Package with vacuum leak detector

Abstract

A package comprises a bag adapted to hold a vacuum when sealed, and having a top side wall and a bottom side wall. The bag contains a component and a vacuum leak detector. When the bag is sealed the vacuum leak detector is positioned between and in contact with either one of the side walls and the component, or the top side wall and the bottom side wall. The vacuum leak detector is adapted to send a signal which corresponds to one of two states, a first state which corresponds to the bag holding a vacuum, and a second state which corresponds to the bag not holding a vacuum.

Description

PACKAGE WITH VACUUM LEAK DETECTORFIELD OF THE INVENTION

[0001] The present disclosure relates generally to packages with vacuum leak detectors.BACKGROUND OF THE INVENTION

[0002] Vacuum sealed packages are used in a wide range of applications, including, for example, the electronic, semiconductor and wafer fabrication industry where components are placed into a vacuum sealed bag, sealed with the air removed, and placed into a carton for shipping. The vacuum helps to ensure moisture sensitive components are kept dry. Further, such packaging allows for matching between a label on the bag and a label on the carton, which can be important for tracking. Currently it is difficult to know if there is a leak in a bag without impractically opening cartons to inspect each bag. It would therefore be desirable to provide a leak detector suitable for detecting leaks in vacuum sealed bags and readily providing an alert that such a leak has occurred.SUMMARY OF THE INVENTION

[0003] In accordance with a first aspect, a package comprises a bag adapted to hold a vacuum when sealed, and having a top side wall and a bottom side wall. The bag contains a component and a vacuum leak detector. When the bag is sealed thevacuum leak detector is positioned between and in contact with either one of the side walls and the component. The vacuum leak detector is adapted to send a signal which corresponds to one of two states, a first state which corresponds to the bag holding a vacuum, and a second state which corresponds to the bag not holding a vacuum.

[0004] From the foregoing disclosure and the following more detailed description of various embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology of vacuum leak detectors. Particularly significant in this regard is the potential the invention affords for providing a relatively low-cost vacuum leak detector which can be used detecting leaks in difficult to spot situations. Additional elements and advantages of various embodiments will be better understood in view of the detailed description provided below.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Fig. 1 shows a vacuum leak detector for a package in accordance with one embodiment.

[0006] Fig. 2 shows an example of a mount for a tag on a base of the vacuum leak detector of Fig. 1

[0007] Fig. 3 shows an example AM tag used herein as part of the vacuum leak detector.

[0008] Fig. 4 shows an AM tag can be attached to a bottom of the cover.

[0009] Fig. 5 shows an assembled and cutaway view of the AM tag positioned between the cover and the base of the vacuum leak detector.

[0010] Fig. 6 shows a schematic process flow for a vacuum leak detector in a package.

[0011] Fig. 7 shows a schematic process to send a first signal indicating the vacuum is maintained (no alarm) and a second signal indicating the vacuum is no longer maintained (alarm).

[0012] It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the package with a vacuum leak detector as disclosed here, including, for example, the specific dimensions of the strips, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to help provide clear understanding. In particular, thin features may be thickened, for example, for clarity of illustration. All references to direction and position, unless otherwise indicated, refer to the orientation illustrated in the drawings.DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0013] It will be apparent to those skilled in the art, that is, to those who have knowledge or experience in this area of technology, that many uses and design variations are possible for the packages with vacuum leak detectors disclosed here. The following detailed discussion of various alternate elements and embodiments will illustrate the general principles of the invention with reference to vacuum leak detector suitable for semiconductor equipment and related components, wafers and wafer fabrication, and similar electrical components positioned in vacuum sealed packages. Other embodiments suitable for other applications will be apparent to those skilled in the art given the benefit of this disclosure.

[0014] The package disclosed here typically comprises a bag having a pair of side walls, a component such as an electrical component, a tray with electrical components, etc., and a vacuum leak detector. The component and the vacuum leak detector are inserted into the package between the side walls, and then sealed as air is withdrawn from an interior of the package. The vacuum leak detector is positioned against one of the walls of the package and the component, and stays in place, in contact with and biased against these elements as long as a vacuum is maintained. The vacuum leak detector is loaded under mechanical strain between one of the side walls and the component. Preferably the vacuum leak detector is positioned near the center of the component and in a relatively stable position, such as a flat surface. Importantly, the vacuum leak detector is held in place with respect to the rest of the bag when the bag holds a vacuum. The vacuum leak detector in the package disclosed herein preferably generates a signal indicative ofone of two states, either a normal active state where the vacuum leak detector is positioned in an ambient pressure environment (such as an unsealed bag), and a non-active state where the detector is positioned in a low pressure / vacuum environment (that is, the bag has been sealed and at least some of the air withdrawn). This signal can be measured when the package containing the vacuum leak detector is positioned between a transmitter and receiver. One type of detector suitable for use here is an acousto-magnetic (AM) tag. The working principle of AM tags is magnetostriction. Magnetostriction is a property of magnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of materials' magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching a saturation value. The AM tag can be comprised of metal strips / clips. One strip gets magnetized and demagnetized, and the other is magnetostrictive — meaning the magnetostrictive strip changes length ever so slightly in the presence of a magnetic field. Electronic article surveillance (EAS) antennas can reach the magnetostrictive strip with a pulsed signal at the strip’s resonant frequency, which can be around 58kHz. The strip expands and contracts along with the sender’s magnetic field. When the sender’s pulse stops, the strip keeps vibrating for a tiny bit of time, emitting a signal in the form of an AC magnetic field that’s picked up by the detector / receiver (that is, the EAS antennas receiver coil) which will trigger an indication that the status of the package has changed. The AM tag can be permanently deactivated by exposing it to strong magnetic fields, for example placing it at an AM deactivator; the AM tag can also be temporarily or at will be deactivated by simply applying pressure at the centre of the AM Tag or bending the AM Tag (10-20°). Note that over-bending may damage the AM Tag.

