KR0161420B1 - Monitoring method of high energy ion implantation - Google Patents

Abstract

In the method for manufacturing a semiconductor device, a method for monitoring the energy and dose injected during the ion implantation process is described.

This is characterized in that the laser beam is irradiated to the region implanted with high energy to measure the TW value of the beam reflected from the implanted region. Therefore, it is possible to secure the reliability of the high energy ion implantation process and to perform stable process management, and to prevent a beam scan trouble in advance.

Description

Monitoring method of high energy ion implantation

1 is a cross-sectional view illustrating a conventional high energy ion implantation method.

2 shows a system for measuring Thermal Wave values.

3a to 3f are graphs showing the correlation between the implanted energy and the amount of implanted impurities during the high energy ion implantation and the TW value.

4A and 4B are cross-sectional views illustrating a method for monitoring high energy ion implantation according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of monitoring energy of implanted ions using a thermal wave value during a high energy ion implantation process.

Ion Implantation technology makes it easy to control the amount of impurity unit injection and distribution, and to reduce side spread, low temperature process, uniformity, and simple source of impurities. It is a method widely used as a step of dope.

The most important advantage of ion implantation is the ability to precisely control the number of atoms of implanted impurities. By annealing the implanted area by applying heat at a temperature of about 600 ~ 1,000 ℃ after implantation, the impurity concentration in silicon can be accurately obtained between 10 ¹⁴ ~ 10 ²¹ atoms / cm ³ , The distribution can be easily adjusted.

However, in the case of high energy ion implantation with an implantation energy of 200KeV or more, when an abnormality occurs in the amount (dose) and implantation depth (energy) of the implanted ion, there is no way to detect it early. No abnormality could be determined.

As an example of such a high energy ion implantation process, there is a retro-grade well process for forming an energy barrier in bulk in the manufacture of highly integrated devices of 16M DRAM or more.

Referring to FIG. 1A, a photoresist pattern 12 for defining a region in which a well is to be formed is formed on the semiconductor substrate 10 by a photolithography process, and then a semiconductor substrate in a region opened by the photoresist pattern is formed. Inject impurity ions with high energy. In this case, for example, to form an N well, phosphorus (P) ions are implanted with a dose of 1.0E13 and an energy of 800 KeV, and to form a P well, for example, boron (B) ions Is injected with a dose of 1.0E13 and an energy of 700 KeV.

Subsequently, ion implantation is performed to form a field. In the case of P type, phosphorus (P) ions are implanted with a dose of 5.0E12 and energy of 300 KeV, and then the photoresist pattern is removed.

As described above, in the case of the high energy ion implantation process of 200KeV or more, since there is no tool to test, the energy of the implanted ions cannot be confirmed. Therefore, there is a problem that can not be stably managed high energy ion implantation process.

Accordingly, an object of the present invention is to provide a high energy ion implantation monitoring method that can more stably manage the high energy ion implantation process.

The present invention to achieve the above object,

A high energy ion implantation monitoring method is provided by irradiating a laser beam to a region of high energy ion implantation to measure a TW value of a beam reflected from the region.

In the present invention, the ion implantation step is preferably implantation energy of 200KeV or more.

In the present invention, the TW value is preferably measured for each run or for each batch.

According to the present invention, it is possible to secure the reliability of the high energy ion implantation process and stable process management, and to prevent a beam scan trouble in advance.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is characterized in that the energy injected by using a thermal wave value (hereinafter referred to as TW) during the ion implantation process using high energy. At this time, the TW value is data indicating the degree of damage on the wafer surface caused by ion implantation, and this value increases as the degree of damage increases. That is, the larger the injection energy, the larger the dose, and the larger the AMU (Atom Mass Unit) of the dopant.

2 shows a system for continuing the TW of Thermal Probe.

Referring to FIG. 2, after the laser beam 20 is irradiated onto the sample wafer 30, the degree of damage is measured by amplifying the diffusely reflected beam 40 at the damaged portion of the wafer.

In FIG. 2, representing ΔR / R as a value is a TW value. That is, since the reflectance (R) of the laser beam on the wafer surface varies depending on the degree of damage, the degree of damage can be known from the TW value. Since the damage caused by ion implantation differs depending on the energy of the ion beam, the dose and the dopant, it is possible to determine whether there is an ion implantation abnormality in the region of 200 KeV or more where the implantation energy cannot be verified by the TW value.

3a to 3f are graphs showing the correlation of TW values with respect to energy and dose in high energy ion implantation processes. FIGS. 3a and 3b are N wells, and FIGS. 3c and 3d are P wells. And 3e and 3f are graphs each showing a TW value for energy and dose amount when forming a P field.

As shown, the larger the implantation energy, the larger the dose, and the larger the AMU (Atom Mass Unit) of the dopant, the higher the TW value.

4A and 4B are cross-sectional views illustrating a method for monitoring high energy ion implantation according to an embodiment of the present invention.

The high energy ion implantation process according to an embodiment of the present invention proceeds to a well region definition, well ion implantation, TW value measurement, field ion implantation, TW value measurement, and PR removal process.

Referring to FIG. 4A, after the photosensitive film pattern 12 is formed on the semiconductor substrate 10 by a normal photographic process to define a region in which a well is formed, impurity ions are applied to the semiconductor substrate with high energy. Inject.

In this case, for example, when N-well is to be formed, phosphorus (P) ions are implanted with a dose of 1.0E13 and an energy of 800 KeV, and when a P-well is to be formed, for example, boron (B). Ions are implanted with a dose of 1.0E13 and an energy of 700 KeV.

Referring to FIG. 4B, after ion implantation for forming the well, the semiconductor substrate of the ion implanted portion is irradiated with a laser beam to measure the TW value to compare the dose and energy of the actually implanted ion with a target value. Check the injection for abnormalities.

Subsequently, ion implantation is performed to form a field. In the case of a P-type field, phosphorus (P) ions are implanted with a dose of 5.0E12 and energy of 300 KeV, and then to confirm the result of the field ion implantation. Measure and compare TW again.

In the case where the measurement of the TW value is periodically performed in a run base, it is preferable to measure each run or to measure each batch. In this case, the batch refers to the number of wafers injected using the same beam.

According to the high energy ion implantation process according to the present invention described above, when an abnormality occurs in the dose amount and energy of ions implanted with high energy, it is detected early and stable process management is achieved, and the reliability of the ion implantation process is improved. It can be ensured and the beam scan trouble of the beam can be prevented in advance.

The present invention is not limited to the above embodiments, and it is apparent that many modifications are possible by those skilled in the art within the technical idea to which the present invention pertains.

Claims (3)

Implanting impurity ions at a high energy into a predetermined region of the semiconductor substrate; And measuring a TW (Thermal Wave) value of the reflected laser beam after irradiating the laser beam to the region. The method of claim 1, wherein the implanting the impurity ions comprises implantation energy of 200 KeV or more. The method of claim 1, wherein the TW value is measured for each run or for each batch.