Method of forming external electrode of semiconductor device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a method for forming an external electrode of a semiconductor device, and more particularly to a method for forming an external electrode advantageous for manufacturing a ball grid array (hereinafter abbreviated as BGA) and three-dimensional mounting. ..

【0002】

[Conventional technology]

Conventionally, various methods for forming an external electrode on a resin-sealed surface of a semiconductor device in which a semiconductor element is resin-sealed have been proposed. For example, as a method of forming a through electrode in which semiconductor devices are laminated 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 method. In the semiconductor device formed in this way, a BGA can also be produced by placing a solder ball on the protruding electrode exposed after grinding.

【0003】

Further, FIG. 8 is an explanatory view showing an example of the E-BGA produced by the conventional method, and FIG. 9 is a view taken along the line X of FIG. As shown in FIG. 8, in the workpiece 45 formed by supporting the multilayer substrate 41 and the semiconductor element 43 connected to the multilayer substrate 41 by a gold wire 42 by a frame body 44, the semiconductor element 43 is made of resin 46. After being sealed with resin, the solder balls 47 are placed on the wiring pattern of the multilayer board 41. In this case, when the semiconductor element 43 is sealed with resin, only the inner portion thereof is resin-sealed by potting liquid resin in order to expose the wiring pattern of the outermost layer of the multilayer substrate 41. Also, when manufacturing m-BGA, it is necessary to expose the wiring pattern of the substrate in the same manner, so resin sealing by potting is performed.

【0004】

[Problems to be Solved by the Invention]

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

【0005】

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

【0006】

In addition, when manufacturing E-BGA and m-BGA, resin sealing can only be performed for each semiconductor device because of resin sealing such as potting, and multiple semiconductor devices can be collectively resin-sealed. It cannot be sealed. Therefore, there is a limit to the improvement of manufacturing efficiency when manufacturing a large number of semiconductor devices.

【0007】

The present invention has been proposed to solve the above problems of the prior art, and an object of the present invention is to form an external electrode of a semiconductor device capable of easily forming an external electrode exposed from a resin sealing surface. It is to provide a method, thereby achieving improved manufacturing efficiency in BGA fabrication and three-dimensional mounting.

【0008】

[Means for solving problems]

In order to achieve the above object, the method for forming an external electrode of a semiconductor device of the present invention is to crush the protruding electrode at the time of resin encapsulation so that the protruding electrode is surely exposed from the resin surface.

【0009】

The invention of claim 1 is a method for forming an external electrode of a semiconductor device, which is connected to a semiconductor element and seals a substrate having a protruding electrode for forming an external electrode with a resin. It is characterized in that the protruding electrode is exposed from the resin surface after the resin is sealed by compressing and crushing the protruding electrode.

【0010】

According to this feature, the protruding electrode is compressed and crushed by the resin sealing mold at the time of resin sealing, so that the tip surface of the crushed protruding electrode is sufficiently brought into close contact with the resin sealing mold. In this state, resin molding can be performed without the resin adhering to this portion. Therefore, after the resin is sealed, the tip surface of the protrusion electrode can be reliably exposed from the resin surface. Further, it is easily feasible to crush the protruding electrode by using the resin sealing mold at the time of resin sealing without requiring any special means.

【0011】

The invention of claim 2 is the method of forming an external electrode of a semiconductor device according to claim 1, in which a molded product including a protruding electrode and a resin are arranged between a resin sealing mold at the time of resin sealing. It is characterized in that resin molding is performed while crushing the protruding electrodes by applying a compressive force to the resin. According to this feature, when the resin is compression-molded, the projection electrode can be crushed and the resin molding can be performed at the same time by the resin sealing mold, so that the step of crushing the projection electrode is unnecessary.

【0012】

According to the third aspect of the present invention, in the method for forming an external electrode of a semiconductor device according to the first aspect, when sealing a resin, a molded product including a protruding electrode is arranged between resin sealing dies, and a compressive force is applied to the protruding electrode. The feature is that the protruding electrode is crushed by adding the resin, and the resin is supplied into the cavity formed between the resin sealing mold in which the protruding electrode is crushed and the substrate of the product to be molded to perform resin molding. It is supposed to be. According to this feature, by crushing the protrusion electrode to ensure that it is firmly adhered to the resin sealing mold and then supplying the resin, the protrusion electrode is formed even if the height at the time of formation varies to some extent. Since the resin does not adhere to the tip surface of the protrusion electrode having a low height at the time, the accuracy of the height at the time of forming the protrusion electrode can be relaxed.

