Patent ID: 12196669

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, example embodiments of the present inventive concept are described in detail with reference to the accompanying drawings. Identical reference numerals are used for the same components in the drawings, and a duplicate description thereof may be omitted,

It will be understood that, although the terms “first”, “second”, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or !section without departing from the spirit and scope of the present inventive concept.

FIG.1is a schematic diagram of an inspection apparatus10according to an example embodiment of the present inventive concept.

Referring toFIG.1, the inspection apparatus10may include a stage110, an inspection signal source120, an alignment device130, a first probe200, and a second probe300.

The inspection apparatus10may non-destructively inspect an inspection object, for example, a wafer W, etc. An inspection object of the inspection apparatus10might not he limited to the wafer W, but may include individualized and packaged semiconductor elements, etc.

Hereinafter, a device under test to be inspected by the inspection apparatus10may be mainly described with reference to the wafer W, as an example, but those of ordinary skill in the art may understand the inspection apparatus10to be capable of inspecting a semiconductor chip and a semiconductor package, based on the descriptions below.

hi this case, the wafer W may include, for example, silicon (Si). The wafer W may include a semiconductor element, such as germanium (Ge), or a compound semiconductor, such as silicon carbide (SiC), gallium arsenide (GaAs), indium arsenide (InAs), and/or indium phosphor (InP). According to an example embodiment of the present inventive concept, the wafer W may have a silicon on insulator (SOI) structure, The wafer W may include a buried oxide layer. According to an example embodiment of the present inventive concept, the wafer W may include conductive regions, for example, a well doped with impurities. In an example embodiment of the present inventive concept, the wafers W may have various device isolation structures, such as a shallow trench isolation (STI), which separates the doped wells from each other.

The inspection apparatus10may inspect the wafer W, on which a series of processes have been performed. In this case, a series of processes may include various processes for forming a semiconductor element, The series of processes may include, for example, an ion doping process, an oxidation process for forming an oxide layer, a spin coating process, a lithography process including exposure and development, a thin layer deposition process including a chemical vapor deposition (CM) process, an atomic layer deposition (AID) process, and a physical vapor deposition (PVD) process, a dry etching process, a wet etching process, a metal wiring process, etc.

According to an example embodiment of the present inventive concept, the inspection apparatus10may include a line inspection apparatus included in various wafer processing devices. Accordingly, the inspection apparatus10may inspect in real time the wafer W processed by a wafer processing device. The wafer processing device may include, for example, an exposure device using a stepper method or a scanner method, a dry/wet etching facility, a plasma etching facility, a cleaning facility, a plasma asher facility, a polishing facility such as a chemical mechanical polishing (CMP) facility, an ion implantation facility, a PVD facility, a CVD facility, an ALD facility, an annealing facility, etc. However, the present inventive concept is not limited thereto, and the inspection apparatus10may be discretely provided outside of the wafer processing device.

The inspection apparatus10may include, for example, a terahertz time domain spectrometer. The inspection apparatus10may inspect the wafer W by providing to the wafer W an ultrashort pulse signal in a certain frequency band in a terahertz range (for example, about 0.1 THz to about 10 THz), and then detecting a frequency-strength distribution of the ultrashort pulse signal having been reflected by the wafer W or having passed through the wafer W. From the inspection result by using the inspection apparatus10, information about, for example, doping concentration of the water W and movement of a carrier may be obtained.

The inspection of the wafer W may be performed by comparing a terahertz time domain spectrum with respect to a standard water W. The inspection of the wafer W may include a scanning inspection on the entire surface of the wafer W, or a spot inspection on some regions of the wafer W. Different portions of the wafer W may be inspected by driving the inspection stage110. The inspection stage110may move the wafer W in an X direction, a direction, and a Z direction, or rotate the wafer W with the Z direction as an axis.

In this case, the X direction and the Y direction may be two directions that are substantially perpendicular to each other and may be parallel to an upper surface of the inspection stage110. The Z direction may include a direction substantially vertical to the upper surface of the inspection stage110. The X direction, the. Y direction, and the Z direction may be substantially perpendicular to each other. Unless otherwise specified, the directions are the same as those in other diagrams below.

The inspection apparatus10may operate in a reflection mode or a transmission mode. The first probe200may be used in a transmission mode inspection, and the second probe300may be used in a reflection mode inspection. In the transmission mode, the inspection signal source120may emit a terahertz wave TW on one surface of the wafer W, and the terahertz wave TW having passed through the wafer W may be detected by the first probe200. In the reflection mode, the second probe300may provide an inspection signal to the wafer W, and the second probe300may detect again the inspection signal reflected by the wafer W.

The inspection signal source120may generate the terahertz wave TW, and emit the terahertz wave TW to the wafer W. The inspection apparatus10may include a beam transfer optics for transferring the terahertz wave TW generated by the inspection signal source120to the wafer W. The beam transfer optics may include various optical components, such as a polarizing or non-polarizing beam splitter, a focusing lens, a collimating lens, a spherical mirror, a non-spherical mirror, etc.

