WO2005034601A1

WO2005034601A1 - Special drying cupboard

Info

Publication number: WO2005034601A1
Application number: PCT/EP2003/010879
Authority: WO
Inventors: Quoc Thai Hoang; Edwin Stanek
Original assignee: Seika Sangyo Gmbh
Priority date: 2003-10-01
Filing date: 2003-10-01
Publication date: 2005-04-14

Abstract

The invention relates to a special drying cupboard comprising a drying chamber (5) for the dry storage of electronic components that are sensitive to humidity. Said drying cupboard is characterised in that the drying chamber (5) has a feeder bank (4) provided with at least one feeder receiving element (10), said receiving elements being arranged in pre-determined positions and used to receive at least one feeder (10a).

Description

Title: Special Drying Cabinet

The present invention relates to a special drying cabinet for storing electronic components in low humidity, in particular ICs (integrated circuits).

Electronic components, in particular ICs with a plastic jacket, tend to remove moisture from the ambient air. If these components are now processed, for example in so-called reflow soldering, the high temperatures occurring here cause the previously absorbed moisture to expand rapidly and thus cause an internal expansion of the component (so-called ^ opcorning ^* ). This often leads to delamination, whereby a shearing force on Haite councils and wire approaches can be exercised, with about micro-cracks can occur up to the outer edge of the plastic sheath.

In order to avoid such unwanted effects, the corresponding components are therefore - if they are not in the production process - stored at the lowest possible humidity in special drying cabinets so that they can not absorb moisture. Preferably, these special driers achieve levels of 10%, 3%, and even 1% or less relative humidity (RL), which is preferably achieved by means of a strong zeolite desiccant. Such special drying cabinets are offered for example by the company ERC Co. of Kanagawa in Japan under the label MacDry in the market. Here, the drying room of the cabinet is removed by means of a strong drying agent, such as a zeolite drying agent moisture and the desiccant automatically regenerated by means of a heater again, so that it does not have to be replaced. The moisture absorbed by the drying agent is

BESTATIGUNGSKOPIE steams and escapes from the cabinet. Metal with memory effect ensures fail-safe ventilation.

For such storage, however, is also to consider how components are processed today. So the components are nowadays usually no longer as piece goods (bulk), but already prepared for the assembly process, used applied in magazines or straps, especially strapped components play an important role. The components are placed in free spaces of a belt and prevented from falling out, for example by a cover. The straps are preferably in the form of a cardboard strap - for instance for chip resistors or capacitors - or as a blister strip, preferably in widths of 8, 12, 16, 24, 32, 44, 56 or 72 mm width. The straps are usually provided on rollers, which preferably have a diameter of 180 to 380mm, which corresponds approximately to capacities of 3000 to 15000 components on a belt. An important special form of such component straps are films for so-called micropack housings with components having a particularly high number of terminals, which are applied to a film as a carrier material.

In order to supply the electronic components so strapped to a placement machine, which boards with the components to form an electronic circuit, feed modules, also called feeders, are required, with different feeders being provided for the different packaging forms of the components. So there are feeder for the already mentioned taped components (also called belt feeder or Tapefeeder), as well as feeders for bulk material (so-called bulk case feeder) or magazines (about so-called rod magazine feeder).

Feeder for strapped components are generally universal belt feed modules that are suitable for both blister belts and paper straps; However, there are also feeder that allow only the processing of certain specific belted components. They provide the assembly machines with the components located on the belt for processing, whereby they are controlled by this via corresponding control signals. The delivery process itself, however, usually regulated automatically by them. The on Roll located belt with the components running for this purpose in the feeder, where the masking tape is removed, so as to allow a placement of placement of the picking the component from the belt - usually upwards. The masking tape can then as waste - preferably rolled up again - removed, the spent Gurtleergut be crushed in a shredder.

If such components are to be stored dry by means of feeders for processing, for example in one of the special drying cabinets mentioned above, to prevent moisture damage, such as the so-called "popcorning" during reflow soldering, the respective feeder with its associated components, be it on belt reels, be it in the magazine of the feeder (at Magazinfeedern) stored in the dry areas, if they are currently not used in the assembly process in production. For this purpose, they are simply placed in the special drying cabinets at any place suitable from the place and removed if necessary again.

However, this has a decisive disadvantage: Due to the above-mentioned unsorted storage, it is logistically difficult and time-consuming to understand how long the individual storage pieces during production, where they are not in the special oven, were exposed to normal (and thus harmful) humidity conditions. Therefore, it can be determined only at high labor and time when converting the feeder, how long they must be dehumidified according to their material and other component properties (about their thickness) in the special oven, a statement that, if you want the existing international IPC standard, but absolutely necessary. A technical overview of the storage times required in the dry storage process and their dependencies on the initial state of the components, as well as the associated problem of the complexity of handling the components and feeders are given in more detail in the further and Fig. 6 and the associated description using an example , Despite the importance of logistical tracking of storage times for the quality assurance of the production of electronic component boards, today Due to the high labor and time required for the storage time tracking when converting the feeder on this cost reasons for the most part omitted.

