JP2001024001A - Method of manufacturing resin-encapsulated semiconductor device and lead frame - Google Patents

Abstract

(57) [Problem] To provide a manufacturing method and a lead frame of a resin-encapsulated semiconductor device with high productivity, low cost, and high quality which can reduce the internal stress of a molded product at the time of correcting the warpage of the molded product in a cutting process, and have high productivity. . A lead frame (4) having an opening (10) on the outer periphery of a plurality of chip mounting regions (Rcp) is prepared, and electrode pads of a semiconductor chip (2) and signal connection terminals (1) are electrically connected to each other. The sealing sheet 6 is interposed between the mold surface facing the cavity recess of the mold 15 and the back surface of the lead frame 4, the molded product 20 is set in the cavity recess 14, and the resin 7 is filled therein. , The sealing sheet 6 is peeled off, the resin is heated and cured while pressing the molded product, and the molded product is cut.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin encapsulation in which an outer periphery of a lead frame on which a semiconductor element is mounted, in particular, a surface on which the semiconductor element is mounted is sealed with a sealing resin and an external electrode is exposed on a bottom surface. The present invention relates to a method for manufacturing a semiconductor device and a lead frame suitable for the method.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for high-density mounting of semiconductor components in order to cope with miniaturization of electronic equipment. As a result, semiconductor devices have become smaller and thinner. I have. Further, various measures have been taken to improve production cost and productivity.

Hereinafter, a method for manufacturing a conventional resin-encapsulated semiconductor device will be described. FIG. 5 is a sectional view showing a manufacturing process of a conventional resin-encapsulated semiconductor device.

First, in the step shown in FIG. 5A, the signal connection terminals 101 (101a, 101b) and the die pad 10
3 to prepare a lead frame 104 having a plurality of. Although the die pad 103 is supported by suspension leads in the drawing, illustration of the suspension leads is omitted. Also, a depressed part is formed on the suspension lead,
The die pad 103 is upset. It should be noted that the lead frame 104 is not provided with a tie bar for stopping the outflow of the sealing resin during resin sealing.

Next, in a step shown in FIG. 5B, the semiconductor chip 102 is bonded onto the die pad 103 of the prepared lead frame 104 with an adhesive. This step is a so-called die bonding step.

Then, in a step shown in FIG. 5C, the semiconductor chip 102 bonded on the die pad 103 and the signal connection terminal 101 are electrically connected by the thin metal wire 105. This step is a so-called wire bonding step. As the thin metal wire 105, an aluminum thin wire, a gold (Au) wire, or the like is appropriately used.

Next, in a step shown in FIG. 5D, the die pad 103, the semiconductor chip 102, the signal connection terminal 10
1. The suspension leads and the thin metal wires 105 are sealed with the sealing resin 107. In this case, the lead frame 104 to which the semiconductor chip 102 is bonded is housed in a sealing mold,
Transfer molded, especially signal connection terminal 1
Resin sealing is performed in a state where the back surface of the seal No. 01 is in contact with the upper mold or the lower mold of the sealing mold.

[0008] Then, the molded article 106 sealed with the resin is taken out of the sealing mold, and is cured in a curing furnace 108 in a step shown in FIG.
And a predetermined heat treatment is performed to completely cure the resin. This step is a so-called post cure step. Finally, in the step shown in FIG. 5F, the signal connection terminals 101 and the sealing resin 107 are cut to obtain individual resin-sealed semiconductor devices.

In the conventional method of manufacturing a resin-encapsulated semiconductor device, the molded article 1 taken out of the encapsulation mold in the encapsulation step
Reference numeral 06 denotes a temperature decrease from the mold temperature to the normal temperature,
FIG. 5D shows the difference in thermal contraction between the lead frame 104 and the lead frame 104.
As shown in FIG. Further, in the post-curing step, the temperature rises from room temperature to the post-curing temperature, and the difference in thermal expansion between the sealing resin 107 and the lead frame 104 causes
As shown in FIG. 5 (e), warpage is caused by A2, and finally, FIG.
In the cutting step shown in (f), the molding is usually performed at room temperature, so that the molded product is warped by A (not shown). Therefore, in the cutting step, the molded product warped by the amount A is divided into individual resin-encapsulated semiconductor devices while correcting it. In the sealing step, the sealing resin 107 is used.
May wrap around to the back side of the signal connection terminal 101 and form resin burrs (resin protrusion).
Usually, after the resin sealing step, before the step of cutting the signal connection terminal 101, a water jet step or a blast step for blowing off resin burrs is introduced.

[0010]

However, in the conventional method for manufacturing a resin-encapsulated semiconductor device, the difference in thermal expansion and thermal shrinkage between the lead frame and the encapsulating resin due to the temperature rise and fall in the encapsulating and post-curing steps. Since the amount of warpage of the molded product caused by the difference is divided into individual resin-encapsulated semiconductor devices while correcting it in the cutting process, an external force is applied to the resin-encapsulated semiconductor device when warpage is corrected and the inside of the molded product is generated by external force Figure 5 with stress
As shown in (f), there is a possibility that a large quality problem such as a resin crack 109a, a signal terminal peeling 109b, or a thin metal wire cutting 109c, or in the worst case, a crack 109d of a semiconductor chip may occur.

