Method for applying a bonding layer

Abstract

A method for applying a bonding layer that is comprised of a basic layer and a protective layer on a substrate with the following method steps: application of an oxidizable basic material as a basic layer on a bonding side of the substrate, at least partial covering of the basic layer with a protective material that is at least partially dissolvable in the basic material as a protective layer. In addition, the invention relates to a corresponding substrate.

Claims

1. A method for bonding a first substrate with a second substrate, said method comprising: applying an oxidizable basic material as a basic layer on a bonding side of the first substrate; at least partially covering the basic layer with a protective layer having a thickness of less than 100 nm, the protective layer being comprised of a protective material containing at least one non-metal chemical element selected from the group consisting of Si, Se, C, O, and Te; and bonding the first and second substrates, wherein the protective material is dissolved completely in the basic material during the bonding.

2. The method according to claim 1, wherein the basic material is oxygen-affine and is comprised of aluminum and/or copper.

3. The method according to claim 1, wherein the step of applying the basic material as the basic layer and/or covering the basic layer with the protective layer is/are carried out by deposition.

4. The method according to claim 1, wherein the covered basic layer is sealed by the protective layer at least predominantly relative to the atmosphere.

5. The method according to claim 1, further comprising: treating the protective layer before the step of bonding with one or more of the following processes: (a) chemical oxide removal; (b) physical oxide removal, in particular with plasma; and (c) ion-assisted chemical etching.

6. The method according to claim 5, wherein said chemical oxide removal process includes a gaseous reducing agent and/or a liquid reducing agent.

7. The method according to claim 5, wherein said ion-assisted chemical etching process includes fast ion bombardment, grinding, and/or polishing.

8. The method according to claim 1, wherein the basic material is one or more materials selected from the group consisting of metals, alkali metals, alkaline-earth metals, alloys, and semiconductors provided with corresponding doping.

9. The method according to claim 8, wherein the protective material further contains one or more materials selected from the group consisting of metals, alkali metals, alkaline-earth metals, alloys, and semiconductors provided with corresponding doping.

10. The method according to claim 9, wherein said semiconductors are selected from the group consisting of element semiconductors and compound semiconductors.

11. The method according to claim 10, wherein said element semiconductors are selected from the group consisting of Si, Ge, Se, Te, and Sn.

12. The method according to claim 10, wherein said compound semiconductors are selected from the group consisting of GaAs, GaN, InP, In.sub.xGa.sub.1-xN, InSb, InAs, GaSb, AIN, InN, GaP, BeTe, ZnO, CuInGaSe.sub.2, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, Hg.sub.(1-x)Cd.sub.(x)Te, BeSe, HgS, Al.sub.xGa.sub.1-xAs, GaS, GaSe, GaTe, InS, InSe, InTe, CuInSe.sub.2, CuInS.sub.2, CuInGaS.sub.2, SiC, and SiGe.

13. The method according to claim 9, wherein said metals are selected from the group consisting of Cu, Ag, Au, Al, Fe, Ni, Co, Pt, W, Cr, Pb, Ti, Te, Sn, Zn, and Ga, wherein said alkali metals are selected from the group consisting of Li, Na, K, Rb, and Cs, and wherein said alkaline earth metals are selected from the group consisting of Mg, Ca, Sr, and Ba.

14. The method according to claim 8, wherein said metals are selected from the group consisting of Cu, Ag, Au, Al, Fe, Ni, Co, Pt, W, Cr, Pb, Ti, Te, Sn, Zn, and Ga.

15. The method according to claim 8, wherein said alkali metals are selected from the group consisting of Li, Na, K, Rb, and Cs.

16. The method according to claim 8, wherein said alkaline earth metals are selected from the group consisting of Mg, Ca, Sr, and Ba.

17. The method according to claim 8, wherein said semiconductors are selected from the group consisting of element semiconductors and compound semiconductors.

18. The method according to claim 17, wherein said element semiconductors are selected from the group consisting of Si, Ge, Se, Te, and Sn.

19. The method according to claim 17, wherein said compound semiconductors are selected from the group consisting of GaAs, GaN, InP, In.sub.xGa.sub.1-xN, InSb, InAs, GaSb, AIN, InN, GaP, BeTe, ZnO, CuInGaSe.sub.2, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, Hg.sub.(1-x)Cd.sub.(x)Te, BeSe, HgS, AI.sub.xGa.sub.1-xAs, GaS, GaSe, GaTe, InS, InSe, InTe, CuInSe.sub.2, CuInS.sub.2, CuInGaS.sub.2, SiC, and SiGe.

