Abstract:
The invention relates to a device for at least partially drying separated electronic components comprising: a carrier for the electronic components; a moisture-absorbing material; and a holder covered with the moisture-absorbing material, wherein the holder and the carrier are displaceable relative to each other such that the electronic components for drying can be brought into contact with the moisture-absorbing material.

Description:
BACKGROUND OF THE INVENTION 
     1) Field of the Invention 
     The present invention relates to a device and method for drying separated electronic components. 
     2) Description of the Prior Art 
     During the process of manufacturing electronic components, such as more particularly semiconductor products, these are usually separated (which can also be referred to as singulated or divided) from a larger unit of electronic components. The electronic components are usually manufactured in a larger unit of electronic components. Examples hereof are for instance packages with a plurality of encapsulated electronic components, and wafers. During separation use is generally made during machining processes of flushing liquid, although the separation can also take place using a cutting liquid. For the least possible impact on the processing steps following separation, it is desirable that the separated electronic components are dried before they are subjected to other processing steps. 
     It is known here to make use of a device according to the preamble of claim  1 . In such devices the separated electronic components are placed on the carrier, after which they are brought into contact with a moisture-absorbing material arranged on a holder by the holder and the carrier being displaced relative to each other. In the known cases the holder is here a roller and the carrier a surface, wherein the roller and the separated electronic components are displaced relative to each other. Such devices have the drawback however that the moisture-absorbing material loses its effect after a period of time because it becomes saturated with absorbed moisture. As soon as the moisture-absorbing material is saturated, the device can no longer carry out its function properly, and there is the danger of the electronic components being subjected to a subsequent processing step when not completely dry. 
     It is an object of the present invention to provide a device for at least partially drying separated electronic components which at least partially obviates the above stated drawbacks. 
     SUMMARY OF THE INVENTION 
     The invention provides for this purpose a device of the above described type, characterized by suction means for suctioning absorbed moisture out of the moisture-absorbing material. Because the moisture is suctioned out of the moisture-absorbing material, this material does not become saturated, and it can be used for sustained drying of separated electronic components. Separated electronic components can thus be dried effectively for a longer period of time, at higher production speeds and with relatively little chance of disruption. In addition, suctioning of the moisture out of the moisture-absorbing material also has a further advantage. Suctioning moisture out of the moisture-absorbing material, instead of for instance displacing moisture by scraping, evaporation or blowing, ensures that the conditions in the space in which the separated electronic components are located can be better controlled; this is because the moisture is removed by suctioning and is therefore no longer a factor in the vicinity of the electronic components. 
     The suction means are preferably adapted to apply an underpressure relative to the pressure in a space in which the moisture-absorbing material is located. An airflow is in this way generated, using which airflow the moisture absorbed from the separated electronic components by the moisture-absorbing material is carried out of the space. A substantial part of the moisture which is present will already evaporate due to the displacement of air in the moisture-absorbing material. 
     Favourable results are obtained when the underpressure is 100-300 mbar lower than the pressure in the space in which the moisture-absorbing material is located. At such a pressure difference a good suctioning of the moisture is achieved without this resulting in undesirable side-effects, such as for instance excess airflow whereby the separated electronic components are displaced in undesirable manner. The thickness of the moisture-absorbing material is preferably 1-10 mm. It is not only the pressure difference which can be determined subject to situational conditions; there are also other variables which can be adjusted as required. Examples of such variables are, among others, the suction flow rate and the temperature. 
     In an advantageous embodiment of the present invention the holder is provided with at least one moisture-permeable segment connecting to the moisture-absorbing material. Such a moisture-permeable segment of the holder makes it possible to suction moisture out of the moisture-absorbing material through the holder. The moisture is hereby suctioned out of the moisture-absorbing material from a direction remote from the side of the moisture-absorbing material with which it makes contact with the separated electronic components. The moisture is in this way carried through the moisture-absorbing material; the moisture-absorbing material functions here as a kind of filter. A significant advantage of this construction is that the moisture-absorbing material prevents strong gas flows coming into contact with the separated electronic components. The suction means will here also be situated on the side of the carrier remote from the moisture-absorbing material. The term “be situated” is here also understood to mean “debouch”. A pump can thus be connected by means of a channel or hose to the side of the carrier remote from the moisture-absorbing material. 