The alignment device130may move the first and second probes200and300to appropriate locations for inspecting the wafer W. The alignment device130may move, for example, the first probe200so that the first probe200detects the terahertz wave TW having passed through the wafer W. The alignment device130may move the first probe200so that a first probe tip220is positioned at the spatial maximum point of the terahertz wave TW on an X-Y plane. The alignment device130may move the first and second probes200and300vertically (for example, in the Z direction so that the first and second probes200and300have an appropriate distance for inspection (for example, tens of micrometers) vertically (for example, in the Z direction) from the upper surface of the wafer W.

FIG.2is a plan view of the first probe200included in the inspection apparatus10.

FIG.3schematically illustrates electrical and optical configurations of the first probe200included in the inspection apparatus10.

Referring toFIGS.1through3, the first probe200may include a first terahertz wave optics, a first excitation optics, and a second excitation optics. The first terahertz wave optics may include a first printed circuit board210, the first probe tip220, a radio frequency (RF) connector230, and an RF signal line240. The first excitation optics may include a first optical connector260, a first optical cable261, a first lens263, and a first mirror265. The second excitation optics may include a second optical connector270, a second optical cable271, a second lens273, a first non-linear optical device275, a third lens277, and a second mirror279.

The first printed circuit board210may fix and mechanically support the first probe tip220. The first probe tip220may be mounted on the first printed circuit board210. The first probe tip220may be mounted on the first printed circuit board210. The first printed circuit board210may include conductive patterns211and213for receiving and reading signals detected by a receiver antenna221.

The receiver antenna221for detecting the terahertz wave TW haying passed through the wafer W may be embedded in the first probe tip220. The receiver antenna221may include, for example, a dipole antenna. The receiver antenna221may include first and second electrodes222and223, and a first photoconductive switch224connected to the first and second electrodes222and223. The first photoconductive switch224may generate a light-excited carrier in response to a first laser beam LB1.

The first probe tip220may he a vertical type. For example, when the first probe200is mounted on the alignment device130, an extension direction of the first probe tip220may be substantially parallel to the Z direction. Accordingly, the first probe200may detect the terahertz wave TW that originated from a narrow region of the wafer W, and the resolution of the inspection apparatus10may be increased.

When the first laser beam LB1is emitted onto the first photoconductive switch224and at the same time, the terahertz wave TW that has passed through the wafer W reaches the receiver antenna221, light-excited carriers may be accelerated by the terahertz wave TW, and accordingly, the terahertz signal in the transmission mode may be sensed. According to an example embodiment of the present inventive concept, the first laser beam LB1may be a gating signal, which tams on/off the receiver antenna221According to an example embodiment of the present inventive concept, the terahertz wave TW may have a pulse train including a plurality of ultrashort pulses, and the receiver antenna221may sense a portion of the plurality of ultrashort pulses, which timely and spatially overlap the first laser beam LB1, (for example, the ultrashort pulses substantially and simultaneously arriving at the first laser beam LB1and the receiver antenna221). In other words, while the first laser beam LB1is emitted, the receiver antenna221may sense the terahertz wave TW having passed through the wafer W, and while the first laser beam LB1is not emitted, the receiver antenna221might not sense the terahertz wave TW having passed through the wafer W.

An electrical signal generated by the receiver antenna221in response to the terahertz wave TW may be output via the conductive patterns211and213, the RF connector230, and the RF signal line240.

The inspection apparatus10may include a first optical bracket250coupled to the first printed circuit board210. The first optical bracket250may be coupled to the first printed circuit board210by using, for example, a combination device251, such as a bolt and a nut,

The first optical bracket250may cover and fix optical components, which are coupled to the first probe200, such as the first optical cable261, the first lens263, the first mirror265, the second optical cable271, the second lens273, the first non-linear optical device275, the third lens277, and the second mirror279.

The first optical cable261, the first lens263, the first mirror265, the second optical cable271, the second lens273, the first non-linear optical device275, the third lens277, and the second mirror279may be fixed to the first optical bracket250by using, for example, epoxy, etc.

According to an example embodiment of the present inventive concept, the first optical cable261, the first lens263, the second optical cable271, the second lens273, the first non-linear optical device275, and the third lens277may be arranged between the first printed circuit board210and the first optical bracket250.

According to an example embodiment of the present inventive concept, the first optical bracket.250may cover one side of the first printed circuit board210and expose (for example, might not cover) the other side thereof Accordingly, the first probe200may be provided in a relatively small size, and the inspection apparatus10may include a desirable number of first probes200. However, the present inventive concept is not limited thereto, and the first optical bracket250may also cover both surfaces of the first printed circuit board210to at least partially surround the first printed circuit board210.

The first optical connector260may be connected to the first optical cable261, The first optical connector260may introduce the first laser beam LB1into the first probe200. The first laser beam LB1introduced by the first optical connector260may be guided along the first optical cable261. The first optical cable261may include an optical fiber.

According to an example embodiment of the present inventive concept, a wavelength of the first laser beam LB1may be in a range of about 300 nm to about 1600 nm. As a non-limiting example, the wavelength of the first laser beam LB1may be about1560nm.

