DE3137301A1 - Method and device for handling small parts in manufacture - Google Patents

Abstract

For reliable (safe) handling during manufacture, the individual parts are bonded in a regular arrangement onto a stretched membrane consisting, for example, of rubber. During manufacture and processing of semiconductor chips, the semiconductor wafer which is intended to be split up to produce the chips or cubes can even be bonded onto the stretched membrane flat as an entity, can then be cut along the fracture lines using a machine and can finally be broken up to form the chips, in that the membrane with the wafer bonded onto it is bulged forwards from the rear so that the wafer breaks along the fracture lines. The chips which are thus produced are then located on the membrane as a regular arrangement of mutually separated individual elements. In order to calibrate the chips, each individual one of them is pressed by the membrane out of the plane of the other chips, using a plunger which is operated by compressed air, and the chips which are adjacent to the item being tested are at the same time held back by an induced suction draft which is applied from underneath the membrane. In this way, the chips are held in the correct position for testing, and subsequent insertion into an electrical circuit, which is moved into position from above, is also ensured. <IMAGE>

Description

Method and device for handling small parts

in manufacturing In manufacturing it is often necessary to have a large Set of small parts to handle that are similar in properties or also are equal and individually examined, checked and finally to the final products need to be put together. If the test shows that any of the parts are ejected must be taken out immediately, or marked, or a record manufacture in such a way that this part is not used in the manufacture of a product may be. Furthermore, it is advantageous to use the parts by means of automatic devices check and handle, but always in such a way that the parts are not damaged will.

The particular technology to which the present invention relates is the production of miniaturized electronic circuits as semiconductor wafers, which are then divided into individual chips. Such plates or discs are generally made flat in the shape of pancakes but mechanical properties similar to those of glass. The individual chips are so small that they are extremely difficult to manipulate by hand or by machine.

It is therefore the aim of the present invention to provide a method and specify a device for making, testing and assembling small parts, who work effectively and economically.

In particular, it is the aim of the present invention to provide semiconductor chips, as required for miniaturized electronic circuits, quickly, reliable, economical and with as little probability of damage as possible to be able to manufacture, test and process.

According to the present invention, a number are handled small parts in one production run by spacing the parts apart arranged on the top of a stretched elastic membrane and on this individually specifies. In this way a group arrangement of known configuration is obtained, as a result of which each part can be individually identified as it is inspected and inserted into the final product.

The method according to the invention is described in the present case applied to semiconductor chips or dice as used in miniaturized electronic Circuits find use; however, it's not just about testing and that Installation of the chips or cubes, but also applicable to their production. So becomes the flat semiconductor wafer from which the chips or cubes are made should, first placed on the stretched elastic membrane and on it with the glued to the entire surface. So then the slice is cut and taken to the split into individual semiconductor chips while they are attached to the stretched membrane is. The resulting individual chips therefore remain on the membrane in the known spaced assignment adhere and are securely held by her.

Furthermore, according to the present invention, it becomes a single part - for example a semiconductor chip - lifted out of the group arrangement for testing, where the previously stretched: membrane, where the part is, still stretches stronger. At the end of the test, the membrane is left in its previous position Return position so that the chip is in its previous position in the array resumes.

The present invention further provides an apparatus for a while laying stretched membrane along a circular part of the same one selected part of the membrane from the plane of said circular part highlights. According to the present invention, this technique is not just used for investigating and measuring the parts, but also used later when the parts are larger Circuit units are inserted.

Fig. 1 is a perspective view of a single semiconductor chip; Figure 2 is a perspective view of a semiconductor wafer from that side forth on which the protruding electrodes or contact lugs are located; Fig. Fig. 3 is a side elevation of the disk of Fig. 2 showing in section an elongated one elastic membrane on which the disc has been placed; Fig. 4 is a side elevation the disc and the stretched membrane in a scribing machine; Fig. 5 is a perspective view the pane after the breaking lines have been marked by the marking machine; Fig. 6 shows the disc and the stretched membrane turned and inserted into a crusher, in which the pane is broken open from the rear will; Fig. Figure 7 is a partial view of the disc showing one of the break lines; Fig. 8 is a Side elevation of the disc and the stretched membrane in a shaker; Fig. 9 is a partial view of the disk corresponding to FIG. 7, but shows the Fracture after removal of the material fragments; Fig. 10 shows the stretched Membrane with the group arrangement on it as well as a special set under it Machine that can be used to lift a specific chip; Fig. 11 is a partial view the machine of Fig.

