Method for aligning structures on a semiconductor substrate

• US 6,709,949 B2
• Filed: 10/21/2002
• Issued: 03/23/2004
• Est. Priority Date: 04/19/2000
• Status: Expired due to Fees

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Hübner, Holger
• Primary Examiner(s): Picardat, Kevin M.
• Application Number:
  US10/277,127
• Publication Number:
  US 20030171008A1
• Time in Patent Office: 519 Days
• Field of Search: 438/401, 438/637, 438/666, 438/667, 438/668, 438/675, 438/975
• US Class Current: 438/401
• CPC Class Codes: H01L 2225/06593 Mounting aids permanently on device; arrangements for alignment
• CPC Class Codes: H01L 25/0657 Stacked arrangements of devices
• CPC Class Codes: H01L 25/50 Multistep manufacturing processes of assemblies consisting of devices, each device being of a type provided for in group H01L27/00 or H01L29/00 H01L21/50 takes precedence
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10S 438/975 Substrate or mask aligning feature

Abstract

In the three-dimensional integration of integrated circuits, a thinned semiconductor substrate is arranged on a second semiconductor substrate and is mechanically and electrically connected thereto. To that end, in the second, thinned semiconductor substrate, continuous contact holes are formed proceeding from a substrate rear side as far as a first metal wiring plane on a substrate front side. In order to align the contact holes with the structures arranged on the front side, a structure is arranged on the front side of the substrate, which can be used as an alignment mark on the front side. The structure is overgrown with a useful layer and uncovered proceeding from the rear side of the substrate, so that the structure can also be used as an alignment mark from the rear side. This avoids an alignment error between the structures arranged on the front side and the rear side.

Claims

1. A method for aligning structures on a front side of a substrate and on a rear side of the substrate being opposite to the front side of the substrate, the method which comprises:

forming a trench or depression on the front side of the substrate;

growing a doped semiconductor layer on the front side of the substrate;

forming a circuit configuration on the front side of the substrate;

removing substrate material from the back side of the substrate up to the doped semiconductor layer to reproduce the trench or depression on the back side of the substrate; and

using the trench or depression on the back side of the substrate as an alignment mark or for forming an etching mask.

2. The method according to claim 1, which further comprises:

forming a contact pad in the trench or depression; and

using the trench or depression on the back side of the substrate to form a mask with an opening opposite the contact pad.

4. The method according to claim 2, which further comprises:

selectively removing additional semiconductor material with respect to the first mask layer;

applying a second mask layer to the back side of the substrate; and

planarizing the back side of the substrate to remove the first mask layer.

3. A method for aligning structures on a front side of a substrate and on a rear side of the substrate being opposite to the front side of the substrate, the method which comprises:

applying a structured first mask layer to the front side of the substrate;

growing a doped semiconductor layer on the front side of the substrate;

growing a further semiconductor layer reproducing a structure of the first mask layer in an inverted form; and

removing substrate material from the back side of the substrate up to the first mask layer and the doped semiconductor layer.