JP2003174124A - Method of forming external electrode of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming external electrodes of a semiconductor device capable of easily forming external electrodes that are exposed on a sealing-resin surface. <P>SOLUTION: Resin material 5 is loaded on the upper face of a lower mold 12 while the object 4 to be molded is arranged between an upper mold 14 and a lower mold 13. After the resin material 5 is heated to be melted, the total of the lower mold 13 is raised to clamp the peripheral part of the object 4 to be molded. By raising the movable lower mold 12 to apply a compressive force to bump electrodes 3 and the melted resin 5, resin molding of the object 4 to be molded is performed while the bump electrodes 3 are squeezed to a specific height. By squeezing the bump electrodes 3 to reduce their height by about 5-50% of the height at their formation, the top-end surfaces of the bump electrodes 3 after the resin molding are surely exposed on the resin surface. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an external electrode of a semiconductor device, and more particularly to forming an external electrode advantageous for manufacturing a ball grid array (hereinafter abbreviated as BGA) and for three-dimensional mounting. It is about the method for.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed for forming external electrodes on a resin-sealed surface of a semiconductor device obtained by sealing a semiconductor element with a resin. For example, as a method of forming a through electrode in a case where semiconductor devices are stacked and three-dimensionally mounted, the entire protruding electrode on the substrate is resin-sealed together with the semiconductor element, and then the resin surface is ground until the protruding electrode is exposed. There is a way. In the semiconductor device thus formed, a BGA can be manufactured by placing solder balls on the protruding electrodes exposed after grinding.

Further, FIG. 8 shows an E-type device manufactured by a conventional method.
It is explanatory drawing which shows an example of BGA, and FIG. 9 is a X arrow line view of FIG. As shown in FIG. 8, a molded article 45 in which a multi-layer substrate 41 and a semiconductor element 43 connected to the multi-layer substrate 41 with a gold wire 42 are supported by a frame body 44 has a semiconductor element 43 formed by a resin 46. After resin sealing, the solder balls 47 are placed on the wiring pattern of the multilayer substrate 41. In this case, when the semiconductor element 43 is sealed with resin,
In order to expose the wiring pattern of the outermost layer of the multilayer substrate 41, only the inner portion is resin-sealed by potting a liquid resin. Also, when manufacturing an m-BGA, it is necessary to similarly expose the wiring pattern of the substrate,
The resin is sealed by potting.

[0004]

However, the above-described conventional method for manufacturing an external electrode of a semiconductor device has the following problems.

First, in the method of sealing the entire protruding electrode with resin, a step of uniformly grinding the entire resin surface after sealing is required, and there is a problem that the manufacturing efficiency is reduced by that much. In addition, there are technical problems that different kinds of materials such as resin and protruding electrodes must be ground at the same time, and there is a problem of warpage due to thermal stress generated during grinding. Even if an attempt is made to seal the surface of the bump electrode with resin in order to solve these problems, there is a portion where the bump electrode is not exposed because the height of the bump electrode varies, and it is necessary to remove it with, for example, a laser. There is.

In the case of manufacturing E-BGA and m-BGA, because of resin sealing such as potting,
Only the individual semiconductor devices can be resin-sealed, and a plurality of semiconductor devices cannot be collectively resin-sealed. Therefore, there is a limit to improving the manufacturing efficiency when manufacturing a large number of semiconductor devices.

The present invention has been proposed in order to solve the above problems of the prior art, and its purpose is to:
An object of the present invention is to provide a method of forming an external electrode of a semiconductor device capable of easily forming an external electrode exposed from a resin sealing surface, thereby realizing improvement of manufacturing efficiency in BGA manufacturing and three-dimensional mounting. .

[0008]

In order to achieve the above object, in the method of forming an external electrode of a semiconductor device of the present invention, the protruding electrode is crushed at the time of resin sealing so that the protruding electrode is reliably exposed from the resin surface. It was made to let.

According to a first aspect of the present invention, there is provided a method of forming an external electrode of a semiconductor device, which is formed by resin-sealing a substrate having a protruding electrode for forming an external electrode, which is connected to a semiconductor element. It is characterized in that the projecting electrodes are exposed from the resin surface after resin sealing by compressing and crushing the projecting electrodes with a metal mold.

