CN-122029957-A - Use of an alternating layer pattern for efficient overlay metrology in multi-stack die applications

Abstract

Embodiments of the present disclosure include a method for forming an element including generating an image of a second die bonded on a first die, the first die bonded on a base substrate, the first die having a first feature formed on a first surface of the first die and the second die having a second feature formed on a second surface of the second die, determining a relative displacement between portions of the first feature and the second feature based on the generated image, and determining an updated alignment instruction based on the determined relative displacement.

Inventors

• ZHANG YAOLONG
• Venkata Kashgar Walletti
• WANG RUIPING
• Mehdi Waze Ira Vanni

Assignees

• 应用材料公司

Dates

Publication Date

20260512

Application Date

20241009

Priority Date

20231011

Claims (20)

1. 1. A method for forming an element, the method comprising: Generating an image of a second die bonded on a first die, the first die bonded on a base substrate, the first die having a first feature formed on a first surface of the first die and the second die having a second feature formed on a second surface of the second die; Determining a relative displacement between portions of the first feature and the second feature based on the generated image, and An updated alignment instruction is determined based on the determined relative displacement.
2. 2. The method of claim 1, wherein: The first feature having a first critical dimension, and The second feature has a second critical dimension, wherein the first critical dimension is less than the second critical dimension, Wherein determining updated alignment instructions includes determining updated alignment instructions that result in centering of the first feature within the second feature of a subsequent element.
3. 3. The method of claim 1, wherein: The first feature having a first critical dimension, and The second feature has a second critical dimension, wherein the first critical dimension is greater than the second critical dimension, Wherein determining updated alignment instructions includes determining updated alignment instructions that result in centering of the second feature within the first feature of a subsequent element.
4. 4. The method of claim 3, wherein the first die includes a third feature disposed on a second surface of the first die offset from the first feature in a direction parallel to a plane parallel to a base surface of the base feature, the second surface opposite the first surface of the first die, and wherein the third feature is aligned with a base feature formed on the base substrate.
5. 5. The method of claim 1, wherein: The first feature having a first critical dimension, and The second feature has a second critical dimension, wherein the first critical dimension and the second critical dimension are equal, wherein Determining updated alignment instructions includes determining updated alignment instructions that cause the second feature to overlay a third feature formed on the base substrate of a subsequent element.
6. 6. The method of claim 1, wherein the first surface of the first die is an element side of the first die, and the first feature is formed in a non-electrical section of the first die.
7. 7. The method of claim 1, wherein the first surface of the first die is a backside of the first die.
8. 8. The method of claim 1, wherein: The first die includes a third feature formed on a second surface of the first die, the third feature being offset from the first feature by a first distance in a first direction, wherein the first direction is a direction parallel to a base surface of the base substrate and the first distance is measured in the first direction; The second die includes a fourth feature formed on a second surface of the second die, the fourth feature being offset from the second feature by the first distance in the first direction; Positioning the second die onto the first die such that the first surface of the first die and the first surface of the second die face each other; The first feature has a first critical dimension; the second feature has a second critical dimension that is less than the first critical dimension; the third feature having a critical dimension equal to the second critical dimension, and The fourth feature has a critical dimension equal to the first critical dimension, Wherein determining updated alignment instructions includes determining updated alignment instructions that result in centering of the second feature within the first feature.
9. 9. The method of claim 1, the method further comprising: Delivering light at a first wavelength toward the first die and the second die, and Determining a relative displacement between the first feature and the second feature based on light reflected from the first die and the second die and captured by an image sensor, and wherein determining the updated alignment instruction is based on the determined relative displacement between the second feature and the first feature.
10. 10. A method for forming an element, the method comprising: Generating a first image of a second die bonded on a first die, the first die bonded to a base substrate, the second die having first features disposed on a first surface of the second die, the base substrate having base features formed on a base surface of the base substrate, and the first image being parallel to a first plane and including at least a portion of the first features of the second die and at least a portion of the base features of the base substrate, the first plane being parallel to the base surface of the base substrate; Determining a first distance in a first direction between the first feature and the portion of the base feature, the first direction being a direction parallel to the first plane, and An updated alignment instruction is determined based on the first distance between the first feature and the base feature.
11. 11. The method of claim 10, wherein determining updated alignment instructions includes determining updated alignment instructions that result in the first distance being equal to a predetermined distance.
12. 12. The method of claim 10, the method further comprising: Generating a second image of the first die bonded to the base substrate prior to generating the first image, the first die having third features formed on a first surface of the first die; determining a second distance in the first direction between the third feature and the portion of the base feature, and An updated alignment instruction is determined based on the second distance between the third feature and the base feature.
13. 13. The method of claim 12, wherein determining updated alignment instructions based on the second distance between the third feature and the base feature comprises determining updated alignment instructions that result in the second distance being equal to a predetermined distance.
14. 14. An optical inspection system, the optical inspection system comprising: A controller; A memory for storing a program to be executed in the controller, the program comprising instructions that when executed cause the controller to: Generating an image of a second die bonded on a first die, the first die bonded on a base substrate, the first die having a first feature formed on a first surface of the first die and the second die having a second feature formed on a second surface of the second die; Determining a relative displacement between portions of the first and second features based on the generated image, and An updated alignment instruction is determined based on the determined relative displacement.
15. 15. The optical inspection system of claim 14, wherein: The first feature having a first critical dimension, and The second feature has a second critical dimension, wherein the first critical dimension is smaller than the second critical dimension, wherein The instructions for determining updated alignment instructions further include instructions for determining updated alignment instructions that result in centering of the first feature within the second feature of a subsequent element.
16. 16. The optical inspection system of claim 15, wherein: The first feature having a first critical dimension, and The second feature has a second critical dimension, wherein the first critical dimension is greater than the second critical dimension, wherein The instructions for determining updated alignment instructions further include instructions for determining updated alignment instructions that result in centering of the second feature within the first feature of a subsequent element.
17. 17. The optical inspection system of claim 16, wherein the first die includes a third feature disposed on a second surface of the first die offset from the first feature in a direction parallel to a plane that is parallel to a base surface of the base feature, the second surface being opposite the first surface of the first die, and wherein the third feature is aligned with a base feature formed on the base substrate.
18. 18. The optical inspection system of claim 15, wherein: The first feature having a first critical dimension, and The second feature has a second critical dimension, wherein the first critical dimension and the second critical dimension are equal, wherein The instructions to determine updated alignment instructions include instructions to determine updated alignment instructions that cause the second feature to overlay a third feature formed on the base substrate.
19. 19. The optical inspection system of claim 15, wherein: The first die includes a third feature formed on a second surface of the first die, the third feature being offset from the first feature by a first distance in a first direction, wherein the first direction is a direction parallel to a base surface of the base substrate and the first distance is measured in the first direction; The second die includes a fourth feature formed on a second surface of the second die, the fourth feature being offset from the second feature by the first distance in the first direction; Positioning the second die onto the first die such that the first surface of the first die and the first surface of the second die face each other; The first feature has a first critical dimension; the second feature has a second critical dimension that is less than the first critical dimension; the third feature having a critical dimension equal to the second critical dimension, and The fourth feature has a critical dimension equal to the first critical dimension, wherein The instructions for determining updated alignment instructions further include instructions for determining updated alignment instructions that result in centering the second feature within the first feature.
20. 20. The optical inspection system of claim 15, wherein the optical inspection system comprises an infrared light source disposed above a stage.

