JP2002181450A - Ic package dehumidifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a defect that much time is needed when an IC package is dried for regeneration by using an ordinary temperature low humidity chamber. SOLUTION: In an IC package dehumidifying device, a heating means is situated in a low humidity chamber. The low humidity chamber comprises a dry unit containing a drying agent and a drying agent heater and an opening and closing means to switch atmosphere in the dry unit to the interior of the low humidity chamber and the outside of the chamber for communication. The heating means is situated at the inner lower part of the low humidity chamber. The interior of the low humidity chamber is maintained approximately at 40 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC package dehumidifier, and more particularly to an IC package dehumidifier applied to an IC package that is held and stored by a medium that cannot withstand high temperatures.

[0002]

2. Description of the Related Art Generally, a plastic (resin) is used as an encapsulant in an IC package. Therefore, if the IC package is left in the air, it absorbs moisture in the air and the moisture absorption rate is 0.15% by weight.
When the moisture absorbed above is mounted on a printed circuit board, the water inside the IC package expands due to reflow heat (240 ° C. for about 4 minutes), destroying the plastic part and releasing water vapor to the outside. The IC package causes delamination or disconnection due to the energy at that time.

In order to prevent this, the IC package in a tray is stored in an aluminum pack, and a desiccant in a bag and a sheet-like indicator that turns white to pink when the humidity becomes high are put. And sealed to prevent ingress of moisture. When using an IC package, open the aluminum pack, take out the IC package in the tray, mount it on the supplier of the mounter, and mount the IC package on the printed circuit board by the mounter. At this time I
The permissible storage time of the C package that can be left in the atmosphere is determined, and generally ranges from about 24 hours to about 120 hours, depending on the material and thickness of the IC package. The IC package that has passed this allowable time is placed in a heat-resistant tray and heated at 120 ° C. for 24 hours in a baking oven to remove moisture.

Recently, in order to increase the mounting speed of the IC package, a tape in which the IC packages are adhered in a row is mounted on a reel in a spiral shape and mounted.

A stick is known in which several tens of IC packages are placed in a hollow box made of a transparent plastic resin and hermetically sealed.

[0006]

However, if the time allowed for the IC package adhered and mounted on the tape to be left in the air exceeds the allowable time, the heat resistance and the adhesive strength of the tape or reel on which the stick or IC package is mounted are reduced. Baking cannot be performed at 50 ° C or higher due to the above problem. Therefore, in order to remove moisture from the IC package, the moisture was removed by placing the IC package in a conventional low-humidity room at a humidity of 5% or less for a long time.

As described above, the conventional method has a disadvantage that it takes a long time to reproduce an IC package.

An object of the present invention is to eliminate the above-mentioned disadvantages.

As a result of various experimental studies, the present inventor has found that as shown in FIG. 4, when the IC package is dehumidified and regenerated by heating, the relationship between the residual moisture content (% by weight) of the IC package and the elapsed time changes depending on the heating temperature. There was found.

The curve in FIG. 4 is for the case where the temperature in the low humidity chamber is 25 ° C. (normal temperature), and the curve is for 40 ° C. As is clear from FIG. 4, when the internal temperature is 25 ° C., the residual moisture content of the IC package does not decrease to 0.03% or less even after drying for 175 hours. Down to

[0011] This is because the rate of moisture absorption and dehumidification of the IC package is proportional to the diffusion coefficient, and if the inside of the refrigerator is raised from 25 ° C to 40 ° C, the diffusion coefficient increases by about 5 times and the dehumidification time of the IC package also increases. It is estimated to be shortened.

The present invention has been made based on such findings.

[0013]

The IC package dehumidifying apparatus according to the present invention is characterized by comprising a low humidity chamber for dehumidifying the IC package and a heating means disposed in the low humidity chamber.

[0014] The low humidity chamber comprises a dry unit including a desiccant and a desiccant heater, and an opening / closing means for switching an atmosphere in the dry unit into and out of the low humidity chamber. I do.

[0015] The heating means is arranged at a lower portion in the low humidity chamber.

The low humidity chamber is maintained at about 40 ° C.

[0017]

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

In the present invention, as shown in FIG. 1 and FIG. 2, a finned heater 2 is provided in a conventionally known low humidity chamber 1 as disclosed, for example, in Japanese Utility Model Laid-Open Publication No. 1-95234, The dehumidifying regeneration of the IC package is performed.

The heater 2 generally uses a mica plate with a nichrome wire wound thereon or a positive star. However, since the heating temperature is low, a sheet-like heating element sheet obtained by adding carbon black or the like to a resin can also be used.

1 and 2, 3 is a glass door, 4 is a dry unit, 5 is a heat insulator, 6 is a temperature control device, 7 is a display panel, 8 is a heater operation lamp, 9 is a dehumidification operation lamp, 10 is a temperature setting button, 11 is an operation button, 12 is a hygrometer, 13 is a caster, 14 is a handle, 1
5 is glass, 16 is a vent, and 17 is a shelf.