In the resin sealing step of the conventional method of manufacturing a resin-encapsulated semiconductor device, a semiconductor chip is inserted into a concave portion of a cavity of a sealing die, and an inner lead of a lead frame is closely attached to the die surface. Although the resin is sealed in this state, the sealing resin still wraps around the back surface of the inner lead, and resin burrs (residual protrusion) are generated on the surface of the external electrode. Therefore, conventionally, a water jet process has been introduced to blow off resin burrs on the external electrodes. However, such a water jet process requires a great deal of time and is required in a mass production process of a resin-encapsulated semiconductor device. Contrary to the demand for simplification of processes such as process reduction. In other words, the occurrence of resin burrs has been a major obstacle to simplifying such a process. In addition, the water jet process may cause a serious quality problem that not only resin burrs but also soft metal plating is peeled off.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the warpage of a molded product in advance before a cutting process and to reduce the internal stress generated by an external force when correcting the warpage of the molded product in the cutting process. By providing a high-quality resin-encapsulated semiconductor device by reducing the size of the semiconductor chip, and by using a sealing sheet to house a plurality of semiconductor chips in a common cavity recess and performing resin encapsulation, high productivity is achieved. An object of the present invention is to provide an inexpensive and high-quality method of manufacturing a resin-encapsulated semiconductor device and a lead frame suitable for implementing the method.

[0013]

According to a first aspect of the present invention, there is provided a method for manufacturing a resin-encapsulated semiconductor device, comprising: a plurality of chip mounting regions having a die pad for mounting a semiconductor chip and signal connection terminals; A first step of preparing a lead frame having a connection portion provided between the chip mounting regions and an opening provided from the outer periphery of the plurality of chip mounting regions to the vicinity of a predetermined mold line; A second step of mounting a semiconductor chip in the chip mounting area, electrically connecting an electrode pad of the semiconductor chip to a signal connection terminal to form a molded product, In a state where the sealing sheet is interposed between the opposing mold surface and the back surface of the lead frame, after setting the molded article in the sealing mold so that each semiconductor chip enters the cavity recess, A third step of filling the cavity recess with a resin and sealing up to the opening of the lead frame, a fourth step of taking out the molded product from the sealing mold and peeling off the sealing sheet from the back surface of the molded product, The method includes a fifth step of heating and curing the resin while applying pressure from the front and back surfaces of the molded article, and a sixth step of cutting the molded article after the resin has been cured.

According to the first aspect of the present invention, since the sealing resin is filled up to the opening provided up to the vicinity of the mold line, the heat shrinkage between the lead frame and the sealing resin is achieved. The warpage of the molded product due to the difference is reduced. Further, in the post-cure step, the resin is heat-cured while being pressed from the front side and the back side of the molded product in the same manner as in the pressurized state of the molded product in the sealing mold (cure pressure after filling the sealing resin). Therefore, the warpage of the molded product is further reduced. A large number of resin-encapsulated semiconductor devices are formed in a common cavity recess provided in the encapsulation mold. However, by using an encapsulation sheet in the third step, the back surface of the signal connection terminal can be formed. Is prevented from forming. Further, since the sealing sheet is formed to bite into the sealing resin side from the lower part of the signal connection terminal, a stand-off when the lower part of the signal connection terminal is used as an external electrode is also ensured. Therefore, quality defects such as cracks of the resin-encapsulated semiconductor device due to warpage of the molded product are prevented, and the cutting process can be performed easily and quickly. Further, the resin burr protruding to the rear surface side can be simplified while simplifying the manufacturing process. It is possible to provide a method of manufacturing a resin-encapsulated semiconductor device with high productivity and high quality, while having electrodes without defects.

According to a second aspect of the present invention, in the method for manufacturing a resin-encapsulated semiconductor device according to the first aspect, the encapsulating sheet in the third step is made of polyimide, polyethylene terephthalate,
It is made of a resin mainly containing polycarbonate or the like, or a conductive metal containing copper, aluminum, stainless steel or iron.