Based on the prior art conventional special drying cabinets for electronic components, it is therefore an object of the present invention to further develop a special drying cabinet so that the important logistical tracking of dry storage times of the individual storage pieces is made possible at the same time reasonable effort during conversion of the feeder.

This object is achieved by a special drying cabinet with a drying space for dry storage of humidity-sensitive electronic components, which is inventively characterized in that the drying room has a feeder bank with one or more, arranged at predetermined positions Feederaufnahmen for receiving one or more feeders. Through this feeder bank, the individual feeders are now no longer unsorted in the special drying cabinet granted, but at fixed positions, namely the respective Feederaufnahmen, set in the special drying oven. Preferably, the reception of the feeder can take place, for example, via a plug-in connection, which is already present at the feeder for connection to the placement machine, particularly preferably by means of a dummy plug or a blind socket on the feeder receiver. However, the recording can also be about a clamp connection or otherwise holding or locking, for example by means of a tongue and groove system, as well as in any other technically suitable manner from equip. Thus, the feeder is assigned a fixed position after being placed in the special drying cabinet, which greatly simplifies the collection of logistic information for the storage time tracking. This considerably simplifies the handling of a bar code reader which reads a code assigned to the feeder during setting and removal, since the respective operator easily removes the bar code at a fixed position on the feeder still in the feeder bank in the drying cabinet without cumbersome re-sorting, depositing, Resuming and similar operations, which can be seen in particular in the case of more frequent removal of entire feeder rows, for example for a new placement program on the assembly machines to be supplied with components. especially time-saving. Even in the event that on the feeder itself not enough space or no suitable place for the ^' attachment of a label, preferably a barcode, is present, the logistical identifier can be attached to the tracking of the storage times at the corresponding Feeder recording of the feeder bank, in the the corresponding feeder is then to be set in each case. In such cases, the present invention makes a logistical tracking of the respective drying times possible in principle only.

In a particularly preferred embodiment of a special drying cabinet according to the invention, the feeder bank also has a belt container with one or more respective feeder receiving associated Gurtrollenaufnahmen for receiving a belt reel, which greatly facilitates the handling of Gurtfeedern with their respective associated belt reels. Here, the ordering function of the present invention is particularly evident, since it not only allows the spatial technical arrangement of the feeder and thus their time-saving logistical tracking, but also the same for the associated Gurtrollen and also for their respective perfect mutual association makes each other , If you also assigns the Gurtcontainer in the right position, so as below the Feederaufnahmen in the same grid as this, so the feeder can be adjusted even with inserted belt with their respective belt reel in the Spezialtrockenschtrank invention, what the changeover times while easier logistical traceability of storage times even further reduced and this embodiment of the present invention particularly distinguished as particularly favorable. This embodiment is also particularly advantageous in those cases in which the feeder is adapted to the respective components to be conveyed by it, since it then helps to avoid confusion of belonging to Gurtrollen even if this without feeding the belt in the feeder in Special drying cabinet to be stored.

Preferably, a support in the Gurtrollenaufnahme for stable positioning of the male Gurtrollen serves, as such a support for stable positioning of the male Gurtrollen at least two rounded in cross-section Can act profiles that are arranged in the Gurtrollenaufnahme that the resulting by the outer circumference of the Gurtrollen Gurtrollenaußenkontur rests on storage of the Gurtrolle in Gurtrollenaufnahme each on at least two of the rounded profiles.

Also, the feeder bank can be designed by means of a pull-out mechanism, such as a drawer, so that it is at least partially moved out of the drying room, which further simplifies the handling of setting and removing the storage items and further reduces the changeover times.

In a further preferred embodiment, the special drying cabinet according to the present invention also has a moisture meter for measuring the relative humidity in the drying room, which allows control of the proper operation of the special drying cabinet.

Preferably, the relative humidity in the drying room over time is recorded as a measurement record, for example, for later control.

The same can be done for the temperature in the drying room.

Also, the special drying cabinet according to the invention may have a Feeder recording with a Feeder sensor, which is able to automatically read out an identifier attached to the feeder, which then allows, when connected as a correspondingly programmed computer system to this sensor, a fully automatic storage time tracking. Likewise, it is of course also possible to provide such a sensor on the Gurtrollenaufnahmen a possible Gurtcontainers that is used for automatic reading of an identifier on the belt reel. In this case, such sensors can be configured both contactless, for example inductive, but also for reading by means of conventional contacting, preferably via a plug or socket attached to the feeder bank and serving to receive the respective feeder. Such an automatic storage time tracking obviously serves to further reduce the changeover times while at the same time increasing the reliability of the process. sity of the logistic storage time data recorded, as this excludes operating errors.

