SUBSTRATE HOLDER AND METHOD FOR PRODUCING A SUBSTRATE HOLDER FOR BONDING

Abstract

The present invention relates to a substrate holder, a bonding device, a method for producing a substrate holder and a method for bonding.

Claims

1. A substrate holder for bonding substrates, comprising: a substrate holder surface, a central elevation arranged on the substrate holder surface with a first mounting surface; and one or more support elevations respectively arranged on the substrate holder surface with second mounting surfaces, wherein a substrate is arranged on the first mounting surface of the central elevation and on the second mounting surfaces of the one or more support elevations, wherein the first mounting surface is larger than the second mounting surfaces.

2. The substrate holder according to claim 1, wherein the one or more support elevations comprise three or more support elevations.

3. The substrate holder according to claim 1, wherein the first mounting surface of the central elevation is at least 1.1-times larger than the second mounting surfaces of the one or more support elevations.

4. The substrate holder according to claim 1, wherein the first mounting surface of the central elevation is of circular construction.

5. The substrate holder according to claim 2, wherein two or more of the three or more support elevations are respectively arranged at radial positions around a central point of the central elevation.

6. The substrate holder according to claim 5, wherein the two or more support elevations respectively arranged at the radial positions around the central point of the central elevation have the same distance from one another along circles respectively defined by the radial positions.

7. The substrate holder according to claim 5, wherein the second mounting surfaces of the two or more support elevations respectively arranged at the radial positions around the central point of the central elevation are constructed identically.

8. The substrate holder according to claim 5, wherein the radial positions around the central point of the central elevation comprise a first radial position and a second radial position, wherein the second mounting surfaces of the support elevations arranged at the first radial position are larger than the second mounting surfaces of the support elevations arranged at the second radial position, and wherein the first radial position has a smaller distance from the central point of the central elevation than the second radial position.

9. The substrate holder according to claim 5, wherein one or more of the radial positions are flush with a vibration amplitude of the substrate.

10. A bonding device for bonding substrates, comprising: one or more substrate holders for bonding the substrate, each of the substrate holders comprising: a substrate holder surface, a central elevation arranged on the substrate holder surface with a first mounting surface, and one or more support elevations respectively arranged on the substrate holder surface with second mounting surfaces, wherein a substrate is arranged on the first mounting surface of the central elevation and on the second mounting surfaces of the one or more support elevations, and wherein the first mounting surface is larger than the second mounting surfaces.

11. A method for producing a substrate holder for bonding substrates, comprising: providing a substrate holder with a substrate holder surface, creating a central elevation with a first mounting surface, and respectively creating one or more support elevations with second mounting surfaces, wherein the first mounting surface is larger than the second mounting surfaces.

12. The method for producing a substrate holder according to claim 11, further comprising: determining a behaviour of a vibration of one of the substrates, and determining positions of amplitudes of the vibration in a direction of the substrate holder of the one of the substrates during bonding of the substrates, wherein the respectively creating the one or more support elevations takes place at one of the determined positions of the amplitudes of the vibration.

13. The method for producing a substrate holder according to claim 12, further comprising: determining a bond error of a substrate stack formed by the bonding of the substrates, determining the positions of the amplitudes of the vibration of the one of the substrates during the bonding of the substrates on the basis of the determined bond error, and arranging the one or more support elevations at the determined vibration amplitude positions based on the determined bond error.

14. A method for bonding substrates with a bonding device, the bonding device including one or more substrate holders for bonding the substrates, each of the substrate holders including a substrate holder surface, a central elevation arranged on the substrate holder surface with a first mounting surface, and one or more support elevations respectively arranged on the substrate holder surface with second mounting surfaces, the first mounting surface being larger than the second mounting surfaces, the method comprising: providing one of the substrates on one of the substrate holders, providing another one of the substrates on another one of the substrate holders, and bonding the one of the substrates with the other one of the substrates to form a substrate stack, wherein the substrates and/or the substrate stack is supported by the first mounting surface of the central elevation during the bonding of the one of the substrates with the other one of the substrates.