Figure 10 shows one of the chips lifted for electrical testing; FIG. 12 is a representation corresponding to FIG. 10, but shows a modified one Shape of lifting machine; Fig. 13 is a partial illustration of the machine of Fig.

12 and shows a selected chip that has been lifted and shown in FIG an arrangement is used; FIG. 14 is a representation corresponding to FIG. 13, but with another modification of the hoist; and Fig. 15 is a partial view a stretched membrane with a chip arrangement, in which the chips by sawing, not Breaking were produced.

Preferred Embodiment (Figs. 1-13) Figs. 1-13 represent the presently preferred embodiment of the present invention.

Fig. 1 shows a typical semiconductor chip 10 with a flat Upper side 11 on which the individual electrodes or protruding contact lugs 12a, 12b, 12c, 12d are trained. In the horizontal, the chip 10 has a rectangular shape; however, its vertical thickness (at right angles to the top 11) is substantial smaller than its other two dimensions. If the chip breaks, don't Saw, it has very irregular side edges.

Fig. 2 shows a semiconductor wafer 15 with a flat circular Shape and flat top 16 on which a large number of protruding electrodes or contacts 17 are formed. These protruding contacts are related to rows and Columns arranged for reasons discussed below.

Fixing the disc on the pre-stretched membrane FIG. 3 shows a stretched elastic membrane 20 on a circular holder or frame 21. The membrane or

elastic film 20 is preferably made of natural latex with considerable Extensibility; it preferably takes on its initial state even after considerable stretching back on.

The membrane or film 20 is so large that it is in the stretched state is considerably larger than the disk 15. The holder or frame 21 is general ring-shaped and almost square in radial section (Fig. 3). The holder includes a Groove 23 which runs around its entire circumference.

The membrane 20, after stretching around the sharp edge 22 of the holder and then pulled over the groove 23, where they can be securely held by means of a clamping ring 24 specifies. The clamping ring can be a separate part or part of the membrane self be.

In performing the novel method of the present invention it is necessary to use a stretched elastic membrane such as the membrane 20. The holder 21 with the clamping ring 24 is a convenient means of stretching the membrane State, and allows you to move and manipulate it at will. After the membrane 20 has been stretched onto the holder 21, it remains there throughout the process of the present invention.

Fig. 3 also shows the disc 15 on the pre-stretched membrane 20. Although not specifically shown in the drawing, the disk 15 is with its entire underside glued to the membrane; this should be done with an adhesive choose whose elasticity properties match those of the membrane.

Tearing and breaking open the disc After the membrane is stretched and the disc has been glued onto it, the next step in the process is tear lines in the exposed surface of the disc, by means of a scribing machine 30 as shown in FIG. The machine 31 has a vertical shaft 31, which has a flat round turntable at its upper end 32 carries. On its upper or circumferential surface, the turntable 32 contains a circumferential Notch or shoulder 33, which finally receive the membrane holder 21 flush can. If the holder assumes the position shown, the stretched membrane 20 lies flat and securely on top of the turntable 32. A suction head 34 on top End of the shaft 31 carries the turntable and it contains openings 35 through which an induced draft can be exerted on the membrane.

The machine 30 also has a cutting tool 36 with a diamond tip on; it serves to set up a group in parallel leler break lines 40 to be drawn. After these parallel lines 40 are torn, the shaft 31 and thus also the turntable become rotated around 900; then you tear another group of parallel ones with the tearing tool Break lines 41, which now run at right angles to break lines 40. the Fig. 5 shows how the disc 15 looks after the two groups are parallel or broken lines at right angles to each other have been completed.