【0013】

According to the invention of claim 4, in the method of forming an external electrode of a semiconductor device according to any one of claims 1 to 3, the height of the protruding electrode is reduced by 5% or more of the height at the time of forming when the resin is sealed. It is characterized by crushing the protruding electrode. 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

Hereinafter, as an embodiment to which the present invention is applied, a specific method for forming an external electrode on a semiconductor device during resin molding will be specifically described with reference to the drawings.

【0015】

[First Embodiment] FIGS. 1 to 3 are views showing an example of a resin sealing step in the case of 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 the product to be molded is arranged between the molds, FIG. 2 is an explanatory view showing an enlarged view of the product to be molded, and FIG. 3 is a compressed product after the state of FIG. It is explanatory drawing which shows the state.

【0016】

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

【0017】

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

【0018】

[Resin sealing process] First, as shown in FIG. 1, the resin material 5 is placed on the upper surface of the movable lower mold 12 with the upper mold 14 and the lower mold 13 facing each other, and the upper mold is placed. Between 14 and the lower mold 13, the central portion where the semiconductor element 2 and the protrusion electrode 3 of the product 4 to be molded are arranged is located on the movable lower mold 12, and the peripheral edge portion of the product 4 to be molded is fixed. Place the product 4 to be molded so that it is located on the mold 11. In this state, the resin material 5 is heated by a heater (not shown) built in the mold 15 to bring it into a molten state.

【0019】

Subsequently, the fixed lower mold 11 and the movable lower mold 12 are raised by an elevating mechanism (not shown), and the peripheral edge portion of the molded product 4 is clamped by the upper surface of the fixed lower mold 11 and the lower surface of the upper mold 14. In this state, as shown in FIG. 3, only the movable lower mold 12 is further raised to apply a compressive force to the protruding electrode 3 and the molten resin material 5. As a result, while crushing the protruding electrode 3 to a predetermined height, in parallel with this, the resin material melted in the cavity formed by the circuit board 1 of the product 4 and the fixed lower mold 11 and the movable lower mold 12. Fill 5 and perform resin molding. In this case, the protrusion electrode 3 is crushed so as to reduce the height at the time of formation of the protrusion electrode 3 by about 5 to 50%. Considering the height from the surface of the circuit board 1, the height A at the time of forming the protrusion electrode 3, the height B of the semiconductor element 2, and the protrusion electrode 3 after being crushed (after resin sealing) The relationship of height C is A> C B.

【0020】

[Action / Effect] The action / effect when the external electrode is formed in the resin sealing step as described above will be described below.

【0021】

First, during the resin sealing process, the protrusion electrode 3 is compressed and crushed by the resin sealing mold 15, so that the tip surface of the crushed protrusion electrode 3 is sufficiently brought into close contact with the mold 15. , Resin molding can be performed without the resin adhering to this portion. In particular, by sufficiently crushing the protrusion electrode 3 so as to reduce the height at the time of forming the protrusion electrode 3 by about 5 to 50%, the crushed tip surface is securely adhered to the resin sealing mold. Can be made to.

【0022】

Therefore, after the resin is sealed, the tip surface of the protrusion electrode 3 can be reliably exposed from the resin surface. For example, when three gold bumps having a diameter of 70 μm and a height of 50 μm are stacked to form a protruding electrode 3 having a height of 150 μm, and the protruding electrode 3 is crushed to a height of 100 μm at the time of resin sealing. The stacked gold bumps are crushed, and the gold bumps having a diameter of about 100 μm, that is, the tip surface of the protrusion electrode 3 is exposed on the resin surface.

【0023】

In this way, crushing the protruding electrode by using the mold used for resin sealing as it is can be easily realized without requiring any special means, and by this method, the tip surface of the protruding electrode 3 can be easily realized. Can be reliably exposed from the resin surface. Therefore, as compared with the conventional technique of burying the protruding electrode in the resin and sealing the resin, the manufacturing efficiency of the semiconductor device can be improved by the amount that it is not necessary to uniformly grind the entire surface of the semiconductor element.

【0024】

Further, according to the method according to the present embodiment, the resin molding can be performed at the same time as the projection electrode is crushed by the resin sealing mold at the time of compression molding of the resin, so that the step of simply crushing the projection electrode. Is unnecessary. Furthermore, unlike the present invention, when the resin is sealed so as to be close to the protrusion electrode, the resin covers the surface of the protrusion electrode unless the variation of the protrusion electrode is suppressed, but the protrusion electrode is surely pressed as in the present invention. In the crushing method, even if there is some variation in the height at the time of forming the protruding electrodes, it is possible to make them uniform by crushing them in order from the highest protruding electrode. Therefore, the accuracy of the height at the time of forming the protrusion electrode can be relaxed.

