JPH0533531B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a molding apparatus for resin encapsulation of semiconductors used in a resin encapsulation process essential for building circuits and elements into semiconductor wafers.

[Technical background of the invention]

Traditionally, in the manufacturing of semiconductor products, automation of front-end processes has been slower than that of back-end processes due to the complexity of the process and the extremely dust-averse work environment, but with the recent trend of increasing production scale, it has become possible to establish highly productive manufacturing lines. is required. As part of this, semiconductor wafers are becoming larger in diameter, and at the same time automation is being promoted in front-end processes, while further automation and high operating rates in back-end processes are desired. From this point of view, various improvements have been made in the die bonding and wire bonding of elements cut into semiconductor pellets, and even in the resin encapsulation process, efforts are being made to improve the efficiency even further. Incidentally, although a transfer molding machine is used in this resin sealing process, the so-called multi-pot type is currently in use. This molding machine will be explained with reference to FIGS. 6 to 11.

Plate plates 51, 51 placed opposite each other are fixed by a support 50 placed in the vertical direction, and a divided mold (not numbered) and a slide table 52 are provided here, with the upper mold being fixed and the lower mold being fixed. A method is adopted in which the mold is movable. A transfer cylinder 53 is attached to the upper plate-like plate 51.
A plunger 55 for resin injection and pressurization is installed at the tip of the piston 54.

The above-mentioned upper mold has spacer blocks 57 on the upper mold base plate 56 fixed to the plate-like plate 51.
A mold base 58 is arranged to form a hollow part 59, in which an ejector plate 60 and an ejector hold 61 are stacked and installed, and a cavity plate 62 is also installed in the mold base 58. On the other hand, the plurality of ejector pins 63 are fixed to the ejector hold 61, and are installed so as to be movable in the axial direction of the support column 50, passing through the mold base 58 and the cavity plate 62. Additionally, a pot 64 is installed in the center of the upper mold to serve as a supply source for the sealing resin.

On the other hand, the lower mold is placed on the slide table 52, and the base plate, spacer block, mold base, hollow part, ejector plate, ejector hold, cavity plate, and a plurality of ejector pins are formed in exactly the same way as the upper mold. Therefore, we will assign the same number and omit the explanation. Incidentally, most of the ejector pins 63 provided in the upper and lower molds are installed at positions directly facing each other. An ejector rod 6 that passes through the slide table 52 and the base plate 56 and supports the ejector plate 60.
5 is formed on the lower plate-like plate 51, and the lower plate-like plate 51 is provided with a transfer cylinder 66 that allows the slide table 52 to pass through the lower plate 51 and move in the axial direction of the column 50.

Although the meaning of the mold was not clear in the above description, the parts between the upper mold base plate 51 and the lower mold base plate 51 in FIG. 6 are collectively referred to as a mold.

By the way, in such a transfer mold, after being heated to a certain temperature, a lead frame 68 is installed on the cavity plate 62 of the lower mold, and then, as shown in FIG. The piston 67 rises to clamp the upper and lower molds.
Here, the resin 69 is supplied to the pot 64, but usually a tablet-shaped resin is used.

Further, as shown in FIG. 8, the piston 54 of the transfer cylinder 53 is lowered and the plunger 55 at the tip injects and press-forms the resin 69, and then the piston 54 of the transfer cylinder 53 is moved down as shown in FIG. is raised, the piston 67 of the transfer cylinder 66 for mold clamping is lowered, and the molded product is ejected. A top view of the molded product obtained through this process is shown in Figure 10, and a cross-sectional view thereof is shown in Figure 11.
Shown in the figure.

[Problems with background technology]

In the above-mentioned molding machine, the transfer cylinder and the mold are each independent, and when installing the mold, it takes time and skill to center the plunger set at the tip of the piston of the transfer cylinder, the pot provided in the mold, and the plunger. This results in wear of the pot and plunger due to centering errors. Since the mold and plunger are independent, each must be heated to a constant temperature, which results in large variations and many molding defects.

Second, space is required between the pot and the plunger to supply the resin, requiring the plunger to be constantly removed from the pot, resulting in longer plunger strokes and increased wear on the pot and plunger.

