solder bump forming jig are placed. Every, chip 8
1 was placed in a nitrogen reflow apparatus "IAR-250CL" (manufactured by Nippon Heat Transfer Instruments Co., Ltd.) and heated in an atmosphere having an oxygen concentration of 100 ppm at a peak temperature of 240.degree. 89 (FIG. 8 (f)). The flattening jig 90 has a length and width of 5 m each.
A titanium plate having a thickness of 2.0 mm and a thickness of 2.0 mm was used.

(4) Jig Removal Step After the molten solder has solidified, the IC chip 81 on which the solder bump forming jig 85 is fixed is taken out of the reflow device and ultrasonically cleaned with a hydrocarbon-based cleaning liquid for 5 minutes. .
As a result, the solder bump forming jig 85 was peeled off from the IC chip 81 on which the solder bumps 34 were formed (FIG. 8).
(G)). Further, the IC chip 81 and the solder bump forming jig 85 were separately subjected to ultrasonic cleaning for 5 minutes to remove residual flux. In this way, an IC chip 80 on which the inner bumps are formed, on which the solder bumps (that is, the solder bumps) 89 are formed, is obtained.

The height of the solder bump formed according to the present embodiment is small despite the pitch being as narrow as 0.15 mm.
The average of all solder bumps (48) was 63 μm.
Note that the standard deviation σ was 3 μm.

B. Fabrication of Semiconductor Device Next, the obtained semiconductor device with solder bumps (IC device 80) was mounted on a wiring substrate for mounting a semiconductor device, and a test semiconductor package was fabricated. As shown in FIG. 13, the wiring board 93 for mounting a semiconductor element used in the present embodiment is provided on the surface of the wiring board 91 for testing (semiconductor element mounting surface) as shown in FIG. In addition, an insulating layer 92 is formed.
The semiconductor element mounting wiring board 93 has an FP (Flat
Package) semiconductor element mounting area 131 for bonding;
There are 48 external connection pads 132 arranged on the outer periphery at a pitch of 0.5 mm. Semiconductor element mounting area 13
In FIG. 1, Cu-Ni-
An electrode pad 133 surface-treated with Au is provided. The electrode pad 133 is provided with an external connection pad 132.
And the wiring 134. Also, pads 132 and 133 and wiring 134 on the surface of test substrate 91 are provided.
The other area is covered with the insulating layer 92.

(1) Mounting Example 1 First, the IC chip 80 is mounted on the semiconductor element mounting region 131 of the semiconductor element mounting wiring board 93 with the positions of the solder bumps 89 and the electrode pads 133 aligned. To connect the electrode pad 133 and the solder bump 89. Next, a solvent type underfill material 94 (“FC-G700” manufactured by Hitachi Chemical Co., Ltd.) is poured between the IC chip 80 and the wiring board 93 for mounting a semiconductor element, and the resin is cured. 9 was obtained. When the function of the IC chip was checked using this semiconductor package, it was confirmed that the connection was made without any defect.

(2) Mounting Example 2 First, an anisotropic conductive film (“Flip Tack” manufactured by Hitachi Chemical Co., Ltd.) is mounted on the semiconductor element mounting area 131 of the semiconductor element mounting wiring board 93. The IC chip 80 on which the solder bump 89 has been formed is placed on the solder bump 89 so that the position of the solder bump 89 and the electrode pad 133 are aligned.
After heating at 180 ° C for 10 seconds while applying the load,
The coating was heated in a drying oven at 180 ° C. for 1 hour to cure the anisotropic conductive film. Thus, the semiconductor package shown in FIG. 11 was obtained. When the function of the IC chip was checked using this semiconductor package, it was confirmed that the connection was made without any defect.

[0051]

According to the present invention, a large-volume solder bump can be formed even with a narrow pitch, and a wiring board and a semiconductor element having high connection reliability and a semiconductor package can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a method of forming a solder bump in Example 1.

FIG. 2 is an explanatory diagram showing a conventional printing method.

FIG. 3 is a plan view showing the shape of a jig for forming a solder bump used in Example 1.

FIG. 4 is an explanatory view showing a melting step when a flattening jig is used.

FIG. 5 is a sectional view of a jig for forming a solder bump, showing an example of a shape of a through hole for forming a solder bump.

FIG. 6 is a sectional view of a jig for forming a solder bump, showing an example of a shape of a through hole for forming a solder bump.

FIG. 7 is a plan view of a jig for forming a solder bump, showing an example of a shape of a through hole for forming a solder bump.

