WO2005015611A2

WO2005015611A2 - Device for stabilising thin discs

Info

Publication number: WO2005015611A2
Application number: PCT/EP2004/051399
Authority: WO
Inventors: Gerhard Pucher; Martin Matschitsch; Herwig Feichter; Paul Ganitzer; Johann Hallegger
Original assignee: Infineon Technologies Ag
Priority date: 2003-08-08
Filing date: 2004-07-07
Publication date: 2005-02-17
Also published as: EP1652228A2; WO2005015611A3

Abstract

The invention relates to a device for stabilising thin discs, in particular, for thin wafers (1), arranged on the circumference (2) of the thin wafer (1) as a support, the cross-section of which is formed from a profile (4) and the outer contour of which projects, at least slightly, over the thin wafer (1).

Description

description

Device for stabilizing thin slices

The present invention relates to a device for stabilizing thin slices, in particular to a support frame for thin wafers according to the preamble of claim 1.

The technological advantages of thin wafers are offset by difficult production conditions because thin wafers lose their mechanical stability and are less or more bent depending on the silicon thickness. Loads caused by transport or processing thin wafers easily lead to wafer breakage and possibly total failure, which is explained as follows:

Such thin semiconductor wafers or wafers have a diameter in the order of 2 to 8 inches, for example disk thicknesses which are in the order of a few 10 to a few 100 μm. Such semiconductor wafers have so far mostly been moved manually or with a handling system from a first processing location to a second processing location. In practice, for example, thin grinding unwantedly produces semiconductor wafers that contain both concave and convex curvatures. These semiconductor wafers can no longer be handled without problems by the handling system. Therefore, they are generally removed manually from a corresponding container using special tweezers and placed in a so-called quartz boat for further processing, for example. A quartz boot is a specific storage cassette for semiconductor wafers. However, the use of tweezers is not without problems, since this easily leads to partial damage, such as the occurrence of Hairline cracks and thus lead to chip failure in the corresponding area of the semiconductor wafer.

The removal or insertion of mechanically weakly loaded wafers from or in material carriers (the quartz boats, plastic orders or the like mentioned above) must also be done without edge contact with these containers, since edge contact damages both the thin wafers and the containers would, because such thin wafers are razor blades similarly sharp.

By selective uptake by conventional special ^¬ tweezers, the thin wafer is not sufficiently supported. Therefore, a wafer handled in this way tends to oscillate slightly beyond the problems already mentioned. Wafer bending - caused by tensioning the wafer - makes it difficult for the operator to mount and dismount. The sharp edges of the wafers cut into the material slots in the narrow slots of the containers and this inevitably leads to breakage of the wafer and damage to the container.

A so-called pneumatic tweezers for handling thin wafers is known from DE 199 48 572 AI. The tweezers shown and described there have a plate designed as a nozzle plate, which has a vacuum bore in its center and which contains numerous nozzle bores on the circumference, which are used to produce a so-called Bernouli pincer, which is also known as the Bernoulli effect is. This Bernoulli effect is to be understood to mean the formation of a hydrodynamic negative pressure, which arises from the fact that gas flows from the center of a nozzle plate through outward-directed nozzles into the edge areas of the nozzle plate and a lower air pressure in the center prevails than in the outside areas, in which the gas from

Center flows out. Thin wafer slices can be handled relatively well with such pneumatic tweezers, the function of which is based on the above-described effect, since the combination of the Bernoulli effect and vacuum as contactless holding elements for wafer slices has decisive advantages.

Despite this relatively good handling, it is difficult to manually store or remove thin wafers from various material carriers such as trays, boats and the like. Although loading and unloading is only carried out by specially trained personnel, the breakage rate during manual handling is still correspondingly high, with the majority of the wafer breaks being initiated from the edge. The highly sensitive movements of the individual processes can only be carried out with great personal commitment from the operator. The time required for these operations in manual thin wafer handling is correspondingly high.

Up until now, automatic thin wafer handling had to be dispensed with, since the wafers were neither centered nor leveled - which is also referred to in technical terms as "flattened" - in the material carriers, as a result of which controlled removal of the bent and non-centered wafers was not guaranteed Wafers - this means their predeterminable positioning in a defined position - have so far been carried out using so-called "standard Fiat aligners", which, however, are not suitable for thin wafers.