In the following non-limiting exemplary embodiments will be discussed with reference to the drawings. In this show:

1 shows an embodiment of a special drying cabinet according to the present invention in a perspective front and side view with the feeder bank pulled out,

2 shows the special drying cabinet according to FIG. 1 with retracted feeder bank, FIG.

3 shows an embodiment of a feeder, in this case a belt feeder for a special tray cabinet according to the present invention in perspective view,

4 shows the special drying cabinet according to FIG. 1 in side view with retracted feeder bank and closed door,

Fig. 5 shows the special drying cabinet according to Fig. 1 in front view with retracted feeder bank and closed door, and

Fig. 6 is a dehumidifying diagram over time for a PBGA with 25 x 25 mm base with a thickness of 1.8 mm.

1 shows an embodiment of a special drying cabinet according to the present invention in a perspective front and side view with the feeder bank 4 pulled out. The special drying oven according to the invention shown here has a housing 1 which surrounds a drying space 5 for the dry storage of moisture-sensitive electronic components. The special drying cabinet rests securely on outrigger - and thus height adjustable - feet 7. If these are screwed in, it can be driven on rollers 8. In order to access the drying space 5 located in the housing 1, the special drying oven has a two-leaf door 2. In the drying room 5, a feeder bank 4 is arranged with one or more feeder seats 10 arranged at predetermined positions for receiving one or more feeders 10a. The feeder 10a is stored in the special drying cabinet in the feeder holder Inserted 10, wherein arranged here from each other in a spaced and arranged in a grid positioning pins 22 for a fixed positioning of the feeder 10a. This positioning of the feeder 10a in the respective Feederaufnahme 10 is here by means of the positioning niestifte 22 designed so that Gurtrollen 15a, which come to lie in a here also to the feeder bank 4 belonging belt container 15 in local Gurtrollenaufnahmen 15b, so to their respective associated Feeder 10a are arranged, that the respective component belt 23 can be performed if required during storage in the special drying cabinet according to the invention of the belt reel 15a in the associated feeder 10a, without obstructing the access path to other to be stored feeders 10a and rollers 15a or disturb , It can also be seen here that the feeder bank 4 has been moved out of the drying space 5 by means of a telescopic rail 9 serving as a pull-out mechanism. In the right upper corner of the - here unfolded - right door leaf of the door 2, in addition a monitoring of the drying room conditions serving combined humidity and temperature measuring device 3 is arranged, which is also able to record the time course of both measured variables as writing.

FIG. 2 shows the special drying cabinet according to FIG. 1 with the feeder bank 4 retracted while retaining the reference numerals already known from FIG.

Fig. 3 shows an embodiment of a feeder 10a for a special drying cabinet according to the present invention in a perspective view, here a Gurtfeeders, such as is used in pick and place machines of the company. Siemens.

FIG. 4 shows the special drying cabinet according to FIG. 1 in side view with the feeder bank 4 retracted and the door 2 closed, likewise retaining the reference designation already known from FIG. In addition to the features already discussed with reference to FIGS. 1 and 2, a connecting cable 6 for producing the power supply and a moisture outlet 14 can be seen here at the back of the special drying cabinet according to the invention. Furthermore, this illustration shows an embodiment of the Gurtrollenaufnahme 15b in detail. In the Gurtrollenaufnahme 15b here are three serving as a support 21 rounded profiles 21a, 21b, 21c for stable positioning of the male belt rollers 15a intended. These are arranged in the Gurtrollenaufnahme 15b that the resulting by the outer circumference of the belt rollers 15a Gurtrollenaußenkontur rests upon storage of the belt reel 15a in Gurtrollenaufnahme 15b respectively on at least two, with larger rollers 15a on three of the rounded profiles 21a, 21b, 21c ,

FIG. 5 shows the special drying cabinet according to FIG. 1 in a front view with retracted feeder bank 4 and closed two-winged door 2, the reference numbering already known from FIG. 1 also being retained here. In addition to the already known, a humidity controller 13 is arranged here in the lower right corner of the left wing of the closed door 2 on the outside thereof.

6 shows a dehumidification diagram over time for an electronic component, here a PBGA (Plastic Ball Grid Array, an IC package mounted in a plastic housing), with a 25 × 25 mm base area with a thickness of 1.8 mm as an example component to illustrate the problem underlying the invention of the need to follow the dry storage times. In this diagram, the abscissa represents the time (in h) and the ordinate the course of the moisture absorption (in% by mass).