Description

Use of an alternating layer pattern for efficient overlay metrology in multi-stack die applications Cross Reference to Related Applications The present application claims the benefit of U.S. non-provisional patent application Ser. No. 18/485,147, filed on 10/11 of 2023, which is hereby incorporated by reference. Technical Field Embodiments of the present disclosure generally relate to a method and apparatus for forming an aligned 3D integrated circuit (3D IC). Background Electronic components such as those included in tablet computers, copiers, digital cameras, smart phones, control systems, and automated teller machines, etc., often include integrated circuit dies for some desired functionality. Three-dimensional (3D) component packages are one type of microelectronic component package structure that integrates multiple manufactured dies into a single stacked compact package. This approach allows a designer to create a more complex and powerful system by integrating different components with improved power consumption levels and performance. The 3D component package may include a three-dimensional integrated circuit (3D IC) fabricated by vertically stacking at least two or more 2D ICs (e.g., dies) using, for example, through-silicon vias (through silicon via, TSVs) or copper-copper (Cu-Cu) connections. In other words, multiple dies can be stacked vertically on top of each other such that they act as a single element, enabling improved element performance with reduced power and footprint (size). In order for a 3D IC in a 3D component package to operate properly, the patterned layers of at least two or more ICs (or dies) must be aligned so that the stacked ICs can be desirably interconnected. Misalignment between 2D ICs may cause shorts, connection failures, or the like. As the complexity of 2D ICs increases and the size decreases, alignment becomes more important and much more complex. Thus, there is a need for an apparatus and method for reliably stacking two or more ICs or dies that solves the problems described above. Disclosure of Invention In one embodiment, a method for forming an element includes generating an image of a second die bonded on a first die, the first die bonded on a base substrate, the first die having a first feature formed on a first surface of the first die and the second die having a second feature formed on a second surface of the second die, determining a relative displacement between portions of the first feature and the second feature based on the generated image, and determining an updated alignment instruction based on the determined relative displacement. In another embodiment, a method for forming an element includes generating a first image of a second die bonded on a first die, the first die bonded to a base substrate, the second die having a first feature disposed on a first surface of the second die, the base substrate having a base feature formed on a base surface of the base substrate, and the first image being parallel to a first plane and including at least a portion of the first feature of the second die and at least a portion of the base feature of the base substrate, the first plane being parallel to the base surface of the base substrate, determining a first distance between the first feature and a portion of the base feature in a first direction, the first direction being a direction parallel to the first plane, and determining an updated alignment instruction based on the first distance between the first feature and the base feature. In another embodiment, an optical inspection system includes a controller, a memory storing a program to be executed in the controller, the program containing instructions that when executed cause the controller to generate an image of a second die bonded on a first die bonded on a base substrate, the first die having a first feature formed on a first surface of the first die and the second die having a second feature formed on a second surface of the second die, determine a relative displacement between portions of the first feature and the second feature based on the generated image, and determine an updated alignment instruction based on the determined relative displacement. In another embodiment, a stacked semiconductor assembly includes a first die bonded on a base substrate, the first die having a first feature formed on a first surface of the first die, and a second die bonded on the first die, the second die having a second feature formed on a second surface of the second die, wherein the second die is aligned to the first die based on the second feature and the first feature. In another embodiment, a stacked semiconductor assembly includes a first die bonded to a base substrate having base features formed on a base surface of the base substrate, and a second die bonded to the first die, the second die having first features disposed on a first surface of the second die, wherein the second die is aligned with the base substr