20. A method for bonding a first substrate with a second substrate, said method comprising: applying an oxidizable basic material as a basic layer on a bonding side of the first substrate; at least partially covering the basic layer with a protective layer having a thickness of less than 100 nm, the protective layer being comprised of a protective material containing at least one non-metal chemical element selected from the group consisting of Si, Se, Te, C, O, and B; and bonding the first and second substrates, wherein the protective material is dissolved completely in the basic material during the bonding.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 a depiction of the binary AlGe phase diagram,

(2) FIG. 2 a depiction of the binary AlGa phase diagram,

(3) FIG. 3 a depiction of the binary AlZn phase diagram,

(4) FIG. 4 a depiction of the binary AlMg phase diagram,

(5) FIG. 5a a diagrammatic cross-sectional depiction of an embodiment of a substrate according to the invention with a full-surface basic layer that consists of a basic material and a full-surface protective layer that consists of a protective material with alignment,

(6) FIG. 5b a diagrammatic cross-sectional depiction according to FIG. 5a with a contact/bonding step, and

(7) FIG. 5c a diagrammatic cross-sectional depiction according to FIG. 5a according to the bonding step.

DETAILED DESCRIPTION OF INVENTION

(8) FIG. 1 shows a first binary AlGe system by way of example. The important part in the phase diagram according to the invention is the mixed crystal area 7. The mixed crystal area 7 is separated from the two-phase areas 9, 10 by the boundary solubility 8. The boundary solubility for germanium decreases with decreasing temperature, starting from the eutectic temperature or the eutecticals 11. The boundary solubility for germanium also decreases with increasing temperature, starting from the eutectic temperature or the eutecticals 11.

(9) FIG. 2 shows a second binary AlGa system by way of example. The important part according to the invention in the phase diagram is the mixed crystal area 7. The mixed crystal area 7 is separated by the boundary solubility 8 from the two-phase areas 9, 10. The boundary solubility for gallium decreases with decreasing temperature, starting from the eutectic temperature or the eutecticals 11. The boundary solubility for gallium decreases also with increasing temperature, starting from the eutectic temperature or the eutecticals 11. The degradation of the eutectic by a eutectic point 6 that lies very near in the concentration of the pure germanium is characteristic.

(10) FIG. 3 shows a third binary AlZn system by way of example. The important part according to the invention in the phase diagram is the mixed crystal area 7. The mixed crystal area 7 is very pronounced here. At temperatures around 370? C., it reaches up to more than 65 mol % of zinc. The mixed crystal area 7 is separated by the boundary solubility 8 from the two-phase area 10. The boundary solubility for zinc decreases with decreasing temperature, starting from the eutectoid temperature or the eutectoids 11.

(11) FIG. 4 shows a fourth binary AlMg system by way of example. The important part according to the invention in the phase diagram is the mixed crystal area 7. The mixed crystal area 7 is separated by the boundary solubility 8 from the two-phase areas 9, 10. The boundary solubility for magnesium decreases with decreasing temperature, starting from the eutectic temperature or the eutecticals 11. The boundary solubility for magnesium also decreases with increasing temperature, starting from the eutectic temperature or the eutecticals 11.

(12) FIG. 5a shows as simple a system according to the invention as possible, comprised of a first substrate 4 and a second substrate 5. Both substrates 4 and 5 are coated with a basic material 1 and a protective material 2. In an embodiment according to the invention, basic material 1 and protective material 2 are not necessarily applied on the full surface on the first substrate 4 but rather have undergone a specific structuring before the bonding. In this step, possible oxide layers of the protective material 2 have already been removed.

(13) FIG. 5b shows a contact or bonding step of the two substrates 4 and 5. If the two substrates were structured, a previous orienting step would have had to have oriented the two substrates to one another before the actual contact or bonding step would take place.

(14) Finally, FIG. 5c shows the mixed crystal 12 that is produced and that is carried out by the diffusion of the protective layer material 2 into the basic material 1.

LIST OF REFERENCE SYMBOLS

(15) 1 Basic Material 2 Protective Material 3 Oxide Layer 4 First Substrate 5 Second Substrate 6 Eutectic Point 7 Mixed Crystal Area 8 Boundary Solubility 9 Two-Phase Area: Liquid, Solid 10 Two-Phase Area: Solid, Solid 11, 11 Eutecticals, Eutectoids 12 Mixed Crystal