[0015] Turning now to the drawings, Fig. 1 shows a cover 100 and base 200 of a vacuum leak detector 10 in accordance with one embodiment. The vacuum leak detector can use an acousto-magnetic tag as noted above. Thus, the vacuum leak detector 10 for a vacuum sealed bag comprises an AM tag, the cover and the base. The AM Tag can be bonded at the bottom side 102 of the cover. The cover 100 and base 200 can be ultrasonically welded together. Alternatively, an adhesive or heat seal can be used to secure the cover to the base. The cover is flexible, having a sloped circumferential edge 101 adapted to allow the detector to flex between an original shape and a warped shape (with respect to the base) and be sufficiently robust to flex back to the original shape after external force is removed. Such relative movement of the cover with respect to the base can correlate with whether or not the bag is holding a vacuum. Typically, the cover and the base can be formed from a relatively flexible and tough material such as a plastic (for example, APET, HIPS, PC, PETG or PVC). The detector is designed to be placed inside a flexible heat-sealable packaging bag, optionally with moisture sensitive and / or specific gas sensitive devices.

[0016] Fig. 2 shows the tag of Fig. 1 with the cover removed. Fig. 3 is an isolated view of an example acousto-magnetic tag 300 shown as having a generally elongate shape. In Fig. 5, a mount 204 can be formed in the base 200, optionally as a unitary projection of the base. The mount is a projection extending up from the base, and can be provided with a series of legs 201 extending from the base to enhance stability. Flats 202 on the mount 204 may be provided to allow for attachment to the cover (such as by an ultrasonic weld at these locations). The mount 204 may alsobe provided with a step down 203 adapted to receive AM tag 300 shown in Fig. 5 so that the AM tag extends in two directions slightly above the base allowing for a gap between the AM tag and the base.

[0017] In Fig. 5, the AM tag is shown having a pair of strips 301 , 302. One of the strips is magnetic, and the other of the strips is magnetostrictive, changing length in the presence of a magnetic field. Optionally more than just a pair of strips may be used to help generate a stronger signal. Fig. 4 shows an underside 102 of the cover 100 where the AM tag 300 may be adhesively bonded or otherwise attached to the underside 102. The AM tag 300 can be mounted perpendicular on the mount as shown in Fig. 5 and allow for resilient deformation of the AM tag in response to pressure of the cover / base. The mount can be ultrasonic welded at locations 202 to permanently bond the cover unit with AM Tag and base together.

[0018] The AM tag strips 301 , 302 are shown encapsuled by the cover 100 and the base 200. The cover 100 and base cooperate to allow for some bending of the strips, typically at an angle of 10-20° with respect to a horizontal line formed between the cover and the base. The cover protects the bag from damaging the AM Tag and helps to ensure that the AM Tag can return to its original shape if / when the AM Tag is restored to active (non-vacuum) state. The base acts to ensure that the AM Tag assembly stays in place and the AM Tag bends at a specific location (in the centre) which also provides a pressure point to immobilize the AM Tag.

[0019] The AM tag can comprise, for example, an AM Anti-Metal Tag which works even in close contact to metal surfaces (which a conventional AM Tag does not).The vacuum leak detector for the vacuum sealed bag works on all AM Tags that work using the principal of magnetostriction.

[0020] In accordance with one embodiment, the vacuum leak detector should be placed with the cover upward on top of the product / component (that is, the cover faces away from the component) so that when the air in the package is being evacuated, the bag will collapse and shrink due to the lower pressure in the packaging bag versus the higher pressure outside the packaging bag. The side wall of the collapsed and shrunk packaging bag will apply force onto the cover causing it to bend, which in turn also bends the vacuum leak detector (the AM Tag). In the sealed bag, the AM Tag is both slightly deformed and effectively immobilized with respect to side walls of the bag and to the component, and the package is able to pass through an electronic article surveillance (EAS) without sounding the alarm. That is, the signal sent to the receiver is in the first state (vacuum maintained). However, if the bag were to leak causing the internal pressure of the bag to return to normal atmospheric pressure, then the collapsed and shrunk packaging bag will return back toward its original form. This acts to relieve pressure on the cover and the AM Tag will return back to the active state (the second state signal indicating no vacuum has been maintained). If the package is passed through the EAS, an alarm can be activated to indicate a bag with a leak has been detected.