As shown in FIG. 5, the break lines 40, 41 are such that they are a Limit the number of chips (for example chip 10 in FIG. 1). So is that Disk surface with the break lines has been divided as described a number of individual chips, which are each identical to the chip 10.

After the break lines have been torn into the pane, like As FIGS. 4 and 5 show, it must be broken from below the break lines will. A special breaking machine 50, as shown in FIG. 6, is used for this purpose.

The holder 21 is turned so that the disc 15 is now from the underside of the membrane 20 depends.

A support 51 has an annular circumferential shoulder 52 which the Retaining ring 21 receives, i.e. - more precisely - that part of the membrane 20, which was previously on the top of the retaining ring, but is now on its underside. An elastic pad 53 is located inside the block 51 and is so thick in the vertical that the disc 15 in particular with the above Electrodes 17 rests on its top.

An arm 54 extends horizontally spaced across the top of the Holder 21 and is weighted with, for example, the weight 55 in a suitable manner. A roller carriage 56 can run along the arm 54. On its bottom the carriage carries a pair of relatively large rollers 57, which are from each other and from the bottom of the arm 54 spaced apart and off. are made of rigid material. A substantial small roller 58 is rotatable on the carriage 56 is rotatably mounted between the rollers 57 and slightly lower than this. Both rollers 57 rest on roller 58 over their entire length; during the sledge 56 runs along on the arm 54, the rotation of the roller 58 causes a co-rotation of idle rollers 57.

The roller 58 is provided to the disk 15 from its back to set out; for this purpose it must have a small diameter and be made from very hard material. While only part of the carriage 56 with one Arm 54 is shown, it will be appreciated that the carriage 56 and breaker roller 58 are long are enough to run over the entire disk 15. A bending of the breaker roller 58 is prevented or at least kept to a minimum by the support rollers 57. the Disk 15 is inserted into breaker 50 so that a group of break lines runs at right angles to the arm 54. When moving the slide along the arm therefore brings the breaker roller 58 a significant downward force on the Slice each over all break lines one after the other so that the slice over breaks through every fault line. The break lines are shown in Figure 6; a typical The breaking line is denoted by the reference numeral 18.

Furthermore, FIG. 6 shows a dashed line 53 'which is exaggerated the indented contour of the top of the elastic pad 53 under the pressure who accepts the crushing roller running over them. Because the elastic pillow is down presses in, the disc 15 can bend so far that it breaks through.

Removal of Broken Fragments Between Chips Fig. 7 shows part of the disc after breaking.

The side 16 of the disc 15 faces downwards; are on this the spaced electrodes 17. The break line 40 was in the area 16 between two of the electrodes were torn. As a result, as shown in Fig. 6, a fracture gap 18, which extends from the fracture line 40 upwards through the entire Thickness of the disc 15 runs. Furthermore, when the disc 15 is broken, a number is of fragments - for example the fragment 19 - which are now in the fracture gap get stuck.

Fig. 8 shows how the broken fragments are removed.

A shaker 60 has a holder 61 similar to the holder 51, which is open in the middle, is running. The holder 21 with the membrane 20 and the chips just formed is set in the holder 61 and an air box 62 arranged at a distance above the holder 21.

The air tubes 63, 64 extend from the air box 62 at an angle to the latter and inclined downwards towards each other. The air box 62 is pressurized with compressed air, which consequently through the tubes 63,64 onto the exposed surface of the membrane 20 flows. The air box 62 is by the recoil of the air jets by a vertical Axis rotated, as the arrow 65 shows. One effect of the compressed air jets is that Pressing the membrane downwards, stretching the gap between the chips to widen; Another effect of the air jets is the membrane and the chips to shake so that they are accelerated out of the cracks. The rotation of the air box ensures that this shaking effect is steady, however occurs irregularly in such a way that eventually all loose fragments fall out.

Figure 9 is a fragmentary view similar to Figure 7 but showing one Fracture gap after the fracture fragments have been removed from it by shaking are.

Lifting a Selected Chip In Fig. 10, the holder 21 and the membrane 20 has again been turned so that they assume their starting position. The membrane now no longer carries a uniform disk 15, but a group arrangement individual chips, which are denoted by the reference numerals 10 ', 10 "and so on.