【0025】

Further, the semiconductor device in which the protruding electrodes are exposed from the resin surface by the method according to the present embodiment is useful for manufacturing BGA and improving manufacturing efficiency in three-dimensional mounting. That is, a BGA can be easily produced by placing a solder ball on the protruding electrode 3 exposed on the resin surface. Further, 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.

【0026】

Furthermore, E-BGA and m-BGA, which could only be resin-sealed in individual semiconductor device units by potting or the like in the prior art, were manufactured and resin-sealed in large-sized molded products for a large number of semiconductor devices. It can be manufactured efficiently in a batch by a method such as separating it later. FIG. 4 is an explanatory diagram showing an example of E-BGA produced by the method according to the present embodiment.

【0027】

As shown in FIG. 4, the multilayer substrate 21 is mounted on the outermost layer of the multilayer substrate 21, the plurality of semiconductor elements 23 connected to the multilayer substrate 21 by gold wires 22, the frame body 24 supporting them, and the multilayer substrate 21. The entire surface of a large-sized object 26, which is composed of gold bumps (projection electrodes) 25 and is used for a plurality of semiconductor devices, is resin-sealed with resin 27 so as to crush and expose the gold bumps 25. The molded product after resin sealing is separated by a package dicing line 28 to prepare individual E-BGA.

【0028】

In this case, by batch resin encapsulation, not only the semiconductor element 23 but also the wiring pattern of the multilayer substrate 21 is all covered with resin for a plurality of semiconductor devices, and only the gold bump 25 can be exposed. The manufacturing efficiency is significantly higher than that of the conventional technique in which the semiconductor elements of individual semiconductor devices are sealed with resin. Further, in the conventional E-BGA as shown in FIG. 8, it was necessary to apply a resist in order to obtain a wiring pattern for mounting the solder balls on the multilayer board, but only the gold bump 25 is exposed. In E-BGA of 4, the resin on the surface replaces the resist, so there is no need to apply a resist.

【0029】

[Second Embodiment] FIGS. 5 to 7 show an example of a resin sealing step in the case of performing transfer molding after crushing a protruding electrode as a second embodiment to which the present invention is applied. 5A and 5B show a state in which a product to be molded is arranged between dies, FIG. 6 shows a state in which the product to be molded is compressed, and FIG. 7 shows a state in which transfer molding is performed.

【0030】

The product to be molded resin-sealed in the present embodiment is the product 4 to be molded composed of the circuit board 1, the semiconductor element 2, and the protrusion electrode 3 as in the first embodiment described above, and the protrusion electrode 3 Is formed from gold bumps. Then, as shown in FIG. 5, in the present embodiment, a mold 33 composed of a lower mold 31 and an upper mold 32 is used as a resin sealing mold for transfer molding the product 4 to be molded. 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, the mold 33 according to the present embodiment is designed so that the upper mold 32 moves up and down with respect to the lower mold 31 by an elevating mechanism (not shown).

【0031】

Further, a pot 31a for charging resin is formed in the lower mold 31, and a plunger 34 for pressurizing the resin is inserted into the pot 31a. On the other hand, the upper mold 32 is formed with a cavity 32a for molding the resin, and a runner 32b and a gate 32c for allowing the resin to flow into the cavity 32a. In the present embodiment, the mold 33 is used to seal the molded product 4 with resin as follows.

【0032】

[Resin sealing step] First, as shown in FIG. 1, the tablet-shaped resin material 5 is put into the pot 31a of the lower mold 31 with the upper mold 32 and the lower mold 31 facing each other. On the upper surface of the lower mold 31, the molded product 4 is arranged so that the central portion where the semiconductor element 2 and the protruding electrode 3 of the molded product 4 are arranged faces the cavity 32a of the upper mold 32.

【0033】

Subsequently, as shown in FIG. 6, the upper die 32 is lowered by an elevating mechanism (not shown), and the peripheral edge portion of the molded product 4 is clamped by the lower surface of the upper die 32 and the upper surface of the lower die 31. , Apply a compressive force to the protruding electrode 3 and crush it to a predetermined height. That is, as in the first embodiment, the protrusion electrode 3 is crushed so as to reduce the height at the time of forming the protrusion electrode 3 by about 5 to 50%.

【0034】

After that, as shown in FIG. 7, the tablet-shaped resin material 5 charged into the pot 31a of the lower mold 31 is melted by heating with a heater (not shown) built in the mold 33, and the pressure of the plunger 34 is applied. Resin molding is performed by pouring from the pot 31a into the cavity 32a via the runner 32b and the gate 32c.

