JP2002043344A - Method of manufacturing resin-sealed semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of products to be taken while preventing bending of a lead frame. SOLUTION: In this method of manufacturing a semiconductor device, a plurality of semiconductor chips mounted on a substrate is sealed with a resin. Among a plurality of semiconductor chips mounted on the substrate, one row of those arrayed in a horizontal direction is assumed as one unit. Each unit is positioned in a cavity in a mold and resin-sealed in this state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a resin-sealed semiconductor device.

[0002]

2. Description of the Related Art A general method of manufacturing a resin-encapsulated semiconductor device includes a process of polishing a back surface of a wafer to make the wafer thinner (a back surface polishing process), a process of cutting chips from the wafer (a dicing process), and a process of cutting chips. Step of mounting on the substrate (die bonding step), step of electrically connecting the chip and the substrate (wire bonding step), step of sealing the chip with resin (molding step), step of removing resin burrs (deburring Process), a process of externally encapsulating the lead with an external material (exterior process), a process of molding the lead (T /
F step) and a step of printing on the package surface (marking step). This is followed by a process (burn-in / test process) that eliminates early failures and improves product reliability.

FIG. 5 shows an example of the shape of a resin sealed in the above-mentioned molding step. In the figure, 1 is a base material, 2 is a chip, and 3 is a mold resin. Each mold resin 3 in the figure includes only one chip.

The procedure of a molding step performed to obtain the apparatus shown in FIG. 5 will be briefly described with reference to FIG.

First, a mold is heated to a predetermined temperature by a heater in advance.

Next, the upper mold is raised and a product is set at a predetermined position in the mold metal (a).

Next, the upper mold is lowered to fix the product (b).

Next, a resin doublet is put into a mold (c).

Next, the plunger is lowered and sealed, and in this state, a resin is injected into each cavity through a resin pod through a runner (d). Next, the resin is held for several minutes while being filled in each cavity. The resin polymerizes and cures.
After molding, raise the upper mold and take out the product and liner
(e).

Next, unnecessary parts other than the product are discarded (f). The shape of the mold resin sealed in the above procedure is set by the cavity of the mold in the molding process. In FIG. 6, only one chip is arranged in one cavity. However, if a plurality of chips are arranged in one cavity and molding is performed, one mold resin has a shape including a plurality of chips. Hereinafter, one of the molds
The resin sealed in one cavity is referred to as “one mold resin”. In the above process, one chip was sealed with one mold resin (single sealing, FIG. 5). This is partly due to restrictions due to the T / F process.
In other words, individualization of products in the T / F process is performed using a T / F mold, which can cut the base material (lead frame), but cannot cut the mold resin. Can not. Therefore, it is necessary to set a certain distance or more between the molding resin and the molding resin adjacent thereto so that the substrate can be cut into individual pieces.

However, the space between the mold resins is a great limitation on the number of products per base material (lead frame), and it has been desired to minimize this space in order to reduce material costs. .

Therefore, as a method of increasing the number of products to be obtained, a method of singulation other than the T / F mold has been studied. As one of the methods, a dicing apparatus used for cutting a wafer is used. A method is being considered. This is T-BG
This method is considered to be promising for non-lead and ball connection type products such as A, P-BGA, QFN, and SON. Since the dicing machine can cut the mold resin, it is possible to cut the mold resin and the base material at the same time by using this, and as in the case of the T / F mold, the mold resin and the adjacent mold resin can be cut. There is no need to set a constant interval between the two. That is, according to this method, a plurality of chips can be sealed with one mold resin (a plurality of chips). Then, for example, m × n chips are sealed with one mold resin (block sealing, FIG. 7), or all chips of the base material are sealed with one mold resin (batch sealing, FIG. 8). ) Is possible, so that the material cost can be reduced.

[0013]

As described above, conventionally, the number of units to be manufactured has been increased by block sealing or batch sealing. However, this method has the following problems.

First, there is a problem that the displacement of the inner leads is likely to occur when the mold resin is poured. For example, in the upper left chip of "one mold resin" in FIG. 7, the inner leads on the right side and the lower side cannot be fixed by a mold, so that a shift may occur. That is, in the multiple sealing method, it is impossible to fix the inner lead by the cut-off surface of the mold, and the inner lead is likely to be displaced.

Second, there is a problem that the resin is not filled when the mold resin is filled, so that a so-called "su" is generated. Since the mold resin is a thermosetting resin, it hardens over time. However, block sealing (Figure 7) or batch sealing
In the example of FIG. 8, the resin injection volume is large and the resin hardly flows, so that the resin is hardened earlier than the completion of the injection, and the inconvenience that the resin is not filled increases easily occurs. .

Third, in general, it is unavoidable that the mold resin is warped when it is hardened. However, if the mold resin is arranged as shown in FIGS. 7 and 8, the warp in the longitudinal direction of the lead frame is large. As a result, the lead frame 1 is warped or rounded in the longitudinal direction. In such a case, there has been a problem that a displacement or a conveyance failure occurs in a process after the molding process. In other words, in the multiple sealing, the resin sealing volume is large and there is no portion for reducing the warp, so that the warp of the mold resin body due to shrinkage of the mold resin tends to increase.

