JP2002353260A - Resin sealing apparatus for wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely perform resin sealing to a wafer without generating a void. SOLUTION: The wafer is arranged in a cavity 20 formed by an upper mold 11 and a middle mold 12. A runner 35 formed by the middle mold 12 and a lower mold 13 guides melted resin, and the melted resin is injected into the cavity 20 from a gate 36 provided on the middle mold 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for resin-sealing a wafer having an already formed chip area of an IC to be a semiconductor IC chip.

[0002]

2. Description of the Related Art Usually, a semiconductor IC chip obtained by cutting a wafer is sealed with a resin. However, recently, an attempt has been made to integrally seal the wafer with a resin before cutting. That is, for example, a cavity is formed on the facing surface of the upper mold and the lower mold, a wafer is arranged in this cavity, and a gate communicating with the cavity is provided on the facing surface of the upper mold and the lower mold,
By injecting liquid molten resin from this gate,
The wafer is sealed with resin.

[0003]

Incidentally, since the wafer has a diameter of 6 inches or more, it is necessary to increase the volume of the cavity for arranging the wafer.
However, when the molten resin is injected from one end of the cavity having a large volume through the gates formed on the opposing surfaces of the upper mold and the lower mold as described above, while the molten resin flows toward the other end of the cavity, In order to start curing, it was difficult to reliably fill the cavity with resin. Also,
If the molten resin is cured before pressurization, voids are liable to be generated, and defective products are generated. To remove voids,
Although it is conceivable to increase the resin injection pressure or change the viscosity of the resin, it is difficult to completely suppress generation of voids. An object of the present invention is to provide a resin sealing device capable of reliably sealing a wafer with a resin without generating voids.

[0004]

The present invention has the following arrangement to solve the above-mentioned problems. That is, the present invention relates to one and the other types which are arranged to be able to approach and separate from each other,
An intermediate mold disposed between these molds, a wafer cavity formed between the opposing surfaces of one of the molds and the intermediate mold, and a wafer arranged with the plate surface having electrodes facing the intermediate mold; A runner formed between the opposing surfaces of the mold and the other mold for guiding the molten resin toward the wafer cavity, and a molten resin formed on the intermediate mold and guided by the runner is injected into the wafer cavity. A resin sealing device for a wafer.

[0005] In this resin sealing device, since the unnecessary resin remains on the runner, an ejecting means for removing the unnecessary resin may be provided in the other mold. Also,
Preferably, an intermediate gate is provided at a position facing an alignment mark area used for positioning the wafer.

Further, a release film may be provided in the wafer cavity to take out the resin-sealed wafer. In this case, an introduction hole for introducing molten resin from the gate into the cavity is provided. It is provided in advance on the film. Further, a cushioning material for buffering the pressing force against the wafer may be provided on the opposite surface forming the cavity for one type of wafer. By providing the cushioning material, the pressing force can be applied evenly to the wafer, so that each electrode of the wafer is securely brought into contact with the wall surface forming the cavity for the wafer, and the electrodes are covered with the resin. Can be prevented.

<Operation> Since a cavity for a wafer is formed by one mold and an intermediate mold, and a gate is provided in the intermediate mold, a gate is communicated at a central position of the cavity or a plurality of cavities are formed at a plurality of positions of the cavity. The gate can be communicated. Therefore, the flow distance of the molten resin in the cavity can be reduced, so that the cavity can be reliably filled with the resin without generating a void, thereby sealing the wafer with the resin.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 is a cross-sectional view in a setting step of a wafer resin sealing device according to the present invention. This resin sealing device includes a mold 14 including an upper mold 11, an intermediate mold 12, and a lower mold 13. The intermediate mold 12 has a plane 1 parallel to each other.
5 and 16. The upper mold 11 has a plane 17 facing the plane 15 of the intermediate mold 12, and the lower mold 13 has
Has a plane 18 facing the plane 16 of FIG. Upper mold 1
1, the intermediate mold 12 and the lower mold 13 are held movably in the vertical direction such that these opposing planes approach and separate from each other.

The wafer 1 is arranged on a plane 15 of the intermediate mold 12. The wafer 1 has a diameter of, for example, 300 mm, and has a large number of chip areas 1a as shown in FIG. That is, an IC circuit for forming an IC chip is formed in each chip area 1a. Then, an electrode 2 for providing a solder pump is formed in each chip area 1a. These electrodes 2 are formed to have a thickness (height) of about 50 μ when the thickness of the wafer 1 is 300 μ. Also, the wafer 1 has an alignment region 1
b. The alignment region 1b is a portion where a mark for positioning the wafer is formed and has no circuit.

The plane 17 of the upper mold 11 and the plane 1 of the intermediate mold 12
5 is formed with a wafer cavity 20 comprising a recess for receiving the wafer 1. Intermediate mold 12
In the setting step shown in FIG. 1, the lower mold 13 and the lower mold 13 are held with flat surfaces 16 and 18 facing each other. A guide portion 30 for guiding the liquefied molten resin to the cavity 20 is provided between the flat surfaces 16 and 18. The lower mold 13 is formed with a pot 32 for accommodating a tablet 31 made of a thermosetting resin containing, for example, silica and an epoxy resin as a binder.

