Method for detecting overlay precision and method for compensating overlay deviation

Patent metadata

Field	Value
Publication number	US-11988968-B2
Application number	US-202017060415-A
Country	US
Kind code	B2
Filing date	Oct 1, 2020
Priority date	Jan 8, 2020
Publication date	May 21, 2024
Grant date	May 21, 2024

Abstract

A method for detecting an overlay precision and a method for compensating an overlay deviation are provided. The method for detecting the overlay precision includes providing a wafer to-be-detected, where the wafer to-be-detected includes a photoresist layer which has been exposed and developed; performing a first detection on the wafer to-be-detected using an optical overlay precision measurement and acquiring first overlay precision information of the photoresist layer; performing a second detection on the wafer to-be-detected using the optical overlay precision measurement, and acquiring second overlay precision information of the photoresist layer, where a wavelength or a polarization direction of a light source of the second detection is different from a wavelength or a polarization direction of a light source of the first detection; and acquiring overlay precision deviation information of the wafer to-be-detected according to the first overlay precision information and the second overlay precision information.

First claim

What is claimed is:

1. A method for detecting an overlay precision, comprising:
providing a wafer to-be-detected, wherein the wafer to-be-detected includes a photoresist layer which has been exposed and developed;
performing a first detection on the wafer to-be-detected using an optical overlay precision measurement and acquiring first overlay precision information of the photoresist layer, the optical overlay precision measurement including an overlay precision measurement based on imaging and image recognition;
performing a second detection on the wafer to-be-detected using the optical overlay precision measurement, and acquiring second overlay precision information of the photoresist layer, wherein a wavelength or a polarization direction of a light source of the second detection is different from a wavelength or a polarization direction of a light source of the first detection; and
acquiring overlay precision deviation information of the wafer to-be-detected according to the first overlay precision information and the second overlay precision information.

2. The method according to claim 1 , wherein:
the photoresist layer includes a plurality of mark patterns;
the first overlay precision information includes a plurality of first overlay precisions, each being acquired according to one mark pattern; and
the second overlay precision information includes a plurality of second overlay precisions, each being acquired according to one mark pattern.

3. The method according to claim 2 , wherein:
the overlay precision deviation information of the wafer to-be-detected includes a plurality of deviation values, each being acquired according to a vector difference between one first overlay precision and one second overlay precision.

4. A method for compensating an overlay deviation, comprising:
providing a plurality of first wafers;
acquiring a first compensation parameter through the plurality of first wafers;
providing a plurality of second wafers, each including a second layer to-be-etched and a second initial photoresist layer on the second layer to-be-etched;
according to the first compensation parameter, exposing and developing the second initial photoresist layer of each second wafer to form a second photoresist layer;
after forming the second photoresist layer, using more than one second wafers in the plurality of second wafers as second wafers to-be-detected, and acquiring second overlay precision deviation information of the second wafers to-be-detected according to a method for detecting an overlay precision, wherein the method for detecting the overlay precision includes:
providing a wafer to-be-detected, wherein the wafer to-be-detected includes a photoresist layer which has been exposed and developed;
performing a first detection on the wafer to-be-detected using an optical overlay precision measurement and acquiring first overlay precision information of the photoresist layer, the optical overlay precision measurement including an overlay precision measurement based on imaging and image recognition;
performing a second detection on the wafer to-be-detected using the optical overlay precision measurement, and acquiring second overlay precision information of the photoresist layer, wherein a wavelength or a polarization direction of a light source of the second detection is different from a wavelength or a polarization direction of a light source of the first detection; and
acquiring overlay precision deviation information of the wafer to-be-detected according to the first overlay precision information and the second overlay precision information; and

according to the second overlay precision deviation information, performing a compensation processing on each of the second wafers, wherein the compensation processing includes removing the second photoresist layer or etching the second layer to-be-etched using the second photoresist layer as a mask.

5. The method according to claim 4 , wherein according to the second overlay precision deviation information, performing the compensation processing on each of the second wafers includes:
when the second overlay precision deviation information is within a preset range, etching the second layer to-be-etched using the second photoresist layer as the mask; and
when the second overlay precision deviation information is outside the preset range, removing the second photoresist layer.

6. The method according to claim 4 , wherein:
each of the plurality of first wafers includes a first layer to-be-etched and a first initial photoresist layer on the first layer to-be-etched.

7. The method according to claim 6 , further including:
using more than one first wafers in the plurality of first wafers as first wafers to-be-detected;
before acquiring the first compensation parameter, exposing and developing the first initial photoresist layer of a first wafer to-be-detected to form a first photoresist layer; and
after forming the first photoresist layer, according to the method for detecting the overlay precision, acquiring first overlay precision deviation information, the first overlay precision information and the second overlay precision information of the first wafer to-be-detected.

8. The method according to claim 7 , wherein according to the second overlay precision deviation information, performing the compensation processing on each of the second wafers includes:
acquiring an error parameter according to the first overlay precision deviation information and the second overlay precision deviation information;
when the error parameter is within a preset range, etching the second layer to-be-etched using the second photoresist layer as the mask; and
when the error parameter is outside the preset range, removing the second photoresist layer.

9. The method according to claim 8 , wherein:
the error parameter is acquired according to a deviation between the first overlay precision deviation information and the second overlay precision deviation information.

10. The method according to claim 8 , wherein:
third deviation information is acquired according to a deviation between the first overlay precision deviation information and the second overlay precision deviation information;
the third deviation information is used as a sample to obtain deviation normal distribution information; and
the error parameter is obtained according to the deviation normal distribution information.

11. The method according to claim 7 , wherein forming the first photoresist layer includes:
using more than one first wafers in the plurality of first wafers as third wafers to-be-detected;
exposing and developing a first initial photoresist layer of a third wafer to-be-detected to form a third photoresist layer;
using the third photoresist layer as a mask, etching a first layer to-be-etched of the third wafer to-be-detected to form a third etched layer;
using a measurement of a scanning electron microscope, acquiring fourth overlay precision information of the third etched layer of the third wafer to-be-detected; and
according to the fourth overlay precision information, exposing and developing the first initial photoresist layer of the first wafer to-be-detected to form the first photoresist layer.

12. The method according to claim 11 , wherein:
the first compensation parameter is acquired according to the fourth overlay precision information and the first overlay precision information of the first wafer to-be-detected; or
the first compensation parameter is acquired according to the fourth overlay precision information and the second overlay precision information of the first wafer to-be-detected.

Assignees

• Semiconductor Mfg Int Shanghai Corp
• Semiconductor Mfg Int Beijing Corp

Inventors

• Bai Song
• Ma Qiliang
• Song Tao
• Sha Sha

Classifications

• H10P74/23

  characterised by multiple measurements, corrections, marking or sorting processes · CPC title

• H10W46/301

  for alignment · CPC title

• H10P74/203

  Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects · CPC title

• H10W46/00 Primary

  Marks applied to devices, e.g. for alignment or identification · CPC title

• G03F7/70633 Primary

  Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching · CPC title