JP2609516B2 - Mounting method of surface mount type semiconductor package - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for preventing peeling and cracking at the interface of a package when mounting a surface-mount type semiconductor package on a mounting board such as a printed board.

[0002]

2. Description of the Related Art In a surface mount type semiconductor package such as a small outline package (SOP), a quad flat package (QFP), and a plastic leaded chip carrier (PLCC), the size of a semiconductor chip accommodated in the package is large. As the size of the package increases, the size and thickness of the package tend to decrease and the package strength tends to decrease.
For this reason, it was difficult to manufacture a highly reliable thin resin-sealed IC.

As an example of a document describing a surface mount type package, “IC mounting technology”, pages 135 to 156, published on January 15, 1980 by the Industrial Research Institute Co., Ltd., can be mentioned. Further, as disclosed in Japanese Patent Application Laid-Open No. 61-178877, a method of putting a desiccant in a magazine or sealing a transport tray in a bag made of a vinyl sheet has been considered.

[0004]

According to the analysis of the reliability and strength of the mounting of these thin packages by the present inventors, when the package is surface-mounted on a mounting substrate such as a printed board, for example, It has been clarified that when heat is applied to the package during solder reflow, the moisture that has penetrated into the package causes rapid volume expansion, which causes peeling and cracks at the package interface.

As a countermeasure, before solder reflow,
For example, it is conceivable to bake at 125 ° C. for a long time generally for 16 to 24 hrs. However, a furnace for baking must be prepared, and above all, since a long bake is required, the work efficiency is reduced. It is considered bad.

According to the analysis of the origin of the moisture causing the cracks, the present inventor has found that, after transfer molding with a resin such as a chip component or the like, before the solder is reflowed, the package is placed in an environmental condition in air. It has been found that cracks occur when moisture enters the package and there is a state where dew condensation is likely to occur.

Although the method described in the above publication can be expected to have a considerable effect, the current state of products, which are becoming thinner and smaller, and encapsulating large chips, and transportation by aircraft. Considering the harsh environment such as
These methods alone proved difficult to solve.

Accordingly, it is an object of the present invention to provide a technology for preventing peeling of a package interface and occurrence of cracks in a surface mount type package.

An object of the present invention is to provide a highly reliable high-density mounting technology.

An object of the present invention is to provide a mounting technology of a surface mount type package which can perform an efficient solder reflow.

An object of the present invention is to provide a mounting technique capable of giving a great degree of freedom to the implementation conditions of an assembly process.

One object of the present invention is to provide an efficient surface mounting technique.

[0013]

The outline of a typical invention among the inventions disclosed in the present application will be briefly described as follows.

The method for mounting a surface-mounted semiconductor package according to the present invention includes the steps of preparing a package in which the surface-mounted semiconductor package and a moisture absorbent are sealed in a moisture-proof laminate bag; For surface mounting,
Removing the surface-mounted semiconductor package from the laminate bag, and removing the surface-mounted semiconductor package from the laminate bag and heating the surface-mounted semiconductor package to a surface-mounted substrate. The package is mounted within one week after being removed from the laminate bag. Further, the surface mounting is performed within three days after the surface mounting type semiconductor package is taken out of the laminate bag.

[0015]

In the mounting method of the surface-mount type semiconductor package having the above-mentioned structure, the surface-mount type semiconductor package is taken out of the laminate bag and before absorbing moisture in the outside air by a solder reflow process or the like. Is mounted on the mounting board, so that peeling of the interface at the package and occurrence of cracks at the time of mounting are prevented. There is no need to bake the surface-mount type semiconductor package using a furnace before mounting, and mounting can be performed efficiently.

[0016]

【Example】

General Description of the Embodiments (Embodiment 1) Next, the present invention will be described based on the embodiments shown in the drawings.

The magazine 2 is housed in a paper box 1 as shown in FIG. An example of the magazine 2 is shown in FIG. As shown in FIG. 4, the surface mount semiconductor package 3 is packed in the magazine 2, and a stopper 4 is attached to an end of the magazine 2 in order to prevent the package 3 from protruding outside the magazine. A plurality of the packages 3 are packed in the magazine 2.