The present invention has been made based on the recognition of such a problem. That is, the object is to provide a method of manufacturing a semiconductor device having a high productivity, in which the number of products per frame is large, and the lead frame (base material) is prevented from bending in the longitudinal direction to facilitate subsequent steps. To provide.

[0018]

That is, a manufacturing method according to the present invention is a method for manufacturing a semiconductor device in which a plurality of semiconductor chips mounted on a substrate are sealed with a resin.
One of a plurality of semiconductor chips mounted on the base material arranged in a row in the width direction is defined as one unit, and each unit is arranged in one cavity of a mold, and in that state, resin sealing is performed. It is characterized by doing.

Further, the manufacturing method of the present invention is characterized in that the resin is poured in the width direction of the base material from one end side of the unit to the other end side.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) In the first embodiment, when one mold resin is viewed, four chips are arranged in the width direction, but one chip is arranged in the longitudinal direction. The feature is that only the chips are arranged so that the lead frame does not curve in the longitudinal direction.

The details will be described below. FIG.
FIG. 4 is a diagram illustrating a method for manufacturing the semiconductor device according to the first embodiment of the present invention. The figure shows the 72 mounted on the substrate.
Although the semiconductor chips are shown, they are continuous left and right in the figure, and show a state where they are sealed with resin. 1 is a base material (lead frame), 2 is a semiconductor chip, 3 is an epoxy resin, 4 is a mold cavity, 5 is a gate
(Resin inlet), 6 is a runner, 7 is a cull, and 8 is a dicing line. The semiconductor chips are mounted such that four semiconductor chips arranged in a line in the width direction of the base member 1 constitute one unit, and eighteen units are arranged in parallel in the longitudinal direction of the base member. Each unit is placed in a separate cavity 4 of the mold, and a gate 5 formed in the mold at one end of the cavity.
Pour the sealing resin. The sealing resin flows from the gate 5 into the cavity 4 through the cull 7 and the runner 6. In the present invention, the epoxy resin 3 was used as the resin. It should be noted that other resins can be used in place of the epoxy resin.

After the poured epoxy resin 3 is cured, dicing is performed along dicing lines 8 to obtain a semiconductor device in which each chip is molded (singulation). FIG. 9 shows an example of a technique for molding one unit of the four chips 2 shown in FIG. 1 in one cavity in relation to FIG. (A) is a perspective plan view,
(B) is a longitudinal sectional view. Briefly, the chip 2 is mounted on the bed 21 via the mounting material 22. The chip 2 and the leads 1a of the lead frame 1 are bonded by wires 23. The lead frame 1 on which the chip 2 is set as described above is housed in the cavity 31 between the upper and lower molds 26 and 27. At this time, the press-cut surface 28 as a frame-shaped surface sandwiched between the upper and lower molds 26 and 27 of the lead frame 1 is formed as shown in FIG.
As can be seen from FIG. The pressed cut surface is a so-called resin dense surface for preventing the resin from flowing out of the cavity 31. The gate 5 as a resin injection port
The air vent 30 for bleeding air during resin injection
Are formed.

According to the manufacturing method of the embodiment of the present invention described above, it is possible to increase the number of products per frame and to reduce the material cost while preventing the bending of the lead frame. On the other hand, in the conventional method shown in FIG. 5, the distance between the mold resins is large, and the number of products per frame is small.

Further, according to the manufacturing method of the present invention, FIG.
And the same high productivity as in the conventional method shown in FIG. This is mainly due to the following three reasons.

First, in this embodiment, the influence of the warpage of the molded resin body due to the shrinkage of the resin during the molding is small. In this embodiment, only four chips are arranged in the width direction of the base material, and even if warpage occurs in the width direction, the influence on the entire base material is small. On the other hand, a large number of chips are usually molded and arranged in the longitudinal direction of the base material. When a warpage occurs in one molded part, they overlap with each other, and the influence on the entire base material is increased. However, in this embodiment, this longitudinal warping hardly occurs. This is because, in the present embodiment, there is a portion formed of only the base material between the mold resins in each row, and the mold resin in each row has a width of only one chip, so that the amount of warpage is originally small. is there. Even in case of multiple sealing, block sealing (Fig. 7)
In the example of the package sealing (FIG. 8), the warpage of the body due to the shrinkage of the resin was large, and the displacement and the conveyance failure occurred in the steps after the molding. However, according to the present embodiment, such inconveniences were hardly caused. Does not happen. Here, in order to sufficiently exhibit the effect of reducing the warpage and stably produce, it is desirable that the interval between the mold resins in each row is 0.3 [mm] or more.

Second, according to the present embodiment, there is little deterioration in the filling property of the resin. Since the mold resin is a thermosetting resin, it flows when heated and hardens over time (Fig. 2
reference).