The solid continuous first curve 16, indicated by a solid line, shows the moisture absorption by the example device over time in various phases:

First of all, the example component is predried in a first phase 17 (period up to 0 h) to produce defined starting conditions.

Then the sample construction is exposed in a second phase 18 simulated room conditions of 30 ° C and 85% relative humidity, which correspond to ambient conditions without drying facilities. This happens for 24 h in a room that guarantees these environmental conditions. The proportion of the moisture-absorbing mass increases rapidly, as the first curve 16 shows, the initial value of about 0.2 increases, which leads to the cracking explained above at a temperature rise at the component, such as occurs during reflow soldering leads.

Starting from this state, the example component is now stored in a special drying oven for a period of time in a third phase 19 at 5% relative humidity, wherein the solid first curve 16 in its last section 16a here, the moisture development in the example component - but now over the temporal Gradient sinking - reproduces.

If, on the other hand, the sample component is immediately stored after drying in the first phase 17 in a special drying cabinet with 5% relative humidity, the moisture absorption of the component develops according to a second dashed curve 20 over the time course. It stays in the safe area for a long time, where there is no cracking.

This example illustrates the importance of proper logistic tracking of the dry storage times of the components to be processed, as the moisture condition of a component is dependent on both its dry storage time and its previous condition. A statement as to whether and how long the component can be processed under normal room humidity conditions depends thus on an initial production of a defined initial state thus significantly on the quality of the detection of dry storage times, so by 'coupling' these times a statement about the processing options to make the relevant components.

However, experience has shown that the quality of detection of such data decreases with the level of effort involved in detection (such as unnecessary and time-consuming manipulations, such as the prior art rearrangement, searching, and sorting described above). Yes, even worse, according to the current state of the art even in spite of the problems resulting therefrom for quality assurance mostly dispenses with the collection of such data for time and therefore also for cost reasons.

Claims

Expectations

1. Special drying cabinet with a drying room (5) for dry storage of moisture-sensitive electronic components, characterized in that the drying room (5) has a feeder bank (4) with one or more feeder receptacles (10) arranged at predetermined positions for receiving one or more feeders ( 10a).

2. Special drying cabinet according to claim 1, characterized in that the feeder receptacle (10) has a plug connection, preferably a blind plug or a blind socket, for receiving the feeder by means of a counterpart there.

3. Special drying cabinet according to claim 1 or 2, characterized in that the feeder bank (4) also has a belt container (15) with one or more belt reel seats (15b) each associated with a feeder holder (10) for receiving a belt reel (15a).

4. Special drying cabinet according to claim 3, characterized in that at least one of the belt reel seats (15b) has supports (21) for stable positioning of the belt reels to be accommodated (15a).

5. Special drying cabinet according to claim 4, characterized in that act as a support (21) for stable positioning of the belt reels to be accommodated (15a) at least two profiles (21a, 21b, 21c) rounded in cross section, which are arranged in the belt reel seat (15b) that the outer roller contour created by the outer circumference of the belt rollers (15a) rests on at least two of the rounded profiles (21a, 21b, 21c) when the belt roller (15a) is deposited in the belt roller receptacle (15b).

6. Special drying cabinet according to one of claims 1 to 5, characterized in that the feeder bank (4) can be at least partially moved out of the drying room (5) by means of a pull-out mechanism (9).

7. Special drying cabinet according to one of claims 1 to 6, characterized in that the special drying cabinet has a moisture measuring device (3) for measuring the relative humidity in the drying room (5).

8. Special drying cabinet according to claim 7, characterized in that the moisture measuring device (3) for measuring the relative humidity in the drying room (5) records the moisture profile over time as a measurement record.

9. Special drying cabinet according to one of claims 1 to 8, characterized in that the special drying cabinet has a temperature measuring device (3) for measuring the temperature in the drying room (5).

10. Special drying cabinet according to claim 9, characterized in that the temperature measuring device (3) for measuring the temperature in the drying room (5) records the temperature curve over time as a measurement record.

11. Special drying cabinet according to one of claims 1 to 10, characterized in that at least one of the feeder receptacles (10) has a feeder sensor which is used for, preferably automatically, reading an identifier attached to the feeder (10a).

12. Special drying cabinet according to claim 3 and one of claims 4 to 11, insofar as these are related to claim 3, characterized in that at least one of the belt reel receptacles (15b) has a belt reel sensor which is used for, preferably automatically,. Reading of an identifier attached to the belt reel (15a) is used.

13. Special drying cabinet according to claim 11 or 12, characterized in that at least one of the sensors is designed as a contactless sensor, preferably as an inductive sensor.