As shown in FIG. 2, silica gel 5 is put between the wall surface of the interior box 1 and the side surface of the magazine 2. When the silica gel 5 is inserted into the end portion of the magazine 2, it is good for absorbing moisture, and the flange portion 7 of the lid 6 is connected to the interior box 1.
When the package 6 is taken out by lifting the cover 6 by folding the inside of the cover 6 and removing the package 3, the end opening side of the cover 6 is first affected by the moisture of the outside air. Preferably, silica gel 5 is provided.

The interior box 1 is placed in a bag 8 as shown in FIG. 5, and after degassing, the opening 9 of the bag 8 is heat-sealed. The bag 8 has, for example, a moisture permeability of 2.0 g / m ³ · 24.
It is composed of a transparent conductive bag based on polyester of hrs or less.

The reason why the bag 8 is made transparent is that it is advantageous in terms of management when the type, quantity, lot number, and the like are written on the surface of the interior box 1.

As an example of the resin film constituting the conductive bag 8, an antistatic agent-kneaded polyethylene, a polyester film, a carbon conductive layer, and an acrylic resin protective layer are laminated from the inside, and a vinylidene chloride is further formed on the film. One obtained by coating a film can be used. The conductive plate bag 8 has a surface specific resistance of 10 ⁶ Ω or less on the outer surface and 10 ¹¹ Ω or less on both the inner surface and the outer surface thereof in order to prevent the IC in the package 3 from being charged.

On the surface of the conductive bag 8, a print or label 10 is attached stating that it should be used immediately after opening and should be placed again in a low humidity environment.

According to the present invention, the surface mount type package 3 is housed in a moisture-proof bag 8, further sealed completely by degassing or a heat seal 9, and moisture-tight on the opening side by silica gel 5. Is absorbed and is not affected by external moisture, so that troublesome baking work is not required, and it is possible to prevent peeling and cracking of the package interface even when solder reflow is performed.

Embodiment 2 Hereinafter, another embodiment of the present invention will be specifically described with reference to the drawings. 6 to 8 for describing the embodiment, components having the same function are denoted by the same reference numerals, and repeated description thereof will be omitted.

FIG. 6 is a perspective view showing the external configuration of a transparent moisture-proof packaging bag according to one embodiment of the present invention.

As shown in FIG. 6, the transparent moisture-proof packaging bag of this embodiment comprises a transparent bag-like moisture-proof member 11, in which the surface-mounted semiconductor device or the like is mounted. Storage container 13 containing a plurality of electronic components 12
4, the interior box 14 is inserted into the bag-shaped moisture-proof member 11, and both ends 11A and 11B are sealed and moisture-proof packaged. 6 and 7, a humidity indicator 15 for detecting the humidity inside the moisture-proof packaging bag 17 is provided on the inner surface of the transparent bag-like moisture-proof member 11 when the moisture-proof packaging is performed. It is provided at a position that can be seen from the outside.

An embodiment of the humidity indicator 15 will be described below.

1. A precautionary note is printed on the inner surface of the transparent bag-shaped moisture-proof member 11 with an ink containing a substance which changes color with humidity, such as cobalt chloride, which becomes the humidity indicator 15. This notice is, for example, "If the color of this notice changes from blue to light purple, remove the surface-mounted semiconductor device from the moisture-proof packaging bag and bake it at 125 ° C for 24 hours."
And so on.

2. As shown in FIGS. 6 and 7, a humidity indicator (humidity detection label) 15 is attached to the inside of the transparent bag-shaped moisture-proof member 11 with an adhesive member 16 having a ventilation hole 16A so that it can be checked from the outside. As the humidity label, for example, a label obtained by sucking a substance that changes color with humidity such as cobalt chloride into paper made of pulp is used.

3. As shown in FIG. 6, a humidity indicator (humidity detection label) 15 is attached to the interior box 14 inside the moisture-proof packaging bag 17, or a precautionary note is printed with a substance that changes color with humidity such as cobalt chloride.

When attaching the humidity indicators (humidity detection labels) 15 of the above 2 (2) and 3 (3), write (print) a "cautionary note" on a substance such as cobalt chloride which changes color with humidity. No need).

Next, the structure of the transparent bag-shaped moisture-proof member 11 of the moisture-proof packaging bag 17 is made of a laminated plate as shown in FIG.