The tablet 3 liquefied in the pot 32
1 is that a guide 32 is formed from the pot 32 by pressing a plunger 33 having the pot 32 as a cylinder as a molten resin.
Through the cavity 20. Guide part 30
Is a cull 3 which is opened on the plane 18 of the lower mold 13 and comprises a circular recess for receiving the molten resin extruded from the pot 32.
And a runner 35 extending from the cull 34 in a matrix on the plane 18 with the cavity 20 as the center.
And each runner 3 is formed on a plane 16 of the intermediate mold 12.
And a gate 36 extending from 5 to the cavity 20 in the thickness direction of the intermediate mold 12 and communicating therewith. Gate 36
Are provided at positions facing the alignment region 1b of the wafer 1, as shown in FIG.

The lower die 13 is provided with an eject mechanism 37. The eject mechanism 37 includes a guide hole 38 extending in the thickness direction of the lower mold 13, a plurality of push pins 39 inserted through the guide hole 38 and arranged to be protrudable into the runner 35. An actuating device 41 is provided for operating between a pushing position and a retracted position from the runner 35 regulated by the stopper 40. The eject mechanism 37 includes a cull 34 and a runner 35 of the guide portion 30.
Unnecessary resin remaining in the mold is discharged from the lower mold 13 and
Aligning the pins 39 with the gate 36 is used to press the alignment region 1b of the wafer 1 and discharge the wafer 1 from the cavity 20.

A cushioning material 42 is mounted on the flat surface 17 of the upper mold 11. The cushioning member 42 is formed from a rubber material having a desired elasticity.

Next, the operation of the resin sealing device according to the present invention will be described. FIG. 3 is a sectional view showing a resin injection start step. As shown in FIG. 3, when the upper mold 11 is moved down and temporarily fastened to the intermediate mold 12, a suction mechanism (not shown) provided on the upper mold 11 is operated, and the wafer 1 arranged in the cavity 20 is moved. It is adsorbed on the upper mold 11 via the buffer material 42. When the wafer 1 is attracted in this manner, the upper mold 11 slightly moves upward.

On the other hand, the lower mold 13 is moved upward and clamped to the intermediate mold 12. When the mold is clamped in this manner, the plunger 33 presses the tablet 31 that has been melted in a liquid state.
The molten resin is guided by the cull 34 and the runner 35 and injected into the cavity 20 from the gate 36.

FIG. 4 is a cross-sectional view showing a resin injection completion step. Before the molten resin is completely injected into the cavity 20, the upper die 11 is moved downward to clamp the intermediate die 12, and the injection of the molten resin is continued. At the time when the molten resin has been completely injected into the cavity 20, the resin has not started to be cured. Therefore, a certain resin pressure is applied thereafter, whereby the injection is completed. At the time of this resin injection, as shown in FIG. 2, a pressing force (clamping force) is applied to the wafer 1 via the buffer material 42, so that even if the pressing force is increased, the wafer 1 can be prevented from breaking. . Further, even when the wall surface forming the cavity 20 has irregularities or inclinations in units of microns, a uniform pressing force can be applied to the wafer 1 via the buffer material 42. Therefore, since the electrode 2 can be reliably brought into contact with the wall surface of the cavity 20, it is also possible to prevent a resin film from being formed on the electrode 2.

FIG. 5 is a sectional view showing an unnecessary resin ejecting step. As shown in FIG. 5, after the resin is injected, before and after the resin is completely cured, the upper mold 11 and the intermediate mold 12 are moved upward in a mold-clamped state and separated from the lower mold 13. Thereafter, when the resin hardens, the eject mechanism 37 starts operating, and the pin 39 moves upward and projects into the runner 35. Thereby, the unnecessary resin portion 43 remaining on the cull 34 and the runner 35 can be ejected from the lower mold 13.

When the discharge of the unnecessary resin is completed, the wafer 1 shown in FIG. 6 is ejected. In this step, the intermediate mold 12 is moved downward so that the lower mold 13 is clamped. Thereafter, the eject mechanism 37 is operated to cause the pins 39 to protrude upward from the gate 36 of the intermediate mold 12, thereby separating the resin-sealed wafer 1 from the intermediate mold 12 and taking out the wafer 1 by arm means (not shown) or the like. . In this case, since the pins 39 press the alignment region 1b, which is an unnecessary portion of the wafer 1, there is no need to sacrifice the chip region by pressing, and therefore, it is possible to prevent a decrease in the yield of the wafer. Thereafter, as shown in FIG. 7, the pellets 31 are put into the pot 32, and are kept in a state of waiting for the placement of wafers.

FIG. 8 is a sectional view showing a setting step of a resin sealing apparatus according to another embodiment. In FIG. 8, a release film (tape) 44 having heat resistance is disposed on the concave portion and the flat surface 15 of the intermediate mold 12 forming the wafer cavity 20. The release film 44 is formed of a material that can be released from the mold, and has an introduction hole at the position of the gate 36 for introducing the resin into the cavity 20. Since the other configuration is the same as the configuration shown in FIG. 1, the same portions are denoted by the same reference numerals and description thereof will be omitted.

