EP1974368A1

EP1974368A1 - Apparatus and method for transferring a plurality of chips from a wafer to a substrate

Info

Publication number: EP1974368A1
Application number: EP06830592A
Authority: EP
Inventors: Volker Brod
Original assignee: Muehlbauer GmbH and Co KG
Current assignee: Muehlbauer GmbH and Co KG
Priority date: 2006-01-17
Filing date: 2006-12-13
Publication date: 2008-10-01
Also published as: DE102006002367B3; WO2007082611A1; WO2007082611B1; US20090297300A1

Abstract

The invention relates to an apparatus and a method for transferring a plurality of chips (6) from a wafer (1) to a substrate, in particular a web (15), wherein at least one first wheel (2) or at least one first roller for successively picking up the chips (6) on its outer circumference (3) by means of a rotational movement (5) of the first wheel (2) or the first roller is provided.

Description

Apparatus and method for transferring a plurality of chips from a wafer to a substrate

description

The invention relates to an apparatus and method for transferring a plurality of chips from a wafer to a substrate according to the preambles of claims 1 and 14.

In the production of wafers, in particular silicon wafers, which have a multiplicity of chips lying in one plane, the wafers are cut up in chip size. The individual chips then still stick to one of their surfaces on a common substrate film and, as a rule, have electrical connections in the form of bumps on the opposite free surface. These first bumped surfaces of the chips must be turned down by means of a flip process of the chip in order subsequently to deposit the chip on a web or card on which further contact connections for contacting the chip with further components, such as antennas, for example , are arranged.

Such flip-chip processes are time-consuming, since, for example, by means of a pipette-like device for generating a vacuum, each chip is picked up or picked from the wafer, then a turning of the chip must take place through 180 ° in order to turn the contact connections from top to bottom, then a transport of the chip and a measurement process of the chip geometry to a mounting axis on which a web is arranged with a plurality of antennas or cards must be made. A measurement of the chip geometry is necessary for this, in order subsequently to fit the chip in a suitable configuration. Taktierungsposition opposite contact terminals, which are already arranged on the web or the substrate material store.

For the required mounting precision of the contact connections arranged on the web or the substrate material, the contact surfaces are measured geometrically prior to the contacting process and bonding process (bonding process) in order to precisely deposit them by means of the likewise measured coordinates (x, y and Phi) of the chip of the chip to reach the bonding position of the web or the substrate material.

In order to carry out such a sequential linking of a plurality of steps belonging to the bonding process, parallelization by means of arranged multi-axis systems is frequently desired. As a result, the throughput of the entire device can be increased, even if it is time-consuming bonding process procedures. However, such a parallelization usually requires the arrangement of long transport paths and the execution of several multi-axis systems. This leads to high manufacturing and operating costs.

Accordingly, it is the object of the present invention to provide an apparatus and a method for transferring a plurality of chips from a wafer to a substrate, in particular a web, in which, while avoiding long transport paths, a shortening of Chip mounting times can be achieved.

This object is achieved on the device side by the features of patent claim 1 and on the method side by the features of patent claim 14.

An essential point of the invention is that in the apparatus for transferring a plurality of chips from a wafer to a web at least a first wheel or at least a first roller for successively receiving the chips on the outer circumference thereof by means of a rotational movement of the first wheel or the first roller is arranged. The arrangement of such a wheel allows a continuously continuous or discontinuous with short pauses recording of the chips, which are arranged within a plane in the wafers and a simultaneous deposition of the chips on the opposite side of the wafer of the first wheel and the first roll on a another wheel or a linear element with a linear surface che. Thus, there is a substantial time saving between the actual picking process corresponding to the picking operation of the wafer and the depositing operation of the chips on the web, which may include antennas, for example for the production of smart label inlays due to the application of a Rotartoric Procedure instead. This makes it possible to increase the throughput of the entire chip-mounting device while saving the previously necessary long transport path and thus rapid production of chips having transponders, cards, etc. per unit time.

Preferably, at least one second wheel or at least one second roller is used to successively receive the chips arranged on the outer circumference of the first wheel / roller by means of a rotational movement on the outer circumference of the second wheel / roller and thereby to a flip process to reach. Thus, advantageously, each chip is reversed quickly and easily in a continuous process, without requiring manufacturing and costly constructions to perform a 180 ° turn of the chip.