In the case of block encapsulation (FIG. 7) or encapsulation (FIG. 8), even if a plurality of encapsulations are used, the resin injection volume is large and the resin does not easily flow. It is easy to cause the disadvantage that the unfilled resin increases. However, in this embodiment, since the chips are arranged in a line at the center of the cavity of the mold, the resin easily flows, and such inconvenience hardly occurs.

Third, according to this embodiment, the increase in the displacement of the inner lead is small. This is because, in the present embodiment, molding can be performed by fixing both sides of each chip with a mold, so that the inner lead can be fixed by the cut-off surface. In the case of block sealing (FIG. 7) or batch sealing (FIG. 8), displacement of the inner leads is easily caused because the inner lead cannot be fixed by the cut-off surface even in the case of a plurality of seals. According to this, such inconveniences hardly occur.

As described above, according to the present embodiment, it is possible to provide a method of manufacturing a semiconductor device having a large number of products per frame and high productivity.

(Second Embodiment) In a second embodiment, in order to reduce product defects in a portion remote from a gate (resin pouring port), a cavity of a mold is removed from the side where resin is poured. The mold is formed in a shape that spreads toward the end side.

FIG. 3 is a view for explaining a method of manufacturing a semiconductor device according to a second embodiment of the present invention, and shows a state in which a chip is sealed with a resin. The first molding method
The embodiment is the same as that of the first embodiment and will not be described.

The method of the present embodiment is particularly effective when there is a large wire flow in a portion away from the gate. Hereinafter, this point will be described. First, as described above, the filling of the resin must be completed before the viscosity of the resin increases, so that the injection speed needs to be increased depending on the type of the mold resin. However, if the injection speed is too high, the wire may be deformed by the pressure applied to the wire during resin filling, and if the deformation is remarkable, this may cause a defect such as a short circuit between the wires. This is a phenomenon called wire flow. The location where the wire flow is likely to occur depends on the type of the resin and the semiconductor element, but the method of this embodiment is effective when the wire flow is large at a portion away from the gate. That is, according to the method of the present embodiment, the cavity of the mold is formed so as to expand from the side into which the resin is poured toward the other end, so that the injection speed in the portion away from the gate is reduced. Partial wire flow can be reduced.

After the resin is cured, dicing is performed along dicing lines 8 to obtain a semiconductor device in which each chip is molded (individualization). After dicing, the size of the mold resin of each chip becomes the same.

(Third Embodiment) In a third embodiment, in order to reduce product defects near the gate (resin pouring port), the cavity of the mold is moved from the resin pouring side to the other end. Molding was performed in a shape narrowing toward the side.

FIG. 4 is a view for explaining a method for manufacturing a semiconductor device according to the third embodiment of the present invention, and shows a state in which a chip is sealed with a resin. The first molding method
The embodiment is the same as that of the first embodiment and will not be described.

The method of this embodiment is particularly effective when there is a large wire flow near the gate. That is, according to the method of the present embodiment, the cavity of the mold is
By making the shape narrower from the resin pouring side to the other end, the injection speed near the gate is reduced,
Wire flow in this area can be reduced.

After the resin is cured, dicing is performed along dicing lines 8 to obtain a semiconductor device in which each chip is molded (individualization). After dicing, the size of the mold resin of each chip becomes the same.

[0039]

According to the present invention, in one mold resin, a plurality of chips are arranged in the width direction of the lead frame, but only one chip is arranged in the longitudinal direction. Warpage can be minimized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the viscosity of mold resin and time.

FIG. 3 is a view for explaining a method for manufacturing a semiconductor device according to a second embodiment of the present invention.

FIG. 4 is a view for explaining a method for manufacturing a semiconductor device according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a sealing mode of single sealing.

FIG. 6 is a diagram showing a process flow of a molding step.

FIG. 7 is a diagram showing a plurality of sealing forms (block sealing).

FIG. 8 is a diagram illustrating a plurality of sealing (batch sealing) sealing forms.

FIG. 9 is a view showing an example of a main part of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead frame (base material) 2 Chip 3 Resin 4 Mold cavity 5 Gate (resin pouring port) 6 Runner 7 Cull 8 Dicing line

Claims (4)

[Claims] 1. A method for manufacturing a semiconductor device, wherein a plurality of semiconductor chips mounted on a base material are sealed with a resin, wherein the semiconductor chip is mounted on the base material in a width direction. A method for manufacturing a semiconductor device, wherein one unit in a row is arranged as one unit, each unit is arranged in one cavity of a mold, and resin sealing is performed in that state. 2. The semiconductor device according to claim 1, wherein the resin is poured in a width direction of the base material from one end of the unit toward the other end of the unit. Production method 3. The semiconductor device according to claim 1, wherein the shape of the cavity of the mold has a shape expanding from the side into which the resin is poured toward the other end. Production method 4. The semiconductor device according to claim 1, wherein the shape of the cavity of the mold has a shape narrowing from a resin pouring side to the other end side. Production method