JPH0582574A - Ultra thin semiconductor device manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] To manufacture a large number of ultra-thin semiconductor devices without defects at the same time. [Structure] A lead frame 10 molded in a specific shape is used, an inner lead 12, a semiconductor element 33, an element mounting portion 11 and a wire 34, a plurality of cavities 23, and a sealing resin in each of the cavities 23. A gate part 21 of a fixed size to be injected, a sub-runner part 22 connected to the sub-runner part 22 having a different size depending on the position of the cavity 23, and a tapered runner 24 connected to the sub-runner part 22 and having a thin end are provided. After sandwiching it in the mold, the sealing resin is placed in the cavity 2
Molding is performed by injecting the resin into the resin 4 and sealing it with a resin, and the external lead 13 of the resin-sealed lead frame 10 is separated and molded, and then bent and molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an ultrathin semiconductor device, and more particularly to an internal lead, a semiconductor element,
When resin-sealing the wires that form the element mounting part and the conduction circuit, prevent voids in the resin-sealing resin and the flow of wires, and seal the sealing resin in a narrow space inside the cavity on the top and bottom of the element in good balance. Prevents unfilled sink sealing resin,
The present invention relates to a method for manufacturing a high quality ultra-thin semiconductor device (sealing thickness: 0.5 to 1.0 mm).

[0002]

2. Description of the Related Art A conventional resin encapsulation method for a semiconductor device is an upper mold in which a large number of lead frames 71 having semiconductor elements 70 mounted thereon are fixed to a press machine (not shown) as shown in FIG. A high-pressure clamp is made between the lower mold 72 and the lower mold 73, and the resin is injected from the central runner 74 through the gate portion 75 into the mold cavity 76 corresponding to the position of the semiconductor element 70. . In the figure, reference numeral 77 denotes a plunger for injecting resin, and 78 denotes an air bleeder for bleeding air from the cavity 76. The runner 74 has a straight shape, and in order to simultaneously and evenly inject the resin into the plurality of cavities 76 of the semiconductor device arranged in the mold, the gate portion 75 is provided with a large size and a small size. I was trying to flush it.

[0003]

However, when the thickness of the semiconductor device is about 0.5 to 1.0 mm, the size of the gate portion 75 is set as described above (runner combination method) so that the resin is evenly distributed. There is a problem in that it is difficult to make a mold for the gate part by making it flow. Further, in the conventional method, since the gate portion 75 is provided in close contact with the cavity 76 and below the lead frame 71, the resin easily flows into the lower cavity 76, and therefore, There is a problem that the resin inflow balance is poor on the lower side, and therefore air remains in the upper cavity 76, causing defects such as voids and unfilling of the sealing resin. The present invention has been made in view of the above circumstances, and an object of the present invention is to manufacture a large number of ultra-thin semiconductor devices without defects at the same time.

[0004]

A method according to the above-mentioned object.
The manufacturing method of the ultra-thin semiconductor device according to, the notch portion formed in a part of the side rail side edge on one side of the element mounting portion, and adjacent to the side rail side edge on the other side of the element mounting portion. A lead frame having a resin puddle formed therein, a notch formed by being connected to the inside of the resin puddle, and a plurality of air puddle on both side rails is used as an element mounting part of the lead frame. A semiconductor element is mounted, the other end of the wire bonded to the pad of the semiconductor element is bonded to the tip of the internal lead, the internal lead, the semiconductor element, the element mounting portion and the wire, a plurality of cavities, A gate portion of a certain size for injecting a sealing resin into each of the cavities,
It is preheated in the pot after being sandwiched in a molding die provided with a sub-runner portion which is connected to these and has a different size depending on the cavity position, and a tapered runner which is connected to the sub-runner portion and has a thin end. The transfer speed of the sealing resin is at least 2
With a step-controlled injection pressure plunger, the mold press process of injecting the sealing resin into the cavity and resin-sealing, and the external lead of the resin-sealed lead frame are separately molded After that, the external lead forming process of bending and forming the external lead into a desired shape is performed. The method for manufacturing an ultrathin semiconductor device according to claim 2 is the method according to claim 1, wherein the resin sealing thickness is 0.5 to 0.8 mm, the sealing resin is spiral flow 40 to 70 inches, and the viscosity is 160
~ 200 poise and the filler particle size is 48
Configured to be submicron. Also,
The method for manufacturing an ultrathin semiconductor device according to claim 3 is the method according to claim 1, wherein the resin sealing thickness is 0.8 to 1.0.
mm, the sealing resin is spiral flow 30-40
Inch, viscosity 220 to 280 poise, and particle size of the filler to be filled are 75 microns (μm) or less. The method for manufacturing an ultrathin semiconductor device according to claim 4 is the method according to claim 1, 2 or 3, wherein the mold press is a mold die.
While being heated and maintained at 65 to 180 ° C., the transfer speed of the sealing resin is high in the middle and low in the subsequent portions.

