JP3053332B2 - Resin sealing method for semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin sealing method for a semiconductor device mounted on a lead frame.

[0002]

2. Description of the Related Art A semiconductor product such as an IC usually has a semiconductor element mounted on a semiconductor mounting portion formed at the center of a lead frame, and wire bonding with surrounding inner leads is performed. The resin is sealed in the cavity. Then, at the time of this resin sealing, for example, as described in JP-A-3-263840, a gate portion communicating with the cavity and an air vent provided outside the cavity opposed to the gate portion are provided, and the air in the cavity is blown by the air. The molten resin is sealed from the gate portion while discharging from the air vent.

[0003]

However, since there is only one gate portion for resin sealing in the resin sealing, the molten resin tends to flow diagonally faster at the opening of the gate portion. However, there has been a problem that it is difficult to uniformly fill the resin up, down, and around the substantially rectangular cavity in plan view. In addition, although the air in the cavity flows toward the air vent provided outside the cavity, the molten resin also flows along with this, and if the molten resin flows into the air vent before the air can not be sufficiently removed, the air vent will There is a problem that the resin is clogged and air remains in the cavity. Therefore, conventionally, the flow of the molten resin is controlled by changing the shape of the gate portion so that the resin injected from the gate portion is evenly filled in the cavity, and the molten resin is completely filled in the cavity. However, the control by the gate was difficult and not sufficient. The present invention has been made in view of such circumstances, and has as its object to provide a resin sealing method for a semiconductor device in which resin sealing in a cavity can be performed almost completely.

[0004]

According to the present invention, there is provided a semiconductor device comprising:
The resin sealing method for a semiconductor device according to the present invention is characterized in that, while holding a lead frame on which a semiconductor element is mounted in a cavity of a sealing mold provided with a gate serving as an inlet for molten resin, In a resin sealing method for a semiconductor device in which a molten resin is injected into a semiconductor device, the molten resin flows into a cavity through an opening of the gate portion at a position close to the opening of the gate portion in a part of the lead frame. A rectifying projection made of low-melting glass opposed to the main flow of the resin is provided and flows into the cavity while giving flow resistance to the molten resin. Further, the shape of the rectifying projection is orthogonal to the flow direction in a plan view. Linear, inverted V-shaped or V-shaped. According to a second aspect of the present invention, there is provided a resin sealing method for a semiconductor device, wherein a semiconductor element is mounted inside the cavity of a mold provided with a gate portion serving as an inlet for molten resin and an air vent for discharging air in the cavity. In a resin sealing method for a semiconductor device in which a molten resin is injected from the gate portion into the cavity while the lead frame is held, and the resin is sealed, a part of the lead frame is close to the opening of the air vent. At the position, a rectifying projection of low-melting glass facing the air flow flowing out of the cavity is provided at the opening of the air vent, and a flow resistance is applied to the molten resin that is going to flow from the cavity toward the air vent. Further, at a position close to the opening of the gate portion in a part of the lead frame, the current flows into the cavity through the opening of the gate portion. Rectifying protrusion of the low melting point glass is further provided opposite to the main flow of the molten resin gives a flow resistance to. 4. The method according to claim 3, wherein the mold is provided with a gate portion serving as an inlet for molten resin and an air vent for discharging air from the cavity. In a resin sealing method for a semiconductor device in which molten resin is injected from the gate portion into the cavity while sealing the resin, the resin is sealed at a position close to the opening of the air vent in a part of the lead frame. Providing a rectifying projection of low-melting glass facing the air flow flowing out of the cavity at the opening of the air vent, to provide a flow resistance to the molten resin that is going to flow from the cavity toward the air vent, Further, the shape of the rectifying projection may be linear, inverted V-shaped or V
It is shaped like a letter. According to a fourth aspect of the present invention, there is provided a resin sealing method for a semiconductor device according to any one of the first to third aspects, wherein the rectifying projection is formed by a screen printing method. I have.