A lifting device 70 has been placed under the membrane.

The lifting device 70 has a main element 71 with a flat top 72, in which an annular groove 73 is formed, which via an internal channel 74 in Flow communication with an air chamber 75 in the lower end portion of the main element 71 is formed. The air chamber 75 is in turn in flow communication with a connection 76 to which a suction source can be connected, which then Via the connection 76, the air chamber 75, the channel 74 and the annular groove 73 on one circular part of the underside of the membrane 20 can act.

Furthermore, the main element 71 includes a in its upper side 72 Central opening 77. A horizontal relief channel 78 runs between the opening 77 and the exterior of the main element. A plunger 80 is in the central opening 77 used; usually its top face is flush with the top 72 of the main element 71, as shown in FIG. 10.

If a special chip, for example chip 10, is to be selected, the following happens. The lifting device 70 is pushed under the membrane so that the plunger is vertically aligned with the chip 10. Then there is negative pressure over the connection 76 on a round part of the underside of the membrane 20 or, more precisely, on applied a narrow strip, which is circular and the upper end surface the groove 73 corresponds. This suction keeps the mentioned strips the diaphragm when the plunger is later lifted.

The plunger 80 is then raised to the associated part of the diaphragm 20 and thus also to raise the selected chip 10; Fig. 11 shows the chip in raised state. The ram 80 is raised automatically with a lifting mechanism, as shown in FIG. 10, as described below.

The plunger 80 is normally in its lower position (Fig. 10) held by means of helical spring 81, which is inside the air chamber 75 on the plunger is put on.

Over the lower end of the plunger 81 is a floating membrane 82 tensioned, the outer edge between the lower end of the main element 71 and a Cap 85 is clamped at the lower end of the element 71. The cap 85 contains Openings 86 so that a flow communication between the atmosphere and a internal chamber 87 arises in the cap. The chamber 87 thus consistently leads atmospheric pressure.

If suction is at connection 76, there is also air chamber 75 as well a negative pressure in the annular groove 73. The same process, as a result, the membrane 20 is held on the annular groove 73, so also causes a pressure difference between the two sides of the movable membrane 82, hence the plunger 80 runs upwards. The negative pressure that is required to create the annular part holding the diaphragm is considerably weaker than driving the plunger upwards required so that these two operations are always in the desired order expire.

Electrical test As FIG. 11 shows, when the Chips 10, that part of the pre-stretched membrane 20 lying within the suction ring 73 stretched even further. The chip 20 is opposite the adjacent chips 10 ', 10' ' has been increased significantly. These two chips are now at an angle, as a result the adjoining chip edges separate from one another. The flat contact plates 90.91 of an electrical test instrument can therefore be applied to the upper ends of the electrodes 12 of the chip 10 are placed. Although FIG. 11 only shows two such contact plates shows, it can be seen that there are actually four of-them, i.e. one each per electrode 12. The test instrument (not shown separately) can be used to measure the Measure the electrical properties of the chip 10.

Return to the starting position After the electrical test is finished the chip 10 is returned to its previous position in the group arrangement, as Fig. 12 shows. This is done by reducing the negative pressure so that the The plunger 80 can return to its rest position under the tension of the spring 81. This The process can be supported by applying compressed air to connection 76. Of the That is, part of the diaphragm 20 located within the suction ring 83 contracts and increases to its original stretched state again. The original distance mapping between the chip 10 and the other chips of the array becomes complete restored.

Precise movement of the chip 10 is achieved in the following manner. The plunger 80 is hollowed out to form a chamber 80a (FIG. 10), which extends over its entire length Length runs and opens at its upper end. Near his lower one end the plunger 80 includes a laterally extending channel 80b that provides a flow connection between the chamber 80a and the air chamber 75 establishes. If the chamber is 75 with When negative pressure is applied, this acts through the chamber 80a on the underside of the membrane 20 immediately below the chip 10. A lateral displacement of the chip 10 relative to the upper end of the plunger 80 is prevented in this way.

