CN-122003132-A - Ion implantation depth measurement method and device

CN122003132ACN 122003132 ACN122003132 ACN 122003132ACN-122003132-A

Abstract

The application provides a method and a device for measuring ion implantation depth, belonging to the field of semiconductor manufacturing. The method comprises the steps of determining a first time length, determining a first etching time length and a second etching time length according to the first time length, etching the second etching time length, determining a first etching rate of a dielectric layer, performing etching of the first etching time length and the second etching time length, determining thickness change of the dielectric layer under each etching time length, determining whether etching processes corresponding to each etching time length correspond to two different types of etching according to the thickness change of the dielectric layer under each etching time length, and determining the thickness of an injection layer if the etching processes correspond to the two different types of etching, otherwise, executing the steps of determining the first etching time length and the second etching time length according to the first time length again. The method for measuring the junction depth by detecting the etching rate change caused by ion implantation solves the problems of high cost and low efficiency of the traditional technology in the technical field of semiconductor manufacturing.

Inventors

ZHAO JINGLI
LI XIJUN
MENG LIYUAN
MU XI
Huang huanhuan

Assignees

西湖大学

Dates

Publication Date: 20260508
Application Date: 20251216

Claims (10)

1. The method is used for measuring the thickness of an injection layer formed after an ion injection process treatment is carried out on a dielectric layer, the dielectric layer is formed on a substrate, and the method comprises the following steps: determining a first time length according to the pre-measured thickness of the dielectric layer, the currently selected etching process and the pre-determined relation between the etching process and the etching speed of the dielectric layer; Determining a first etching duration and a second etching duration according to the first time, wherein the first etching duration is smaller than the second etching duration, and the first etching duration and the second etching duration are both smaller than the first time; Etching the dielectric layer which is not treated by the ion implantation process for the second etching duration according to the currently selected etching process, and determining the first etching rate of the dielectric layer according to the first thickness variation value of the dielectric layer and the second etching duration in the etching process; Etching the dielectric layer treated by the ion implantation process according to the currently selected etching process for the first etching duration and the second etching duration respectively, and determining thickness change of the dielectric layer under each etching duration; Determining whether etching processes corresponding to each etching duration correspond to two different types of etching according to thickness change of the dielectric layer under each etching duration, wherein the two different types of etching are respectively etching the injection layer only and simultaneously etching the injection layer and the dielectric layer; If so, determining the thickness of the injection layer according to the first etching rate and the thickness change of the dielectric layer under each etching duration, otherwise, executing the steps of determining the first etching duration and the second etching duration according to the first duration again.
2. The method of claim 1, wherein determining whether the etching process corresponding to each etching duration corresponds to two different types of etching according to the thickness variation of the dielectric layer under each etching duration comprises: Assuming that only the injection layer is etched in the second etching duration, and determining an assumed etching rate of the injection layer according to the thickness change of the dielectric layer in the second etching duration and the second etching duration; assuming that the injection layer and the dielectric layer are etched simultaneously under the first etching duration, and calculating a first assumed duration of etching the injection layer under the first etching duration according to the thickness change of the dielectric layer under the first etching duration, the first etching rate and the assumed etching rate; When the first assumed time length is greater than or equal to the second etching time length, determining that etching processes corresponding to each etching time length correspond to two different types of etching; And when the first assumption duration is smaller than the second etching duration, determining that the etching process corresponding to each etching duration does not correspond to two different types of etching.
3. The method of claim 2, wherein calculating a first hypothetical duration of etching the implant layer for the first etch duration based on the thickness variation of the dielectric layer for the first etch duration, the first etch rate, and the hypothetical etch rate comprises: Constructing a first association relation between a first assumption duration of etching the injection layer under the first etching duration and a second assumption duration of etching the dielectric layer under the first etching duration according to the first etching duration; establishing a second association relation corresponding to thickness variation according to the first etching rate, the first assumption duration, the second etching rate, the second assumption duration and the thickness variation of the dielectric layer under the first etching duration; And combining the first association relation and the second association relation to form an equation set, and solving the equation set to obtain the first assumption duration and the second assumption duration.
4. The method of claim 1, wherein determining the thickness of the implant layer based on the first etch rate and the thickness variation of the dielectric layer over each etch period comprises: determining the assumed etching rate of the injection layer according to the thickness change of the dielectric layer under the second etching duration and the second etching duration; And calculating the thickness of the injection layer according to the thickness change of the dielectric layer under the first etching duration, the first etching rate and the assumed etching rate.
5. The method of claim 1, wherein the ion implantation process is performed using an ion type comprising at least one of argon ion, boron ion, phosphorus ion, arsenic ion, oxygen ion, nitrogen ion, magnesium ion, and aluminum ion.
6. The method of claim 1, wherein the substrate is a silicon substrate and the dielectric layer is silicon dioxide, and wherein the ratio of flow rates of EtOH gas to HF gas in the currently selected etching process is controlled to be between 0.5:1 and 2:1.
7. The method of claim 1, wherein the ion implantation process is performed at an implant dose ranging from 1e15 ions/cm 2 to 1e17 ions/cm 2 .
8. The method of claim 1, wherein the thickness variation of the dielectric layer at each etching duration is determined based on ellipsometry measurements.
9. The method of claim 1, wherein the etching process is a vapor phase etching, and wherein a chamber pressure of the vapor phase etching is controlled in a range of 100 mTorr to 500 mTorr.
10. An ion implantation depth measuring device is characterized by comprising a determining module, an etching module and a processing module; the determining module is used for determining a first time length according to the pre-measured thickness of the dielectric layer, the currently selected etching process and the pre-determined relation between the etching process and the etching speed of the dielectric layer; The determining module is further configured to determine a first etching duration and a second etching duration according to the first duration, where the first etching duration is less than the second etching duration, and the first etching duration and the second etching duration are both less than the first duration; The etching module is used for etching the dielectric layer which is not processed by the ion implantation process for the second etching duration according to the currently selected etching process, and determining the first etching rate of the dielectric layer according to the first thickness variation value of the dielectric layer and the second etching duration in the etching process; The etching module is further used for respectively etching the dielectric layer treated by the ion implantation process according to the currently selected etching process for the first etching duration and the second etching duration, and determining thickness change of the dielectric layer under each etching duration; The processing module is used for determining whether the etching process corresponding to each etching duration corresponds to two different types of etching according to the thickness change of the dielectric layer under each etching duration, wherein the two different types of etching are respectively etching the injection layer only and simultaneously etching the injection layer and the dielectric layer; If so, determining the thickness of the injection layer according to the first etching rate and the thickness change of the dielectric layer under each etching duration, otherwise, executing the steps of determining the first etching duration and the second etching duration according to the first duration again.

