Handling system for laminar objects

Apparatus for applying adhesive film to an annular frame having a substantially circular disc of uniformly tensioned film adhered to one surface thereof, said film covering the whole of the central aperture of the frame and not extending beyond the outer periphery of the frame at any point, said frame being substantially undamaged by contact with a cutting device used in forming the disc of film.

This invention relates to a handling system for laminar objects and, more 
particularly to a method of, and appparatus for applying adhesive film to 
an annular frame to allow an object to be mounted within the frame. 
Semi-conductor wafers are frequently mounted in this manner both for 
protection during transportation and so that they may be readily supported 
as they are cut into individual "chips". 
Modern cutting machines for cutting silicon wafers into chips generally 
employ frames which have an irregular outer periphery to allow indexing 
and correct location of the frame with its associated wafer and because of 
the irregular outlines of the frame it is not possible easily to apply the 
adhesive film to the frame and to get the necessary omnidirectional 
tension in the film. The irregular outline of the frame means that usually 
a manual operation of cutting away excess film is necessary and automation 
of the process is difficult. 
This invention provides apparatus for applying adhesive film to an annular 
frame which comprises means for locating the frame relative to the film to 
be applied thereto, means for clamping the film relative to the frame so 
that the film extends parallel to the plane of the frame and is spaced 
therefrom, and a plunger arranged coaxially of the frame and moveable in a 
direction perpendicular to the plane of the film and the frame and 
operating to press the film against the frame while it is clamped in the 
film clamping means thereby subjecting the film to an omnidirectional 
tensioning and causing it to adhere to the frame and cutting means for 
cutting the film while it is under tension. 
The frame may have any desired outer and inner configuration but will 
normally encompass a circular aperture. The outer periphery of the frame 
may be substantially rectangular, oblong or circular or of any other 
desired shape to register with a particular apparatus with which the frame 
is to be used. The cutting means is preferably such that the film applied 
to the frame is a circular disc of diameter such that it overlaps the 
aperture in the frame sufficiently to allow good adhesion to the frame 
without overlapping the outer periphery of the frame and particularly 
overlapping into indented areas on the outer periphery of the frame. 
Although the cutting means may comprise a die punch or the like the cutting 
means preferably comprises a rotatable cutting blade arranged to cut the 
film without contacting the surface of the frame, thereby avoiding damage 
to the frame by the cutting means and, in such case there are preferably 
additionally provided means for smoothing down the cut edge onto the 
frame, such means for example comprising a roller or other pressure 
applying means which follow the cutting means. 
The apparatus of the invention may also comprise means for automatically 
feed the frames to the film applying area, for example from a cassette or 
other delivery means, such apparatus, for example comprising a 
reciprocating slide which engages the frame and pushes it into the 
locating means. 
The apparatus also preferably includes means for withdrawing the frames 
with their applied film. Such means may simply comprise means for 
accepting a frame ejected from the apparatus by introduction into the 
locating means of the next frame to be processed or it may comprise means 
for removing such a frame from the area of the film applying means and, 
optionally, for loading the film into a cassette where it can be 
transferred to other processing steps, or even for passing the frame to a 
position in which other operations are carried out thereon. Such means 
may, for example, comprise a conveyor or series of conveyors consisting of 
rubber or like band mounted round the wheels or rollers and running on 
either side of the apparatus to contact opposed sides of a frame leaving 
the locating means. 
Although it is possible for the apparatus to utilise oversized blanks of 
film the apparatus preferably includes means for feeding the film from a 
roll and for taking up excess film, preferably on a further roll. The 
cutting of discs from a continuous film generates a considerable amount of 
waste and the cut film collection device is preferably such that the waste 
is compacted as far as possible to avoid the dimensions of the waste roll 
becoming too large. Preferably therefore, the draw-off from the cutting 
position comprises a diabolo shaped roll in conjunction with a cylindrical 
nip roll and a pressure roll is supplied to ensure that the film wound on 
the take-up roll is under as much compression as possible. The film 
clamping means is preferably located at an adjustable distance below the 
locating means so that the tension on the film may be adjusted to allow 
the apparatus to accommodate films of different characteristics and 
different stretchability. 
The plunger may be operated from a pneumatic, hydraulic or other system but 
may also be operated manually, as may also the cutting means and, where 
applicable the edge smoothing means. 
Preferably, in order to avoid blocking the film within the apparatus any 
parts of the apparatus which come into contact with an adhesive surface of 
the film are coated with an anti-stick coating such as a silicone coating 
or a PTFE coating. 
The invention also includes a method of producing frames having an applied 
film which comprises locating a frame with its plane substantially 
parallel to and spaced from a film to be applied thereto, said film being 
held in said spaced relationship by clamping means, applying pressure from 
a plunger against the film to stretch and uniformly tension the film and 
press it against the frame, thereby adhering the film to the frame, and 
cutting the film while it is under tension and, if desired smoothing down 
the cut edges of the film against the frame. 
Preferably the cutting operation is carried out with a cutting means that 
act on a portion of the film that is not in contact with the frame and the 
cutting means does not contact the frame, therefore avoiding the 
possibility of damage of the frame. 
The apparatus also includes a frame having a substantially circular disc of 
uniformly tensioned film adhered to one surface thereof, said film 
covering the whole of the central aperture of the frame and not extending 
beyond the outer periphery of the frame at any point, said frame being 
substantially undamaged by contact with a cutting device used in forming 
the disc of film.