According to the method of manufacturing a resin-encapsulated semiconductor device of the second aspect, in addition to the same effects as those of the first aspect, each signal connection is performed while many semiconductor chips are sealed in a common cavity recess. It is possible to secure the stand-off of the terminal for signal and prevent resin burr on the back surface of the terminal for signal connection. Further, the materials of the sealing sheet base material and the adhesive having the role of securing the stand-off and preventing the resin burr can be arbitrarily combined and selected from the viewpoints of the purpose, function and cost. For example, when the conductive metal substrate peels the sealing sheet from the back surface of the molded article in the fourth step, the base material of the sealing sheet is a conductive metal,
Even if the attached frame is a resin substrate, the electrolytic peeling method can be used, and the sealing sheet can be reliably peeled off from the molded product. Furthermore, since the base material of the sealing sheet after peeling is metal, it can be recycled as waste material, is environmentally friendly and can reduce the manufacturing cost of the resin-sealed semiconductor device. Further, since the resin base material has a large elastic modulus with respect to the conductive metal base material, the resin base material can easily bite into the signal connection terminal with a small pressing force, and it is easy to secure the stand-off.

According to a third aspect of the present invention, in the method for manufacturing a resin-encapsulated semiconductor device according to the first or second aspect, the adhesive of the sealing sheet in the third step is a silicone-based, phenol-based or epoxy-based adhesive. It is an adhesive that is heat-pressed and attached to a lead frame or a substrate.

According to the method of manufacturing a resin-sealed semiconductor device according to the third aspect, the same effects as those of the first or second aspect can be obtained.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a resin-sealed semiconductor device according to the first aspect, wherein the molded product is taken out of the sealing mold after the third step, and the resin is pressed from the front and back sides of the molded product. Is performed, followed by a fourth step of peeling off the sealing sheet from the back surface of the molded article.

According to the method of manufacturing a resin-encapsulated semiconductor device according to the fourth aspect, in addition to the same effects as those of the first aspect, the resin is in a stable state in which the resin is crosslinked by heat curing, so that it can be molded at the time of peeling. Swell the sealing sheet by immersing the product in a solvent, etc.
Alternatively, a method of dissolving is easily adopted, and the sealing sheet can be more reliably and easily peeled off from the molded product. In addition, the degree of freedom in the order of the manufacturing steps is increased, and the manufacturing method can be arbitrarily selected according to the equipment status.

According to a fifth aspect of the present invention, in the method for manufacturing a resin-encapsulated semiconductor device according to the first aspect, a plurality of molded products are laminated in the tower in the fifth step, and the laminated endmost molded product is pressed. The lid is pressed with a lid to press all of the laminated molded products.

According to the method of manufacturing a resin-encapsulated semiconductor device according to the fifth aspect, in addition to the same effects as those of the first aspect, a tower having a simple structure and a simple pressurizing method can be manufactured. By simply preparing a tower, existing sealing equipment and post-cure equipment do not need to be modified, mass production of molded products with less warpage can be achieved, and high-quality and inexpensive resin-encapsulated semiconductor devices can be manufactured.

According to a sixth aspect of the present invention, in the method of manufacturing a resin-encapsulated semiconductor device according to the first or fifth aspect, in the fifth step, a plurality of molded products are pressed in a standing state.

According to the method of manufacturing a resin-encapsulated semiconductor device of the sixth aspect, in addition to the same effects as those of the first or fifth aspect, the fluctuation of the pressurization amount due to the weight of the molded product itself is ignored. Thus, there is no difference in the amount of pressure between the front side and the bottom side of the molded product laminated on the tower, a stable molded product with a small amount of warpage can be produced, and a high-quality resin-encapsulated semiconductor device can be produced.

According to a seventh aspect of the present invention, there is provided a lead frame for a resin-encapsulated semiconductor device, wherein a plurality of chip mounting areas having a die pad and a signal connection terminal for mounting a semiconductor chip are provided between the plurality of chip mounting areas. And a lead frame provided with an opening provided from the outer periphery of the plurality of chip mounting areas to the vicinity of a predetermined mold line, the outer frame of the lead frame being an extension of the connection part. It has a slit for thermal stress relaxation provided,
The opening is characterized in that the opening is larger than the mold line from the outer periphery of the plurality of chip mounting areas.

According to the lead frame of the resin-encapsulated semiconductor device, since the sealing resin is filled up to the opening provided up to the vicinity of the mold line, the heat shrinkage of the lead frame and the sealing resin occurs. The warpage of the molded product due to the difference is reduced. Further, since the slit is provided on the extension of the lead frame connecting portion, thermal deformation of the lead frame itself due to thermal expansion of the connecting portion at a high temperature such as a wire bonding step is absorbed by the slit. In addition, since the opening is larger than the mold line, the contact area between the lead frame and the sealing resin can be reliably reduced, and only the amount of the sealing resin corresponding to the thickness of the lead frame is required, resulting in high quality and economy. The amount of warpage of the molded product can be alleviated.