In FIG. 8, reference numeral 18 denotes an antistatic agent-kneaded polyethylene layer, which is the innermost layer of the moisture-proof packaging bag 17. This antistatic agent kneaded polyethylene layer 1
Reference numeral 8 has a thickness of, for example, 63 μm, and has functions such as triboelectricity prevention, heat sealing properties, and opening properties. On the polyethylene layer 18 incorporating the antistatic agent, a polyester film layer 19 having a pinhole resistance function is provided. On the polyester film layer 19, a polyester film layer 20 having a barrier layer having a function of preventing water vapor from entering is provided. The barrier layer 20
For example, a 14 μm thick polyester film is coated with a vinylidene chloride film. A polyester film layer (thickness of 12 μm) 21 is provided on the barrier layer 20 in which a polyester film (14 μm) is coated with vinylidene chloride, and a carbon conductive layer 22 having a thickness of, for example, 1 μm is provided thereon. Can be Further, an acrylic protective film layer 23 is provided thereon. The polyester film layer 21 has a function of reinforcing mechanical strength and dielectric strength, and the carbon conductive layer 22 has a function of preventing static electricity. The carbon conductive layer 22
There is no deterioration over time and there is no humidity dependency. Protective layer 2
The material No. 3 has a function of protecting the carbon conductive layer 22 and a function of preventing carbon flake dust, and has high abrasion resistance and good printability.

Next, a method of using the humidity indicator 15 in the moisture-proof packaging bag 17 of this embodiment will be briefly described.

First, as shown in FIG. 7, on the inner surface of the transparent bag-shaped moisture-proof member 11, a humidity indicator 15 for detecting the humidity inside the moisture-proof package 17 is provided at a position visible from the outside. A moisture-proof member 11 is prepared. A storage container 13 containing a plurality of electronic components 12 such as surface-mounted semiconductor devices is stored in an inner box 14 in the bag-shaped moisture-proof member 11, and the inner box 14 is placed in the bag-shaped moisture-proof member 11. Insert
Both ends 11A and 11B are hermetically sealed and wrapped.

When the color of the humidity indicator 15 or the cautionary note changes from blue to light purple when using the electronic component 12 such as a surface-mounted semiconductor device, the electronic component 1
2 is taken out of the moisture-proof packaging bag 17 and baked at 125 ° C. for 24 hours, and then mounting such as surface mounting is performed by solder reflow, infrared lamp, vapor phase reflow, or the like.

As can be seen from the above description, according to the present embodiment, the humidity indicator 15 for detecting the humidity inside the transparent moisture-proof packaging bag 17 is provided at a position visible from the outside. Since the internal moisture absorption state can be confirmed from the outside, the management can be easily performed.
Further, since the moisture-proof packaging bag 17 is not broken, it is not necessary to perform repacking after confirmation.

Embodiment 3 Hereinafter, another embodiment of the present invention and a semiconductor process common to the above two embodiments will be described with reference to the drawings. Hereinafter, description will be mainly given of a DRAM as an example.

(1) Manufacturing process in general; The structure and process of a semiconductor chip (DRAM, logic IC) at the heart of a semiconductor device (integrated circuit device, electronic device) according to the present invention are described in US Pat.
l NO.78531, filed Oct. 3.1985) and USP 46252.
27 (US. Serial NO. 744151 filed Jun. 13.1985), which is incorporated herein by reference.

When the wafer process is completed, the wafer is divided into chips by a dicing method using a rotating blade. For an overview of the steps before and after these, see Electric Integra
tedCircuits '' by John Allison, 1975 by Mcgraw-Hill
Book Company pages 5-10, especially FIG. 1.3 (P
7) Regarding dicing technology, US Pat.
55 (US. Serial No. 608733, filed 1975.8.28), which are incorporated herein by reference.

Thereafter, each chip is die-bonded to a lead frame, which is described in German Patent Publication DE 3116406 for various packages.
A1: JP-A-58-134452; JP-A-61-21
No. 8139; Japanese Patent Application Laid-Open No. 61-218150;
No. 209951, JP-A-60-257160, JP-A-61-32452 and JP-A-61-78149, each of which is incorporated herein by reference.

Next, each bonding pad of each pellet and the inner lead end of the lead frame are made of copper, Al,
Bonding is performed using a bonding wire (about 30 μm in thickness) made of Au or the like. For these,
US patents and US patent Applications and US as above
P45647334 (US. Serial NO.476268, filed Mar.
17.1983); USP4301464 (US. Serial NO.5507)
0, filed Jul. 5.1979); Japanese Patent Application No. 60-221832.
No .: British Patent Publication GB2157607A, which is incorporated herein by reference.