15. The method for bonding according to claim 14, wherein the one of the substrates and/or the substrate stack is additionally supported during the bonding of the one of the substrates with the other one of the substrates by the one or more support elevations at a position of a vibration amplitude of the one of the substrates in a direction of the one of the substrate holders.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0101] Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments, as well as on the basis of the drawings. In the figures:

[0102] FIG. 1a schematically shows a schematic illustration of an embodiment of a substrate holder according to the invention in a view from above,

[0103] FIG. 1b schematically shows a schematic illustration of a substrate holder according to the invention according to FIG. 1a in a side view,

[0104] FIG. 2 schematically shows a schematic illustration of a substrate holder according to the invention in a side view with a vibrating substrate stack.

DETAILED DESCRIPTION OF THE INVENTION

[0105] In the figures, the same components or components with the same function are labelled with the same reference numbers.

[0106] Neither the substrate holder nor the elevations (central elevation and support elevations), the substrate stack, the amplitudes or other features are illustrated to the correct scale. In particular, the elevations and above all the amplitudes of the deformed substrates are illustrated many times larger, in order to facilitate the illustration and to improve the understanding for the desired effect of reducing the local distortions.

[0107] In particular, only those features of the substrate holder which are used for understanding the invention are illustrated. In particular, the illustration of superfluous features was avoided. An actual substrate holder generally consists of more components.

[0108] FIG. 1a shows a plan view of a substrate holder 1 according to the invention. A central elevation can be seen in the form of a central elevation 2, which has a larger central elevation diameter d than the elevations in the form of support elevations 2′, 2″. It has emerged from empirical measurements that the contact point has the largest distortions and amplitudes during a bonding process of two substrates 5, 5′ (not drawn in). In this case, it has surprisingly been shown that a better bonding result can be achieved if the first mounting surface 6 of the central elevation 2 is larger than a second mounting surface 6,6″ of a support elevation 2′, 2″. In the substrate holder 1 illustrated by way of example, the mounting surfaces 6, 6′, 6″ of the elevations, that is to say the central elevation 2 and the support elevations 2′, 2″, are round. In this respect, due to the larger central elevation diameter d, the central elevation 2 in each case has a larger first mounting surface 6 than the second mounting surfaces 6′, 6″ of the support elevations 2′, 2″ with the support elevation diameters d′, d″.

[0109] A plurality of support elevations 2′, 2″ are distributed over the substrate holder 1. These were arranged along the substrate holder surface 8 such that vibration maxima that arise, that is to say the amplitudes arise precisely at the positions thereof, when a particular upper substrate 5′ is bonded relatively to a particular lower substrate 5, (see FIG. 2). In particular, the position of the substrates 5, 5′ is known relative to the substrate holder 1. Only as a result of this can the well defined positions of the support elevations 2′, 2″ be determined clearly.

[0110] In a less preferred embodiment, a reference 4 is provided, in relation to which a substrate 5, 5′ is aligned. In most cases, only the lower substrate 5 is aligned relative to the reference 4, whilst the upper substrate 5′ is aligned relative to the lower substrate 5. The reference 4 may for example be a positioning pin, by means of which the position of a notch of a substrate, in particular a wafer, is determined. A surface would also be conceivable, along which a flat side of a substrate, particularly a wafer, is positioned. Furthermore, an alignment mark would be conceivable, in relation to which a substrate 5 is positioned and orientated. Eight symmetrically arranged fixing elements 3 can also be seen. In the simplest case, these are vacuum openings for generating a vacuum between the elevations 2, 2′, 2″. The use of different types of fixing elements is likewise conceivable. If this a zone substrate holder, each zone or each segment preferably has at least one fixing element.