The present invention is based on the object of providing a device with the aid of which thin wafers can be handled better and, above all, more safely. This object is achieved by a device with the features of claim 1. Advantageous embodiments of the device can be found in the dependent claims.

The particular advantages of the device according to the invention lie in the fact that thin wafers which are flexible per se maintain this property through the new device, but are mechanically reinforced and stabilized by the device. The edges of the thin wafer are protected from damage. The device compensates for voltages in the wafer, so that a planarization effect occurs. Both the front and the back of the thin wafer remain free for measurements and other handling steps, electrical measurements also not being influenced by the device. The transport of individual thin wafers is both manual and with the help of assembly devices, i.e. Vending machines possible. In contrast to other carrier technologies such as foils, the thin wafer can be stored indefinitely because its active surfaces such as the front and back are not contaminated by adhesives or the like

The device according to the invention for stabilizing thin slices is particularly advantageous if on the circumference of the

Dunnwafers a support frame is attached, the cross section of which is formed by a profile, and the outer contour of which at least slightly projects beyond the thin wafer, e.g. in the range from 0.1 millimeter to 1.5 millimeter, in particular in the range from 0.5 millimeter to 1 millimeter.

It is also advantageous if the contour of the support frame is matched to the outer contour of the thin wafer. It is also advantageous if the cross section of the profile of the support frame has the shape of a polygon.

It is particularly advantageous if the polygon is designed as a trapezoid and if the trapezoid is designed asymmetrically. It is also particularly advantageous if the trapezoid encloses two right angles and if the corners of the right angles are essentially designed as broken edges. It is also advantageous if one side of the trapezium is inclined towards the center of the wafer and is formed from a material such as a composite material, this composite material being a highly crosslinked resin with a high degree of filling, e.g. Is carbon fiber and low residual stress on ice.

A device according to the invention can be designed very advantageously if the polygon is designed as a triangle. It is particularly advantageous if the triangle is designed as an equilateral triangle and if one side of the triangle is inclined towards the center of the wafer. It can be beneficial to form the triangle from a material such as quartz glass.

A support frame can also be particularly advantageous if the profile is designed as a right angle with legs of unequal length.

It is advantageous if the longer leg lies in a plane that runs parallel to the plane of the thin wafer and has adhesive openings for receiving adhesive with which the thin wafer is detachably attached to the curved profile.

In addition, it is advantageous if the shorter leg lies in a plane that runs perpendicular to the plane of the thin wafer, and if the outer contour of the shorter leg projects at least slightly beyond the peripheral contour of the thin wafer. A support frame is particularly favorable if the edges of the angle profile are broken, wherein the broken edges can be formed by radii or facets.

A support frame is also advantageous if it is made of metallic or artificial material.

It is also advantageous if the support frame can remain on the thin wafer when it is separated, but even if the support frame is detached from it when the thin wafer is separated, it is of great advantage in the process steps described above.

It is also advantageous if the support frame can remain on it during process steps, such as checking the thin wafer, writing, heating, intermediate storage, if necessary.

The active surfaces - like the front and back - of the thin wafer remain free of contamination despite the stiffening by the support frame without any special and / or additional effort.

Due to the low overall height of the support frame, both manual and automatic handling of the thin wafer is possible. Handling with boats and hordes is also possible.

With the aid of the drawings, the invention is explained in more detail with reference to exemplary embodiments.

FIG. 1 shows a thin wafer with an attached support frame; Figure 2 is a circular support frame in plan view; Figure 3 shows a detail of the support frame of Figure 2; FIG. 4 shows a further detail from FIG. 2; FIG. 5 shows a plan view of a support frame with a flattened portion (Fiat); FIG. 6 shows a detail of a support frame according to FIG. 5; FIG. 7 further details of this support frame; FIG. 8 shows a plan view of a further thin wafer with a support frame; FIG. 9 shows a detail of the thin wafer from FIG. 8; FIG. 10 shows a view of a further thin wafer with a support frame; FIG. 11 shows a side view of the thin wafer from FIG. 10 and FIG. 12 shows a detail of the thin wafer from FIG. 11.