Further, in order to prevent a software defect of the memory due to α rays on the chip after the bonding is completed,
A high-purity polyimide layer or a silicone resin layer having a thickness of about 0 μm to 200 μm is formed by potting. These resin coats are described in the above-mentioned German Patent Publication DE 3116406A1, and are incorporated herein by reference. In addition, a resin coat for preventing a soft defect due to α rays may be formed during a wafer process. At this time, a thickness of about 10 μm to 80 μm is appropriate, and these are formed by forming a combination of spin coating and photolithography so as to cover at least the memory cell mat.

After the completion of the wire bonding or the like, the lead frame is sealed in an epoxy resin material by a transfer molding method. Regarding these encapsulation technologies, see US Patents and US Patent Applications above.
Medium and "VLSI Technology" SMSze
Author, 1983 by Mcgraw-hill Book Company, P574-5
81, which is incorporated herein by reference.

The molded lead frame is taken out of the mold, and after completely removing burrs on the leads, unnecessary portions of the lead frame are cut off, the sealing body is separated from the frame, and the leads are formed into a desired shape. Is performed.

After this step, the products are sorted, and the products that have passed the test are marked.
This marking operation may be performed before the lead is cut. That is, after resin sealing, the exposed surface of the lead frame is plated with Sn or the like by an electroplating method. Thereafter, the resin sealing body and the exposed surface of the lead frame are cleaned (washed with water) to remove the plating solution adhering to the resin sealing body and the surface of the lead frame. After drying, the mark is applied by an automatic marking machine.

The marking is performed by moving the lead frame on which a plurality of semiconductor devices are fixed in a certain direction,
Each MO sealed with offset mark by rotary drum (transfer drum) or letterpress direct mark
A mark indicating a product type, a grade, and the like is simultaneously attached to a resin sealing body of a semiconductor device such as an S type. At this time, friction occurs between the transfer drum or letterpress and the resin sealing body, and static electricity is generated. However, since the entire frame has the same potential, the whole of the semiconductor pellet is grounded without being affected. Thereafter, the printed mark is baked or dried by an ultraviolet or infrared dryer or a simple heat treatment, and is simultaneously adhered to the resin sealing body.

Thereafter, each semiconductor device is separated and cut by punching, cutting and bending. At the same time, each lead wire of each semiconductor device such as a MOS type is formed as an independent lead wire, and each lead wire is identical. The semiconductor device is bent into an L-shape to complete a MOS semiconductor device such as a dual in-line type device without electrostatic breakdown.

As described above, in the case of marking with ink, baking (marking / marking) at 150 ° C. for 3 to 5 hours.
Bake) is applied. On the other hand, in the case of marking with a laser, baking for drying the ink is not particularly required. Laser marking is described in European Patent Publication EP157008A2, which is incorporated herein by reference.

After the baking is completed, within a few days, preferably within a few hours, a suitable auxiliary member (directly or according to various package types) is placed in the moisture-proof bag shown in the above two embodiments. A resin-sealed electronic device (integrated circuit device, semiconductor device) is hermetically sealed with a desiccant such as silica gel via a magazine, tray, tape and reel.

Thereafter, the resin sealing device is packed in a cardboard for transportation and shipped while being sealed in the bag. These semiconductor devices are taken out of the moisture-proof bag immediately before the mounting operation. In a normal environment, it is appropriate to remove it within a few days, preferably several hours before.
It has been shown by the present inventors that when exposed to outside air for one week or more, water in the outside air is almost completely absorbed. The mounting operation is performed by various solder reflow processes.

(2) Details of moisture-proof bag and film; FIG.
1 is a perspective view showing an external configuration of an opaque moisture-proof packaging bag according to one embodiment of the present invention. As shown in FIG. 9, the opaque moisture-proof packaging bag according to the present embodiment includes an opaque bag-like moisture-proof member 31 in which electronic components such as surface-mounted semiconductor devices are mounted. A storage container 13 containing a plurality of storage containers 12 is housed in an interior box 14, the interior box 14 is inserted into a bag-shaped moisture-proof member 31, and both ends 32A and 32B are hermetically sealed and packaged. When the moisture-proof packaging is performed, a humidity indicator 15 for detecting the humidity inside the moisture-proof packaging bag 31 is provided on the inner surface of the opaque bag-like moisture-proof member 31 as shown in FIGS. It is provided at a position that can be seen from the outside.