[0027]

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

FIG. 1 shows a manufacturing process of a resin-sealed semiconductor device according to one embodiment of the present invention, and FIG. 2 shows a lead frame used for the resin-sealed semiconductor device according to this embodiment. First, FIG. 1A is a cross-sectional view of a lead frame 4 used in the resin-sealed semiconductor device according to the present embodiment, and FIG. 2A is a plan view showing the entire structure of the lead frame 4. is there. In the figure, the description is simplified in a right region indicated by a broken line. FIG.
2B and 2C are partial plan views showing a part of FIG. 2A in an enlarged manner. The lead frame 4 has a large number of chip mounting areas R for mounting the semiconductor chip 2.
cp is provided, and in each chip mounting region Rcp,
A die pad 3 for mounting the semiconductor chip 2, a suspension lead 8 for supporting the die pad 3, and a chip mounting region Rc;
and a signal connection terminal 1 extending inward from each of four sides of p. The suspension lead 8 is provided with a depressed portion for upsetting the die pad 3 above the position of the signal connection terminal 1. Between the chip mounting regions Rcp, there is provided a connection portion A11 which also serves as a root of the signal connection terminal 1. Note that the signal connection terminal 1 includes an extension of a length in consideration of a cutting allowance because the signal connection terminal 1 is cut in a later step so as to be an external electrode of the resin-encapsulated semiconductor device.

Here, the outer frame 9 of the lead frame 4 has
An opening 10 corresponding to the length of one side of the chip mounting region Rcp is provided up to the vicinity of the mold line, and the sealing resin 7 is filled up to the opening 10. Therefore, the contact area of the lead frame 4 with the sealing resin 7 is reduced. Therefore, it is possible to prevent a difference in the amount of heat shrinkage between the lead frame 4 and the sealing resin 7 largely caused by the warpage of the molded product 21.
That is, since the opening 10 of the lead frame 4 is only the sealing resin 7, the amount of heat shrinkage of the lead frame 4 can be ignored. In particular, since the contact area of the lead frame 4 with the sealing resin 7 is concentrated on the outer frame 9, the lead frame 4 having the opening 10 according to the present embodiment has a great effect in reducing the warpage of the molded product 21. Can be In this embodiment, since the sealing sheet 6 is used, the pressure of the molten sealing resin 7 filled in the cavity concave portion 14 causes the connection portion B1
2 does not deform. In the case where the sealing sheet 6 is not used and the length of one side of the chip mounting region Rcp is long and the connection portion B12 may be deformed by the pressure of the sealing resin 7, FIG.
2B, the support 13 may be installed at a position corresponding to the center of the opening 10 in FIG. In this embodiment, when the length of one side of the chip mounting region Rcp is 10 mm or more, the support 13 is provided. The runners (portions indicated by circles in FIG. 2A), which are injection paths of the sealing resin melted in the sealing resin process, are provided only in the outer frame 9 of the lead frame 4, and are provided in the chip mounting region Rcp. It is not provided in the area between them.

Next, in the step shown in FIG. 1B, the semiconductor chip 2 is bonded onto the die pad 3 of the prepared lead frame 4 with an adhesive. This step is a so-called die bonding step. Then, the semiconductor chip 2 bonded on the die pad 3 and the signal connection terminal 1 are electrically bonded by the thin metal wire 5. This step is a so-called wire bonding step. The molded article 20 includes the lead frame 4, the semiconductor chip 2 mounted on the lead frame 4, and the thin metal wires 5.

Next, in a step shown in FIG. 1C, a sealing sheet 6 is attached to the back surface of the lead frame 4 to which a number of semiconductor chips 2 are joined. The sealing sheet 6 is in close contact with the surface of the lead frame 4 facing the surface to which the semiconductor chip 2 is bonded, that is, the entire back surface of the lead frame 4, but is set up by the depressed portion of the suspension lead 8. It does not adhere to a part of the suspension lead 8 or the die pad 3. The sealing sheet 6 plays a role of a stopper so that the sealing resin 7 does not flow around the back surface of the signal connection terminal 1 when the resin is sealed. It serves to prevent burrs from being formed. Second, as shown in a partially enlarged view of FIG. 1C, the sealing sheet 6 enters above the back surface of the signal connection terminal 1 and is sealed with resin in that state, so that a stand-off can be secured. . The adhesive 6a of the sealing sheet 6 is a silicone-based adhesive, and the substrate 6b is a polyimide-based film or a conductive metal such as copper or aluminum.
Both the adhesive 6a and the base material 6b have heat resistance at a high temperature during the sealing step or the post-curing step.
Has an adhesive strength to withstand the resin sealing pressure in the sealing step.
Furthermore, after resin sealing, it can be easily peeled off from the molded product. The thickness of the sealing sheet 6 in the present embodiment is, for example, 25 μm for the adhesive 6a and 50 μm for the base material 6b. The amount of the sealing sheet 6 entering above the back surface of the signal connection terminal 1 is determined by the thickness of the sealing sheet 6, the sticking pressure, the time, and the temperature. The size of the step between the rear surface and the back surface is determined by the thickness of the sealing sheet 6 and the application pressure. In the present invention, since the sealing sheet 6 having a total thickness of 75 μm is used, the size of the step, that is, the protruding amount of the external electrode is about half that, which is the maximum thickness of the sealing sheet 6. In the present embodiment, the sealing sheet 6 is attached to the back surface of the lead frame 4 after the wire bonding step. However, the sealing sheet 6 may be attached to the back surface of the lead frame 4 before the die bonding step. I do not care. Since the semiconductor chip 2 and the thin metal wires 5 are not in the lead frame state, the sealing sheet can be more easily attached.