According to this feature, the protruding electrode is compressed and crushed by the resin-sealing mold during resin sealing, so that the tip end surface of the crushed protruding electrode can be sufficiently moved to the resin-sealing mold. In the state of being in close contact, resin molding can be performed without the resin adhering to this portion. Therefore, the tip end surface of the bump electrode can be surely exposed from the resin surface after the resin sealing. Further, it is possible to easily crush the protruding electrodes by using the resin-sealing mold at the time of resin-sealing without requiring any special means.

According to a second aspect of the present invention, in the method of forming an external electrode of a semiconductor device according to the first aspect, a molded article including a protruding electrode and a resin are arranged between resin molding dies during resin sealing. The present invention is characterized in that resin molding is performed while pressing the protruding electrodes by compressing the protruding electrodes and the resin. According to this feature, since it is possible to simultaneously perform resin molding while crushing the projecting electrodes by the resin sealing mold during compression molding of the resin, it is not necessary to crush the projecting electrodes.

According to a third aspect of the present invention, in the method of forming an external electrode of a semiconductor device according to the first aspect, a molded product including a protruding electrode is disposed between resin molding dies during resin sealing to form a protruding electrode. The protruding electrode is crushed by applying a compressive force to the resin, and the resin is supplied by supplying the resin into the cavity formed between the resin-sealing die that crushed the protruding electrode and the substrate of the molding target. It is characterized by that. According to this feature, the bump electrode is crushed to be surely brought into close contact with the resin sealing mold, and then the resin is supplied, so that the bump electrode can be formed even if there is some variation in height during formation. Since the resin does not adhere to the tip surface of the protruding electrode having a low height, the accuracy of the height when forming the protruding electrode can be relaxed.

According to a fourth aspect of the present invention, in the method of forming an external electrode of a semiconductor device according to any one of the first to third aspects, the height of the protruding electrode at the time of resin sealing is 5% or more of the height at the time of formation. It is characterized in that the protruding electrodes are crushed so as to reduce the number. According to this feature, by sufficiently crushing the protruding electrode, the crushed tip surface can be surely brought into close contact with the resin sealing mold.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A specific method of forming an external electrode on a semiconductor device during resin molding will be specifically described below as an embodiment to which the present invention is applied with reference to the drawings.

[First Embodiment] FIGS. 1 to 3 are views showing an example of a resin encapsulation process for crushing a protruding electrode during compression molding, as a first embodiment to which the present invention is applied. FIG. 1 is an explanatory view showing a state in which a molded product is arranged between molds, FIG. 2 is an explanatory view showing an enlarged molded product, and FIG.
[Fig. 2] is an explanatory view showing a state in which the article to be molded is compressed after the state of Fig. 1.

As shown in FIG. 2, in the present embodiment, a circuit board 1, a semiconductor element 2 flip-chip connected to the circuit board 1, and a circuit board 1 are molded products to be compression-molded. A molded product 4 including the protruding electrodes 3 formed around the semiconductor element 2 is shown. Here, the bump electrode 3 is formed by stacking gold bumps manufactured by a wire bonder higher than the semiconductor element 2.

As shown in FIG. 1, in the present embodiment, a frame-shaped fixed lower mold 11 and its inside are moved as a resin-sealing mold for compression-molding such a molded product 4. A lower mold 13 including a movable lower mold 12 and a mold 15 including an upper mold 14 are used. The mold 15 has a built-in heater (not shown) for heating and melting the resin material. The lower die 13 is moved up and down with respect to the upper die 14 by an elevator mechanism (not shown). In the present embodiment, the mold 15 is used to seal the molded product 4 with resin as follows.

[Resin Encapsulation Step] First, as shown in FIG. 1, with the upper mold 14 and the lower mold 13 facing each other,
The resin material 5 is placed on the upper surface of the movable lower die 12, and the semiconductor element 2 of the molding target 4 is placed between the upper die 14 and the lower die 13.
The molded product 4 is arranged such that the central portion where the projecting electrodes 3 and the protruding electrodes 3 are arranged is located on the movable lower mold 12, and the peripheral edge of the molded product 4 is located on the fixed lower mold 11. In this state, the resin material 5 is heated to a molten state by a heater (not shown) built in the mold 15.