By means of the second wheel or the second roller, the chips can be deposited successively on the web either directly in the area in which the antenna connection surfaces of the antennas already arranged on the web are arranged, or indirectly via a displacement of the second wheel or several wheels axial direction laterally to a Radi- alrichtungsebene of the first wheel such that after a successful displacement movement of the second wheel a laterally spaced from the first wheel web is fitted.

Ideally, at least two second wheels / rollers are shifted left and right sides left and right with respect to the radial direction plane of the first wheel and are alternately arranged above the first wheel for receiving the individual chips from the first wheel to the second wheel. This allows rapid transfer of the chips from the first wheel to the substrates to be populated, such as webs.

According to a preferred embodiment, each chip is retained on the first wheel / the first roller on its first surface by means of a respective vacuum-activating first element. At the second wheel / roller, each chip is retained on its second surface opposite the first surface by means of a vacuum-activating second element. - A -

The vacuumizing acting second elements are displaceable in the radial direction of the wheel / the roller and optionally druckbeaufschlagbar designed to exert a pressure for establishing a contact between the chip and the contact terminals of the antennas on the chips when depositing the chips on the web.

In addition, the first and the second vacuumizing elements are rotatably mounted about an axis extending in the radial direction of the wheel / roller in order to obtain an optimized alignment of the chips adhering to these elements also with respect to their rotational position.

For example, a so-called nanobond technology that produces a permanent contact connection by simply pressing the chips onto the contact surfaces of the antennas can be used by the pressurizable, vacuum-acting second elements on the second wheel / roller. This is achieved by the formation of existing on the antenna and the chip contact surfaces as a self-guiding smallest hairs and self-conducting smallest eyelets, which represent, for example, the antenna pads. Here, the contact surfaces are designed as large as possible.

The chips are thus mounted in the chip assembly by simply placing it and simply pressing on the antenna contact terminals and at the same time electrically contacted with these contact terminals. As a result, the previously used anisotropically conductive adhesives for producing a permanent contact between the antenna contact surfaces and the contact surfaces of the chip or the chip module, which usually require a curing time of several seconds, are unnecessary. Such curing time would in turn reduce the throughput of the entire device. Thus, through the combination of nanobond technology in conjunction with rotational extraction of the individual chips from the wafer, a high throughput device is obtained.

In principle, in order to increase the throughput of the entire apparatus, ie to increase the number of chips during a chip mounting process within a predetermined time, a plurality of first wheels or first rollers can be guided in parallel and independently operable over the wafer and equipped with chips. Likewise, several can Second wheels / second rollers are used as flip-chip printing wheels or flip-chip pressure rollers for performing the flip process.

As an alternative to the second wheels / second rollers, the use of at least one linear element is conceivable which comprises a plurality of third-order vacuum-effecting third elements arranged on a generally linear surface for successively picking up the chips arranged on the outer circumference of the first wheel / roller second surface by means of a sliding movement in the longitudinal direction linear element has.

The linear element, which is present, for example, as a bar-like linearly designed transport element can store a linear flip-chip printing process either several chips that depend on the third elements, parallel on the web or store the chips one after the other.

A parallel deposition of the chips is appropriate, provided that the tolerances of the contact surfaces of the chips and the antennas are large. For this purpose, a discontinuously performed placement, so a brief stoppage of the web for storage of the individual chips on the antenna contact pads, offers.

In contrast, when using at least one second printing wheel or a second pressure roller, a continuous continuous weaving band is preferably used, since this enables a continuous application of the individual chips on the web due to the rotational movement. Alternatively, here as well a discontinuous application of the chips in such a way that the web is briefly stopped for each chip can be carried out.

The third vacuum-acting elements are in turn also displaceable and possibly pressurizable, this being done in a direction perpendicular to the longitudinal direction of the linear element. Likewise, the third vacuumizing elements can be rotated about an axis extending perpendicular to the longitudinal direction of the linear element in order to obtain an optimized alignment of the chip with respect to contact connections of the antennas on the Web. A method of sequentially transferring a plurality of the chips from the wafer to the web advantageously uses rotational movement of the first wheel / roller to receive the chips from at least one of the first wheels or at least one of the first rollers on its outer periphery and thereafter from the first wheel to the outer periphery of a second wheel / roller or the surface of at least one linear element. For this purpose, the vacuumizing elements on the outer circumference of the first wheel, the second wheel and the surface of the linear element are arranged as close as possible behind each other, wherein the distance between the first and second elements on the first and second wheel may differ from each other, thereby optionally desired Speed matching on the deposition process of the chips on the substrate material, such as a web or maps to achieve.