The first optical cable261may be connected to the first lens263. Accordingly, the first laser beam LB1guided along the first optical cable261may be transferred to the first lens263. The first lens263may focus the first laser beam LB1The first laser beam LB1focused by the first lens263may be reflected by the first mirror265. The first laser beam LB1reflected by the first mirror265may be focused on the first photoconductive switch224,

According to an example embodiment of the present inventive concept, after being reflected by the first mirror265, the first laser beam LB1may be transferred through a free space optics, not an optical fiber circuit or an optical integrated circuit. In other words, an air gap may be arranged between the first mirror265and the first photoconductive switch224of the receiver antenna221. Accordingly, an occurrence of multiple reflections of the terahertz signal transferred by the receiver antenna221and a sensing of external noise by the receiver antenna221may be prevented. Accordingly, the reliability of the inspection apparatus10may be increased.

The second optical connector270may be coupled to the first optical bracket250. The second optical connector270may be connected to the second optical cable271, The second optical connector270may introduce a second laser beam LB2into the first probe200. The second laser beam LB2introduced by the second optical connector270may be guided along the second optical cable271. The second optical cable271may include optical fiber.

According to an example embodiment of the present inventive concept, a wavelength of the second laser beam LB2may be in a range of about 300 nm to about 1600 nm. As a non-limiting example, the wavelength of the second laser beam LB2may be about 1560 nm. The second laser beam LB2may be generated by the same laser device generating the first laser beam LB1but the present inventive concept is not limited thereto.

The second optical cable271may be connected to the second lens273. Accordingly, the second laser beam LB2guided along the second optical cable271may be transferred to the second lens273. The second lens273may focus the second laser beam LB2on the first non-linear optical device275. According to an example embodiment of the present inventive concept, because a focus of the second lens273is on the first non-linear optical device275, a frequency conversion efficiency of the first non-linear optical device275may be maximized.

The first non-linear optical device275may receive the second laser beam LB2, and output a second laser beam LB2′ having a different frequency from that of the second laser beam LB2. As an example, the first non-linear optical device275may include a second harmonic generator, and generate the second laser beam LB2′ haying a frequency larger than the frequency of the second laser beam LB2. For example, the frequency of the second laser beam LB2′ may be about two times greater than the frequency of the second laser beam LB2. An example of the second harmonic generator may include any one of periodically poled lithium niobate (PPLN) crystal and beta barium borate (BBE) or β-BaB2O4crystal. Another example of the second harmonic generator may include lithium triborate (LBO) or LiB3O5, monoclinic bismuth borate (BIBO) or BiB3O6, potassium titanyl arsenate (KTA) or KTiOAsO4, potassium titanyl phosphate (KTP) or KTiOPO4. As an example, when a wavelength of the second laser beam LB2is about 1560 nm and the first non-linear optical device275includes a second harmonic generator, a wavelength of the second laser beam LB2′ may be about 780 nm.

However, the present inventive concept is not limited thereto, and the first non-linear optical device275may include an arbitrary device for generating light of a predetermined wavelength for example, a wavelength of about 800 nm or less) for exciting the wafer W in response to the second laser beam LB2.

The first non-linear optical device275may generate the second laser beam LB2′ by using various (for example, second-order, third-order, and fourth-order or higher-order) non-linear optical phenomena.

In this case, an example of a second-order non-linear optical phenomenon may include an optical parametric process in addition to second harmonic generation (SHG).

An example of the a third-order non-linear optical phenomenon may include third harmonic generation (THG), third-order sum frequency generation (TSFG), four-wave mixing (FWM), stimulated Raman scattering (SRS), optical Kerr effect (OKE), Raman induced Kerr effect (RIKE), stimulated Rayleigh scattering, stimulated Brillouin scattering (SBS), stimulated Kerr scattering, stimulated Rayleigh-Bragg scattering, stimulated Mie scattering, self-phase modulation (SPM), cross phase modulation (XPM), optical-field induced birefringence, and electric-field induced SHG.

An example of fourth-order or higher non-linear optical phenomenon may include hyper-Raman scattering, hyper-Rayleigh scattering, and coherent anti-Stokes hyper-Raman scattering.

The second laser beam LB2′ output by the first non-linear optical device275may reach the third lens277. The third lens277may focus the second laser beam LB2′ on the second minor279. The second laser beam LB2′ focused by the third lens277to the second mirror279may be reflected by the second mirror279. The second laser beam LB2′ reflected by the second mirror279may be focused on the wafer W The second laser beam LB2° may excite a portion of the wafer W, and in this case, sensitivity of inspection of doping concentration carrier movement of the excited portion of the wafer W may be increased,

FIG.4schematically illustrates electrical and optical configurations of the second probe300included in the inspection apparatus10,

Referring toFIGS.1and4, the second probe300may include a second terahertz wave optics, a third excitation optics, a fourth excitation optics, and a fifth excitation optics. The second terahertz wave optics may include a second printed circuit board310, a second probe tip320, first and second RF connectors331and333, and first and second RF signal lines341and343. The third excitation optics may include a third optical connector360, a third optical cable361, a fourth lens363, and a third mirror365. The fourth excitation optics may include a fourth optical connector370, a fourth optical cable371, a fifth lens373, and a fourth mirror375. The fifth excitation optics may include a fifth optical connector380, a fifth optical cable381, a sixth lens383, a second non-linear optical device385, a seventh lens387, and a fifth mirror389.