FIG. 3 shows the details of the dry unit 4, 18 is a desiccant case, 19 is a heater, 20 is a pendulum-shaped upper shutter, 21 is a pendulum-shaped lower shutter,
Reference numeral 22 denotes a shape memory alloy coil for opening and closing the inside of the compartment, 23 is a bias coil spring, 24 is a timer, 25 is a lower outside opening, 26 is an upper outside opening, 27 is a lower inside opening,
Reference numeral 28 denotes an opening in the upper chamber, and 29 denotes a lever.

Since the IC package dehumidifier of the present invention has the above-described configuration, when the power is turned on, the heater operation lamp 8 on the front is turned on. Therefore, first, the temperature rise temperature value is set, and the heating time is set. Press the operation button 10. As a result, the heater 2 at the lower part of the refrigerator is heated, and the inside of the low humidity refrigerator is heated. If the set temperature is set to, for example, 40 ° C., the inside of the refrigerator is kept at 40 ° C. by turning on / off the heater 2 or controlling the voltage by the humidity control device 6.

On the other hand, the dry unit 4 is also energized at the same time,
First, the shape memory alloy coil 22 is replaced with a bias coil spring 23.
, The shutters 20 and 21 operate and the interior is closed and the exterior is open.

At the same time, the heater 19 in the desiccant case 18
And the desiccant is heated to about 150 ° C. for about 40 minutes to be regenerated. During this time, the moisture in the desiccant is released out of the refrigerator through the upper opening 26. When the regeneration of the desiccant is completed and the desiccant is lowered to about 60 ° C. and the energization of the shape memory alloy coil 22 is stopped, the force of the bias coil spring 23 becomes stronger and the shutters 20 and 21 operate. The interior becomes “open” and the exterior becomes “closed”, and the desiccant starts to be adsorbed.

When it is desired to keep the humidity in the refrigerator at a low level of 5% or less, two dry units 4 are provided and a time lag is provided so that when one is being reproduced, the other is adsorbed. Except at the time of regeneration, the inside of the refrigerator becomes lower in humidity because the two dry units 4 perform the adsorption action.

In such an environment of 40 ° C. and a humidity of 5% or less, the IC
Dehumidify (bake) the package. The baking time varies depending on the thickness and the material of the IC package, but is generally several tens of hours. During this operation, the elapsed baking time is displayed on the display panel 7. When the baking is completed, the heater operation lamp 8 is turned off, and characters indicating the completion of the baking are displayed on the display panel 7. Thereafter, the function becomes only a general low-humidity storage, and the inside of the storage returns to normal temperature and becomes a normal-temperature low-humidity storage.

[0027]

According to the IC package dehumidifier of the present invention, the following effects can be obtained.

1) The dehumidification time can be reduced to about 1/3 to 1/4 compared with the case where a room temperature and low humidity chamber is used for dehumidification of an IC package.

2) After the IC package is dehumidified, it becomes a normal low-humidity storage, so there is no need to worry about moisture absorption, and the IC package can be taken out and used as needed.

[Brief description of the drawings]

FIG. 1 is a front view of an IC package dehumidifier according to the present invention.

FIG. 2 is a side view of the IC package dehumidifier of the present invention.

FIG. 3 is an explanatory diagram of a dry unit in the IC package dehumidifier of the present invention.

FIG. 4 is a diagram showing a relationship between dehumidification by a low-humidity storage and temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low humidity storage 2 Heater 3 Glass door 4 Dry unit 5 Insulation material 6 Humidity control device 7 Display panel 8 Heater operation lamp 9 Dehumidification operation lamp 10 Temperature setting button 11 Operation button 12 Hygrometer 13 Caster 14 Handle 15 Glass 16 Vent 17 Shelf Plate 18 Desiccant case 19 Heater 20 Pendulum-shaped upper shutter 21 Pendulum-shaped lower shutter 22 Shape memory alloy coil for opening / closing drive inside the warehouse 23 Bias coil spring 24 Timer 25 Lower exterior exterior opening 26 Upper exterior exterior opening 27 Lower part Internal opening 28 Upper opening 29 Lever

Claims (4)

[Claims] 1. An IC package dehumidifying apparatus comprising: a low humidity chamber for dehumidifying an IC package; and a heating unit disposed in the low humidity chamber. 2. The low-humidity storage includes a dry unit including a desiccant and a desiccant heater, and an opening / closing means for switching an atmosphere in the dry unit into and out of the low-humidity storage. I according to claim 1, characterized in that:
C package dehumidifier. 3. The method according to claim 1, wherein said heating means is arranged at a lower portion in said low humidity chamber.
C package dehumidifier. 4. The IC package dehumidifying apparatus according to claim 1, wherein the inside of the low humidity chamber is maintained at about 40 ° C.