An embodiment of the indicator 15 will be described below. A precautionary note is printed on the inner surface of the opaque bag-shaped moisture-proof member 31 with an ink containing a substance that changes color with humidity, such as cobalt chloride, which becomes the humidity indicator 15. This notice is, for example, "When the color of this notice changes from blue to light purple, remove the surface-mounted semiconductor device from the moisture-proof packaging bag and bake it at 125 ° C. for 24 hours."

As shown in FIGS. 9 and 10, the periphery of the humidity indicator (humidity detection label) 15 is directly adhered to the inside of a transparent window provided in a part of the opaque bag-shaped moisture-proof member 31 with an adhesive member. And make it visible from the outside. As the humidity detection label, for example, a label made by sucking a material made of pulp, which changes its color due to humidity, such as cobalt chloride, is used. For example, it may be soaked in a position corresponding to the window 33 on the surface of the interior box.

As shown in FIGS. 9 and 10, a humidity indicator (humidity detection label) 15 is attached to the inner box 14 inside the moisture-proof packaging bag 31 or a cautionary note is made of a substance which changes color due to humidity such as cobalt chloride. Print with. When the humidity indicator (humidity detection label) 15 is attached, it is not necessary to write (print) a “cautionary note” with a substance that changes color with humidity such as cobalt chloride.

Next, the structure of the moisture-proof member 34 at the transparent window of the moisture-proof packaging bag is made of a laminated plate as shown in FIG.

On the other hand, the moisture-proof bag other than the transparent window 33 shown in FIG. 10 is made of an opaque sheet having an aluminum film 35 as shown in FIG.

In FIG. 11, reference numeral 36 denotes an antistatic material kneaded polyethylene layer, which is the innermost layer of the moisture-proof packaging bag 31. The antistatic material-kneaded polyethylene layer 36 has a thickness of, for example, 60 μm, and has functions such as triboelectricity prevention, heat sealing properties, and opening properties. An aluminum foil 35 having excellent moisture resistance is laid on the polyethylene layer 36. Since aluminum is a metal, the transmittance of water vapor is very low as compared with an organic film, so that the intrusion can be effectively prevented. The thickness of this aluminum is, for example, about 10 μm. Further, on the aluminum, a polyethylene film layer 39 of about 20 μm having excellent moldability is provided. Further, a polyester film layer (12) having excellent mechanical strength and high withstand voltage is formed on the polyethylene film.
(thickness of μm) 38 is provided thereon.
A carbon conductive layer 37 having a thickness of m is provided, and an acrylic protective layer 40 is further provided thereon. The polyester film layer 38 has a function of reinforcing mechanical strength and dielectric strength, and the carbon conductive layer 37 has an antistatic function. The carbon conductive layer 37 does not deteriorate with time,
Does not have humidity dependency. The material of the protective layer 46 has a function of protecting the carbon conductive layer 37 and a function of preventing carbon flake dust, and has high wear resistance and good printability.

Next, a method of using the humidity indicator 15 in the moisture-proof packaging bag 31 of this embodiment will be briefly described.

First, as shown in FIG. 10, on the inner surface of the opaque bag-shaped moisture-proof member 31, the indicator 15 for detecting the humidity inside the moisture-proof package 31 is located at the position of the transparent window 33 so that it can be seen from the outside. The provided bag-shaped moisture-proof member 31 is prepared. A storage container 13 in which a plurality of electronic components 12 such as surface mounted semiconductor devices are stored in the bag-shaped moisture-proof member 31.
Is stored in the interior box 14, the interior box 14 is inserted into the bag-shaped moisture-proof member 11, and both ends 32A and 32B are sealed and moisture-proof packed.

When the humidity indicator 15 or the color of the cautionary note changes from blue to light purple when using the electronic component 12 such as a surface-mounted semiconductor device, the electronic component 1
2 is taken out of the moisture-proof packaging bag 31 and baked at 125 ° C. for 24 hours, and then mounting such as surface mounting is performed by solder reflow, infrared lamp, vapor phase reflow, or the like.