Subsequently, the fixed lower mold 11 and the movable lower mold 12 are raised by an elevator mechanism (not shown) to move the fixed lower mold 1
The peripheral edge of the molded product 4 is clamped by the upper surface of 1 and the lower surface of the upper mold 14. In this state, as shown in FIG. 3, only the movable lower die 12 is further raised to apply a compressive force to the protruding electrode 3 and the molten resin material 5. Thereby, the protruding electrode 3
While squeezing to a predetermined height, in parallel with this, the circuit board 1 of the article to be molded 4, the fixed lower mold 11 and the movable lower mold 1
The cavity formed by 2 is filled with the molten resin material 5 to perform resin molding. In this case, the protruding electrode 3
The protruding electrode 3 is crushed so as to be reduced by about 5 to 50% of the height at the time of forming. When considering the height from the surface of the circuit board 1, the height A when the protruding electrode 3 is formed, the height B of the semiconductor element 2, and the protruding electrode 3 after being crushed (after resin sealing) The relation of height C is A> C ≧ B,
Becomes

[Function and Effect] The function and effect when the external electrodes are formed in the resin sealing process as described above will be described below.

First, in the resin sealing step, the protruding electrode 3 is compressed and crushed by the resin sealing mold 15 so that the tip surface of the crushed protruding electrode 3 is sufficiently adhered to the mold 15. In this state, resin molding can be performed without the resin adhering to this portion. In particular, by sufficiently crushing the protruding electrode 3 by reducing it by about 5 to 50% of the height at the time of forming the protruding electrode 3, the crushed tip surface is surely brought into close contact with the resin sealing mold. Can be made.

Therefore, the tip end surface of the protruding electrode 3 can be surely exposed from the resin surface after the resin sealing.
For example, 3 gold bumps with a diameter of 70 μm and a height of 50 μm are used.
Stacked to form a protruding electrode 3 having a height of 150 μm,
When the bump electrode 3 is crushed to a height of 100 μm during resin sealing, the stacked gold bumps are crushed, and the gold bump having a diameter of about 100 μm, that is, the tip surface of the bump electrode 3 is exposed on the resin surface. To do.

As described above, it is possible to easily use the mold used for resin sealing to crush the protruding electrodes without any special means. By this method, the protruding electrodes 3 can be formed. It is possible to reliably expose the tip end surface of the resin from the resin surface. Therefore, the manufacturing efficiency of the semiconductor device can be improved as compared with the conventional technique in which the protruding electrode is buried in the resin and sealed with the resin, because it is not necessary to uniformly grind the entire surface of the semiconductor element.

Further, according to the method of the present embodiment, since resin molding can be performed at the same time while crushing the protruding electrodes by the resin-sealing mold during resin compression molding, the protruding electrodes are crushed. Only the process is unnecessary.
Furthermore, unlike the present invention, in the case of resin sealing just before the protruding electrode, the resin will cover the surface of the protruding electrode unless the variation of the protruding electrode is suppressed, but as in the present invention, the protruding electrode is pressed securely. In the crushing method, even if there is some variation in height when forming the bump electrodes, the bump electrodes can be uniformly crushed in order from the highest bump electrode. Therefore, the accuracy of the height when forming the bump electrode can be relaxed.

The semiconductor device in which the protruding electrode is exposed from the resin surface by the method according to the present embodiment is BGA.
It is useful for manufacturing and for improving manufacturing efficiency in three-dimensional mounting. That is, the BGA can be easily manufactured by placing the solder balls on the protruding electrodes 3 exposed on the resin surface. In addition, the protruding electrode exposed from the resin surface of the semiconductor device manufactured by the method according to the present embodiment can also be used as a through electrode for three-dimensional mounting.

Further, in the prior art, E-BGA and m-BGA, which could only be resin-sealed in individual semiconductor device units by potting or the like, were used to prepare large-sized molded products for a large number of semiconductor devices. It becomes possible to efficiently manufacture them collectively by a method such as separating after sealing. FIG. 4 is an explanatory diagram showing an example of an E-BGA manufactured by the method according to this embodiment.

As shown in FIG. 4, a multilayer substrate 21
A plurality of semiconductor elements 23 connected to the multi-layer substrate 21 by gold wires 22, a frame body 24 for supporting them, the multi-layer substrate 21.
Of the gold bumps (protruding electrodes) 25 placed on the outermost layer of the above, the entire surface of a large-sized molded object 26 for a plurality of semiconductor devices is crushed and exposed by the resin 27. It is resin-sealed. The molded products after resin sealing are separated by the package dicing line 28, and individual E-BGAs are manufactured.