Next, in the step shown in FIG. 1D, a sealing mold 15 comprising a lower mold 15a having a cavity concave portion 14 and an upper mold 15b having a substantially flat mold surface is prepared. Then, the lead frame 4 is mounted on the lower frame so that each semiconductor chip 2 enters the common cavity recess 14 of the lower mold 15a with the side on which the plurality of semiconductor chips 2 are mounted on the lead frame 4 facing downward. Align with the mold 15a. Then, in this state, the lead frame 4 and the sealing sheet 6 are squeezed by the parting surface 16 around the cavity recess 14, and the molded object 20 on which the plurality of semiconductor chips 2 are mounted is sealed with the sealing resin 7. Stop. At this time, the sealing resin 7 fills the upper surface side of the semiconductor chip 2, that is, the surface to which the thin metal wires 5 are connected, and the lower part of the die pad 3, and the sealing resin 7 above the semiconductor chip 2.
Are sealed so that the upper end surface of the metal wire 5 is at a height position equal to or higher than the loop height of the thin metal wire 5. Then, the lower end surface of the sealing resin 7 below the die pad 3 and the sealing resin 7 above the semiconductor chip 2
Is the thickness of the sealing resin 7.

Here, the sealing resin 7 is transmitted to the opening 10 formed in the lead frame 4 through the cavity concave portion 14.
It is sealed with resin. The above-described sealing resin 7 is filled in the gaps of the lead frame such as the cavity recesses 14 and the openings 10 (for example, between the signal connection terminals 1 and the lower surface of the die pad 3). Thereafter, the molded article 20 and the sealing resin 7 are given pressure and heat from the sealing mold 15 for a certain period of time, and the sealing resin 7 is cured to some extent, and the molded article 20 and the sealing resin 7 are integrated into a molded article. It becomes 21.

Next, as shown in FIG. 1 (e), the molded article 21 is taken out of the sealing mold 15. At this time, the molded product 21
Is returned to normal temperature, and the sealing resin 7 and the lead frame 4 thermally shrink. However, there is a difference in the amount of heat shrinkage between the sealing resin 7 and the lead frame 4, which causes the molded product 21 to warp and cause a problem. However, an opening 10 is provided in the lead frame 4 of the present embodiment, and the sealing resin 7 is resin-sealed. Therefore, most of the molded product 21 is the sealing resin 7, and particularly, at the time of heat shrinkage, the portion of the outer frame 9 of the lead frame 4 where the sealing resin 7 is easily pulled by the lead frame 4 is resin-sealed by the opening 10. From that
The difference in heat shrinkage between the sealing resin 7 and the lead frame 4 is reduced, and the warpage of the molded product 21 is almost eliminated.

Next, in a step shown in FIG. 1F, when the sealing sheet 6 attached to the back surface of the lead frame 4 is removed by peeling off, the lower part of the signal connection terminal 1 protrudes from the back surface of the sealing resin 7. A molded article 21 having the above-mentioned structure is obtained. Here, the peel-off of the sealing sheet 6 is caused by the adhesive 6a.
When heated above the glass transition temperature Tg, the adhesive 6a is softened and easily peeled off. As another method, the adhesive 6a may be swelled and peeled off by peeling off the sealing sheet 6 by immersing the molded article 21 in an alkaline electrolyte to make the lead frame 4 conductive.

Next, in the step shown in FIG. 1 (g), the molded product 21 from which the sealing sheet 6 has been peeled off is held on the back side holding jig 18a.
And the front side holding jig 18b is placed on the front side of the set molded article 21 to create a state where pressure is applied from the front and back sides of the molded article 21. The back side holding jig 18
Even if the front side of the molded article 21 comes above a, it is only necessary that the pressing jig 18 can be pressed from the front and back sides of the molded article 21.

Then, the molded product 21 pressurized by the holding jig 18 is set in the curing furnace 17 and heated at a predetermined temperature for a predetermined time. This step is a so-called post cure step. As described above, in the present embodiment, since the molded product 21 is resin-sealed to the opening 10 of the lead frame 4 and has almost no warpage, even if the pressing jig 18 is pressed, defects such as cracks may occur. There is no. Further, the holding jig 1
The sealing resin 7 of the molded article 21 pressurized at 8 is completely cured by heating from the curing furnace 17. Then, the molded product 21 in which the sealing resin 7 is completely cured is taken out of the curing furnace,
It is flowed to the next step, but the sealing resin 7
Does not undergo anisotropic thermal expansion and contraction, and as a result, the molded article 21 is in a state with almost no warpage.