As can be seen from the above description, according to the present embodiment, the humidity indicator 15 for detecting the humidity inside the opaque moisture-proof packaging bag 31 is provided at a position visible from the outside. Since the internal moisture absorption state can be confirmed from the outside, the management thereof can be easily performed. Further, since the moisture-proof packaging bag 31 is not broken, it is not necessary to perform repacking after confirmation.

Although the present invention has been described in detail with reference to the embodiments, it is needless to say that the present invention is not limited to the above-described embodiments and can be variously modified without departing from the scope of the invention. .

For example, the present invention can be applied to everything related to the packaging of electronic components affected by humidity other than the electronic components such as the surface-mounted semiconductor device.

(3) Details of the resin-encapsulated electronic device to be applied; FIG. 12 has a lead shape called “gull wing” and is generally a small-outline package (SOP).
Is called.

FIG. 13 shows a flat plastic package (FP).
P) or a quad flat package (QFP) for surface mounting. Further, FIG. 14 shows a small outline J-bend packege especially used for a memory or the like.
(SOJ).

FIG. 15 shows a plastic leaded chip carrier.
(PLCC) is used for high-density mounting. FIG.
6 belongs to the Bull lead type, mini-square package
(MSP).

FIG. 17 differs from the conventional one in that a lead is inserted into a hole in a substrate, belongs to an insert type, and is generally called a dual in-line package (DIP).

As described above, in FIGS. 12 to 17, the semiconductor chip 42 is fixed on a holding member such as a tab or island made of a thin metal plate via the Ag paste 43. Ag spo with the bonding pad on the chip
The inner end (inner lead) of the lead on which the t plating layer 44 is formed is subjected to ball & wedge bonding using a capillary with an Au wire 45 or the like (30 μm diameter). The lead 46 is formed by punching out a 42 alloy or copper alloy film. These are transfer-molded with an epoxy resin, that is, an epoxy resin 41.

(4) Details of Transporting Auxiliary Member: A large number of resin sealing devices are hermetically sealed after being accommodated in various transporting auxiliary members depending on the application.

The auxiliary members will be described.

FIG. 18 shows the magazines 54 and the housing of the resin sealing devices (transistors, ICs, LSIs) therein. MSP type resin sealing device 53 inside
Are overlapped with each other, and at the end thereof, a polyethylene pre-stopper 52 and a main stopper made of hard nitrile rubber are caught. The magazine body is made of carbon-containing hard polystyrene or conductive soft vinyl chloride.

FIG. 19 shows a tray 55 as an auxiliary member. The tray is made of vinyl chloride that has been subjected to an antistatic treatment, and the resin sealing device 53 is placed in the square recesses 56 arranged in an array. In this case, each hollow 5
6 may be directly filled with silica gel or the like, and the upper surface may be hermetically sealed with a moisture-proof sheet. Generally, after stacking trays,
After being housed in a paper interior box, it is sealed in a moisture-proof bag.

FIG. 20 shows a so-called tape and reel system in which a resin sealing device 5 is placed on a carrier tape 57 wound around a reel 59 via an adhesive tape 58.
3 are held in one row. This is hermetically sealed in the moisture-proof bag one reel at a time while being wound on the reel 59.

FIG. 21 shows another type of tape and reel system. In this case, the 1
The resin sealing device 53 is housed in the square recess 56 of the row, and the upper surface is heat-sealed by the cover tape 60.
Then, it is wound around a reel in this state, and is sealed in the same manner as above. Also in this case, if the cover tape 60 is a moisture-proof sheet as shown in FIG. 8 or FIG. 11 and silica gel or the like is put in the recess 56, an external moisture-proof sheet becomes unnecessary.

The production and other details of a magazine and the like are described in JP-A-62-16378, which is incorporated herein by reference.

(5) Details of shipping and packing of ICs and the like; FIG.
5 shows a row of packaging for shipping a resin sealing device 53 (insertable or surface mount device). A large number of resin sealing devices 53 are housed in a line in the tubular magazine 2, and are formed by a stopper pin 64 and a stopper pawl 4.
Secured inside it. After a predetermined number of the magazines are collectively housed in an inner box 1 made of paper or a sheet having low hygroscopicity, the magazines are housed in a bag made of a moisture-proof sheet as shown in FIG. 8 or FIG. The inside pressure is slightly lower than the outside air, and the moisture-proof bag is evacuated so as to be in close contact with the outer surface of the interior box, and hermetically sealed by a method such as pressurization or heating. This facilitates storage in the outer box and is convenient because no storage space is required.