When the wafer 1 is placed in the cavity 20, a resin injection start step is performed as shown in FIG.
That is, the upper mold 11 is moved downward to suck the wafer 1, and the release film 4 is moved to the intermediate mold by a suction mechanism (not shown).
4 causes the plunger 33 to press the tablet 31 in the lower mold 13, so that the molten resin
It is guided by the gate 36 through the runner 35 and injected into the cavity 20 through the introduction hole of the release film 44.

Next, before the molten resin is completely injected into the cavity 20, as shown in FIG. Inject completely with pressure. Then, unnecessary resin part 4
3 is removed from the lower mold 13 by the eject mechanism 37 in the same manner as in the above embodiment (see FIG. 5). Then, as shown in FIG. 11, the intermediate mold 12 is moved downward to be clamped to the lower mold 13, the both ends of the release film 44 are gripped by arms or the like, and the film 44 is moved upward, and Release the mold. After that, the release film 44 is peeled from the wafer 1.

According to this embodiment, a plurality of intermediate molds provided with cavities and gates corresponding to wafers having different dimensions or alignment area positions are prepared, and various wafers can be prepared simply by combining each intermediate mold with a release film. It can be resin-sealed. That is, the upper mold 11 and the lower mold 13
Various wafers can be resin-sealed only by changing the intermediate mold without changing.

[0023]

According to the present invention, a cavity for a wafer is formed on a surface facing one mold and an intermediate mold, and a molten resin is guided by runners formed on the intermediate mold and the other mold, and provided on the intermediate mold. Since the molten resin is injected from the gate into the cavity, the molten resin can be filled into the cavity before the curing is started even if the wafer size is large. Therefore, the resin can be reliably sealed in the wafer without generating voids.

[Brief description of the drawings]

FIG. 1 is a sectional view of a resin sealing device according to the present invention in a setting step.

FIG. 2 is an enlarged cross-sectional view of a main part of the apparatus when resin injection is completed.

FIG. 3 is a cross-sectional view of the same device in a resin injection start step.

FIG. 4 is a cross-sectional view of the same device in a resin injection completion step.

FIG. 5 is a sectional view of the same device in an unnecessary resin discharging step.

FIG. 6 is a cross-sectional view of the same device in a wafer removal step.

FIG. 7 is a cross-sectional view of the apparatus in a waiting step in which pellets are charged.

FIG. 8 is a sectional view of a resin sealing device according to another embodiment in a setting step.

FIG. 9 is a cross-sectional view of the apparatus of the embodiment in FIG. 8 in a resin injection start step.

FIG. 10 is a cross-sectional view of the embodiment apparatus of FIG. 8 in a resin injection completing step.

FIG. 11 is a cross-sectional view of the apparatus of the embodiment in FIG. 8 in a wafer unloading step.

[Explanation of symbols]

 Reference Signs List 1 wafer 11 upper mold 12 intermediate mold 13 lower mold 14 mold 15, 16, 17, 18 plane 20 cavity 30 guide part 31 tablet (pellet) 32 pot 33 plunger 34 cull 35 runner 36 gate 37 eject mechanism 38 guide hole 39 extrusion Pin 40 Stopper 41 Actuator 42 Buffer material

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F202 AA36 AD02 AH37 CA30 CB01 CB17 CK02 CK06 CM01 4F206 AD02 AH37 JA07 JB17 JF02 JL02 JN25 JP30 JQ81 JT07 5F061 AA01 DA04 DA05 DA15

Claims (5)

[Claims] An apparatus for sealing a resin on a wafer having electrodes formed on a plurality of chip regions and protruding from a plate surface, wherein one and the other molds are arranged so as to be able to approach and separate from each other. An intermediate mold disposed between the one mold and the other mold; and a plate formed between the opposing surfaces of the one mold and the intermediate mold, wherein the wafer has the plate surface having the electrodes as the intermediate mold. A cavity for a wafer disposed to face, a runner formed between facing surfaces of the intermediate mold and the other mold, and for guiding a molten resin toward the cavity for the wafer; and a runner formed in the intermediate mold. A gate for injecting the molten resin guided by the runner into the wafer cavity to seal the wafer. 2. The wafer sealing device according to claim 1, wherein the other mold is provided with an ejecting means for discharging unnecessary resin remaining in the runner from the runner. 3. The wafer sealing device according to claim 1, wherein the intermediate type gate is provided at a position facing an alignment mark area of the wafer. 4. The wafer resin sealing device according to claim 1, wherein a release film having an introduction hole for introducing molten resin from the gate is provided in the wafer cavity. 5. A cushioning material for buffering a pressing force against the wafer and uniformly applying the pressing force to the wafer is provided on an opposing surface of the one mold forming the wafer cavity. Item 2. A resin sealing device for a wafer according to Item 1.