Since there is only one plunger, there is a distance from the cull to the resin sealing part as shown in Figure 10, which requires a long runner, a large amount of resin, and a long injection time. The distance from to each resin sealing part becomes uneven, leading to many molding defects.

The supply of the lead frame requires many operations because the resin supply is a separate operation, and furthermore, the molding time becomes longer because the next operation cannot be started until the resin is melted after the resin is supplied.

[Purpose of the invention]

The present invention provides a new molding apparatus for resin encapsulation of semiconductors which eliminates the above-mentioned drawbacks, and is particularly aimed at improving the operating rate.

[Summary of the invention]

In the present invention, only the lower mold is movable, a plurality of transfer cylinders and pots are provided therein, and the plunger is always fitted into the pot. Therefore, the lower mold placed on the slide table has two hollow parts, one of which is provided with a plate that supports the ejector pin group that can be moved up to the top surface of the mold, and the other is An equal pressure mechanism is formed in the hollow portion to drive a plunger that transmits pressure to a plurality of pots formed on the top surface of the mold.

A transfer cylinder formed by passing through a slide table was directly connected to the plate, and a transfer cylinder for moving the lower mold was also attached to this slide table.

[Embodiments of the invention]

The present invention will be explained in detail with reference to FIGS. 1 and 5.

Platy plates 2, 2, which are arranged opposite to each other, are fixed to the vertically installed support 1, and the mold is divided into an upper mold and a lower mold. It was designed to be movable. Furthermore, the upper mold is not provided with a transfer cylinder as in the past, but is fixed on an ejector pin group.

Therefore, an upper mold base plate 3 is fixed to the plate-shaped plate 2, and a spacer block 4 and a mold base 5 are installed here to form a hollow part 6, and an ejector plate 7 and an ejector hold 8 are laminated here. A cavity plate 9 is also installed adjacent to the mold base 5. On the other hand, the ejector pins 10 are fixed to the ejector hold 8 and are formed to be movable in the axial direction of the support column 1 through the mold base 5 and the cavity plate 9.

On the other hand, a slide table 11 is formed in the vicinity of the other plate-like plate 2 so as to be movable in the axial direction between the columns 1, and a transfer cylinder is used as a means for achieving this. This transfer cylinder 12
is formed on the slide table 11 and performs its function by a piston 13 that penetrates the plate-like plate 2 and moves.

The lower mold is provided with a two-stage hollow part, and the lower hollow part is provided with an equal pressure transmission mechanism 13, and the upper mold is provided with an ejector pin mechanism similar to the upper mold.

That is, first, the pressure transfer manifold 14 is fixed to the slide table 11, and the spacer block 15 and the pullback transfer manifold 16 are stacked thereon, and the lower hollow part 17 is arranged.
is provided, and an equal pressure mechanism a is provided here. A spacer block 18, a mold base 19, and a cavity plate 20 are arranged also in this transfer manifold 14 to obtain an upper hollow part 21. Like the upper mold, an ejector plate 22 and an ejector hold 23 are provided here, and a plurality of ejector pins 24 are locked to the ejector hold 23, and the mold base 18 and cavity plate 19 are An ejector plate 22 and an ejector hold 23 are provided here, and an ejector pin 24 is secured to the latter. Formed to be movable along the direction. Note that this ejector pin 24... is the ejector pin 1 formed on the upper mold.
Place it so that it directly faces 0...

A plurality of pots 25 are formed in the lower mold at positions directly opposite to some of the ejector pins 10 of the upper mold. Plate 20, mold base 19, ejector hold 23, ejector plate 22
Also, a through hole is formed in the pullback transfer manifold 16.

The plunger rod 26 is connected to a uniform pressure mechanism a placed in the lower hollow part 17, and the dotted line in the figure shows the piping for the hydraulic cylinder, which is the mechanism. move it.

Through holes are provided in the pullback transfer manifold 16, the pressure transfer manifold 14, and the slide table 11, and the ejector plate 21 is made up of a transfer cylinder attached to the plate-like plate 2 so that the ejector rod 6 can be moved.
and press and move the ejector hold 22.