On the other hand, the presence or absence of pinholes can be easily determined by enclosing dry N ₂ or the like slightly under pressure so that a gap is formed between the moisture-proof sheet and the interior box.

Although the above has been described mainly with reference to a magazine as an example, a tray or a tape and reel can be similarly packed. Further, the resin-sealed ICs may be sealed one by one or a plurality of resin-sealed ICs directly in a moisture-proof bag. Further, the auxiliary member may be directly enclosed in the moisture-proof bag without using the interior box.

Further, the desiccant is put in a paper bag or the like and put inside the interior box. However, it may be placed in a recess of a magazine or a carrier tape or another suitable place in an airtight seal. For example, it may be applied and diffused on the inner surface of the moisture-proof sheet.

The moisture-proof bag airtightly sealed as described above is
A predetermined number of cardboard boxes are housed in an outer box 61, sealed with an adhesive tape 62, and bound around the outer periphery by a binding band 63 before being shipped.

Other airtight sealing methods, especially those using a tray, are described in the above-mentioned Japanese Patent Application Laid-Open No. 61-178877, which is incorporated herein by reference.

(6) Details of Memory Chip and DRAM Device: The relationship between the sectional structure of the memory IC device of the present invention and the package will be described. Here, an SOP type package will be described as an example.

In FIG. 23, a number of FETs constituting the DRAM are formed on the upper main surface of Si substrate 71. Si
An insulating film (inorganic film) 72 made of a field oxide film, an interlayer PSG (Phospho-silicate-Glass) or the like, which forms these elements, is formed on the substrate. Furthermore, a number of Al bonding pads 75 are provided thereon.

On the other hand, the aforementioned Si substrate 71 has
It is fixed to an island or tab 78 made of 42 alloy via a g paste 77. The size of the chip 71 is approximately 10 mm × 5 mm × 0.4 mm (vertical ×
Width × thickness). The lead 80 is made of the same 42 alloy as the island, and a partial Ag plating 79 is provided on the inner lead portion. After ball and wedge bonding is performed between the inner end of the lead 80 and the bonding pad by using a 30 μmφ Au wire or the like,
A polyimide resin 73 is formed by potting over substantially the entire upper surface of the chip. Thereafter, these structures are transfer-molded with the epoxy resin 76 in units of a lead frame. A lead portion projecting from the mold resin 76 is subjected to solder plating 81.

At this time, the lead and island portions 42
The thickness of the alloy member is 0.15 mm, the thickness of the sealing resin on the package top is about 1 mm, the thickness of the polyimide film is about 0.1 mm, the thickness of the Ag paste is about 50 μm,
The thickness of the lower surface of the sealing resin is about 1 mm.

In a package sealed with such a thin resin, when a large amount of moisture is absorbed, first, vaporization and expansion of moisture occur on the lower surface of the tab 78 due to rapid heating during soldering and mounting. Subsequently, the resin and the metal are separated, and the package is swollen. At this time, it has been clarified by the present inventors that package cracks occur if the resin cannot withstand the generated stress.

(7) Details of mounting process; First, an outline of the surface mounting process will be described.

Desired wiring is formed by a Cu film or the like on a substrate made of glass-epoxy or the like, and a solder paste is formed on a soldered portion (footprint) on the substrate by a method such as screen printing. , The resin sealing device is mounted on the solder paste by a vacuum chuck or the like, and the solder reflow method, that is, the vapor phase reflow method,
The solder in the paste is melted and leaked by a heating furnace method, an infrared reflow method, or the like.

FIG. 24 shows this implementation. In the figure, reference numeral 91 denotes an SOJ type resin sealing device;
2 indicates an SOP type, and 93 indicates an MSP type. Reference numeral 94 denotes a wiring board, and reference numeral 95 denotes reflowed or dipped solder.

FIG. 25 shows a solder dipping method. In this case, the MSP-type resin sealing device 93 is fixed to the substrate 94 by an adhesive 96 such that the lead is placed on the screen-printed solder paste as shown in FIG. Subsequently, as shown in FIG. 3 (b), it is dipped downward into a solder jet 98, and then cooled to the state shown in FIG. 3 (c).

[0092]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application are briefly described as follows.
It is as follows.