The second printed circuit board310may fix and mechanically support the second probe tip320. The second probe tip320may be mounted on the second printed circuit board310. The second printed circuit board310may provide a signal for driving an emitter antenna321, and may include conductive patterns311,313,315, and317for outputting an electrical signal generated by a detector antenna325.

The second probe tip320may be a vertical type. For example, when the second probe300is mounted on the alignment device130, an extension direction of the second probe tip320may be substantially parallel to the Z direction, According to an example embodiment of the present inventive concept, an inspection by using the second probe tip320may he limited in a small region of the wafer W, and accordingly, the resolution of the inspection apparatus10may be increased.

The emitter antenna321for irradiating a terahertz wave signal to the wafer W and the detector antenna325for detecting the terahertz wave signal, which has been emitted by the emitter antenna321and reflected by the wafer W, may be embedded in the second probe tip320. Each of the emitter antenna321and the detector antenna325may include, for example, a dipole antenna.

The emitter antenna321may include third and fourth electrodes322and323, and a second photoconductive switch324connected to the third and fourth electrodes322and323. The second photoconductive switch324may generate a light-excited carrier in response to a fourth laser beam LB4.

When the fourth laser beam LB4is emitted onto the second photoconductive switch324and, at the same time, terahertz power is provided to the emitter antenna321by a first RF signal line341, a light-excited carrier may be accelerated and the terahertz wave may be emitted. The fourth laser beam LB4may be a gating signal for turning on/off the emitter antenna321. According to an example embodiment of the present inventive concept, terahertz power in form of pulse train including a plurality of ultrashort pulses may be provided to the emitter antenna321, and the emitter antenna321may generate ultrashort pulses in a terahertz band in response to a portion of the plurality of ultrashort pulses, which timely and spatially overlap the fourth laser beam LB4. For example, while the fourth laser beam LB4is emitted, the emitter antenna321may emit the ultrashort pulses in a terahertz wave band, and while the fourth laser beam LB4is not emitted, the emitter antenna321might not emit the ultrashort pulses in a terahertz wave band.

The detector antenna325may include fifth and sixth electrodes326and327, and a third photoconductive switch328connected to the fifth and sixth electrodes326and327. The third photoconductive switch328may generate a light-excited carrier in response to a third laser beam LB3. Similar to descriptions of the first laser beam LB1given with reference toFIGS.2and3, the third laser beam LB3may be a gating signal for turning on/off the detector antenna325.

The inspection apparatus10may include a second optical bracket350coupled to the second printed circuit board310, The second optical bracket350may be coupled to the second printed circuit board310by using, for example, a combination device351, such as a bolt and a nut,

The second optical bracket350may cover and fix optical components, which are integrated in the second probe300, such as the third optical cable361, the fourth lens363, a third mirror365, the fourth optical cable371, the fifth lens373, the fourth mirror375, the fifth optical cable381, the sixth lens383, the second non-linear optical device385, the seventh lens387, and the fifth mirror389.

The third optical cable361, the fourth lens363, the third mirror265, the fourth optical. cable371, the fifth lens373, the fourth mirror375, the fifth optical cable381, the sixth lens383, the second non-linear optical device385, the seventh lens387, and the fifth minor389may be fixed to the second optical bracket350by using, for example, epoxy, etc.

According to an example embodiment of the present inventive concept, the third optical cable361, the fourth lens363, the fourth optical cable371, the fifth lens373, the fifth optical cable381, the sixth lens383, the second non-linear optical device385, and the seventh lens387may be arranged between the second printed circuit board310and the second optical bracket350.

As a non-limiting example, the second optical bracket350may cover both surfaces (e.g., opposing sides) of the second printed circuit board310. For example, the third and fourth optical connectors360and370may be arranged on a first surface of the second printed circuit board310, and the fifth optical connector380may be arranged on a second surface opposite to the first surface of the second printed circuit board310, but the present inventive concept is not limited thereto. For example, the second optical bracket350may cover only the first surface of the second printed circuit board310, and the third through fifth optical connectors360through380may be arranged on the first surface thereof.

The third optical connector360may be coupled to the second optical bracket350. The third optical connector360may be connected to the third optical cable361. The third optical connector360may transmit the third laser beam LB3into the second probe300. The third laser beam LB3introduced by the third optical connector360may be guided along the third optical cable361. The third optical cable361may include optical fiber.

According to an example embodiment of the present inventive concept, wavelengths of the third laser beam LB3and the fourth laser beam LB4to be described below may be in a range of about 300 nm to about 1600 nm. As a non-limiting example, the wavelengths of each of the third and fourth laser beams LB3and LB4may be about 1560 nm.

The third optical cable361may be connected to a fourth lens363. Accordingly, the third laser beam LB3guided along the third optical cable361may be transferred to the fourth lens363, The fourth lens363may focus the third laser beam LB3to the third mirror365. The third laser beam LB3focused by the fourth lens363on the third mirror365may be reflected by the third mirror365The third laser beam LB3reflected by the third minor365may be focused on the third photoconductive switch328.

The fourth optical connector370may be connected to the fourth optical cable371. The fourth optical connector370may transmit the fourth laser beam LB4into the second probe300. The fourth laser beam LB4transmitted by the fourth optical connector370may be guided along the fourth optical cable371. The fourth optical cable371may include optical fiber.