     During the contact with the separated electronic components the moisture-absorbing material can also remove dirt and/or dust particles from the components as well as moisture. The moisture-absorbing material thus fulfils a dual function; not only does it have a drying function, it also acts simultaneously as cleaning means. The dirt and/or dust taken up by the moisture-absorbing material can be suctioned out of the moisture-absorbing material in order to thus prevent increasing contamination of the moisture-absorbing material. Conversely, it is also possible to apply the moisture-absorbing material as “dirt filter”. This will particularly be the case if the suctioning takes place from the side of the moisture-absorbing material opposite the side with which the moisture-absorbing material makes contact with the electronic components. If the contamination of the moisture-absorbing material reaches an undesirable level, the moisture-absorbing material will have to be replaced or cleaned (compare this to a contaminated filter which is changed or cleaned). 
     In a further embodiment of the present invention the holder is substantially cylindrical, wherein the moisture-absorbing material engages in the form of a cylinder jacket round an outer side of the holder. The moisture absorbed from the separated electronic components can hereby be suctioned via the interior of the holder. The holder with a covering of moisture-absorbing material in the form of a cylinder jacket can be rolled over the electronic components. 
     In an alternative embodiment the holder is substantially flat and the moisture-absorbing material is pushed onto the separated electronic components such that they are as it were tamponed for the purpose of absorbing moisture. Recesses are usually arranged in the flat carrier, thereby ensuring the position of the electronic components on the carrier. These recesses usually connect to an underpressure system whereby the electronic components can be held in the openings through support from an underpressure. 
     In a particular embodiment variant of the device the carrier is provided with recesses for at least partially receiving the electronic components, wherein the openings are connected to an underpressure system, wherein a layer of moisture-absorbing material is received in the openings. With this embodiment variant drying can also take place on the side of the electronic components directed toward the carrier. Due to the suctioning through the moisture-absorbing material placed in the openings of the carrier the moisture will also be suctioned out of this moisture-absorbing material. 
     At an advantageous size of the pores of the moisture-absorbing material the diameter of these pores amounts to 100-200 micron. 
     The moisture-permeable segment of the holder adjoining the moisture-absorbing material can have a grid structure, optionally in combination with holes arranged in the holder. For a sufficient discharge of moisture through the carrier, 30 to 70% of the area of the permeable segment is open. 
     The present invention also comprises a method for at least partially drying separated electronic components, comprising the processing steps of: A) providing on a carrier a number of separated electronic components lying in one plane; B) bringing the separated electronic components into contact with a moisture-absorbing material; and C) suctioning moisture present in the moisture-absorbing material out of the moisture-absorbing material using suction means. The moisture can here be suctioned out of the moisture-absorbing material from the side along which it has previously been absorbed by the moisture-absorbing material, although it is also possible for the moisture to be suctioned out of the moisture-absorbing material from a side opposite the side along which it has previously been absorbed by the moisture-absorbing material. Another advantageous option is that a cylindrical outer side of the moisture-absorbing material is rolled over the separated electronic components for drying. In yet another embodiment variant moisture is also absorbed by the carrier by means of moisture-absorbing material connected to the carrier. For the advantages of this method reference is made to the advantages already described above of the device according to the present invention. It is of course also possible to subsequently dry the electronic components on two sides, although for this purpose the separated electronic components will then have to be taken from the carrier by means of a gripper element (manipulator) such that the side of the electronic components initially directed toward the carrier also becomes accessible to moisture-absorbing material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be elucidated on the basis of the following non-limitative exemplary embodiments. Herein: 
         FIG. 1  is a perspective view of a schematically represented device according to the present invention; 
         FIG. 2  is a partially cut-away view of a schematically represented alternative embodiment of a device according to the present invention; 
         FIG. 3  is a perspective view of a third embodiment of a device according to the present invention; and 
         FIGS. 4A-C  show diverse views of a carrier, and a component of such a carrier, as can be applied in an alternative embodiment variant of the device according to the present method. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a schematic view of a device  1  for drying separated electronic components  3  provided with a flat carrier  2  on which the electronic components  3  are located. Device  1  is also provided with a moisture-absorbing material  4  arranged round a part of the outer wall of a cylindrical holder  5 . Holder  5  and carrier  2  can be displaced relative to each other in or opposite to the direction of arrow P 1 . The moisture-absorbing material  4  on holder  5  can be brought into contact with electronic components  3  located on carrier  2  by rolling holder  5  with moisture-absorbing material  4  over electronic components  3  (see arrow P 2 ). Disposed above holder  5  with moisture-absorbing material  4  is a suction nozzle  7  for suctioning absorbed moisture out of moisture-absorbing material  4 . This moisture is further discharged using an airflow  8 . 