A thin wafer 1 shown schematically in FIG. 1 has a flattened portion, a so-called Fiat 3, on its circumference 2. Such a Fiat 3 serves to align the thin wafer 1 in the individual process steps. Due to its stop surface - which can be placed on a corresponding counter surface of a device - an exact alignment of the thin wafer 1 is always guaranteed. A support frame 4 is arranged on one side - the front side - of the thin wafer 1, which for this reason is intended to carry the technical term "front sidering". It is technically advantageous to arrange the support frame 4 on the front side of the thin wafer 1, ie on the side which forms most of the active components. In an alternative exemplary embodiment, however, the support frame is attached to the rear of the wafer.

FIG. 2 shows a top view of a circular support frame 42. Details of this support frame 42 are shown in FIGS. 3 and 4.

Figure 3 shows a detail, which is a section of the Support frame 42, in which an adhesive bore 52 can be seen. Some of these adhesive bores 52 are attached to the circumference of the support frame 42 in order to connect the thin wafer 1 to the support frame 42, if necessary in a detachable manner.

In FIG. 4 it can be seen in an enlarged detail that the support frame 42 has an angular cross section and is attached to the front side 1F of the thin wafer 1 with the aid of an adhesive K, which is in each case in one of these adhesive holes 52, of which in FIG Figure 4 shows an adhesive bore 52 is shown enlarged. The adhesive holes 52 are arranged in the long leg 4L of the angular support frame 42 at some points distributed over its circumference. The short leg 4K of the support frame 42 forms the outer boundary of the support frame 42 and projects with its outer circumference slightly beyond the outer circumferential edge 2 of the respective thin wafer 1. This forms a shock protection for the sensitive edge 2 of the thin wafer 1.

The adhesive K is selected according to the requirements and it can be advantageous if it can be released by thermal action. However, it is not necessary to release the front face (support frame) 4, 42 after finishing. Since the front side frame (support frame) 4, 42 can be mass-produced in an extremely inexpensive manner, it is particularly advantageous if it is left on the thin wafer 1 until the end of the manufacturing processes and sawed open when the thin wafers are separated, for example by sawing. With this measure, the cheap Frontsidermg (support frame) 4.42 is “sacrificed”, but the handling of the thin wafer 1 remains optimal until the end of the manufacturing processes. 5 shows a further embodiment of a front side ^¬ is rings (support frame) 45 shown schematically. From the ^¬ deviation from the exemplary embodiment according to Figure 2 consists We ^¬ sentlichen that a so-called Fiat is incorporated at a point 35 of the circumference 25, as shown in principle already shown in FIG. 1 Adhesive bores 55 for receiving a suitable adhesive K are located at various points of the support frame 45, which need not be explained further here, since what has been said in relation to the exemplary embodiment described above applies analogously.

FIG. 6 shows an enlarged detail of the support frame 45 from FIG. The transition from the circular periphery 25 of the support frame 45 to the Fiat 35 is shown. An adhesive bore 55 is preferably arranged at this point.

FIG. 7 shows in its sub-figures 7a and 7b a variant of the support profile of the support frame 45, which is indicated by the specification of the section in FIG. 5. In Figure 7a, the edges of the profile of the support frame 45 are provided with facets, in Figure 7b the edges are rounded.

An additional variant of the invention is shown in FIG. A thin wafer 18 is shown schematically in FIG

Top view. The grids of the later separating cuts are indicated. An enlarged detail of the thin wafer 18 from FIG. 8 is shown in the associated FIG. 9. A support frame 49 is attached to the front side 18F of the wafer 18 with the aid of an adhesive K9. This variant of the support frame 49 shows the profile of a support frame 49 which is trapezoidal in cross section. The cross section of the trapezoidal support frame 49 is asymmetrical and an inner surface 49F of the pro Fils of the support frame 49 forms an annular surface 49F facing the center of the thin wafer 18, which is inclined so that the subsequent method steps, for example the photo-technical steps, can take place without hindrance. The photoresist to be applied can be well spun on with uniform homogeneity or an excessive amount can be spun off well. The outer peripheral region of the support frame 49 forms the outer region of the trapezoidal profile. This outer area extends slightly beyond the circumference of the thin wafer 18 and protects it against damage. The profile of the support frame 49 includes two right angles in this area and the edges of the right angles are broken, so that in each case a radius is created which is less sensitive to impacts than sharp edges. However, the basic shape of the polygon is basically retained because a radius is known to be a polygon with an infinite number of corners. Of course, the polygon can also be designed as a trapezoid with other aspect ratios without departing from the inventive concept. However, this construction shown in the exemplary embodiment is preferred.