The fourth optical cable371may be connected to the fifth lens373. Accordingly, the fourth laser beam LB4guided along the fourth optical cable371may be transferred to the fifth lens373. The fifth lens373may focus the fourth laser beam LB4to the fourth mirror375. The fourth laser beam LB4focused by the fifth lens373to the fourth mirror375may be reflected by the fourth mirror375, The fourth laser beam LB4reflected by the fourth mirror375may be focused on the second photoconductive switch324.

According to an example embodiment of the present inventive concept, after the third and fourth laser beams LB3and LB4are reflected by the third and fourth mirrors365and375, respectively, the third and fourth laser beams LB3and LB4may be transferred to the third and second photoconductive switches328and324, respectively, via a free space optics rather than fiber optics and optical integrated circuits. For example, air gaps may be respectively arranged between the third mirror365and the third photoconductive switch328of the detector antenna325, and between the fourth mirror375and the second photoconductive switch324of the emitter antenna321.

The fifth optical connector380may be connected to the fifth optical cable381. The fifth optical connector380may introduce a fifth laser beam LB5into the second probe300. The fifth laser beam LB5transmitted by the fifth optical connector380may be guided along the fifth optical cable381. The fifth optical cable381may include optical fiber.

According to an example embodiment of the present inventive concept, a wavelength of the fifth laser beam LB5may be in a range of about 300 nm to about 1600 nm. As a non-limiting example, the wavelength of the fifth laser beam LB5may be about 1560 nm, The third through fifth laser beams LB3through LB5may be generated by the same laser device generating the first laser beam LB1, but the present inventive concept is not limited thereto.

The fifth optical cable381may be connected to the sixth lens383. Accordingly, the fifth laser beam LB5guided along a fifth optical cable381may be transferred to the sixth lens383. The sixth lens383may focus the fifth laser beam LB5on the second non-linear optical device385. According to an example embodiment of the present inventive concept, because the sixth lens383focuses the fifth laser beam LB5on the second non-linear optical device385, a frequency conversion efficiency of the second non-linear optical device385may be increased (e.g., maximized),

The second non-linear optical device385is substantially the same as the first non-linear optical device275described with reference toFIGS.2and3, and thus, duplicate descriptions thereof may be omitted. The second non-linear optical device385may output a fifth laser beam LB5′ having a wavelength of about 780 nm in response to the fifth laser beam LB5.

The fifth laser beam LB5′ output by the second non-linear optical device285may reach the seventh lens387. The seventh lens387may focus the fifth laser beam LB5′ to the fifth mirror389. The fifth laser beam LB5′ focused by the seventh lens387to the fifth mirror389may he reflected by the fifth mirror389, The fifth laser beam LB5′ reflected by the fifth mirror389may be focused on the wafer W. The fifth laser beam LB5′ may excite a portion of the wafer W, and in this case, carrier movement of the excited portion of the wafer W and sensitivity of doping concentration inspection may be increased.

Referring toFIGS.1through4, the first excitation optics for exciting the first photoconductive switch224and the second excitation optics for exciting the wafer W may be integrated in the first probe200, and the third excitation optics and the fourth excitation optics for respectively exciting the second and third photoconductive switches324and328and the fifth excitation optics for exciting the wafer W ma be integrated in the second probe300. In other words, light paths of the first and second excitation optics (for example, light paths of the first and second laser beams LB2and LB3) may be inside the first probe200, and light paths of the third to fifth excitation optics (for example, light paths of the third through fifth laser beams LB$ through LB5) may be inside the second probe300.

According to an example embodiment of the present inventive concept, in configuring the inspection apparatus10, which is a terahertz time domain spectrometer, spaces for excitation optics separately provided for respective probes of existing technology may be drastically reduced. Accordingly, despite of the limited space of the inspection apparatus10, the inspection apparatus10may include a plurality of probes (for example, the first and second probes200and300) for inspecting the wafer W simultaneously (or alternately). The first and second probes200and300may inspect the wafer W, simultaneously, alternately, or in an arbitrary sequence.)

Furthermore, because the first through fifth excitation optics described above are embedded in the first and second probes200and300and fixed, the time for aligning optical components of the first through fifth excitation optics may be reduced. In addition, noise generated during an operation of the inspection apparatus10due to deviation from the alignment set for the optical components of the first through fifth excitation optics may be removed. Accordingly, the inspection speed of the inspection apparatus10may be increased and the reliability of the inspection apparatus10may be increased.