If two or more second wheels or two or more second rollers are used, they are alternately pushed back and forth to the transfer position of the first roller, and then perform the assembly of the arranged on the web antennas with the chips.

All vacuumizing elements engage contactless areas of the surfaces of the chips to avoid damage to the contact surfaces. This can be done, for example, by touching a surface of the chip between two contact surfaces of a pipette-like vacuum device.

Further advantageous embodiments will become apparent from the dependent claims.

Advantages and expediencies can be found in the following description in conjunction with the drawing. Hereby show:

1 shows a schematic representation of the device according to the invention GE measured a first embodiment of the invention;

FIG. 2 shows a schematic representation of the device according to the invention in accordance with a second embodiment of the invention; FIG. 3 shows a schematic representation of the device according to the invention in accordance with a third embodiment of the invention; and

4 shows a schematic representation of the device according to the invention in accordance with a fourth embodiment of the invention.

In Fig. 1, we are shown in a schematic representation of the device according to the invention according to a first embodiment of the invention. As can be seen from this illustration, chips 6 are taken from a wafer 1 with a multiplicity of chips arranged thereon by means of a rotating first chip receiving wheel 2 with an outer circumference 3 and individual vacuum-effecting first elements 4 arranged thereon. The direction of rotation of the first wheel 3 is represented by the reference numeral 5. For picking the individual chips from the wafer, for example, known methods such as an ejector needle for releasing the chips from the underlying substrate film may be used.

The vacuum-insulating elements 4 arranged at high density on the outer circumference 3 of the first wheel 2 make it possible for a large amount of chips (dice) to be transferred from the wafer to the chip-receiving wheel 2 by its rotational movement 5. Here, the chips 6 between the chip pads 7, which are arranged on a first surface 8 of the chip, held, as shown by the left of the first wheel 2 enlarged reproduction of the chip in its arrangement on the outer circumference 3 of the first wheel 2 is shown.

At the same time as the removal of the individual chips from the wafer 1, a transfer of individual chips 6 to a second wheel 10 takes place on the opposite side of the first wheel 2 such that the chips no longer communicate with the first surface 8 but with their second one Surface 9 by means of second vacuumizing acting elements 14 which are arranged on the outer periphery 12 of the second wheel 10, are held. The rotational movement of the second wheel 10 is represented by the arrow 1 1. An exact tuning of the running speeds of both wheels 2, 10 should be such that an exact recording of the individual chips 6 by the second vacuumizing elements 14 to avoid damage to the contact surfaces 7 is possible. This resulting from the interaction of the two wheels 2, 10 flip process of the individual chips can be used to easily and quickly by means of a rotational movement of both wheels, the individual chips 6 from the wafer 1 to a Web 15, which is in the direction of the 16th preferably continuously or discontinuously moved to transfer.

On the web 15 individual antennas 17 are arranged. The web 15 is after the successful placement process by a transfer of the arranged on the outer circumference 12 of the second wheel 10 chips on the web on a dedicated wheel 18, which turns along the arrow 19 wound. In this case, the chips on the outer periphery of the second wheel 10 at the time of transfer to the web 15 have a position that causes the second elements 14 to engage the second surface 9 of the chip. Thus, a mechanical and conductive connection of the contact surfaces 7 of the chip and the contact surfaces of the antennas 17 not shown here is possible by simply pressing the chips 6 onto the antenna contact surfaces. This is done by a displacement and pressurization of the second vacuumizing elements 14 in the radial direction of the wheel 10th

A synchronization between the alignment of the individual chip contact surfaces 7 and the contact surfaces (bond pads) of the antennas, not shown here, is achieved by means of optical sensors and a position correction of the second vacuum-effecting elements and the variation of the rotational speed of the flip-chip pressure wheel 10 reached. For this purpose, the optical sensors are arranged in a chip inspection device 13 for measuring the chip position. The web speed of the web or the band can be kept constant or changed here.

As an alternative to a continuous belt, a discontinuous belt may be used to control the positioning synchronization so that the chips are loaded in a stop-and-go process.