An implementation can be exemplified with a support frame that protrudes approx. 0.5 to 1mm beyond the wafer edge. The support frame could have dimensions of approximately 0.5 mm in thickness and 2 to 4 mm in width and could be applied to the wafer after the last high-temperature step of approximately 900 ° C., and could then remain on the wafer until it was separated.

The support frame 49 preferably consists of a composite material that is temperature-resistant up to approx. 420 ° C. fibers and low residual stresses. As

Adhesive K9, a material with the trade name "Imid" can be used because its viscosity can be adjusted according to the requirements. When realizing, the skilled person will ensure that the selected composite material is temperature and chemical resistant and the required properties of the thin wafer 18 are not negatively influenced .

The additional variant shown in FIG. 10 shows a further thin wafer 110 with a support frame 410, which otherwise resembles the exemplary embodiments from FIGS. 1 and 5 because it is also shown with a Fiat 310. In this exemplary embodiment, the diameter is 150 mm with a tolerance of 0 to -0.1 mm and is adapted to the diameter of the thin wafer 110 to be protected. With a width of the support frame 410 of 3 mm, its inner diameter is accordingly approximately 144 mm. The Fiat 310 is arranged so that there is a distance of 69.3 mm from the center of the wafer with a tolerance of +0 and -0.1 mm. Alternatively, positive tolerances are chosen.

FIG. 11 shows a highly schematic side view of the thin wafer 110 from FIG. 10, and FIG. 12 shows an enlarged detail from this FIG. 11. The

In this exemplary embodiment, support frame 410 consists of a material such as quartz glass and the polygonal profile cross-section is realized by an uneven triangle. The width of the base of the triangle is 3mm and the height of the triangle is 1mm. The gluing of the quartz glass 410 is advantageously carried out using a silicon adhesive K10 with a layer thickness of 0.1 mm. The width of the adhesive ring is approximately 2.1mm and its distance from the outer edge of the support frame 410 is approx. 0.3mm. Thus, a thin wafer 110 reinforced in this way is inexpensive

Material combination silicon / silicon / quartz glass dimensionally stable and insensitive to temperature fluctuations. Similar to the previous embodiment, that edge of the

Triangular inclined, which towards the center of the Dunnwafer

110 points out. The slope of the outer edge of the support frame

410 to the plane of the thin wafer 110 is 43 ° and the inclination of the inner edge is 26.2 ° to the plane of the thin wafer 110. This results in an annular surface 410F in the case of the rotating body formed by the profile, which faces the center of the thin wafer 110 at an angle of Is inclined 26.2 °. The above figures are for guidance only and can also be chosen differently by a person skilled in the art if the constellation is appropriate.

In other exemplary embodiments, different profile configurations are chosen. The final profile shape will depend on the dimensioning of the support frame 4, 42, 45, 49, 410 and its manufacturing method.

The support frame described here by means of various exemplary embodiments can be used advantageously not only for thin wafers, but also for other thin slices and in general for fragile objects.

The invention also relates to a production method in which the following steps are carried out independently of the listing sequence: provision of a substrate for an integrated circuit arrangement, in particular a semiconductor substrate, materially connecting the substrate to a support frame, in particular to the support frame according to the invention or with a support frame according to an embodiment and in particular by gluing,

- Further processing of the substrate after connecting.

The substrate is preferably thinned before the connection or after the connection, in particular by thin grinding or by wet chemical etching.

The method is particularly effective for thinned substrates, but is also used for undiluted substrates or wafers, in particular for wafers with a diameter of 300 millimeters or more than 300 millimeters.