Next, in the step shown in FIG.
Is cut along the connecting portions A11 and B12 of the lead frame 4 using a dicing saw or a cutting die to obtain individual resin-sealed semiconductor devices. Here, since the molded article 21 has almost no warpage, there is no need to correct the warpage of the molded article 21 at the time of cutting, no extra stress is applied to the molded article 21, and the molded article can be cut easily and quickly. And a high-quality resin-encapsulated semiconductor device can be obtained.

In FIG. 1, the sealing sheet 6 was peeled off from the back surface of the molded article 21 (FIG. 1 (f)), and then post-cured (FIG. 1 (g)).
The sealing sheet 6 may be peeled off from the back surface of the semiconductor device 1, and there is no problem in the quality of the resin-sealed semiconductor device. Since the resin is crosslinked by heat curing during post cure, it is in a stable state, so it is easier to adopt a method of swelling or dissolving the sealing sheet by immersing the molded product in a solvent etc. The sealing sheet can be peeled off from the molded article.

In the present embodiment, the structure for eliminating the amount of warpage of the molded product 21 is provided by providing the opening 10 in the lead frame 4 and employing a method of applying pressure at the time of post-curing. Is changed, that is, even if the external dimensions of the resin-encapsulated semiconductor device are changed and the layout of the lead frame 4 is changed,
The warpage of the molded product 21 can be eliminated without changing the planar size of the cavity concave portion 14 of the sealing mold 15.
In other words, by simply changing the type of the lead frame 4 with one type of sealing die 15, a molded product 21 without warpage can be manufactured, and the investment in the sealing die can be made without producing a new sealing die. It is possible to produce a wide variety of resin-encapsulated semiconductor devices with a short delivery time.

FIG. 3 shows a modified lead frame used for the resin-sealed semiconductor device according to the present embodiment. As in FIG. 2, an opening 10 corresponding to the length of one side of the chip mounting region Rcp is provided in the outer frame 9 of the lead frame 4 up to the vicinity of the mold line. Filled up to part 10. Therefore, the contact area of the lead frame 4 with the sealing resin 7 is reduced. Therefore, it is possible to prevent a difference in the amount of heat shrinkage between the lead frame 4 and the sealing resin 7 largely caused by the warpage of the molded product 21. Further, a slit 19 is formed on the extension of the connecting portion A11 of the lead frame 4.
The slit 19 absorbs the thermal deformation of the lead frame itself due to the thermal expansion of the connecting portion A11 particularly at a high temperature such as a wire bonding step.

FIG. 4 shows an example of pressurizing a molded article according to the present embodiment. As shown in FIG. 4A, the molded article 21 sealed with resin in the sealing step is stacked on the tower 31. afterwards,
When a certain amount of molded product 21 is stocked in the tower 31, FIG.
As shown in (b), the endmost molded products 21 stacked by the pressure lid 35 are pushed, and the pressure lid 35 is fixed to the tower 31. The pressure lid 35 is generated by a spring 33 provided between the pressure plate 32 and the lid 34, with the pressure plate 32 being in surface contact with the back side (or the front side) of the laminated endmost molded product 21. The entire molded article 21 between the pressure plate 32 and the tower 31 can be pressed at a predetermined pressure with the predetermined pressure. Further, as shown in FIG.
The plurality of molded articles 21 pressurized in (b) are put into the curing furnace 17 together with the tower 31 and heated for a predetermined time. Here, the tower 31 of the curing furnace 17 is placed sideways. That is, the pressurized molded product 21 is put into the curing furnace 17 in a state of standing. This is because the molded product 21 itself has a weight and the molded product 21 on the bottom surface of the tower 31 is stacked with the weight of the laminated molded product 21, and the pressure applied to the molded product 21 on the bottom surface portion and the surface portion of the tower 31 is different. That's why.

With these configurations, a plurality of molded products 21 can be heated at a constant pressure, and a high-quality resin-encapsulated semiconductor device with no warpage can be manufactured with improved productivity.

According to the method of manufacturing a resin-encapsulated semiconductor device of the present invention according to the above embodiment, a large number of semiconductors are interposed in a sealing die with respect to a lead frame to which a semiconductor chip is joined. When the chip is sealed with resin in the common cavity recess of the sealing mold, the opening provided in the lead frame is filled with sealing resin to reduce the warpage of the molded product, and the molded product during post cure By pressurizing the molded product to eliminate the warpage of the molded product, it is possible to provide a method of manufacturing a resin-encapsulated semiconductor device having high quality and high productivity while having external electrodes protruding to the rear surface side. Further, according to the lead frame of the present invention, it is possible to provide a lead frame suitable for carrying out the above-mentioned method of manufacturing a resin-sealed semiconductor device. Although a system film or a conductive metal such as copper or aluminum was used, a resin containing polyethylene terephthalate or polycarbonate as a main component, or a conductive metal containing stainless steel or iron may be used. As the adhesive for the sealing sheet 6, a silicon-based adhesive is used, but a phenol-based or epoxy-based adhesive may be used, and the sealing sheet 6 is heated and pressed to be attached to the lead frame 4 or the substrate. Then, the sealing sheet 6 is removed from the lead frame or the substrate at least after the sealing. The sealing sheet 6 can be used to prevent resin burrs even if the substrate has a shape in which resin burrs occur, for example, holes.