【0035】

[Action / Effect] The action / effect when the external electrode is formed in the resin sealing step as described above will be described below.

【0036】

First, during the resin sealing step, the protrusion electrode 3 is compressed and crushed by the resin sealing mold 33, so that the tip surface of the crushed protrusion electrode 3 is sufficiently brought into close contact with the mold 33. Since the resin can be molded without the resin adhering to this portion, the tip surface of the protruding electrode 3 is surely exposed from the resin surface after the resin is sealed, as in the first embodiment. This makes it possible to improve the manufacturing efficiency of semiconductor devices. The semiconductor device obtained by this method is also useful for improving the manufacturing efficiency in manufacturing BGA and three-dimensional mounting, similarly to the semiconductor device obtained by the method according to the first embodiment.

【0037】

In addition to the above-mentioned effects and effects, in the method according to the present embodiment, all the protruding electrodes are sufficiently crushed regardless of the height to be brought into close contact with the mold, and then the resin is supplied. Even if there is considerable variation in the height at the time of formation, it is necessary to reliably prevent inconveniences such as resin entering between the tip surface of the low protrusion electrode and the mold while crushing the high protrusion electrode. Can be done. Therefore, even if there is considerable variation in the height at the time of forming the protrusion electrodes, all the protrusion electrodes can be reliably exposed from the resin surface, so that the accuracy of the height at the time of forming the protrusion electrodes can be further relaxed. The effect is obtained.

【0038】

[Other Embodiments] The present invention is not limited to the above-described embodiments, and a wide variety of other embodiments can be implemented. For example, it includes the following forms.

【0039】

First, in the above-described embodiment, the case where one of the upper mold and the lower mold is raised and lowered to perform resin sealing has been described, but the other mold is raised and lowered, or both the upper and lower molds are raised and lowered in opposite directions. The same effect can be obtained even in the case of. That is, in the present invention, as long as the protruding electrode is crushed by the resin sealing mold, the specific configuration of the mold body to be used can be appropriately selected.

【0040】

Further, in the above-described embodiment, the case where the protrusion electrode is formed by stacking gold bumps has been described, but the method for forming the protrusion electrode can be freely selected. For example, the protrusion electrode is formed by a solder ball, a stud rod, or the like. It is also possible to form.

【0041】

[Effect of the invention]

As described above, according to the present invention, the protruding electrode can be reliably exposed from the resin surface by crushing the protruding electrode at the time of resin sealing, so that the external electrode exposed from the resin sealing surface can be easily exposed. It is possible to provide a method for forming an external electrode of a semiconductor device that can be formed in the above. As a result, it is possible to improve the manufacturing efficiency in the fabrication of BGA and the three-dimensional mounting.

[Simple explanation of drawings]

[Figure 1]

As a first embodiment to which the present invention is applied, it is a figure which shows an example of the resin sealing process at the time of crushing a protrusion electrode at the time of compression molding, and the description which shows the state which arranges the object to be molded between molds. It is a figure.

[Figure 2]

It is explanatory drawing which enlarges and shows the article | part to be molded shown in FIG.

[Fig. 3]

It is explanatory drawing which shows the state which compressed the part to be molded after the state shown in FIG.

[Fig. 4]

It is explanatory drawing which shows an example of E-BGA produced in the resin sealing process shown in FIG.

[Fig. 5]

As a second embodiment to which the present invention is applied, it is a figure which shows an example of the resin sealing process in the case of performing transfer molding after crushing a protrusion electrode, and is the state which arranges the part to be molded between molds. It is explanatory drawing which shows.

[Fig. 6]

It is explanatory drawing which shows the state which compressed the part to be molded after the state shown in FIG.

[Fig. 7]

It is explanatory drawing which shows the state which performed the transfer molding after the state shown in FIG.

[Fig. 8]

It is explanatory drawing which shows an example of E-BGA produced by the conventional method.

[Fig. 9]

It is an X arrow view of FIG.

[Explanation of symbols]

1 ... circuit board 2 ... Semiconductor device 3 ... Projection electrode 4 ... Molded product 5 ... Resin material 11 ... Fixed lower mold 12 ... Movable lower type 13 ... Lower mold 14 ... upper mold 15 ... mold 21 ... Multilayer board 22 ... gold wire 23 ... Semiconductor device 24 ... Frame 25 ... Product to be molded 26 ... Gold bump 27 ... resin 28 ... Package dicing line 31 ... mold 31a ... pot 32 ... Lower type 32a ... cavity 32b ... Lanna 32c ... gate 33 ... Upper model 34 ... Plunger