In this case, not only the semiconductor elements 23 but also the wiring patterns of the multilayer substrate 21 are covered with the resin in the plurality of semiconductor devices by the collective resin sealing, and only the gold bumps 25 can be exposed. The manufacturing efficiency is markedly higher than that of the prior art in which the semiconductor element of each semiconductor device is resin-sealed by potting. Further, in the conventional E-BGA as shown in FIG. 8, it was necessary to apply a resist in order to form a wiring pattern for mounting the solder balls on the multilayer substrate.
In the E-BGA of FIG. 4 in which only 5 is exposed, the resin on the surface serves as a substitute for the resist, so that it is not necessary to apply the resist.

[Second Embodiment] FIGS. 5 to 7 show an example of a resin encapsulation process in the case where transfer molding is performed after the protruding electrodes are crushed, as a second embodiment to which the present invention is applied. FIG. 5 is a diagram illustrating a state in which a molded product is arranged between molds, FIG. 6 is a state in which the molded product is compressed,
FIG. 7 shows a state where transfer molding is performed.

The molded product to be resin-sealed in this embodiment is the molded product 4 including the circuit board 1, the semiconductor element 2 and the protruding electrode 3 similar to that of the first embodiment, The bump electrode 3 is formed of a gold bump. Then, as shown in FIG. 5, in the present embodiment, a metal mold 33 including a lower mold 31 and an upper mold 32 is used as a resin-sealing mold for transfer-molding such a molded product 4.
To use. The mold 33 is similar to the mold 15 in the first embodiment in that a heater (not shown) for heating and melting the resin material is built in the mold 33. Further, in the die 33 according to the present embodiment, the upper die 32 is moved up and down with respect to the lower die 31 by an elevator mechanism (not shown).

Further, a pot 31a for resin injection is formed in the lower mold 31, and a plunger 34 for resin pressurization is inserted into the pot 31a. On the other hand, in the upper mold 32,
Cavity 32a for resin molding and this cavity 32
A runner 32b and a gate 32c for allowing the resin to flow into a are formed. In the present embodiment,
With the mold 33, the molded product 4 is sealed with resin as follows.

[Resin Encapsulation Step] First, as shown in FIG. 1, with the upper die 32 and the lower die 31 arranged facing each other,
The tablet-shaped resin material 5 is placed in the pot 31a of the lower mold 31.
And the central portion of the lower die 31 on which the semiconductor element 2 and the protruding electrode 3 of the article to be molded 4 are arranged is located on the upper die 3.
The molded product 4 is arranged so as to face the two cavities 32a.

Subsequently, as shown in FIG. 6, the upper die 32 is lowered by an elevating mechanism (not shown), and the peripheral edge of the article 4 is clamped by the lower surface of the upper die 32 and the upper surface of the lower die 31. By doing so, a compressive force is applied to the protruding electrode 3 to crush it to a predetermined height. That is, similarly to the first embodiment, the protruding electrode 3 is crushed so as to be reduced by about 5 to 50% of the height when the protruding electrode 3 is formed.

Thereafter, as shown in FIG. 7, the tablet-shaped resin material 5 put in the pot 31a of the lower die 31 is
While being melted by heating by a heater (not shown) built in the die 33, the pressure of the plunger 34 causes the pot 31a to melt.
Is poured into the cavity 32a through the runner 32b and the gate 32c to perform resin molding.

[Function and Effect] The function and effect when the external electrodes are formed in the resin sealing process as described above will be described below.

First, in the resin sealing step, the protruding electrode 3 is compressed and crushed by the resin sealing mold 33 so that the tip surface of the crushed protruding electrode 3 is sufficiently adhered to the mold 33. Since the resin molding can be performed in this state without the resin adhering to this portion, the tip end surface of the protruding electrode 3 can be surely removed from the resin surface after the resin sealing as in the first embodiment. It can be exposed, and the manufacturing efficiency of the semiconductor device can be improved. The semiconductor device obtained by this method is also useful for manufacturing BGA and improving the manufacturing efficiency in three-dimensional mounting, like the semiconductor device obtained by the method according to the first embodiment.