[0111] Preferably, a reference 4 is dispensed with and the alignment of the lower substrate 5 takes place directly in relation to the elevations 2, 2′, 2″. The lower substrate 5 is placed on the substrate holder according to the invention. The upper substrate 5′ is positioned relatively to the lower substrate 5 with the aid of an optical alignment system. Thereafter, the upper substrate 5′ is brought closer to the lower substrate 5, preferably initially centrally, in that a contacting element (not drawn in), for example a pin or the fluid flow of a nozzle, bends the upper substrate 5′. Contacting processes of this type, particularly for fusion bonds, are known to the person skilled in the art in the field and are not described in more detail here.

[0112] FIG. 1b shows a side view of a substrate holder 1 according to the invention with a centrally arranged central elevation 2 and a plurality of support elevations 2′, 2″. The elevations 2, 2′, 2″ have a diameter d, d′, d″ in each case. In this case, the support elevation diameters are constant or the same size along a radial position x′, x″. The elevations 2, 2′, 2″ can generally also have different shapes (not drawn in here). The central elevation 2, which has a larger first mounting surface, is positioned centrally on the round substrate holder surface in the embodiment illustrated. Starting from the central point 7 of the substrate holder 1 or the central elevation 2, the support elevations 2′, 2″ are arranged at a certain radial position x, x″. The support elevations 2, 2″ are distributed symmetrically. The support elevations 2′ are in this case arranged at a radial position x′ and the support elevations 2″ at a further radial position x″ which is further from the central point 7. The respective second mounting surfaces 6′ of the support elevations 2′ and the respective second mounting surfaces 6′ of the support elevations 2″ are smaller in the illustrated embodiment. In this respect, the size of the mounting surface 6, 6′, 6″ of the support elevations decreases outwards and thus with the radial position.

[0113] The radial positions x′, x″ of the support elevations 2′, 2″ are in this case arranged such that the same are flush with a position of a vibration maximum of an elastic vibration, created during bonding, in the direction of the substrate holder. In this manner, the substrate 5 or the substrate stack can be supported during bonding at the amplitudes of the vibration maxima, at which the expected and preferably calculated and measured vibration maxima occur. The exact position and number of the support elevations 2′, 2″ is determined in particular by empirical experiments and/or theoretical vibration calculations.

[0114] FIG. 2 shows a side view of a substrate holder 1 according to the invention, on which a lower substrate 5 and an upper substrate 5′ are bonded to one another. The state directly after the complete contacting of both substrates 5, 5′ can be seen. The illustration of an upper substrate holder is omitted. One can see that a vibration process is created on the basis of the bonding process, in particular allowing the upper substrate 5′ to fall. The amplitude, which decreases from the centre to the edge in particular, is illustrated in an exaggerated manner. The actual amplitudes lie in the micrometre to nanometre range. However, it can be seen that the amplitudes in the direction of the substrate holder 1 arise at the positions of the elevations 2, 2′, 2″. In this case, the largest amplitude arises in the direction of the substrate holder at the position of the central elevation 2 having the larger first mounting surface 6. In this manner, the lower substrate 5 or the substrate stack can advantageously be supported and a local distortion can be minimized. The support elevations 2′, 2″ are in this case likewise arranged in the regions at which a maximum deflection of the vibration in the direction of the substrate holder occurs. In this manner, the errors between the first substrate 5 and the second substrate 5′ with respect to one another are minimized.

REFERENCE LIST

[0115] 1 Substrate holder [0116] 2 Elevation, central elevation [0117] 2′, 2″ Elevation, support elevation [0118] 3 Fixing element [0119] 4 Reference [0120] 5, 5′ Substrate [0121] x′, x″ Radial position [0122] d Diameter, central elevation diameter [0123] d′, d″ Diameter, support elevation diameter [0124] 6 Mounting surface, first mounting surface (central elevation) [0125] 6′, 6″ Mounting surface, second mounting surface (support elevation) [0126] 7 Central point [0127] 8 Substrate holder surface