The concentric position of the suction ring 73 with respect to the chip 10 is very essential, since symmetrical forces arise when the membrane is stretched and therefore the chip 10 is held precisely in the lateral target position.

Raising the Chip Again Fig. 12 shows a modified form 100 of the membrane handling device used when the chips are in electrical Circuit arrangements are to be inserted. The flat top 72, the suction groove 73, the channel 74, the air chamber 75 and the external connection 76 correspond to those the version of the device explained above, as well as the lower end cap 85 with the air channels 86 and the chamber 87 and the movable membrane 82. Also the central opening 77 is essentially the same as above but with one difference. There is no laterally running channel 78 here. Contains in its place the main element 101 has a laterally running channel 102 at a different location. In particular, the piston 110 is wide at the lower end and narrow at the upper end, the two sections merging into one another at a circumferential shoulder 111. In the lower or retracted position of the plunger or piston - compare Fig. 12 - the channel 102 is in flow communication with the above shoulder 111 Central opening 77. With a short further upward movement of the plunger runs but the shoulder on the canal 102 over, which is consequently locked will.

Here, too, the plunger 110 contains the air chamber 80a and its connecting channel 80b. Another lateral channel 112 is provided, which is far enough below the lateral channel 102, but also so far enough above the air chamber 75 that Normally no air can pass through it to the inner chamber 80a. The central opening However, 77 is widened at one point in its inner surface by an auxiliary channel 77a, which runs in the longitudinal direction of the plunger or piston 110. Will the plunger 110 now raised further after the channel 102 has already been closed, After a further short stroke length, the lateral channel 112 enters into flow connection with the lower end of the auxiliary channel 77a, so that negative pressure through the connection 76, the air chamber 75, the channel 80b, the air chamber 80a, the channel 112, the channel 77a and the central opening 77 can reach the underside of the membrane 20. It arises so an inner vacuum ring on the circumference of the central opening 77, which is also concentric as the suction ring 73 already described runs and roughly with the lateral Boundaries of the chip 10 covers.

Insertion into a circuit The machine used to insert the part in a circuit arrangement works as follows. If there is negative pressure at port 76, the membrane 20 is held along the ring 73, -the same below the Chips 10 through the open top of plunger 110. Due to the pressure difference The plunger 110 runs upwards over the movable membrane 82, and after a short time Stroke the relief channel 102 is closed. The parts are at this point in time the arrangement (not shown separately) so that the chip 10 and the chips 10 ', 10 '' have been slightly raised at their edges. With further upward movements of Tappet 110 comes the channel 112 in flow connection with the channel 77a, so that a negative pressure acts in the inner suction ring 77, as a result of which the adjacent Chips 10 ', 10' 'supporting part of the membrane is pulled down again so that they again rest on the top of the support elements, as FIG. 13 shows.

The chip 10 is completely free and separated from its neighbors, so that it can be inserted into the circuit.

As FIG. 13 shows, the chips 121, 122 are previously on the underside of a substrate 120 has been applied. The chip 10 is now in the target position between the chips 121, 122 inserted, with its electrodes the bottom of the element 120 touch; it is now in the target position in which it can be set. A laser beam 125 incident from the top of the substrate 120 provides the thermal energy to make the desired connection. The chip 10 is then from the carrier or

the membrane 20 is removed or released, which then returns to its normal position returns. The chip 10 is preferably released by applying the negative pressure maintains on the underside of the membrane but lifts the substrate away vertically, so that the chip already attached to the substrate tears off the membrane.

Alternative Embodiments FIG. 14 shows the chip 10 by means of a heat-pressure device 135 is welded to the substrate 132. The construction the handling device corresponds to that of FIGS. 12 and 13, but with a with the air chamber 80a of the plunger concentric tube 130 a jet of cooling water is directed towards the underside of the membrane 20 immediately below the chip 10.

15 shows an alternative to the method according to the invention; the chips are then cut along the dividing lines 140 using a saw separated from each other by breaking the disc.