The apparatus comprises a feed roll 1 and a take-up roll 2 for feeding 
adhesive film 3 through the apparatus. In its passage through the 
apparatus the film passes through clamping means 4 comprising an upper 
plate 5 and a lower plate 6, the upper plate 5 being a stationary plate 
and the lower plate 6 being moveable to grip the film therebetween. 
Arranged above the level of the upper plate 5 are provided means (not 
shown) for locating a frame 7 with its plane substantially parallel to the 
plane of the film 3. The frame 7 is held, while in the frame locating 
means by a cover plate 8. A plunger 9 carried on a pneumatic ram 9a 
operates substantially centrally through the apparatus and coaxially 
between the clamping means 4 and the central aperture of the frame 7. 
Carried on a moveable sub-assembly are a knife 10 and a brush 11 arranged 
on opposite sides of a rotating disc 12 such that the diameter of the 
circle described by the knife and the brush is slightly larger than the 
diameter of the plunger 9. 
The moveable gripper plate 6 is driven from a motor 13 as also is the 
rotatable disc 12. 
The apparatus also includes a frame feed mechanism indicated generally by 
reference numeral 14 and comprising a base plate 15, adjustable frame 
locaters 16 and a reciprocatable slide 17. 
The apparatus also includes means designated generally by the reference 
numeral 18 for removing frames from the film applying area, said means 
comprising a plurality of rollers or wheels 19 carrying conveying band 20. 
In operation of the apparatus film from the feed roll 1 is passed over 
tensioning roll 21 between the plates 5 and 6 of the clamping means 4 and 
then through a nip formed between a soft surfaced roll 22 and a hard 
surfaced diabolo roll 23 to be taken up on the take-up roll 2. A pressure 
roll 24 is used to iron the waste film onto the take-up roll 2. 
With an apertured frame 7 in position in the frame locating means the 
moveable plate 6 is brought into contact with the stationary plate 5 to 
clamp the film therebetween. The plunger 9 then is operated to force the 
film against the frame 7 against the resistance of the cover plate 8. 
Pressure pads 25 on the periphery of the plunger ensure that no damage is 
caused to the film or the frame in this operation. 
With the plunger still in position and the film still under tension the 
rotary disc 12 is advanced to a position in which the knife 10 slits the 
film where it is stretched in the area between where it leaves the 
clamping means 4 and it is clamped against the frame 7 by the plunger 9 
and on rotation of the disc 12 the knife cuts a circular disc of film. The 
brush 11 which follows the knife smooths down the cut edge of the film 
against the frame 7. Means for rotating disc 12, knife 10 and brush 11 
after being raised to the cutting position shown by ram 9a in the drawing 
are not shown, but are within the skill of a mechanization engineer. 
The plunger is then withdrawn as also is the knife sub-assembly and the 
moveable clamping plate 6 and the cover plate 8 is lifted. The slide 17 is 
then operated to act on the bottom most frame 7 in the frame feed 14 and 
pushes on the finished frame in the film applying location ejecting it 
onto the frame removal device 18 whence it can be further treated. The 
surfaces of the feed rollers, the fixed clamping plate 5, the cover plate 
8 and roller 21, all of which come into contact with the adhesive surface 
of the film 3 are all preferably treated with a non-stick finish to avoid 
blocking of the film. 
Preferably the clamping means 4 is arranged such that its operative level 
below the plane of the frame 7 can be adjusted so that the tension applied 
to the film can be adjusted to suit different types of film and/or 
different applications and/or conditions of applications.