The inspection apparatus10may include a controller for driving the inspection stage110, an operation of the inspection signal source120, driving the alignment device130, and driving electronic devices and optical components included in the first and second probes200and300. The inspection apparatus10may further include a processor for detecting and analyzing signals generated by the first and second probes200and300. The controller and the processor may be implemented as hardware, firmware, software, or a combination thereof. For example, the controller and the processor may include a computing device, such as a workstation computer, a desktop computer, a laptop computer, and a tablet computer. The controller and the processor may also include a simple controller, a microprocessor, a complex processor, such as a central processing unit (CPU), and a graphics processing unit (GPU), a processor including software, dedicated hardware, or firmware, The controller and the processor may be implemented as, for example, application specific hardware, such as a digital signal processor (DSP), a field programmable gate array (FPGA), and an application specific integrated circuit (ASIC),

According to an example embodiments of the present inventive concept, the operations of the controller and the processor may be implemented by instructions stored in a machine-readable medium that may be read and executed by one or more processors. In this ease, the machine-readable medium may include an arbitrary mechanism for storing and/or transferring information in a form readable by a machine (for example, a computing device). For example, the machine-readable medium may include read-only memory (ROM), random access memory (RAM), a magnetic disk storage medium, an optical storage medium, a flash memory device, electrical, optical, acoustical, or other different forms of radio signals (for example, carrier wave, infrared signals digital signals or the like), and other arbitrary signals.

Firmware, software, routines, and instructions may be configured to perform the operations described for the controller and the processor, or any process to be described below. However, this is only for convenience of description, and it should be understood that the operations of the controller and the processor described above may also be executed by a computing device, a processor, or other devices executing firmware, software, routines, instructions, etc.

Those of ordinary skill in the art may, based on descriptions of the present inventive concept, realize an inspection apparatus including a plurality of first probes200, an inspection apparatus including a plurality of second probes300, and an inspection apparatus including the plurality of first probes200and the plurality of second probes300according to example embodiments of the present inventive concept.

FIG.5is a diagram of a first probe201according to an example embodiment of the present inventive concept.

The first probe201ofFIG.5may include a probe of a transmission type, which is similar to the first probe200described with reference toFIGS.2and3. The first probe201may be adopted as an alternative for the first probe200inFIGS.1through3.

Referring toFIG.5, similar to the first probe200inFIGS.1through3, the first probe201may include a first terahertz wave optics including the first printed circuit board210, the first probe tip220, an RF connector230, and the RF signal line240, and a first excitation optics including the first optical connector260, the first optical cable261, the first lens263, and the first minor265. Configurations of the first terahertz wave optics and the first excitation optics are substantially the same as descriptions given with reference toFIGS.1through3, and thus, duplicate descriptions thereof may be omitted.

According to an example embodiments of the present inventive concept, the first probe201may include the second optical connector270, the second optical cable271, the second lens273, and a second mirror279. The second optical connector270may transmit the second laser beam LB2′ into the first probe201. The second laser beam LB2′ transmitted by the second optical connector270may be guided along the second optical cable271. The second laser beam LB2′ transmitted by the second optical cable271may be focused by the second lens273, which is connected to the second optical cable271, to the second mirror279, which reflects the second laser beam LB2′. The second laser beam LB3′ reflected by the second mirror279may be focused on the wafer W.

In an example, the first and second laser beams LB1′ and LB2′ may have predetermined wavelengths for exciting the first photoconductive switch224and the wafer W, respectively. For example, each of the wavelengths of the first and second laser beams LB1′ and LB2′ may be in a range of about 200 nm to about 800 nm. According to an example embodiment of the present inventive concept, for example, each of the wavelengths of the first and second laser beams LB1′ and LB1′ may be about 780 nm.

In another example, the second laser beam (LB2inFIG.2) generated by the same oscillator as the first laser beam LB1′, which has a wavelength in a range of about 200 nm to about 1600 nm, may be transferred to a non-linear optical device outside of the first probe201. The second laser beam LB2′ generated by the non-linear optical device may be transmitted via the second optical connector270into the first probe201.

FIG.6is a diagram of a first probe202according to an example embodiment of the present inventive concept.

The first probe202ofFIG.6may include a probe of a transmission type, which is similar to the first probe200described with reference toFIGS.2and3. The first probe202may be adopted as an alternative for the first probe200inFIGS.1through3.

Referring toFIG.6, similar to the first probe200inFIGS.1through3, the first probe201may include a first terahertz wave optics including the first printed circuit board210, the first probe tip220, an RF connector230, and the RF signal line240, and a first excitation optics including the first optical connector260, the first optical cable261, the first lens263, and the first mirror265. Configurations of the first terahertz wave optics and the first excitation optics are substantially the same as descriptions given with reference toFIGS.1through3, and thus, duplicate descriptions thereof may be omitted.

According to an example embodiment of the present inventive concept, a second excitation optics of the first probe202may additionally include a lens274and a non-linear optical device276, in addition to the second optical connector270, the second optical cable271, the second lens273, the first non-linear optical device275, the third lens277, and the second mirror279.

According to an example embodiment of the present inventive concept, the lens274may be arranged on a light path of the second laser beam LB2″ between the first non-linear optical device275and the third lens277. The non-linear optical device276may be arranged on a light path of the second laser beam LB2′ between the lens274and the third lens277. According to an example embodiment of the present inventive concept, the lens274may focus the second laser beam LB2′ on the non-linear optical device276,

The non-linear optical device276may output a second laser beam LB2″ in response to the second laser beam LB2′ from the lens274. According to an example embodiment of the present inventive concept, the second laser beam LB2″ may be generated based on the second-order non-linear optical phenomenon including SHG, the third-order non-linear optical phenomenon, and the fourth-order non-linear optical phenomenon, described with reference toFIGS.1through3. According to an example embodiment of the present inventive concept, the second laser beam LB2″ may have a shorter wavelength than that of the second laser beam LB2′. As a non-limiting example, the non-linear optical device276may perform SHG, and when a wavelength of the second laser beam LB2′ is about 780 nm, a wavelength of the second laser beam LB2may be about 390 nm.