Claims (14)

Claims method for converting a semiconductor wafer to a group arrangement of individual chips, thereby g e -k e n n n z e i c h n e t that you choose an elastic membrane, stretch the membrane and move it along her Fixed to a fixed bracket, the disc on top of the pre-stretched Applying the membrane and placing it with the entire underside on top of the pre-stretched Membrane glues, then while it is fixed on the pre-stretched membrane, the disk along two groups of parallel lines to form an arrangement of individual ones Chips and finally lifts a selected part of the pre-stretched membrane and further stretches to a selected one of the chips beyond the array to raise. 2. The method according to claim 1, characterized in that g e k e n n -z e i c h n e t that when the chosen chip has been lifted, its electrical properties checks. 3. The method according to claim 2, characterized in that g e k e n n -z e i c h n e t that after the selected chip has been tested, the selected part of the Membrane ~ releases so that the selected chip is in its previous position in the group arrangement returns. 4. The method according to claim 3, characterized in that g e k e n n -z e i c h n e t that the previously tested chip can be returned to the group arrangement after it has been returned is, raises again, inserts it into electrical circuitry, and then detaches from the membrane. 5. The method according to claim 4, characterized in that g e k e n n -z e i c h n e t that the selected chip is inserted into an electrical circuit arrangement by it is brought into contact with part of the circuit arrangement and a laser beam directed from the other side of the part onto the chip, so that the part heats up and thereby the chip is attached to him. 6. The method according to claim 1 or 2, characterized g e k e n nz e i c h n e t that after lifting the chosen chip, you put it in an electrical one Inserts circuit arrangement and then releases it from the membrane. 7. The method according to any one of the preceding claims, characterized g e k e It is not noted that after placing the disc in a group arrangement individual chips has broken open the pre-stretched membrane by means of negative pressure engages their underside along the perimeter of a selected surface area the top of which is a chosen one of the chips. 8. The method according to claim 7, characterized in that g e k e n n -z e i c h n e t that the selected part of the membrane is lifted by lifting it in its center and at the same time on their underside along the circumference of the central part with negative pressure attacks so that it is held there against an upward movement. 9. The method according to claim 1 for the production and handling of chips in the production of miniaturized electronic circuits, in which one initially forms a flat disk, one flat surface of which has a plurality protruding from contact lugs, then the disc to a number of individual chips divided with at least two such contacts, then each chip individually checks and finally inserts selected chips into electrical circuits, thereby it is indicated that the selected elastic membrane is larger than that Disc is and you hold it in the stretched state essentially horizontally, the disk on top of the pre-stretched membrane with the contacts facing up hangs up, lifts the selected chip and the connections on its protruding contacts to check its electrical properties, manufactures the selected part of the membrane returns to its original position in such a way that the selected chip is in its original position in the group arrangement reassumes, lifting other parts of the diaphragm to others To lift and test chips, and after that the chosen part of the membrane again to lift the selected chip as well, and then the selected chip in inserts an electrical circuit arrangement. 10. The method according to claim 9, characterized in that g e k e n n -z e i c h n e t that when the selected part of the membrane is to be raised, a negative pressure on the underside of the membrane around a circular part of the same, which is concentric with the selected part of the membrane. 11. Device for handling a stretched horizontal elastic Membrane from its underside, not shown by a support element with a flat top, which lie against the underside of the membrane from below lets, wherein an annular groove is formed in the flat top, by means for applying a negative pressure to the annular groove, around a corresponding annular To grasp part of the underside of the membrane through a central opening in the bearing element, which is concentric with the annular groove, one located in the central opening Plunger and a selectively operable device which raises the plunger so that an associated part of the membrane is raised relative to the annular part. 12. The apparatus of claim 11, g e k e n n -z e- i h n e t further by means for applying a negative pressure to the periphery of the central opening. 13. Apparatus according to claim 11 or 12, characterized in that it is -k e n n z e i c h n e t that the device for lifting the plunger by the device, which applies a negative pressure to the annular groove, is actuated. 14. The apparatus of claim 11, 12 or 13, g e -k e n n z e i c Furthermore, by means of a device for applying negative pressure to the circumference the central opening.