The highest possible throughput of the device according to the invention, ie the highest possible speed of the chip-mounting process is achieved when both wheels 2, 10 rotate continuously without being stopped. Alternatively, the wheels can be discontinuously moved, so alternately stopped and moved on.

A parallelization of the method described in this figure and the device associated therewith is conceivable for increasing the throughput of the entire device, in that the removal of the chips from the wafer is effected by a plurality of chip receiving wheels arranged parallel to one another. Likewise, a plurality of second wheels 10 take over the chips picked up by the first wheels and provide a wide multi-lane web-equipped with antennas with chips at the same time.

In Fig. 2, the device according to the invention according to a second embodiment of the invention is shown in a schematic representation. This embodiment shown in FIG. 2 differs from the embodiment shown in FIG. 1 in that the second wheel 10 is displaced along an axis 20, as represented by reference numeral 21. As a result, the second wheel 10 is a locally spaced mounting axis, on which the web 15 is arranged, supplied, wherein the chip inspection, so the measurement of the chip position by means of the device 13 takes place at the location of the mounting axis. Once again, the individual chip positions relative to the first and second vacuumizing elements 4, 14 are shown enlarged in separate views.

In Fig. 3, the device according to the invention according to a third embodiment of the invention is shown in a schematic representation. This embodiment differs from the embodiment shown in Fig. 2 in that not only one but two or more second wheels 10, 10a, 10b are used to be shifted alternately to the first wheel 2 for receiving the chips, as by the arrows 21 a and 21 b is reproduced. For this purpose, axes 20a and 20b are used. In this way it is possible that after previous measurement of the chip positions according to the devices 13a and 13b, two antenna webs 15a and 15b can be populated almost simultaneously. This results in a higher throughput since the antenna webs 17a and 17b are associated with the two or more second wheels 10a and 10b operating separately from each other. Likewise, there are two or more existing for the web take-up wheels 18a and 18b. The webs as the substrate material are preferably moved continuously along the arrow directions 16a and 16b. Thus, for example, that period of time during which the second wheel 10a deposits the chips on the antennas 17a may be used to populate the second wheel 10b with chips 6 currently located on the first wheel 2 loaded.

FIG. 4 shows a schematic representation of the device according to the invention in accordance with a fourth embodiment of the invention. If the reference numbers reproduced in this figure correspond to the reference numbers reproduced in the remaining figures, these are the same or equivalent components.

Again, the chips are picked up by the chip pick-up wheel 2 in a position as shown enlarged on the left side of the wheel, and then to third vacuumizing elements 23 attached to a linear beam-shaped element 23 a surface 22 a are transmitted. For the representation of the transmission process, the first wheel 2 is shown again stylistically below the third vacuumizing elements 23, which is one and the same wheel 2.

The vacuumizing third elements 23 hold each chip on the second surface 9, which is opposite to the surface 8 containing the chip contact surfaces 7. As a result, a flip process of the individual chips 6 is already carried out without having to use another second wheel. Subsequently, a displacement of the third elements takes place along the direction of the arrow 24, in order thereby to obtain a position in relation to a multi-track antenna-equipped web 26.

A chip inspection device 25 in turn monitors the positioning and the measurement of the chip alignment. Optionally, the individual third vacuumizing elements 23 are rotated by a rotation about an axis which is perpendicular to the linear element 22, and then driven by means of a pressurized displacement movement down to the here in a transferred manner from above web to the chips on it to take off and align it. The antennas 28 are thus - if a simultaneous depression of the elements 23 happens to be equipped at the same time with the chips 6 within a row and the web 26 is then pushed according to the direction of arrow 27 by a row forward. Thus, a parallel assembly of 1 n rows is possible.

Again, in order to increase the throughput of the entire system, a parallelization of a process represented in this way can be achieved by means of devices arranged in parallel within a chip assembly system.

The laying down of the chips on the web 26 takes place either sequentially, ie one after the other, or in parallel.

Such a linear element is also called a flip-chip print axis. Such flip-chip axes can be used for simultaneous or sequential placement of multiple rows on the antenna web 26.

All disclosed in the application documents features are claimed as essential to the invention, provided they are new individually or in combination over the prior art.

Claims

claims

1. Device for transferring a plurality of chips (6) from a wafer (1) to a substrate, in particular a web (15), characterized by at least one first wheel (2) or at least one first roller for successively picking up the chips (6 ) at its / its outer periphery (3) by means of a rotational movement (5) of the first wheel or the first roller.