[0045]

According to the method for manufacturing a resin-encapsulated semiconductor device according to the first aspect of the present invention, the sealing resin is filled up to the opening provided near the mold line. The warpage of the molded article due to the difference in heat shrinkage is reduced. Further, in the post-cure step, the resin is heat-cured while being pressed from the front side and the back side of the molded product in the same manner as in the pressurized state of the molded product in the sealing mold (cure pressure after filling the sealing resin). Therefore, the warpage of the molded product is further reduced. A large number of resin-encapsulated semiconductor devices are formed in a common cavity recess provided in the encapsulation mold. However, by using an encapsulation sheet in the third step, the back surface of the signal connection terminal can be formed. Is prevented from forming. Further, since the sealing sheet is formed to bite into the sealing resin side from the lower part of the signal connection terminal, a stand-off when the lower part of the signal connection terminal is used as an external electrode is also ensured. Therefore, quality defects such as cracks of the resin-encapsulated semiconductor device due to warpage of the molded product are prevented, and the cutting process can be performed easily and quickly. Further, the resin burr protruding to the rear surface side can be simplified while simplifying the manufacturing process. It is possible to provide a method of manufacturing a resin-encapsulated semiconductor device with high productivity and high quality, while having electrodes without defects.

According to the method of manufacturing a resin-encapsulated semiconductor device of the second aspect, in addition to the same effects as those of the first aspect, each signal connection is performed while many semiconductor chips are sealed in a common cavity recess. It is possible to secure the stand-off of the terminal for signal and prevent resin burr on the back surface of the terminal for signal connection. Further, the materials of the sealing sheet base material and the adhesive having the role of securing the stand-off and preventing the resin burr can be arbitrarily combined and selected from the viewpoints of the purpose, function and cost. For example, when the conductive metal substrate peels the sealing sheet from the back surface of the molded article in the fourth step, the base material of the sealing sheet is a conductive metal,
Even if the attached frame is a resin substrate, the electrolytic peeling method can be used, and the sealing sheet can be reliably peeled off from the molded product. Waste Since substrate of the sealing sheet metal after peeling off further
It is recyclable as a material , is environmentally friendly, and can reduce the manufacturing cost of the resin-encapsulated semiconductor device. Further, since the resin base material has a large elastic modulus with respect to the conductive metal base material, the resin base material can easily bite into the signal connection terminal with a small pressing force, and it is easy to secure the stand-off.

According to the method of manufacturing a resin-sealed semiconductor device according to the third aspect, the same effects as those of the first or second aspect can be obtained.

According to the method for manufacturing a resin-encapsulated semiconductor device of the fourth aspect, in addition to the same effects as those of the first aspect, since the resin is in a stable state in which the resin is cross-linked by heat curing, it is formed at the time of peeling. Swell the sealing sheet by immersing the product in a solvent, etc.
Alternatively, a method of dissolving is easily adopted, and the sealing sheet can be more reliably and easily peeled off from the molded product. In addition, the degree of freedom in the order of the manufacturing steps is increased, and the manufacturing method can be arbitrarily selected according to the equipment status.

According to the method of manufacturing a resin-encapsulated semiconductor device of the fifth aspect, in addition to the same effects as those of the first aspect, a tower having a simple structure and a simple pressurizing method can be manufactured. By simply preparing a tower, existing sealing equipment and post-cure equipment do not need to be modified, mass production of molded products with less warpage can be achieved, and high-quality and inexpensive resin-encapsulated semiconductor devices can be manufactured.

According to the method of manufacturing a resin-encapsulated semiconductor device of the sixth aspect, in addition to the same effects as those of the first or fifth aspect, the variation in the amount of pressurization due to the weight of the molded product itself is ignored. Thus, there is no difference in the amount of pressure between the front side and the bottom side of the molded product laminated on the tower, a stable molded product with a small amount of warpage can be produced, and a high-quality resin-encapsulated semiconductor device can be produced.

According to the lead frame of the resin-encapsulated semiconductor device of the present invention, since the sealing resin is filled up to the opening provided near the mold line, the heat shrinkage of the lead frame and the sealing resin is caused. The warpage of the molded product due to the difference is reduced. Further, since the slit is provided on the extension of the lead frame connecting portion, thermal deformation of the lead frame itself due to thermal expansion of the connecting portion at a high temperature such as a wire bonding step is absorbed by the slit. In addition, since the opening is larger than the mold line, the contact area between the lead frame and the sealing resin can be reliably reduced, and only the amount of the sealing resin corresponding to the thickness of the lead frame is required, resulting in high quality and economy. The amount of warpage of the molded product can be alleviated.