FIG.7is a flowchart of an inspection method according to an example embodiment of the present inventive concept

Referring toFIGS.1and7, the first probe200may be aligned with an inspection position (P10). The terahertz wave TW may spatially have a Gaussian distribution. According, to an example embodiment of the present inventive concept, by scanning the position of the first probe200in the X direction and the Y direction so that an intensity of the terahertz wave TW sensed by the receiver antenna (221ofFIG.2) of the first probe200may be increased, the first probe200may be aligned. When only the reflection mode inspection using the second probe300is performed, the alignment of P10may also be omitted.

Next, the wafer W may be inspected by using the first probe200and/or the second probe300(P20). For example, the wafer W may be inspected by using the first probe200in a transmission mode, the wafer W may be inspected by using the second probe300in a reflection mode, or different points on the wafer W may be simultaneously inspected by using the first and second probes200and300.

According to an example embodiment of the present inventive concept, the inspection apparatus10may inspect the wafer W by simultaneously using the first and second probes200and300, Accordingly, in the inspection of the wafer W, the time for moving the wafer W may be reduced.

FIGS.8and9are schematic diagrams describing inspection of an inspection apparatus according to an example embodiment of the present inventive concept.

Referring toFIG.8, a plurality of different inspection spots IS on the wafer W are illustrated. As a non-limiting example, there may be nine inspection spots IS on the wafer W. An inspection apparatus may include, for example, nine first probes (200ofFIG.1), or nine second probes (300ofFIG.1). As another example, an inspection apparatus may include one or more of the first probes (200ofFIG.1) and one or more of the second probes (300ofFIG.1), and a sum of the numbers of first and second probes (200and300of FIG.) may be nine.

According to an example embodiment of the present inventive concept, the wafer W may be inspected by using an inspection apparatus, which includes the same number of first and second probes (200and300ofFIG.1) as the number of inspection spots IS. Accordingly, all the inspection spots IS may be simultaneously inspected and at the same time, the time for aligning the first and second probes (200and300ofFIG.1) with the inspection spots IS may be reduced, and thus, the wafer W may be inspected at a speed of nine times faster than that of a conventional inspection apparatus.

Referring toFIG.9, the wafer W may be divided into a plurality of different scanning regions SR from each other. As a non-limiting example, the wafer W haying a diameter of about300ram may be divided into 60 scanning regions SR. In this case, each of an X direction length and a Y direction length of each scanning region SR may be about 37.5 mm.

According to an implementation example, an X direction length LX1of the first probe200inFIG.1may be in a range of about 1 mm to about 10 mm, and an X direction length LX2of the second probe300inFIG.1may be in a range of about 2 mm to about 20 mm. Y direction lengths LY of the first and second probes200and300may be substantially the same as each other. The Y direction lengths LY of the first and second probes200and300may be in a range of about 2 mm to about 25 mm. Accordingly, any one of the first probe (200ofFIG.1) or the second probe (300ofFIG.1) corresponding to an inspection region of a wafer divided into60pieces, may be arranged, and 60 scanning regions SR may be .substantially and simultaneously inspected. Accordingly, an inspection apparatus according to an example embodiment of the present inventive concept may scan a front side of the wafer W at a speed of60times or more.

FIG.10is a flowchart describing a manufacturing method of the first probe (200ofFIG.1) of the inspection apparatus (100ofFIG.1), according to an example embodiment of the present inventive concept,FIG.10illustrates a method of providing the first excitation optics of the first probe (200ofFIG.1)

FIGS.11A through11Care side cross-sectional views for describing the method of manufacturing a first probe illustrated in FIG,10.

Referring toFIGS.10and11A, the first optical cable261and the first lens263may be provided to the first optical bracket250(P110). The first optical cable261and the first lens263may be arranged at pre-set positions on the first optical bracket250. The first optical cable261and the first lens263may be fixed by the first optical bracket250.

Referring toFIGS.10and11B, the first printed circuit board210including the first probe tip220may be coupled to the first optical bracket250) (P120). The first printed circuit board210and the first optical bracket250may be fixed to each other by using a fixing device, such as a bolt and a nut, but the present inventive concept is not limited thereto.

Referring toFIGS.3,10, and11C, the first mirror265may be provided to the first optical bracket250(P130). According to an example embodiment of the present inventive concept, the first mirror265may be aligned with respect to the first optical bracket250by using a first feedback circuit FC1and a manipulator Ma. The first mirror265may be aligned by using a first active alignment method. The first active alignment method may generate a feedback signal based on current output by the receiver antenna221. The first feedback circuit FC1may sense a magnitude of an optical current generated by the receiver antenna221of the first probe tip220, and the manipulator Ma may adjust a position and a direction of the first mirror265so that the magnitude of the optical current is increased. (e.g., maximized), based on the feedback signal of the first feedback circuit FC1. Accordingly, the first mirror265may be aligned so that the focus of the first laser beam LB I is positioned on the first photoconductive switch224of the receiver antenna221. The first mirror265aligned by using the method described above may be fixed to the first optical bracket250by using, for example, epoxy, etc.