FIG. 8 is a schematic view illustrating a method of forming solder bumps in Example 2.

FIG. 9 is a cross-sectional view illustrating a mounting example of a semiconductor chip according to a second embodiment.

FIG. 10 is a cross-sectional view illustrating a mounting example of a semiconductor chip according to a second embodiment.

FIG. 11 is a plan view showing a shape of a semiconductor element used in Example 2.

FIG. 12 is a plan view showing the shape of a jig for forming a solder bump used in Example 2.

FIG. 13 is a plan view showing the shape of a wiring board for mounting a semiconductor element used in Example 2.

[Explanation of symbols]

Reference numeral 10: a jig for forming a solder bump, 11: a through-hole for retreating a convex portion of a substrate, 12: a through-hole for forming a solder bump, 12a: a through-hole (large) for forming a solder bump, 12b: a through-hole (small) for forming a solder bump ), 21 ... substrate to be printed (wiring board), 2
2 ... screen frame, 23 ... screen, 24 ... metal mask, 25 ... solder paste pattern, 26 ... squeegee, 27 ... solder paste, 28 ... through hole, 30 ... board, 31 ... pad, 32 ... solder resist, 33 ... Fixing flux, 34 solder bump, 40 flattening jig, 41 flattened solder bump, 80 IC chip with inner bump formed, 81 IC chip, 82 solder resist, 83 electrode Pad, 84 ...
Flux for fixing, 85 ... Jig for forming solder bumps, 8
6 through hole for solder bump formation, 87 solder paste, 88 doctor blade, 89 solder bump, 9
0: flattening jig, 91: test substrate, 92: insulating layer,
Reference numeral 93 denotes a wiring board for mounting a semiconductor element, 94 denotes an underfill material, 95 denotes an anisotropic conductive film, 131 denotes a semiconductor element mounting area, 132 denotes a pad for external connection, and 133 denotes an electrode pad.
134 wiring.

Claims (12)

[Claims] 1. A jig placing step of placing a solder bump forming jig having a through hole for forming a solder bump at a predetermined position on a surface of a printing substrate, and a printing screen and / or a printing mask. A printing step of filling the solder paste in the through holes for forming the solder bumps by printing the solder paste through a soldering step; a melting step of melting the filled solder paste into solder bumps; And a jig removing step of removing the solder bump forming jig from above in this order, wherein the printed material is a wiring board or a semiconductor element. 2. The solder bump forming jig, wherein at least the inner wall of the solder bump forming through hole is made of at least one of stainless steel, stainless alloy, titanium, titanium alloy and silicon nitride. The method for forming a solder bump according to claim 1, wherein 3. The solder bump forming method according to claim 1, wherein the solder bump forming jig is provided with a retracting concave portion or a retracting through hole at a position corresponding to the convex portion on the surface of the printing substrate. . 4. The solder bump forming jig is provided with the evacuation through-hole, and printing in the printing step is performed via the printing mask covering an opening of the evacuation through-hole. The method according to claim 3, wherein the solder bump is formed. 5. The melting in the melting step is performed in a state where a flattening jig having a flat surface on the side of the solder bump forming jig is placed on the solder bump forming jig. The method of claim 1, wherein: 6. A method of manufacturing a wiring board, comprising a step of forming a solder bump on the surface of the wiring board by the method of forming a solder bump according to claim 1. 7. A method of manufacturing a semiconductor device, comprising the step of forming a solder bump on the surface of a semiconductor device by the method of forming a solder bump according to claim 1. 8. A wiring board having solder bumps formed by melting a solder paste and having a height of 0.4 to 0.9 times the pitch width. 9. A semiconductor device having solder bumps formed by melting a solder paste and having a height of 0.4 to 0.9 times the pitch width. 10. A semiconductor comprising: a step of mounting a semiconductor element on a surface of a wiring board; and a step of forming solder bumps on the surface of the wiring board by the method of forming a solder bump according to claim 1. Package manufacturing method. 11. A method of manufacturing a semiconductor package, comprising: a step of forming a solder bump on a semiconductor element by the method of forming a solder bump according to claim 1; and a step of mounting the semiconductor element on a wiring board. . 12. A semiconductor device comprising: a semiconductor element; and a wiring board on which the semiconductor element is mounted, wherein at least one of the semiconductor element and the wiring board is formed by melting a solder paste, and has a height of 0 pitch. A semiconductor package having solder bumps not less than 4 times and not more than 0.9 times.