2. Apparatus according to claim 1, characterized by at least one second wheel (10) or at least one second roller, the / the outer circumference (12) on the outer circumference (3) of the first wheel (2) / the first roller arranged chips ( 6) successively receives by means of a rotational movement (11), and on a first surface (8) with contact surfaces (7) opposite the second surface (9) rotates rotated by 180 °.

3. A device according to claim 2, characterized in that by means of the second wheel (10) or the second roller, the chips (6) can be deposited successively on the web (15) by means of a continuous depositing operation.

4. Device according to claim 3, characterized in that the second wheel (10) / the second roller is axially displaceable on the web (15) before the chips (6) are deposited.

5. Device according to one of claims 2-4, characterized in that two second wheels (10a, 10b) / two second rollers on the left and right sides relative to the radial direction plane of the first wheel (2) / the first roller are displaceable.

6. Device according to one of claims 2-5, characterized in that on the first wheel (2) / the first roll each chip (6) on its first surface (8) by means of a respective vacuum-acting first element (4) can be fastened ,

7. Device according to one of claims 2-6, characterized in that on the second wheel (10) / the second roller each chip (6) on its second surface (9) by means of a vacuumizing second element (14; 14a; 14b) can be fastened.

8. Apparatus according to claim 6 or 7, characterized in that the vacuumizing second elements (14; 14a; 14b) in the radial direction of the wheel (10) / the roller are displaceable and optionally druckbeaufschlagbar.

9. Device according to one of claims 6-8, characterized in that the vacuumizing elements (14; 14a, 14b) are rotatably mounted about an axis extending in the radial direction of the wheel (10) / the roller axis.

10. The device according to claim 1, characterized by at least one linear element (22) on a surface (22 a) a plurality of series arranged vacuumizing third elements (23) for successively receiving the on the outer circumference (3) of the first wheel (2) / the first roll arranged chips (6) on its second surface (9) by means of a sliding movement (24) in the longitudinal direction of the linear element (22).

11. The device according to claim 10, characterized in that by means of the linear element (22) the chips (6) successively or simultaneously on the web (26) can be stored.

12. The device according to claim 10 or 11, characterized in that the third vacuum-acting elements (23) perpendicular to the longitudinal direction of the linear element (22) are displaceable and optionally druckbeaufschlagbar.

13. Device according to one of claims 10- 12, characterized in that the third vacuum-activating elements (23) are rotatably mounted about a perpendicular to the longitudinal direction of the linear member (22) extending axis.

14. A method for transferring a plurality of flip chips (6) from a wafer (1) to a substrate, in particular a web (15), characterized in that the chips (6) of at least one first wheel (2) or at least a first roller on its outer periphery (3) by means of a rotational movement (5) of the

Rades (2) / the role to be recorded successively.

15. The method according to claim 14, characterized in that the chips (6) from the first wheel (2) / the first roller on an outer periphery (12) of at least one second wheel (10) / at least one second roller are transmitted.

16. The method according to claim 15, characterized in that the second wheel (10) / the second roller after transfer of the chips (6) axially displaced (21).

17. The method according to claim 15, characterized in that two second wheels (10a, 10b) / two second rollers after transfer of the chips (6) are displaced axially in the opposite direction (21a, 21b).

18. Method according to claim 14, characterized in that the chips (6) are transferred from the first wheel (2) / the first roller to a linear surface (22a) of a linear element (22).

19. The method according to any one of claims 14- 16, characterized in that the chips (6) on the outer circumference (3) of the first wheel (2) / the first roller by means of first vacuum-acting elements (4) with their first surfaces (8) and on the outer circumference (12) of the second wheel (10) (wheels (10a, 10b)) of the second roller (s) by means of second vacuumizing elements (14; 14a; 14b) and on the linear surface (22a ) of the linear element (22) are held by means of third vacuum-effecting elements (23) with their second surfaces (9).

20. The method according to claim 19, characterized in that the vacuumizing elements (4; 14; 14a; 14b; 23) touch the chips (6) in the non-contact region of the surfaces (8,9) of the chips (6).

A method according to any one of claims 14-20, characterized in that the web (15; 15a; 15b) is continuously fed during transfer of the chips (6) from the second wheel (10; 10a; 10b) / of the second roller or the linear element (22) on the web (15; 15a; 15b; 26) is moved or stopped for a short time.