[0005]

In the method for manufacturing an ultra-thin semiconductor device according to any one of claims 1 to 4, a notch is formed at a side edge of a side rail of an element mounting portion of the lead frame, and the lead frame exists on the gate portion. Therefore, the resin injected through the gate portion is divided into the upper portion and the lower portion of the lead frame and injected into the cavity at this portion. In addition, since the resin reservoir is formed on the side rail on one side of the element mounting part, the notch is formed inside it, and the side rail has multiple air reservoirs, the top and bottom of the lead frame are used. Since any excess sealing resin in the cavity in the above is smoothly removed, and the air smoothly escapes to the air reservoir through the air vent provided in the mold, the resin can be smoothly injected and injected into the cavity. And, the gate parts for injecting the sealing resin into the cavities are of a fixed size, so that it is easy to mold, and the size of the sub-runner part varies depending on the position of the cavities (becomes larger toward the end), In addition, since the runner has a conical shape with a taper toward the end, by pushing the preheated sealing resin in the pot with the plunger, a substantially uniform amount of the sealing resin flows into the cavities at a uniform transfer speed. Furthermore, since the transfer speed of the plunger is controlled in at least two stages, the extrusion speed of the sealing resin can be slowed at the last part to completely expel the air in the cavity and inject the sealing resin. .

[0006]

Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is a plan view of a lead frame used in a method of manufacturing an ultrathin semiconductor device according to an embodiment of the present invention.
2 is a partially omitted cross-sectional view of the ultrathin semiconductor device, FIG. 3 is the same plan view, FIG. 4 is the same cross-sectional view, FIG. 5 is a plan view of a lower mold of a mold used in the method, and FIG. FIG. 7 is a detailed cross-sectional view of the sealing resin pressing portion, and FIG. 7 is a detailed view of the gate portion.

As shown in FIG. 1, in a lead frame 10 used in a method of manufacturing an ultrathin semiconductor device according to an embodiment of the present invention, a punch and a die for sequentially removing unnecessary portions of a band-shaped material are arranged in an appropriate order. The element mounting portion 11 formed by a punching press processing apparatus for punching and forming a desired shape by using a die device configured by arranging and the inner leads 12 respectively arranged in the front and rear direction of the element mounting portion 11. An external lead 13, a dam bar 14, an air reservoir 16 formed on both side rails 15, a cutout portion 17 formed on a side edge of the side rail 15 on one side of the element mounting portion 11, and the other side. The side rail 15 has a conducting portion 18 and a resin reservoir portion 19 formed on the side edge thereof.

In the lower die 20 of the molding die located under the cutout portion 17, as shown by a chain double-dashed line in FIG.
2 is provided and passes through the cutout portion 17 to form a cavity 23.
The sealing resin can be injected into the inside in a well-balanced manner. The resin reservoir 19 into which the remainder of the resin injected into the cavity 23 is provided with a conducting portion 18 connected to the cavity 23.
Is formed by providing the notch 18a in the lead frame 10 as shown in FIG. 2 (A), but the surface of the lead frame 10 is partially etched or electrolyzed as shown in FIG. 2 (B). It is also possible to form the groove 18b by processing and form the conducting portion by the groove 18b.

FIG. 5 shows a lower die 20 of a molding die in which a plurality of lead frames 10 are arranged in two rows in the traveling direction.
A plan view of the runner 24 formed in the center and
A sub-runner portion 22 and a gate portion 21 connected to the runner 24, and a cavity 23 filled with a sealing resin.
A plurality of air vents 25 formed outside the cavity 23, a cull portion 26 formed at the base end portion of the runner 24, and a resin reservoir portion 27 formed at the end of the runner 24. ing. The runner 24 is
The width A of the base end portion becomes larger than the width of the terminal end portion B, and the passage resistance is gradually reduced corresponding to the resin pressure which becomes lower toward the terminal end portion, and is tapered as a whole. The shape of the gate portion 21 is the same for each cavity 23, but the sub-runner portion 22 gradually increases from the base end portion side to the terminal end portion side, and due to the variation of the runner 24 and the sub-runner portion 22, It is possible to inject substantially the same amount of sealing resin into all the cavities 23 by one injection and to inject at the same transfer speed. Then, the gate portion 21 connected to the sub-runner portion 22 has an upward slope, and half of the sealing resin is injected into the cavity 23 in the upper portion of the lead frame 10 through the gap formed between the notch portion 17 and the center thereof. Then, the other half is distributed and injected into the cavity 23 below the lead frame 10.

FIG. 6 shows a resin injecting device 28 for injecting a sealing resin. As shown in the figure, a pot 30 is formed in an upper die 29 of a molding die, and the pot 30 moves up and down. The plunger 31 is provided to press the sealing resin heated to a predetermined temperature toward the lower putting surface 32. Here, the pressing means of the plunger 31 composed of a cylinder (not shown) has a pressing speed of 2
It becomes possible to adjust stepwise, and the moving speed of the plunger 31 becomes 10 mm / sec in the first portion S1 (position of 15 to 3 mm from the putting surface 32).
In the next step S2, the moving speed becomes 5 mm / sec, and the injection speed of the sealing resin is reduced.

Therefore, in the method for manufacturing an ultra-thin semiconductor device according to the embodiment of the present invention, first, as shown in FIG. 1, the element mounting portion 11 arranged at the center and the element mounting portions 11 arranged at the front and rear of the element mounting portion 11, respectively. An inner lead 12, an outer lead 13 and a dam bar 14, an air reservoir 16 formed on the side rails 15 on both sides, a cutout portion 17 formed on the side rail 15 on one side of the element mounting portion 11,
A lead frame 10 including a conducting portion 18 and a resin reservoir portion 19 formed on the other side rail 15 is prepared, a predetermined semiconductor element 33 is mounted on the lead frame 10, and a wire 34 between the lead wire 10 and the internal lead 12 is provided. Then, the upper die 29 is placed on the lower die 20 as shown in FIG.

Then, the sealing resin prepared in advance is 165
Heated to ~ 175 ° C and placed in pot 30. This sealing resin has a semiconductor device thickness of 0.5 to 0.8.
In the case of mm, spiral flow 40 to 70 inches (preferably 55 inches), viscosity 160 to 200 poi
se (preferably 180 poise), it is preferable to use an epoxy resin with a filler particle size of 48 microns maximum, and the semiconductor device has a thickness of 0.8 to 1.0 m.
In the case of m, the spiral flow is 30 to 40 inches (preferably 33 inches) and the viscosity is 220 to 280 poise.
It is preferable to use (preferably 250 poise). Regarding the filling speed of the sealing resin, the moving speed of the plunger 31 is 10 mm / sec in the first portion S1, and the moving speed is 5 mm / s in the next portion S2.
At ec, the injection speed is relatively high at the beginning, and the injection speed is reduced at the last part to completely expel the air inside. As a result, as shown in FIG. 7, the sealing resin is filled into the cavity 23 from each sub-runner portion 22 through the gate portion 21 through the runner 24, and a part thereof flows into the resin reservoir portion 19 for injection and injection. To complete.
FIG. 4 shows a cross section of the ultrathin semiconductor device in such a state, and 35 shows a sealing resin.

[0013]

As is apparent from the above description, the manufacturing method of the ultrathin semiconductor device according to the first to fourth aspects is such that the lead frame used in the present invention has the side rail side on one side of the element mounting portion. A cutout portion formed on the edge, and a resin reservoir formed on the side rail on the other side of the element mounting portion,
Since the notch portion formed by being connected to the inside of the resin reservoir is provided, the sealing resin is substantially evenly filled on the upper and lower sides of the lead frame, and the unfilled or uneven curing which is a drawback of the conventional technique is caused. It is possible to manufacture an ultra-thin semiconductor device that is free from defects such as warpage and cracks. The runner that sends the resin to the cavities has a tapered end with a thin end, and the size of the sub-runner part that connects to the runners is adjusted by the runner / sub-runner variation method, so each cavity is thin. Also, the resin flows in a well-balanced and even manner, and a large number of ultra-thin semiconductor devices can be manufactured efficiently at the same time. Then, since the gate part for filling the resin into each cavity is uniformly manufactured, the mold manufacturing becomes easy. Equipped with an injection pressure plunger in which the transfer speed of the preheated sealing resin in the pot is controlled in at least two stages, molding can be performed without leaving air etc. in the cavity, so high quality The ultrathin semiconductor device can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of a lead frame used in a method for manufacturing an ultrathin semiconductor device according to an embodiment of the present invention.

FIG. 2 is a partially omitted sectional view of the ultrathin semiconductor device.

FIG. 3 is a plan view of the same.

FIG. 4 is a sectional view of the same.

FIG. 5 is a plan view of a lower mold of a mold used in the method.

FIG. 6 is a partial cross-sectional view of a sealing resin pressing portion.

FIG. 7 is a detailed view of a gate unit.

FIG. 8 is a cross-sectional view showing a method of manufacturing a semiconductor device according to a conventional example.

[Explanation of symbols]

 10 lead frame 11 element mounting portion 12 inner lead 13 outer lead 14 dam bar 15 side rail 16 air reservoir 17 notch portion 18 conducting portion 18a notch 18b groove 19 resin reservoir portion 20 lower mold 21 gate portion 22 sub-runner portion 23 cavity 24 Runner 25 Air Vent 26 Cull Part 27 Resin Retaining Part 28 Resin Encapsulation Device 29 Upper Mold 30 Pot 31 Plunger 32 Putting Surface 33 Semiconductor Element 34 Wire 35 Sealing Resin

Claims (4)

[Claims] 1. A cutout portion formed on a part of a side rail side edge on one side of the element mounting portion, and a resin reservoir formed adjacent to a side rail side edge on the other side of the element mounting portion. A lead frame having a cutout portion formed inside the resin reservoir and a plurality of air reservoirs on the side rails on both sides is used, and a semiconductor element is mounted on an element mounting portion of the lead frame. The other end of the wire bonded to the pad of the semiconductor element is bonded to the tip of the internal lead, and the internal lead, the semiconductor element, the element mounting portion and the wire are sealed in a plurality of cavities and in each of the cavities. A gate portion of a fixed size for injecting a stop resin, a sub-runner portion connected to these and having a different size depending on the cavity position, and the sub-runner An injection pressure plunger in which the transfer speed of the preheated sealing resin in the pot is controlled in at least two stages after being clamped in a molding die that is connected to the And a step of mold pressing for injecting the encapsulating resin into the cavity for resin encapsulation, and separately molding the outer leads of the resin-encapsulated lead frame, and thereafter forming the outer leads into a desired shape. A method of manufacturing an ultra-thin semiconductor device, which comprises a step of forming an external lead by bending and forming. 2. The resin sealing thickness is 0.5 to 0.8 mm, the sealing resin is spiral flow 40 to 70 inches,
The method for manufacturing an ultrathin semiconductor device according to claim 1, wherein the viscosity is 160 to 200 poise and the particle size of the filler to be filled is 48 microns or less. 3. The resin sealing thickness is 0.8 to 1.0 mm, the sealing resin is spiral flow 30 to 40 inches,
The method for manufacturing an ultrathin semiconductor device according to claim 1, wherein the viscosity is 220 to 280 poise and the particle size of the filler to be filled is 75 microns or less. 4. The mold press heats and holds the mold die at 165 to 180 ° C., and the transfer speed of the sealing resin is halfway high and the rest is low. 4. The method for manufacturing the ultrathin semiconductor device according to 2 or 3.