[0005]

In the resin sealing method for a semiconductor device according to the first aspect of the present invention, the flow resistance is reduced in a part of the lead frame into the inside of the cavity from the opening of the gate portion in opposition to the main flow of the molten resin flowing into the cavity. Since the rectifying projections of the low-melting glass to be provided are provided, the main flow portion of the molten resin which has flowed into the cavity from the opening of the gate portion hits the rectifying projections and thereby spreads on both sides, thereby smoothly entering the cavity. The molten resin is filled. In the resin sealing method for a semiconductor device according to the second and third aspects, the flow of air flowing out of the cavity is set at a position close to the opening of the air vent formed outside the cavity in a part of the lead frame. A rectifying projection made of low-melting glass is provided to oppose, so that the molten resin flowing in the cavity is given a flow resistance by the rectifying projection, so that the speed of the resin flowing toward the air vent is reduced, whereby The air vent is prevented from being clogged with the molten resin to discharge air and to prevent the generation of air bubbles and the like inside. In particular, in the resin sealing method for a semiconductor device according to the second aspect, since the rectifying projection is provided near the gate portion in the cavity and near the air vent, it is possible to reduce the flow rate of the molten resin in the cavity. The resin is more uniformly filled into the cavity by giving resistance. In particular, in the resin sealing method for a semiconductor device according to the fourth aspect, since the rectifying projection is formed by the screen printing method, a free-form rectifying projection can be formed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. FIG. 1 is a plan view of a lead frame to which a resin sealing method for a semiconductor device according to a first embodiment of the present invention is applied, FIG. 2 is a partial side view thereof, and FIG. 3 is another example of a rectifying projection. FIG. 4 is a plan view of a lead frame to which a resin sealing method for a semiconductor device according to a second embodiment of the present invention is applied.

As shown in FIG. 1, a lead frame 10 to which a resin sealing method for a semiconductor device according to a first embodiment of the present invention is applied comprises a peripheral outer lead 11 and an inner inner lead 12. A semiconductor element 14 is mounted on a heat sink 13 provided on the inside of the inner lead 12 via an insulating layer.
Means that wire bonding (not shown) is performed.

When inserted into a resin sealing mold,
As shown in FIG. 1, a portion of the region A becomes a resin sealing portion surrounded by a mold, and is located on a front side of a position B corresponding to an opening 15 of a gate portion for injecting a resin into a cavity formed by the mold. Is provided with a rectifying projection 16. When the gate portion is a single gate, as shown in FIG. 2, the rectification projections 16 and 17 are placed 0.5 m above the inner lead 12 having a thickness of about 0.25 mm in side view.
The rectifying projection 17 on the lower side is formed at a position retracted in the flow direction from the rectifying projection 16 formed on the upper side.

As shown in FIG. 2, the frontal flow flowing into the cavity 18 from the opening 15 formed in the upper portion of the lead frame 10, that is, the molten resin flowing in the diagonal direction is diffused to the surroundings by giving resistance, and further downward. Resistance is also given to the molten resin that has flowed into the cavity 18 on the side at the rear portion, so that the molten resin flows evenly not only in the diagonal direction but also in the surroundings.

Although the rectifying projections 16 and 17 are formed in a V-shape in plan view as described above, the resistance to the molten resin can be increased. In addition, FIG.
As shown in (B), (C), and (D), a rectifying projection 19 having a triangular shape in plan view, a rectifying projection 20 having a right-angled bent shape in plan view, and a tray cross-sectional shape in plan view. The rectifying projection 21 or a straight line-shaped rectifying projection 22 which is orthogonal to the flow of the resin in plan view can also be used.

When the rectifying projections 16, 17, 19 to 22 are formed on the inner leads 12, a low melting glass powder and an adhesive are mixed to form a gel, which is screen-printed. It is mounted in a predetermined shape of a lead frame, then fired to remove the adhesive and fired and solidified the low melting point glass, whereby free-form rectifying projections can be formed and adjacent inner leads It also has the effect of retaining the number 12. It is also possible to provide a frame-shaped or linear rectifying projection on the outside of the wire bonding part of the lead frame, thereby applying a brake to the flow of the molten resin flow to prevent bending of the wire or mounting. A void or the like can be prevented in a portion that becomes a shadow of the semiconductor blocking performed.

Next, a lead frame 24 to which a resin sealing method for a semiconductor device according to a second embodiment of the present invention is applied will be described with reference to FIG. Rectifying projections 30 to 32 are also provided on the inner lead 29 on the front side of the air vents 26 to 28 provided in the mold at the position. This rectifying projection 3
Although 0 to 32 are linear segments perpendicular to the air vent direction, they may have the same shape as the rectifying projections described in the first embodiment. In addition, near the opening of the gate portion 25, the aforementioned rectifying projection 16,
A rectifying projection 33 having the same structure and the same operation and effect as 17 or 19 to 22 is provided.

The rectifying projections 30 to 33 are made of low-melting glass, and are formed so as to protrude a small distance from the lead frame on the front and back surfaces while bridging the adjacent inner leads 29. The rectifying projections 33 also support the support leads 35 of the central element mounting portion 34 in an insulating manner. In FIG. 4, reference numeral 36 denotes a semiconductor element.