(1) Since the surface-mount type semiconductor package is mounted on the mounting substrate within one week after the surface-mount type semiconductor package is taken out of the laminate bag, interface peeling and cracking of the surface-mount type semiconductor package during mounting are generated. Is prevented.

(2) In order to prevent the occurrence of interface peeling and cracking, it is not necessary to bake the surface mount type semiconductor package using a furnace before mounting, and an efficient and highly reliable mounting technology is required. can get.

[Brief description of the drawings]

FIG. 1 is a perspective view of a package showing a first embodiment of the present invention.

FIG. 2 is a perspective view of an interior box showing the embodiment of the present invention.

FIG. 3 is a perspective view of an example of a magazine.

FIG. 4 is an explanatory sectional view of a magazine end;

FIG. 5 is a diagram illustrating an example of a bag.

FIG. 6 is a perspective view showing an external configuration of a transparent moisture-proof packaging bag according to a second embodiment of the present invention.

FIG. 7 is an enlarged cross-sectional view taken along the line II-II shown in FIG. 6, and is an enlarged cross-sectional view of a mounting portion of a humidity indicator mounted on an inner surface of a transparent bag-shaped moisture-proof member.

8 is a partially cutaway perspective view showing the configuration of a transparent bag-shaped moisture-proof member of the moisture-proof packaging bag shown in FIG.

FIG. 9 is a perspective view showing an external configuration of a transparent moisture-proof packaging bag according to a third embodiment of the present invention.

10 is an enlarged cross-sectional view taken along the line II-II shown in FIG. 9, and is an enlarged cross-sectional view of a mounting portion of a humidity indicator mounted on an inner surface of a transparent bag-shaped moisture-proof member.

11 is a partially cutaway perspective view showing the configuration of an opaque bag-shaped moisture-proof member of the moisture-proof packaging bag shown in FIG.

FIG. 12 is a partially cutaway perspective view showing a resin-sealed semiconductor device package to which the first to third embodiments of the present invention are applied;

FIG. 13 is a partially cutaway perspective view showing a resin-sealed semiconductor device package to which the first to third embodiments of the present invention are applied;

FIG. 14 is a partially cutaway perspective view showing a resin-sealed semiconductor device package to which the first to third embodiments of the present invention are applied;

FIG. 15 is a partially cutaway perspective view showing a resin-sealed semiconductor device package to which the first to third embodiments of the present invention are applied;

FIG. 16 is a partially cutaway perspective view showing a resin-sealed semiconductor device package to which the first to third embodiments of the present invention are applied;

FIG. 17 is a partially cutaway perspective view showing a resin-sealed semiconductor device package to which the first to third embodiments of the present invention are applied;

FIG. 18 is a perspective view showing an outline of a transfer auxiliary member used in the first to third embodiments of the present invention.

FIG. 19 is a perspective view showing an outline of a transfer auxiliary member used in the first to third embodiments of the present invention.

FIG. 20 is a perspective view showing an outline of a transfer auxiliary member used in the first to third embodiments of the present invention.

FIG. 21 is an explanatory view showing an outline of a transfer auxiliary member used in the first to third embodiments of the present invention.

FIG. 22 is an explanatory diagram showing details of a packaging method in the first to third embodiments of the present invention.

FIG. 23 shows a memory I according to the first to third embodiments of the present invention.
It is sectional drawing of C device.

FIG. 24 is a schematic view showing a completed state of surface mounting according to the first to third embodiments of the present invention.

FIGS. 25 (a), (b) and (c) are schematic diagrams of a similar package using a solder dip method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Interior box 2 Magazine 3 Surface-mount type semiconductor package 4 Stopper 5 Silica gel (Hygroscopic agent) 6 Lid 7 Flange part 8 Bag body 9 Bag body opening part (heat seal) 10 Printing or label

Claims (1)

(57) [Claims] A step of preparing a package in which a surface-mount type semiconductor package and a moisture absorbent are sealed in a moisture-proof laminate bag; and a step of mounting the surface-mount type semiconductor package on a surface. Removing the semiconductor package from the laminate bag, and heating the entire surface-mounted semiconductor package within three days after removing the surface-mounted semiconductor package from the laminate bag, and surface-mounting the semiconductor package on a surface-mounted substrate. A method of mounting a surface-mount type semiconductor package, characterized in that cracks in the package during surface mounting are prevented.