[Brief description of the drawings]

FIGS. 1A to 1C are explanatory diagrams sequentially showing manufacturing steps of a resin-sealed semiconductor device according to an embodiment of the present invention.

FIGS. 2A and 2B show a lead frame used in a resin-sealed semiconductor device according to an embodiment of the present invention, wherein FIG. FIG. 3 (c) is a view similar to FIG. 3 (b), but showing another embodiment.

FIG. 3 is a partially enlarged plan view of a lead frame used in a resin-sealed semiconductor device according to another embodiment of the present invention.

4A and 4B show an example of pressurizing a molded product according to another embodiment of the present invention, wherein FIG. 4A is a cross-sectional view of a state where the molded product is inserted into a tower, FIG. (C) is a cross-sectional view of the pressurized and heated state.

FIG. 5 is an explanatory view sequentially showing a method of manufacturing a conventional resin-encapsulated semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Signal connection terminal 2 Semiconductor chip 3 Die pad 4 Lead frame 5 Fine metal wire 6 Sealing sheet 7 Sealing resin 8 Suspension lead 9 Outer frame 10 Opening 11 Connecting part A 12 Connecting part B 13 Support 14 Cavity recess 15 Sealing metal Mold 16 Parting surface 17 Curing furnace 18 Holding jig 19 Slit 20 Molded product 21 Molded product 31 Tower 32 Press plate 33 Spring 34 Cover 35 Press cover

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 23/50 H01L 23/50 B 25/10 25/14 Z 25/11 25/18 (72) Inventor Takahiro Matsuo 1-1, Yukicho, Takatsuki-shi, Osaka Matsushita Electronics Corporation F term (reference) 4M109 AA01 BA01 CA21 DA02 5F061 AA01 BA01 CA21 CA24 EA01 5F067 AA06 AA07 AA09 AB03 BA02 BD05 BD10 DB01 DE01 DF17

Claims (7)

[Claims] A plurality of chip mounting regions each having a die pad for mounting a semiconductor chip and a signal connection terminal; a connecting portion provided between the plurality of chip mounting regions; and a plurality of chip mounting regions. A first step of preparing a lead frame having an opening provided from an outer peripheral portion to a vicinity of a predetermined mold line, and mounting the semiconductor chip on the plurality of chip mounting areas, and providing electrode pads of the semiconductor chip. A second step of electrically connecting the signal connection terminal and the signal connection terminal to form a molded product; and between a mold surface facing the cavity recess of the sealing mold and the back surface of the lead frame. In a state where the sealing sheet is interposed, the molded article is set in the sealing mold so that the respective semiconductor chips enter the cavity recesses, and then set in the cavity recesses. A third step of filling with grease and sealing up to the opening of the lead frame; a fourth step of taking out a molded product from the sealing mold and peeling the sealing sheet from the back surface of the molded product; A resin-sealed semiconductor device comprising: a fifth step of heating and curing a resin while applying pressure from the front and back surfaces of the molded article; and a sixth step of cutting the molded article after the resin has been cured. Manufacturing method. 2. The resin according to claim 1, wherein the sealing sheet in the third step is a resin containing polyimide, polyethylene terephthalate, polycarbonate or the like as a main component, or a conductive metal containing copper, aluminum, stainless steel or iron. A method for manufacturing a sealed semiconductor device. 3. The adhesive of the sealing sheet in the third step is a silicone-based, phenol-based or epoxy-based adhesive, and is heat-pressed and attached to a lead frame or a substrate. The manufacturing method of the resin-sealed semiconductor device according to the above. 4. The method for manufacturing a resin-encapsulated semiconductor device according to claim 1, wherein after the third step, a molded product is taken out from the sealing mold and the resin is heat-cured while being pressed from the front and back surfaces of the molded product. A method of manufacturing a resin-encapsulated semiconductor device, comprising: performing a fifth step of performing a fifth step of removing the sealing sheet from the back surface of the molded product. 5. The resin according to claim 1, wherein in the fifth step, a plurality of molded products are laminated in the tower, the laminated endmost molded product is pressed with a pressure lid, and all of the laminated molded products are pressurized. A method for manufacturing a sealed semiconductor device. 6. The method of manufacturing a resin-encapsulated semiconductor device according to claim 1, wherein in the fifth step, a plurality of molded products are pressurized in an upright state. 7. A plurality of chip mounting areas having a die pad and a signal connection terminal for mounting a semiconductor chip, a connecting portion provided between the plurality of chip mounting areas, and the plurality of chip mounting areas. And an opening provided from the outer peripheral portion of the lead frame to the vicinity of a predetermined mold line, comprising a slit for reducing thermal stress provided in an outer frame of the lead frame on an extension of the connecting portion. The lead frame is characterized in that the opening is larger than the mold line from the outer periphery of the plurality of chip mounting areas.