JP4019550B2 - Semiconductor package manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a semiconductor package.
[0002]
[Prior art]
Recently, electronic devices have become smaller, lighter, and more functional, and with this, higher integration of LSIs and chip parts has progressed, and the form has rapidly changed to multi-pin and miniaturization. ing. For this reason, printed wiring boards are required to have higher wiring patterns in order to improve the mounting density of electronic components.
[0003]
In addition, with the development of electronic equipment, the size of wiring boards and electronic components has been reduced, while semiconductor chips are becoming larger in order to add and advance circuit functions. For the package to be used, it has become expensive if metal packages and ceramics have been used as before, and organic materials have been used to reduce the cost of the equipment.
[0004]
Therefore, as a container for mounting a semiconductor chip, an organic material such as a film carrier, a leadless chip carrier, a flip chip, a pin grid array, a ball grid array, or the like that directly mounts a semiconductor chip on a wiring board has been developed. Are beginning to be marketed.
[0005]
Also in the wiring board, interlayer thinning, wiring miniaturization, and interlayer connection hole diameter reduction are performed, and interstitial via holes (hereinafter referred to as IVH) for connecting only conductors between adjacent layers, are also provided. Very via holes (hereinafter referred to as BVH) are being used, and the diameters of IVH and BVH are also being further reduced.
[0006]
In recent years, in a ball grid array package (hereinafter referred to as BGA) in which solder balls are used to connect a semiconductor mounting substrate and a wiring board, the semiconductor mounting substrate is bonded and fixed to an ordinary lead frame, and the lead frame semiconductor The use of a semiconductor package that can be mass-produced in the same manner as the package has been studied.
[0007]
This is to perform a series of operations such as solder ball mounting, semiconductor chip mounting / wire bonding, and resin sealing, and it is not necessary to attach / fix the semiconductor mounting board later. If the material for the semiconductor mounting substrate is used up to the point where it becomes, the material is wasted and it is not economical, so the semiconductor mounting substrates are arranged without gaps, manufactured at once with a large substrate, cut and bonded to the metal frame・ It is more economical to fix.
[0008]
[Problems to be solved by the invention]
Such a semiconductor package is cut when the solder ball mounting, semiconductor chip mounting and wire bonding are completed and sealed with resin, so that the frame becomes unnecessary, but the semiconductor mounting substrate is attached to the frame. The portion where the is fixed is left in the semiconductor package.
[0009]
By the way, when an adhesive is dropped on a metal frame with a dispenser, dried, and a substrate for mounting a semiconductor is stacked and then pressed and heated, voids are generated at the location of the adhesive, and solder balls are mounted. The problem is that the semiconductor package after chip mounting, wire bonding, and resin sealing may be broken at the temperature at which the solder ball melts when mounting the semiconductor package on the wiring board. There is.
[0010]
An object of this invention is to provide the method of manufacturing the semiconductor package excellent in suppression of generation | occurrence | production of a void.
[0011]
[Means for Solving the Problems]
The semiconductor package manufacturing method of the present invention is a method of manufacturing a semiconductor package in which a semiconductor mounting substrate is bonded to a metal frame and continuously mounted on a lead frame, and the semiconductor package is mounted on a metal frame. After dropping the adhesive with a dispenser to the place where the substrate is to be bonded under a certain humidity, it is dried while maintaining that humidity, and the semiconductor mounting substrate is stacked, and the stacking is integrated by pressing and heating. Features.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The adhesive is made of a thermoplastic resin, and the humidity maintained during the dripping and the subsequent drying is preferably 20 to 40% Rh, and more preferably 25 to 35% Rh.
[0013]
【Example】
Example 1
A copper plate having a thickness of 0.2 mm was punched out to produce a copper frame.
[0014]
A hole is made in MCL-E-679 (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is a 0.6 mm thick copper clad laminated with 12 μm thick copper foil, and the inner wall of the hole is formed by electroless plating. After metallization, unnecessary copper foil is removed by etching to form a solder ball land, a semiconductor connection terminal, and a wiring connecting the terminal and the solder ball land, and then an etching resist is added to 3 wt% sodium hydroxide. The substrate was peeled off with an aqueous solution to form a circuit to obtain a semiconductor mounting substrate.
[0015]
About 50 μg of Hymar (trade name, manufactured by Hitachi Chemical Co., Ltd.), which is an adhesive made of a thermoplastic resin, was dropped onto the four corners of the metal frame.
[0016]
The atmosphere at this time was 35% Rh at room temperature by supplying dry air using a dryer.
[0017]
In addition, air dried by a dryer was supplied until it was transported to the tunnel drying furnace, and the air volume was controlled so that the humidity detected by the humidity sensor was within 35 ± 3%. Then, it conveyed to the tunnel drying furnace and dried at 140 degreeC for 150 second.
[0018]
The metal frame and the semiconductor mounting substrate were overlapped and laminated and integrated by pressing and heating at a pressure of 10 kgf / cm ² and a temperature of 250 ° C.
[0019]
The semiconductor package thus produced was floated in a molten solder bath at 260 ° C. for 10 seconds in an accelerated test, but there was no rupture due to voids.
[0020]
Example 2
The same procedure as in Example 1 was performed except that air dried by a dryer was supplied until the air was transported to the tunnel drying furnace, and the air volume was controlled so that the humidity detected by the humidity sensor was within 15 ± 3%. A semiconductor package was produced. The semiconductor package thus produced was floated in a molten solder bath at 260 ° C. for 10 seconds in an accelerated test, but there was no rupture due to voids.
[0021]
Example 3
The same procedure as in Example 1 was performed except that air dried by a dryer was supplied and the air volume was controlled so that the humidity detected by the humidity sensor was within 25 ± 3% until it was transported to the tunnel drying furnace. A semiconductor package was produced. The semiconductor package thus produced was floated in a molten solder bath at 260 ° C. for 10 seconds in an accelerated test, but there was no rupture due to voids.
[0022]
For comparison of comparative examples, a semiconductor package was manufactured under the same conditions and the same materials as in the examples except that the air dried by the dryer was not supplied until it was transferred to the tunnel drying furnace. The semiconductor package thus produced floated in a molten solder bath at 260 ° C. for 10 seconds in an accelerated test, and 5 out of 100 semiconductors were ruptured by voids.
[0023]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a method for manufacturing a semiconductor package excellent in suppressing generation of voids.

Claims (2)

A method of manufacturing a semiconductor package in which a semiconductor mounting substrate is bonded to a metal frame and continuously mounted on a lead frame, and an adhesive is used to attach the semiconductor mounting substrate to a metal frame with a dispenser. After being dripped under a certain humidity, the air is dried using a dryer until it is transported to the tunnel dryer. A method for manufacturing a semiconductor package, comprising stacking semiconductor mounting substrates, and heating and pressurizing to integrate the layers. The method for manufacturing a semiconductor package according to claim 1, wherein the adhesive is made of a thermoplastic resin, and the humidity maintained during the dripping and the subsequent drying is 20 to 40 % Rh.