Claims

claims

1. Device for stabilizing thin slices, in particular for thin wafers, characterized in that the device is provided with a support frame (4, 42, 45,) that can be attached to the circumference of the thin wafer (1, 18, 110) by means of an adhesive (K, K9, K10). 49, 410) is realized, the cross section of which is formed by a rigid profile and the outer contour (2, 22, 25, 29, 210) of which at least slightly projects beyond the thin wafer (1, 18, 110).

2. Device according to claim 1, characterized in that the contour of the support frame (4, 42, 45, 49, 410) is geometrically matched to the outer contour of the thin wafer (1, 18, 110).

3. Device according to claim 1, characterized in that the cross section of the profile of the support frame (4, 42, 45, 49, 410) has the shape of a polygon.

4. Device according to one of the preceding claims, characterized in that the profile is designed as a trapezoid (49).

5. The device according to claim 4, characterized in that the trapezoid (49) is asymmetrical.

6. The device according to claim 4 or 5, characterized in that the trapezoid (49) via its longest side by means of an adhesive (K9) with the thin wafer (18)

7. Device according to one of claims 4 to 6, characterized in that the trapezoid (49) includes two right angles, and that the corners of the right angles are formed essentially as broken edges.

8. Device according to one of claims 4 to 7, characterized in that one side (49F) of the trapezoid (49) is inclined to the center of the wafer (18) hm.

9. Device according to one of claims 4 to 8, characterized in that the trapezoid (49) is formed from a composite material, preferably from fiber-reinforced resin.

10. Device according to one of claims 1 to 3, characterized in that the profile is designed as a triangle (410).

11. The device according to claim 10, characterized in that the triangle (410) is designed as an equilateral triangle.

12. The device according to claim 10 or 11, characterized in that the triangle (410) is connected via its longest side by means of an adhesive (K10) to the thin wafer (110).

13. Device according to one of claims 10 to 12, characterized in that one side (410F) of the triangle (410) is inclined towards the center of the wafer (110).

14. Device according to one of claims 10 to 13, characterized in that the triangle (410) is formed from a glass or ceramic material, preferably from quartz glass.

15. The device according to one of claims 1 to 3, characterized in that the profile is designed as an angle profile (4) with legs of different lengths (4L, 4K).

16. The apparatus according to claim 15, characterized in that the angle profile is designed as a right angle (4) with legs of different lengths (4L, 4K).

17. The apparatus of claim 15 or 16, characterized in that the longer leg (4L) lies in a plane which runs parallel to the plane of the thin wafer (1).

18. Device according to one of claims 15 to 17, characterized in that in the longer leg (4L) there are adhesive openings (5, 52, 55) for receiving adhesive (K) with which the thin wafer (1) on the support frame (4 , 42, 45) is detachably attached.

19. Device according to one of claims 15 to 18, characterized in that the shorter leg (4K) lies in a plane which is perpendicular to the plane of the thin wafer (1).

20. The apparatus according to claim 19, characterized in that the outer contour of the shorter leg (4K) at least slightly projects beyond the peripheral contour (2, 22, 25) of the thin wafer (1).

21. Device according to one of the preceding claims, characterized in that the support frame (4, 42, 45) is made of metallic or artificial material.

22. Device according to one of the preceding claims, characterized in that the edges of the profile are broken.

23. The device according to claim 22, characterized in that the broken edges are formed by radii or facets.

24. Device according to one of the preceding claims, characterized in that the support frame (4, 42, 45, 49, 410) remains on it when the thin wafer (1, 18, 110) is separated.

25. Device according to one of claims 1 to 23, characterized in that the support frame (4, 42, 45, 49, 410) is separated from the Dunnwafer (1, 18, 110) when it is separated.

26. Device according to one of the preceding claims, characterized in that the support frame (4, 42, 45, 49, 410) remains on this in further process steps, such as when testing the thin wafer (1, 18, 110).

27. Production method, with the steps: providing a substrate for an integrated circuit arrangement, materially connecting the substrate (1, 18, 110) with a support frame (4, 42, 45, 49, 410), further processing of the substrate (1, 18 , 110) after connecting.

28. Manufacturing method according to claim 27, characterized in that the support frame (4, 42, 45, 49, 410)

Support frame (4, 42, 45, 49, 410) according to one of claims 1 to 26.