[0021] Fig. 6 shows a simplified schematic of the assembly and use of the package with a vacuum leak detector in accordance with one embodiment. An electronic component 11 , here a JEDEC tray (a type of tray widely used for semiconductors and other types of electronic components, optical and photonic products, and purelymechanical parts) plus semiconductors, is inserted into the bag 12 (which is shown with a top side wall and a bottom side wall) along with the vacuum leak detector 10. Air is removed from the package as the bag is sealed, urging the side walls of the bag together against the component (and the vacuum leak detector). The vacuum leak detector is positioned under load abutting against a wall of the package and the component. It is understood to those skilled in the art and given the benefit of this disclosure that a vacuum only means a pressure inside the sealed package is below atmospheric pressure and not just a full vacuum. Typically, the vacuum leak detector is squeezed somewhat between the side wall and the component so as to resist relative movement of the vacuum leak detector with respect to the side wall when there is a vacuum in the bag.

[0022] Fig. 7 shows a simplified schematic process where a first signal is sent indicating the vacuum is maintained, and a second signal is sent indicating the vacuum is no longer maintained. The vacuum leak detector 10 generates a signal which corresponds to one of two states, a first state which corresponds to the bag 12 is holding a vacuum (i.e, there is no leak in the bag) and the vacuum leak detector is held in place and slightly bent with respect to the pair of surfaces it is abutting against, and a second state which corresponds to the bag not holding a vacuum (i.e., there is a leak in the bag) with corresponding relaxation of the vacuum leak detector, including the edge of the cover). The signal, either first signal (no leak) or second signal (leak) can be picked up by an electronic article surveillance device as shown. The vacuum leak detector is moveable between a first position where the first signal is generated, to a second position where the second signal is generated. Relative movement of the vacuum leak detector with respect to the top side wall changes thesignal to the second state.

[0023] In the example of Fig. 7, the cover and the AM tag of the vacuum leak detector are typically mildly deformed when the package is in the first (and normal), vacuum position. Both the cover and the AM tag are resiliently deformable and are biased in response to pre-loading when the component is placed in the bag and the bag is sealed. The vacuum leak detector is placed in contact with both the component and one of the walls of the bag, so the act of sealing places the vacuum leak detector under a squeezing pressure. The pressure is released if the vacuum is not maintained, such as by a tear in the bag. The release of pressure would allow the AM tag to release and return towards an unbiased position, resulting in generation of the second signal (no vacuum) if passed through the electronic article surveillance device. Thus, the vacuum leak detector (cover and AM tag in particular) is resiliently deformable between a first position corresponding to the first state and a second position corresponding to the second state. Advantageously the packages disclosed herein greatly simplify the inspection process, as many packages can rapidly be passed through the EAS detector.

[0024] From the foregoing disclosure and detailed description of certain embodiments, it will be apparent that various modifications, additions and other alternative embodiments are possible without departing from the true scope of the invention. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to use the invention in various embodiments and with various modifications as are suited to the particular usecontemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

Claims

What is claimed is:

1. A package comprising, in combination:a bag adapted to hold a vacuum when sealed and having a top side wall and a bottom side wall;a component; anda vacuum leak detector, wherein when the bag is sealed the vacuum leak detector is positioned between and in contact with one of the side walls and the component;wherein the vacuum leak detector is adapted to send a signal which corresponds to one of two states, a first state which corresponds to the bag holding a vacuum, and a second state which corresponds to the bag not holding a vacuum.

2. The package of claim 1 wherein the vacuum leak detector comprises an acousto-mechanical tag.

3. The package of claim 2 wherein the vacuum leak detector is placed under load between the top side wall and the component so as to resist movement of the vacuum leak detector with respect to the side wall when there is a vacuum in the bag, and the signal is in the first state.

4. The package of claim 3 wherein relative movement of the vacuum leak detector with respect to the side wall changes the signal to the second state.

5. The package of claim 1 wherein the vacuum leak detector comprises an acousto-mechanical tag, a base, a cover, a mount.

6. The package of claim 5 wherein the cover has a flexible circumferential edge allowing for relative movement of the cover with respect to the base.

7. The package of claim 5 wherein the acousto-magnetic tag comprises at least a pair of strips: a first strip adapted to be magnetized and demagnetized, and a second strip which is magnetostrictive.

8. The package of claim 7 wherein the acousto-mechanical tag sits between the cover and the base on the mount.

9. The package of claim 8 further comprising a step down formed in the mount, wherein the acousto-magnetic tag sits on the mount at the step down.

10. The package of claim 9 wherein the mount further comprises a plurality of legs extending from the base.

11. The package of claim 1 wherein the vacuum leak detector is moveable between a first position where the first signal is generated, to a second position where the second signal is generated, and in the first position the cover and the acousto-magnetic tag are deformed.

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