       FIG. 2  shows a roller  10  which can form part of a second embodiment of a device according to the invention. Moisture-absorbing material  4  is designated with the same reference numeral as in  FIG. 1 . Roller  10  consists of a tubular carrier  11 , the outer side of which is partially enclosed by moisture-absorbing material  4 . Tubular carrier  11  is provided with a gas and moisture-permeable segment  12 . Openings  13  are arranged for this purpose in tubular carrier  11 . There are diverse alternatives, such as grids and gauze, as alternative to the gas and moisture-permeable openings  13 . Suction means  14  represented highly schematically connect to the hollow interior  15  of tubular carrier  11 . Suction means  14  can generate an underpressure in the hollow interior  15  of tubular carrier  11  such that gas flows are created as according to arrows P 3 . The arrows P 3  in  FIG. 2  show that the suction means connect on two sides to the hollow interior  15  of tubular carrier  11 , although it is of course also possible for the suctioning to take place from only one of the two sides. Such a single-sided suctioning is structurally simpler. Gas (generally air) is suctioned out of the atmosphere for the purpose of generating the gas flows. Gas is suctioned out of the atmosphere surrounding roller  10  and flows as according to arrows P 3  through moisture-absorbing material  4  and openings  13  in tubular carrier  11  to suction means  14 . Moisture present in moisture-absorbing material  4  is entrained by these gas flows P 3 . Moisture-absorbing material  4  hereby dries and desirably does not become saturated, whereby a continuous absorption of moisture can take place. Roller  10  will be pressed with a limited pressure (preferably only several Newton) against the electronic components for drying (not shown) and then rolled thereover. 
       FIG. 3  shows a third embodiment of a device  20  according to the present invention. In this embodiment moisture-absorbing material  21  is arranged on a flat holder plate  22 . Holder plate  22  with moisture-absorbing material  21  can be moved intermittently (see arrow P 4 ) relative to electronic components  24  located on a carrier  23  such that electronic components  24  are dried by means of tamponing. Arranged in holder plate  22  are openings  25  through which a gas flow can be generated (see arrow P 5 ), whereby in this variant the gas flow is also suctioned through moisture-absorbing material  21 . At least a part of the moisture present in moisture-absorbing material  21  will here be entrained in gas flow P 5 , as a result of which the moisture-absorbing material  21  dries and desirably does not become saturated. 
       FIG. 4A  shows a schematic view of a carrier  30  in which a number of recesses  31  are arranged. Recesses  31  are adapted to the dimensioning of a specific size of electronic component such that these latter can be placed in recesses  31 . Connecting to each opening  31  is a suction opening  32 , whereby the components can be held more firmly in openings  31  using underpressure.  FIG. 4B  shows carrier  30  in a situation where separated electronic components  33  have been placed in the openings. Electronic components  33  protrude here to a limited extent above carrier  30 . In this situation electronic components  33  can be dried on the side remote from carrier  30  by being brought into contact with a moisture-absorbing material as shown for instance in the foregoing figures.  FIG. 4C  shows a segment  34  of a moisture-absorbing material which has dimensions such that it can be placed in an opening  31  of carrier  30 . Segments  34  of moisture-absorbing material are here desirably placed in openings  31  of carrier  30  such that they are not unintentionally released when electronic components  33  are taken out of openings  31 . The segments  34  of moisture-absorbing material thus arranged in openings  31  will, if they are so dimensioned that they make contact with the underside (the side directed toward carrier  30 ) of electronic components  33 , will also dry the underside of components  33 . Moisture will be suctioned out of segments  34  of moisture-absorbing material as a result of the suction of gas through suction opening  32  such that it is possible to prevent the segments  34  of moisture-absorbing material becoming saturated with moisture. 
     In addition to the shown embodiments, diverse variations are possible in the form of the holder and the moisture-permeable parts. The moisture-absorbing material can consist of a variety of materials, such as for instance a hydrophilic foam, a PVA sponge or polyurethane.