FIG.12is a flowchart describing a manufacturing method of the first probe (200ofFIG.1) of the inspection apparatus (100ofFIG.1), according to an example embodiment of the present inventive concept.FIG.12illustrates a method of providing the second excitation optics of the first probe (200of FIG.).

FIGS.13A through13Dare side cross-sectional views for describing the method o - manufacturing a first probe illustrated inFIG.10.

Referring toFIGS.12and13A, the second optical cable271, the second lens273, and the third lens277may be provided to the first optical bracket250(P210). The second optical cable271, the second lens273, and the third lens277may be arranged at pre-set positions on the first optical bracket250. The second optical cable271and the second lens273may be fixed to the first optical bracket250by using, for example, epoxy, etc. For example, the third lens277may be loosely fixed to the first optical bracket250; however, the present inventive concept is not limited thereto.

Next, referring toFIGS.12and13B, the first non-linear optical device275may be provided to the first optical bracket250(P220). According to an example embodiment of the present inventive concept, the alignment of the first non-linear optical device275may be performed by a second feedback circuit FC2and the manipulator Ma. The first non-linear optical device275may be aligned by using a second active alignment method. The second active alignment method mays generate a feedback signal in response to the intensity of the second laser beam LB2′, which is generated by the first non-linear optical device275in response to the second laser beam LB2. The second feedback circuit FC2may measure the intensity of the second laser beam LB2′, and the manipulator Ma may adjust a position of the first non-linear optical device275so that the intensity of the second laser beam LB2′ is increased (e.g., maximized) in response to a feedback signal of the second feedback circuit FC2. Accordingly, the first non-linear optical device275may be aligned to be positioned at a focus of the second lens273with respect to the second laser beam LB2,

Next, referring toFIGS.12and13C, the third lens277may be aligned and fixed to the first optical bracket250(P230). According to an example embodiment of the present inventive concept, the alignment of the third lens277may be performed by a third feedback circuit. FC3and the manipulator Ma. The third lens277may be aligned by using a third active alignment method. The third active alignment method may generate a feedback signal based on the second laser beam The third feedback circuit FC3may include a beam profiler configured to measure a space-intensity distribution of the second laser beam LB2′. According, to au example embodiment of the present inventive concept, the third feedback circuit FC3may measure a beam profile of the second laser beam L82′, and the manipulator Ma may adjust a position of the third lens277so that a focus of the second laser beam LB2′ is arranged at a pre-set position based on a feedback signal of the third feedback circuit FC3based on the measured beam profile of the second laser beam Next, the third lens277, which is aligned by using the method described above, may be fixed to the first optical bracket250by using, for example, epoxy, etc.

Next, referring toFIGS.12and13D, a printed circuit board on which a probe tip is mounted and an optical bracket may be coupled to each other (P240). P240is substantially the same as P120inFIG.10, and thus, duplicate descriptions thereof may be omitted.

Next, referring toFIGS.12and13E, the second mirror279may be provided to the first optical bracket250(P250). According to an example embodiment of the present inventive concept, the second mirror279may be aligned with respect to the first optical bracket250by the first feedback circuit FC1and the manipulator Ma. The second mirror279may be aligned by using the third active alignment method described above-According to an example embodiment of the present inventive concept, the third feedback circuit FC3may measure the beam profile of the second laser beam LB2′, and the manipulator Ma may align the second mirror279so that the focus of the second laser beam LB2′ overlaps a probe in a vertical direction (for example, the Z direction inFIG.1) and is spaced apart from the first probe tip220by a pre-set focus height Fh.-. The second minor279aligned by using the method described above may be fixed to the first optical bracket250by using, for example, epoxy, etc.

FIG.14is a flowchart describing a manufacturing method of the first probe (200ofFIG.1) of the inspection apparatus (100ofFIG.1) according to an example embodiment of the present inventive concept. FIG,10illustrates a method of providing the first excitation optics of the first probe (200ofFIG.1),

FIG.15is a side cross-sectional view for describing the method of manufacturing a first probe illustrated inFIG.14,

Referring toFIGS.14and15, a first optical cable261′, the first lens263, a non-linear optical device267, and a lens269may be provided to the first optical bracket250, and the first printed circuit board210on which the first probe tip220is mounted and the first optical bracket250may be coupled to each other. P310is substantially the same as operations described with reference toFIGS.12through13D, and thus, duplicate descriptions thereof may be omitted.

Next, the first mirror265may be provided to the first optical bracket250(P320). Providing the first mirror265is substantially the same as P130described with reference toFIGS.10and11C, and thus, duplicate descriptions thereof may be omitted.

Those of ordinary skill in the art should be understand manufacturing of the second probe300ofFIG.4, the first probe201ofFIG.5, and the first probe202ofFIG.6, in addition to manufacturing of the first probe200ofFIG.2, based on descriptions given with reference toFIGS.10through15,

While the present inventive concept has been described with reference to embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made thereto without departing from the spirit and scope of the present inventive concept