In addition to the above-described effects, the method according to the present embodiment supplies the resin after all the protruding electrodes, regardless of height, are sufficiently crushed and brought into close contact with the mold. Even if there is considerable variation in the height of the bump electrodes when they are formed, it is possible to ensure that there is no inconvenience such as resin getting between the tip surface of the low bump electrodes and the mold while the high bump electrodes are crushed. Can be prevented. Therefore, even if there is a considerable variation in height when forming the protruding electrodes, all the protruding electrodes can be surely exposed from the resin surface, so the accuracy of the height when forming the protruding electrodes can be further relaxed. The effect is obtained.

[Other Embodiments] It should be noted that the present invention is not limited to the above-described embodiments, and various other forms can be implemented. For example, the following forms are included.

First, in the above-described embodiment, the case where one of the upper mold and the lower mold is moved up and down to perform the resin sealing has been described. However, the other mold is moved up or down, or the upper and lower molds are moved in opposite directions. The same effect can be obtained even when it is moved up and down. That is, in the present invention, the specific configuration of the die body used can be appropriately selected as long as the protruding electrodes are crushed by the resin sealing die.

In the above embodiment, the case where the bump electrodes are formed by stacking gold bumps has been described, but the method of forming the bump electrodes can be freely selected. For example, solder balls or stud rods can be used. It is also possible to form protruding electrodes.

[0041]

As described above, according to the present invention,
Since the protruding electrode can be surely exposed from the resin surface by crushing the protruding electrode during resin sealing, an external electrode forming method for a semiconductor device capable of easily forming an external electrode exposed from the resin sealing surface is provided. Can be provided. As a result, it is possible to improve the manufacturing efficiency of the BGA and the three-dimensional mounting.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a resin sealing process when a protruding electrode is crushed during compression molding as a first embodiment to which the present invention is applied, in which a molded product is arranged between molds. It is explanatory drawing which shows a state.

FIG. 2 is an explanatory view showing an enlarged product to be molded shown in FIG.

FIG. 3 is an explanatory diagram showing a state in which the molded article is compressed after the state shown in FIG.

FIG. 4 is an E-BG produced in the resin sealing process shown in FIG.
It is an explanatory view showing an example of A.

FIG. 5 is a diagram showing an example of a resin sealing process when transfer molding is performed after the protruding electrodes are crushed as a second embodiment to which the present invention is applied. It is explanatory drawing which shows the state which has arrange | positioned.

FIG. 6 is an explanatory view showing a state in which the molded article is compressed after the state shown in FIG.

7 is an explanatory diagram showing a state where transfer molding is performed after the state shown in FIG.

FIG. 8 is an explanatory diagram showing an example of an E-BGA manufactured by a conventional method.

9 is a view taken in the direction of arrow X in FIG.

[Explanation of symbols]

1 ... Circuit board 2 ... Semiconductor element 3 ... Projection electrode 4 ... Molded product 5 ... Resin material 11 ... Fixed lower mold 12 ... Movable lower mold 13 ... Lower mold 14 ... Upper mold 15 ... Mold 21 ... Multilayer substrate 22 ... Gold wire 23 ... Semiconductor element 24 ... Frame body 25 ... Article to be molded 26 ... Gold bump 27 ... Resin 28 ... Package dicing line 31 ... Mold 31a ... pot 32 ... Lower mold 32a ... Cavity 32b ... runner 32c ... gate 33 ... Upper mold 34 ... Plunger

Claims (4)

[Claims] 1. A method of forming an external electrode of a semiconductor device, comprising a substrate connected to a semiconductor element and having a protruding electrode for forming an external electrode, which is resin-sealed. A method for forming an external electrode of a semiconductor device, comprising exposing the protruding electrode from the resin surface after resin sealing by compressing and crushing the protruding electrode. 2. When the resin is sealed, a molded product including the protruding electrode and the resin are arranged between the resin sealing molds, and a compressive force is applied to the protruding electrode and the resin to push the protruding electrode. Perform resin molding while crushing,
The method for forming an external electrode of a semiconductor device according to claim 1, wherein: 3. At the time of the resin sealing, a molded product including the protruding electrode is arranged between the resin sealing molds, and the protruding electrode is crushed by applying a compressive force to the protruding electrode, The resin molding is performed by supplying a resin into a cavity formed between the resin-sealing mold in which the electrodes are crushed and the substrate of the molding target. Method for forming external electrodes of semiconductor device of. 4. The bump electrode is crushed so as to reduce the height of the bump electrode by 5% or more of the height at the time of the resin sealing.
Item 7. A method for forming an external electrode of a semiconductor device according to item.