The uniform pressure mechanism a is configured so that the same pressure is transmitted to the pot 25 even if there are variations in the amount of resin supplied into the pot 25, and a spring is used as a means for this purpose, for example. .

In the molding apparatus having the above configuration, the lead frame 29 is supplied to the lower mold of the transfer mold heated to a constant temperature, and the sealing resin tablet (not shown) is supplied to the pot 25. Then the second
As shown in the figure, the mold clamping transfer cylinder 12
After the piston 13 of the pressurizing transfer manifold 14 rises to clamp the upper and lower molds, the piston 28 of the pressure transfer manifold 14 rises and the plunger 27 injects and pressure-moldes the resin tablet. At this time, an equal pressure mechanism a applies an equal pressure force to each plunger 27.
Added separately by. This applies pressure to the spring attached to the terminal end of the ejector rod b to adjust the amount of resin charged into the pot 25 within the range of variation.

Next, as shown in FIG. 3, the ejector rod b of the pull-back transfer manifold 16 is lowered, and further
3 also descends and the molded product is ejected. FIG. 5 is a sectional view of the molded product obtained in FIG. 4.

〔Effect of the invention〕

The molding machine according to the present invention eliminates the need for centering the pot and plunger when installing the mold, and can prevent wear of the pot and plunger due to this centering. Because this mold and plunger are always fitted,
It is heated at the same time, and the temperature variation is 170
±10°C was reduced to 170±3°C, eliminating molding defects caused by temperature.

Secondly, the plunger stroke inside the pot has been significantly narrowed from 150mm to 30mm, reducing wear on the pot and plunger to 1/5th of the previous level.

As shown in FIG. 4, from the cull 30 to the resin sealing part 3
The distance to 3 is short and uniform at 12mm, and the amount of resin is reduced by about 10% compared to the conventional type, preventing molding defects. Incidentally, it should be noted that the conventional distance was as long as 220 to 400 mm and was uneven.

Furthermore, the resin injection time is shortened to 30 seconds to 10 seconds, and since the lead frame and resin are supplied at the same time, mechanical operations are reduced, and the resin melts during mold clamping, making it possible to perform the next operation.

The molding time has been improved from 180 seconds to 60 seconds, resulting in an improvement in the operating rate, which in turn contributes to streamlining the post-processing of semiconductor devices, and has a significant practical effect.

[Brief explanation of drawings]

Figure 1 is a sectional view of a molding machine according to the present invention, Figures 2-
Figure 3 is a cross-sectional view of the molding machine shown in Figure 1 for each operation, Figure 4 is a plan view of a molded product obtained from the molding machine shown in Figure 1, Figure 5 is a cross-sectional view of Figure 4, and Figure 6 is a conventional Figures 7 to 9 are cross-sectional views of the molding machine shown in Figure 6 for each operation, Figure 10 is a plan view of the molded product obtained with the Figure 6 molding machine, and Figure 11 is a cross-sectional view of the molding machine. is a sectional view of FIG.

Claims (1)

[Claims] 1 A column arranged in the vertical direction, a plate-like plate arranged opposite to each other via this column, a pair of molds installed between these plates, and connected to one fixed mold to form. a hollow part, an upper hollow part connected to the other movable mold, a lower hollow part connected to the upper hollow part, and a first ejector plate and an ejector installed in the upper hollow part. a first ejector pin connecting the first cavity plate and ejector plate constituting the other movable mold and the ejector hold; a second ejector plate installed in the hollow part; an ejector hold, a pullback transfer manifold and a transfer manifold constituting the lower hollow part, an equal pressure mechanism installed in the lower hollow part, and an equal pressure mechanism installed between the pullback transfer manifold and the transfer manifold, a piston that is engaged with the pressure mechanism; a slide table that is arranged adjacent to the transfer manifold; a cavity plate that constitutes the other movable mold; A mold base forming a part, a pot installed to penetrate the mold base and the cavity plate, and a plunger rod connecting the sealing resin placed in the pot and the uniform pressure mechanism. and adjusting the variation in the amount of sealing resin injected into the pot by means of the pullback transfer manifold and the transfer manifold, and a piston fixed to the equal pressure mechanism installed between them via a plunger rod. A molding device for semiconductor resin encapsulation characterized by: