Source: http://www.google.com/patents/US4934920?dq=5815142
Timestamp: 2015-05-04 10:30:38
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Matched Legal Cases: ['art 6', 'art 7', 'art 6', 'art 7', 'art 6', 'art 7', 'art 7', 'arts 6', 'arts 6', 'arts 6', 'arts 6', 'art 110', 'art 109', 'art 110', 'art 110', 'art 109', 'art 110']

Patent US4934920 - Apparatus for producing semiconductor device - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsAn apparatus for producing a semiconductor device includes a dust-proof cover which covers a dust-generating portion in the apparatus such as a mold for effecting resin-molding of the semiconductor device composed of a lead frame and semiconductor chips wire- and die-bonded thereto, and a dust-collecting...http://www.google.com/patents/US4934920?utm_source=gb-gplus-sharePatent US4934920 - Apparatus for producing semiconductor deviceAdvanced Patent SearchPublication numberUS4934920 APublication typeGrantApplication numberUS 07/206,743Publication dateJun 19, 1990Filing dateJun 15, 1988Priority dateJun 17, 1987Fee statusLapsedAlso published asUS5026668Publication number07206743, 206743, US 4934920 A, US 4934920A, US-A-4934920, US4934920 A, US4934920AInventorsShunji Yamauchi, Minoru Tanaka, Kenitiro Sakamoto, Yutaka Morita, Toru Kidera, Hiroki MiedaOriginal AssigneeMitsubishi Denki Kabushiki KaishaExport CitationBiBTeX, EndNote, RefManPatent Citations (32), Referenced by (7), Classifications (16), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetApparatus for producing semiconductor device
US 4934920 AAbstract
An apparatus for producing a semiconductor device includes a dust-proof cover which covers a dust-generating portion in the apparatus such as a mold for effecting resin-molding of the semiconductor device composed of a lead frame and semiconductor chips wire- and die-bonded thereto, and a dust-collecting device for collecting dust which is suspended by the air inside the dust-proof cover.
1. An apparatus for processing of a semiconductor chip and a lead frame comprising:dust-proof cover means for shielding from ambient air a space around a semiconductor chip and a lead frame being processed and for containing dust created within said cover means during the processing; dust collecting means for collecting and removing the dust created during the processing within said dust-proof cover means from the interior of said dust-proof cover means; and means for generating streams of air of variable flow directions within said dust-free cover means. 2. An apparatus according to claim 1, including said dust collecting means for extracting air inside said dust-proof cover means.
3. An apparatus according to claim 1 including said dust collecting means for establishing a lower pressure inside said dust-proof cover means than outside said dust-proof cover means.
4. An apparatus according to claim 1, wherein said means for generating streams of air includes air blowing means for blowing air, and means for oscillating said air blowing means to vary the direction of blowing of the air.
5. An apparatus according to claim 1 wherein said dust-proof cover means includes a frame and a thin plate mounted on said frame with an intermediately disposed elastic member.
6. An apparatus according to claim 5 wherein said frame is a rigid material.
7. An apparatus according to claim 5 wherein said thin plate is steel.
8. An apparatus according to claim 5 wherein said thin plate is of an acrylic resin.
9. An apparatus for resin-molding a semi-conductor chip mounted on a lead frame comprising:a mold press for resin-molding; a loader for supplying semiconductor chips mounted on lead frames to be resin-molded to said mold press; an unloader for taking the resin-molded semiconductor chips with the lead frame from said mold press; first, second, and third dust-proof covers respectively independently surrounding said mold press, said loader, and said unloader; and dust collecting means for extracting dust and air from inside said first, second, and third dust-proof covers. 10. An apparatus for resin-molding a semiconductor chip mounted on a lead frame with a resin within a mold comprising:a mold press for resin-molding; a loader for supplying a material to be resin-molded to said mold press; an unloader for taking the resin-molded semiconductor chips with said lead frames from said mold press; first, second, and third dust-proof covers respectively independently surrounding said mold press, said loader, and said unloader; and pressure reducing means for establishing in the interior of said first, second, and third dust-proof covers a pressure which is lower than the pressure outside said dust-proof cover. 11. An apparatus for resin-molding a semiconductor device comprising:resin-molding means having a mold for resin-molding semiconductor chips which have been mounted to lead frames; feeding means having a loader for automatically feeding said lead frame with said mounted semiconductor chip mounted thereto into said mold of said resin-molding means; ejecting means having an unloader for automatically taking the resin-molded semiconductor chips with said lead frames out of said mold; a first dust-proof cover surrounding said resin-molding means; a second dust-proof cover surrounding said feeding means; and a third dust-proof cover surrounding said ejecting means. 12. An apparatus according to claim 11 further comprising:a first shutter disposed at the boundary between said first dust-proof cover and said second dust-proof cover for opening and closing to selectively provide communication between the interior of said first and second dust covers; and a second shutter disposed at the boundary between said first dust-proof cover and said third dust-proof cover for opening and closing to selectively provide communication between the interior of said first dust-proof cover and the interior of said third dust-proof cover. 13. An apparatus according to claim 11 wherein each of said first, second, and third dust proof covers has a frame and a thin plate fixed to the frame with an intermediately disposed elastic member.
14. An apparatus according to claim 11 further comprising air supply means for generating, within said first dust-proof cover, streams of air of varied flowing directions.
15. An apparatus according to claim 14 wherein said air supply means includes an air blowing means for blowing air, and oscillating means for oscillating said air blowing means to vary the direction of flow of air.
16. An apparatus according to claim 11 further comprising dust collecting means for extracting air from the interiors of said first, second, and third dust-proof covers.
17. An apparatus according to claim 16 wherein said dust collecting means includes a single dust collecting device and first, second and third dust collecting ducts through which said dust collecting device is connected to said first, second, and third dust-proof covers.
18. An apparatus according to claim 17 wherein each of said first to third dust-proof covers is provided with an opening.
19. An apparatus according to claim 18 further comprising a filter disposed in each of said openings.
The present invention relates to an apparatus and a method for providing a more dust-free environment, particularly for the production of semiconductor devices.
FIG. 1 illustrates a known resin molding apparatus for resin-molding a semiconductor device. This apparatus is disclosed in Japanese Patent Laid-Open Publication No. 55-96642. This apparatus is provided in the center thereof with a press machine 1 which is equipped with an upper platen 2 and a lower platen 3 which are disposed to oppose each other. The upper platen 2 is fixed in place by means of tie-bars 4. The lower platen 3 is connected to a hydraulic cylinder 5 for sliding up and down the tie-bars 4 by the hydraulic cylinder 5. An upper mold part 6 of a mold is provided on the lower face of the upper platen 2, while a lower mold part 7 cooperating with the upper mold part 6 is disposed on the upper face of the lower platen 3, such that the upper and lower mold parts vertically oppose each other. The lower mold part 7 is provided with a plurality of cavities for receiving semiconductor chips bonded to a lead frame and a pot for receiving a tablet. These cavities are connected to the pot through runners. The upper mold part 6 also has a plurality of cavities corresponding to those in the lower mold part 7.
The operation of the described semiconductor resin molding apparatus is as follows. A lead frame (not shown) is prepared with semiconductor chips die-bonded thereto and with the electrodes of the semiconductor chips wire-bonded thereto. A tablet (not shown) also is provided. The lead frame and the tablet are fed onto the lower mold part 7 on the lower platen 3 of the press machine 1 by means of the loader 8. In this state, the semiconductor chips bonded to the lead frame and the tablet are respectively disposed in the cavities and the pot. Then, the hydraulic cylinder 5 operates to raise the lower platen 3 along the tie bars 4 so that the upper and lower mold parts 6 and 7 are brought together to close the mold. Then, the tablet received in the pot is heated and melted by a suitable heating means such as a heater. The molten tablet is forced out by a plunger or the like means and injected through the runners into the cavities, whereby the semiconductor chips are resin-molded.
This known apparatus for producing semiconductor devices suffers from the following disadvantages. Both the frame 13a and the thin plate 13b constituting the cover 13 covering the whole resin molding apparatus are rigid. Therefore, often a gap 13d is undesirably formed between the frame 13a and the thin plate 13b as shown in FIG. 3 due to the deflection of the thin plate 13b between adjacent fixing screws 13c and surface roughness between the frame 13a and the thin plate 13b.
According to another aspect of the present invention, there is provided a method of producing semiconductor devices, comprising the steps of covering at least the semiconductor chip and the lead frame with a dust-proof cover; cleaning the interior of the dust-proof cover; and then executing a production process on the semiconductor chips and the lead frame.
The dust-proof cover 14 is assembled in a manner which will be explained hereinunder with reference to FIG. 7. As the first step, the frame 14a is placed along the edges of the respective zones A to E to surround the actuating portion for actuating the press machine 1, feeding means, ejecting means, controller and the mechanical part of the press machine 1. At the same time, the elastic member 14d is fixed by, for example, an adhesive, at its portion where it is to be joined to the frame 14a. The elastic member 14d fixed to the frame 14a is brought into close contact with the frame 14a and is temporarily fixed to the latter by means of an adhesive. Subsequently, the thin plate 14b is fixed to the frame 14a by means of the screws 14c (as shown in FIG. 6). Since the thin plate 14b is mounted on to the frame 14a through the intermediary of the elastic member 14d, it is possible to eliminate any gap between the frame 14a and the thin plate 14d which may otherwise exist due to the roughness of the surfaces of the frame 14a and the thin plate 14b or due to a partial deflection of the thin plate 14b between adjacent screws 14c after the mounting of the thin plate 14b. The first shutter 20 and the second shutter 21 may be already attached to the thin plate 14b. The air inlets 22 also may be formed in the thin plate 14b before the assembly of the cover. The dust collecting ducts 24 are connected to the dust-proof cover 14 thus formed.
Then, the tablet in the pot is heated and melted by a suitable heating means such as a heater, and is forced out by, for example, a plunger and injected into the cavities through the runners, whereby the semiconductor chips are molded and sealed by the resin.
Thereafter, the resin sealing the semiconductor chips is cooled and solidified and the controller 20 operates to activate the motor and raise the upper platen 2. At the same time, the second shutter 22 is opened so that the molded semiconductor device as the product is taken out of the mold by the unloader 9 and is stored in the magazine 10.
After the product is taken out by the unloader 9, the controller 20 operates to close the second shutter 22 and to start the cleaner 11 brushing on the upper and lower mold parts 6 and 7, whereby the resin burrs are removed from the upper and lower mold parts 6 and 7.
Subsequently, an air nozzle (not shown) provided on the front upper wall of the dust-proof cover 14 starts to blow air on the upper and lower mold parts 6 and 7 thereby blowing resin dust into the dust collecting duct 24. In this state, the interiors of the zones A to C are maintained at a reduced pressure so that the dust is prevented from being released outside of the dust-proof cover 14. Electronic devices such as the controller 20, as well as precision mechanisms such as the reduction gear 16, are disposed in the zones D and E which are separated from the zone A so that they are kept away from the dust.
As has been described, according to the first embodiment of the present invention, it is possible to prevent the generation of dust and the scattering of the same. It therefore becomes possible to produce semiconductor devices in a clean room of a relatively low class, e.g., 10,000 to 100,000. In addition, production under inferior environmental condition becomes possible because the influence of the environmental conditions is reduced.
A lead frame (not shown) carrying semiconductor chips die-bonded thereto with the electrodes of the chips wire-bonded thereto and a tablet (not shown) are fed onto the lower mold part 110 as in the case of the first embodiment. Subsequently, the upper die part 109 and the lower die part 110 are brought together to close the mold. Then, the tablet is heated and melted, and is injected into the cavities thereby to resin-mold the semiconductor chips. After the curing of the resin, the molded semiconductor device on the lower mold part 110 is taken out of the dust-proof cover 102.
Subsequently, both the right and the left side covers 104 and 105 are closed and the brushing of the upper mold part 109 and the lower mold part 110 is carried out with the cleaner (not shown). During the brushing, air is blown from the air nozzles 110 so that the fine particles of the resin are collected by the dust collector 108 through the duct 107.
As will be seen from FIG. 11, a manifold 212 is secured to the third mounting plate 208 by means of bolts 215 and nuts 216. A pipe (not shown) is embedded in the manifold 212 extending in the longitudinal direction of the manifold 212. An air supply tube 219 is connected through a joint 218 to one end of the pipe. The other end of the pipe is closed by a plug 217. The pipe is provided on one side thereof with a plurality of ring joints 213 disposed along the length of the pipe as shown in FIG. 9. A nozzle 214 made of, for example, copper is connected to each ring joint 213 as shown in FIG. 12. Thus, air supplied from the air supply tube 219 is blown from the respective nozzles 214.
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