KR100253357B1 - Apparatus for measuring interface roughness using scm - Google Patents

Abstract

PURPOSE: An interfacial surface roughness measuring device is provided to measure a roughness of an interfacial surface precisely with a SCM by separating roughness of the interface and roughness of the surface from thickness of an oxide film. CONSTITUTION: A roughness measuring apparatus of an interface comprises a finding indicator(13) reflecting light having the designated frequency according to roughness of a test piece(23) with adjusting an angle; a detecting unit(12) detecting the roughness of the surface by the light reflected from the indicator; a sensor(21) detecting the surface roughness and the interface roughness of an oxide film(22) by variables of capacitance generated in the test piece in applying direct current and alternating current to the indicator and the test piece; and a lock-in amplifier(20) amplifying and outputting an output signal of the sensor. The surface roughness of the test piece, and the roughness of the interfacial surface between the oxide film and silicon are detected with measuring the angle change of the light reflected by the indicator.

Description

Interfacial roughness measuring device using SMC M {APPARATUS FOR MEASURING INTERFACE ROUGHNESS USING SCM}

The present invention relates to an apparatus for measuring interfacial roughness using SCM, and more particularly, to an apparatus for measuring interfacial roughness using SCM to separately measure surface roughness and interfacial roughness of an oxide film.

In general, SCM is a device developed for measuring a dopant profile, which will be described below with reference to the accompanying drawings for measuring a dopant profile using SMC.

Figure 1 is a block diagram showing a configuration for a surface roughness measuring apparatus using a conventional SMC, as shown in the laser diode 10 for emitting light having a constant frequency; A mirror 11 reflecting light emitted from the laser diode 10 at an appropriate angle; A detector needle 13 which contacts the specimen surface 14 and reflects the light reflected by the mirror 11 at varying angles according to the roughness of the specimen surface 14; A detector 12 receiving light reflected from the detector 13 and detecting roughness of the surface accordingly; It is composed of a scanner 15 for scanning the specimen 14, the operation of the conventional device configured as described above is as follows.

First, the tip at the end of the probe 13 is in contact with the specimen surface 14 and then scanned by the scanner 15, and accordingly the probe 13 moves according to the roughness of the specimen surface 14 do.

At this time, the roughness of the specimen surface 14 is detected by the detector 12 detects the change in the angle of the light reflected on the opposite surface of the tip (TIP) at the end of the detection needle (13).

That is, the light emitted from the laser diode 10 is irradiated to the rear surface of the detection needle 13 which is moved by the scanner 15 using the mirror 11, and at this time, the angle change of the reflected light is detected by the detection unit 12. The roughness of the specimen surface 14 is determined by measuring using.

Here, the interfacial roughness is measured by the same method as the method of measuring the roughness of the specimen surface 14 by removing the oxide film as the surface layer.

That is, after removing the oxide layer, which is the surface layer of the sample to be measured, by chemical etching, the tip (TIP) at the tip of the probe 13 is contacted with the interface, and then scanned by the scanner 15. The probe 13 moves according to the roughness.

At this time, the roughness of the interface is detected by the detection unit 12 detects the change in the angle of the light reflected by the opposite surface of the tip (TIP) at the end of the detection needle (13).

However, as described above, there is a problem in that the sample to be measured is mainly removed by using a chemical etching method, but silicon as a substrate is etched to some extent so that the roughness of the interface cannot be accurately measured.

Accordingly, the present invention devised in view of the above problems provides an apparatus for measuring interfacial roughness using SMC to measure accurate interfacial roughness by separating and measuring surface roughness and interfacial roughness information from the thickness of an oxide film. There is a purpose.

1 is a block diagram showing the configuration of a surface roughness measuring apparatus using a conventional SM.

Figure 2 is a block diagram showing the configuration of the surface roughness measuring apparatus using the present invention SM.

***** Description of the symbols for the main parts of the drawings *****

12: Detection part 13: Detection probe

15: scanner 20: lock-in amplifier

21: sensor 22: oxide film

23: Semiconductor

The present invention for achieving the above object is a detection needle for reflecting the light having a constant frequency by changing the angle according to the rough sound of the specimen surface; A detector for detecting the roughness of the surface by the light reflected from the detector needle; A sensor for sensing information about surface roughness and interfacial roughness of an oxide film as a change value of capacitance generated inside the specimen when a DC voltage and an AC voltage are applied to the detection needle and the specimen; And a lock-in amplifier configured to amplify and output the output signal of the sensor to a predetermined level.

Hereinafter, with reference to the accompanying drawings the operation and effects of the embodiment of the configuration of the apparatus for measuring the surface roughness using the present invention SM.

Figure 2 is a block diagram showing the configuration of the interface roughness measuring apparatus using the present invention SMC, as shown in the detection needle for changing the angle by reflecting light having a constant frequency according to the roughness of the surface of the specimen (23) 13); A detector 12 which detects roughness of the surface by the light reflected from the detector 13; When a DC voltage and an alternating voltage are applied to the detector needle 13 and the specimen 23, information about the surface roughness and the interface roughness of the oxide film 22 is sensed as a change in capacitance generated in the specimen 23. A sensor 21; A lock-in amplifier 20 for amplifying and outputting the output signal of the sensor 21 to a predetermined level will be described below.

First, when a DC voltage and an alternating voltage are applied to the detection needle 13 of SMC, a dopant existing in the specimen 23 accumulates toward the oxide film 22 present on the surface or depletes into the specimen 23.

At this time, the accumulation and depletion of the dopant is dependent on the shape of the dopant and the polarity of the DC voltage applied to, for example, if the dopant is a blood type, when the positive DC voltage is applied to the multiple carriers in the specimen 23 When the holes are pushed toward the inside of the specimen 23 to form a depletion layer and a negative DC voltage is applied, the holes are accumulated toward the surface.

Here, the value of the capacitance measured under the condition in which the holes are accumulated is detected by the sensor 21 and amplified by the lock-in amplifier 20 by a predetermined level.

의 관계식에서 알수 있듯이 유전율과 두께에 의해서 결정되므로 산화막(22)의 2차원적인 두께에 대한 정보를 얻을 수 있는데, 이 정보는 표면 거칠기와 계면 거칠기가 함께 들어있는 정보로서 둘 중에 하나를 알면 나머지 정보를 알 수 있다.At this time, the value of the capacitance is the value of the oxide film 22, and the value of the capacitance is

As can be seen from the relational equation, the information on the two-dimensional thickness of the oxide film 22 can be obtained because it is determined by permittivity and thickness. This information includes surface roughness and interfacial roughness. It can be seen.

Therefore, the roughness of the surface of the specimen 23 is obtained by detecting the change in the angle of the light irradiated and reflected on the detector needle 13 of the SMC by using the surface roughness, and the oxide film 22 and the silicon ( The interfacial roughness between Si) is obtained.

As described in detail above, the present invention has the effect of measuring the exact interface roughness by measuring the surface roughness and the interface roughness information separately from the thickness of the oxide film, and thereby obtaining the process conditions for obtaining the optimum interface conditions.

Claims (1)

A detection needle that reflects light having a constant frequency by changing an angle according to roughness of the surface of the specimen; A detector for detecting the roughness of the surface by the light reflected from the detector needle; A sensor for sensing information on the surface roughness and the interface roughness of the oxide film as a change value of capacitance generated inside the specimen when a DC voltage and an AC voltage are applied to the probe and the specimen; And a lock-in amplifier configured to amplify and output the output signal of the sensor to a predetermined level.

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