The rectifying projections 30 to 32 applied to the second embodiment can be formed on the lead frame shown in the first embodiment.

[0015]

According to the first aspect of the present invention, there is provided a method for rectifying a low-melting point glass which provides a flow resistance to a main flow of a molten resin flowing into a cavity in a part of a lead frame. Since the projection is provided, the molten resin flowing into the cavity from the opening of the gate portion is uniformly and smoothly filled in the cavity. Thus, a semiconductor device having few defects such as bubbles inside can be provided. In the resin sealing method for a semiconductor device according to the second and third aspects, the rectifying projection of low melting point glass is provided on the front side of the air vent, so that the molten resin contains air in the cavity. Thus, a semiconductor device with less defects such as bubbles can be provided. Further, in the resin sealing method for a semiconductor device according to the first to fourth aspects, since the low-melting glass is used for the rectifying projection, the insulating property is good and the melting temperature of the sealing resin is affected. There is an effect that the support of the lead arranged inside is also performed together.

[Brief description of the drawings]

FIG. 1 is a plan view of a lead frame to which a resin sealing method for a semiconductor device according to a first embodiment of the present invention is applied.

FIG. 2 is a partial side view of the same.

FIG. 3 is a partial plan view showing another example of a rectifying projection.

FIG. 4 is a plan view of a lead frame to which a resin sealing method for a semiconductor device according to a second embodiment of the present invention is applied.

[Explanation of symbols]

10: Lead frame, 11: Outer lead, 12:
Inner lead, 13: heat sink, 14: semiconductor element, 15: opening, 16: rectifying projection, 17: rectifying projection, 18: cavity, 19: rectifying projection, 20: rectifying projection, 21: rectifying projection, 22: rectifying projection, 24:
Lead frame, 25: gate, 26: air vent,
27: air vent, 28: air vent, 29: inner lead, 30: rectifying projection, 31: rectifying projection, 32:
Rectification projection, 33: Rectification projection, 34: Element mounting part, 3
5: Support lead, 36: Semiconductor element

Claims (4)

(57) [Claims] 1. A molten resin is injected from the gate portion into the cavity while a lead frame having a semiconductor element mounted thereon is held in a cavity of a sealing mold provided with a gate portion serving as an inlet for the molten resin. A resin sealing method for a semiconductor device, wherein a part of the lead frame is located at a position close to the opening of the gate portion and faces a main flow of the molten resin flowing into the cavity from the opening of the gate portion. A rectifying projection made of low-melting glass is provided so as to flow into the cavity while giving flow resistance to the molten resin. Further, the shape of the rectifying projection is a straight line which is orthogonal to the flow direction in plan view and has an inverted V shape. A resin sealing method for a semiconductor device, wherein the method is a letter shape or a V shape. 2. A mold provided with a gate portion serving as an inlet for molten resin and an air vent for discharging air in the cavity, wherein the lead portion having a semiconductor element mounted therein is held inside the cavity. A resin sealing method for a semiconductor device, in which molten resin is injected into the cavity from the cavity, the resin sealing is performed at a position close to the opening of the air vent in a part of the lead frame. A rectifying projection made of low-melting glass opposed to the air flow flowing out from the inside, to provide a flow resistance to the molten resin which is about to flow toward the air vent from the inside of the cavity; At a position close to the opening of the gate portion, the flow is opposed to the main flow of the molten resin flowing into the cavity from the opening of the gate portion. Resin sealing method of a semiconductor device characterized by rectifying protrusions of the low-melting glass that gives resistance is further provided. 3. A mold provided with a gate portion serving as an inlet for molten resin and an air vent for discharging air in the cavity, wherein the gate portion holds a lead frame on which a semiconductor element is mounted inside the cavity. A resin sealing method for a semiconductor device, in which molten resin is injected into the cavity from the cavity, the resin sealing is performed at a position close to the opening of the air vent in a part of the lead frame. A rectifying projection made of low-melting glass facing the air flow flowing out from the inside is provided, and a flow resistance is given to the molten resin that flows from the inside of the cavity toward the air vent. Further, the shape of the rectifying projection is A resin sealing method for a semiconductor device, wherein the resin sealing method has a linear shape, an inverted V-shape, or a V-shape orthogonal to a flow direction when viewed in a plan view. 4. The method according to claim 1, wherein the rectifying projection is formed by a screen printing method.