Description

Ion implantation depth measurement method and device Technical Field The present application relates to the field of semiconductor manufacturing technology, and in particular, to a method and apparatus for measuring ion implantation depth. Background In the field of semiconductor manufacturing, ion implantation technology is a key process for realizing device doping, and the electrical properties of a semiconductor material are accurately regulated and controlled by implanting high-energy ions into the material. The depth of ion implantation, namely junction depth, is one of the core parameters for determining the performance of the device, and effective and reliable monitoring of the junction depth is a necessary link for ensuring the yield and the performance of the product. Currently, the industry relies mainly on time-of-flight secondary ion mass spectrometry (TOF-SIMS) techniques for measuring ion implantation junction depths. According to the technology, the ion beam is used for sputtering a sample and carrying out mass spectrometry on secondary ions escaping from the sample, so that high-precision characterization of concentration distribution of doping elements in the depth direction can be realized, and the junction depth position is determined. However, this mainstream technology has significant limitations. First, the TOF-SIMS equipment itself and its subsequent maintenance costs are extremely high, making the application of this technology a high threshold, which is difficult to popularize in extensive production line monitoring. Secondly, to achieve excellent depth resolution and detection sensitivity, a single measurement is often time consuming and cannot meet the requirements of modern semiconductor manufacturing for fast, high throughput detection. In addition, the technology has severe requirements on the professional of the operating environment and personnel. These factors together result in the current methods of measuring ion implantation junction depths being costly, limited in efficiency, and severely dependent on a particular large analytical instrument. Thus, there is a need to develop an alternative measurement solution that combines low cost and high efficiency. Disclosure of Invention In view of the above, the present application provides a method and apparatus for measuring a junction depth by detecting a change in etching rate caused by ion implantation, which solves the problems of high cost and low efficiency of the conventional art. Specifically, the application is realized by the following technical scheme: The first aspect of the present application provides an ion implantation depth measurement method, the method comprising: determining a first time length according to the pre-measured thickness of the dielectric layer, the currently selected etching process and the pre-determined relation between the etching process and the etching speed of the dielectric layer; Determining a first etching duration and a second etching duration according to the first time, wherein the first etching duration is smaller than the second etching duration, and the first etching duration and the second etching duration are both smaller than the first time; Etching the dielectric layer which is not treated by the ion implantation process for the second etching duration according to the currently selected etching process, and determining the first etching rate of the dielectric layer according to the first thickness variation value of the dielectric layer and the second etching duration in the etching process; Etching the dielectric layer treated by the ion implantation process according to the currently selected etching process for the first etching duration and the second etching duration respectively, and determining thickness change of the dielectric layer under each etching duration; Determining whether etching processes corresponding to each etching duration correspond to two different types of etching according to thickness change of the dielectric layer under each etching duration, wherein the two different types of etching are respectively etching the injection layer only and simultaneously etching the injection layer and the dielectric layer; If so, determining the thickness of the injection layer according to the first etching rate and the thickness change of the dielectric layer under each etching duration, otherwise, executing the steps of determining the first etching duration and the second etching duration according to the first duration again. The second aspect of the application provides an ion implantation depth measuring device, which comprises a determining module, an etching module and a processing module; the determining module is used for determining a first time length according to the pre-measured thickness of the dielectric layer, the currently selected etching process and the pre-determined relation between the etching process and the etching speed of the dielectric