[go: up one dir, main page]

WO2004008119A1 - Procede et appareil de detection - Google Patents

Procede et appareil de detection Download PDF

Info

Publication number
WO2004008119A1
WO2004008119A1 PCT/GB2003/003045 GB0303045W WO2004008119A1 WO 2004008119 A1 WO2004008119 A1 WO 2004008119A1 GB 0303045 W GB0303045 W GB 0303045W WO 2004008119 A1 WO2004008119 A1 WO 2004008119A1
Authority
WO
WIPO (PCT)
Prior art keywords
accordance
photoluminescence
semiconductor structure
device fabrication
structures
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/GB2003/003045
Other languages
English (en)
Inventor
Victor Higgs
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Aoti Operating Co Inc
Original Assignee
Aoti Operating Co Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aoti Operating Co Inc filed Critical Aoti Operating Co Inc
Priority to AU2003281077A priority Critical patent/AU2003281077A1/en
Publication of WO2004008119A1 publication Critical patent/WO2004008119A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64—Fluorescence; Phosphorescence
    • G01N21/6489—Photoluminescence of semiconductors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
    • G01N21/9501—Semiconductor wafers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
    • H01L22/20—Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Definitions

  • the invention relates to a non-destructive method and apparatus for detecting surface layer metal contamination and other defects in the structure of semiconductors such as silicon, in particular for the detection of defects in supplied precursor materials such as semiconductor wafers prior to device fabrication thereupon.
  • the invention in particular provides for an improved quality control metric to be applied to supplied semiconductor materials in advance of device fabrication.
  • Incoming precursor materials such as wafers (both polished and epitaxial wafers) may contain a range of defects. It is acknowledged that the control of these defects in the staring material is a critical factor in the achievement of high IC yields in the devices fabricated thereupon (International Semiconductor Roadmap for Semiconductor Materials 2001, SEMATECH, 3101 Industrial Terrace Suite 106, Austin TX 78758). Defects include both surface chemical residues, such as organics and transition metals, and grown- in micro defects. Structural defects, such as epitaxial stacking faults and other large area defects, must also be controlled on epitaxial wafers. The removal and prevention of surface defects is a current state-of-the-art challenge for silicon and other semiconductor wafer technology.
  • Silicon-on-insulator wafers are also now used in Si device fabrication; these wafers offer the potential for high speed and low-power applications. However, theses wafers need to be characterized to determine the SOI material properties and how this impacts subsequent device properties.
  • the move to use 300 mm starting wafers is also creating a driving force to use 300 reclaim wafers (re-cycled and cleaned processed wafers), because using reclaim wafers will reduce the overall cost of the transition from 200 mm wafers to 300 mm.
  • There is however a reluctance to use reclaim wafers for some applications because the wafers may contain high levels of surface metal contamination due to incomplete surface cleaning. Again, a method which could characterise defects accurately on all such wafers would be of great benefit.
  • TXRF total x-ray reflection fluorescence
  • a method of quality control of structures of semiconductors such as silicon prior to device fabrication comprises the steps of: exposing the surface of a semiconductor structure under test to at least one high-intensity beam of light from a suitable light source, preferably a laser, and in particular a high-intensity laser, and collecting photoluminescence (PL) produced by excitation of the semiconductor structure by the light beam; making an analysis of the collected photoluminescence signal and using that analysis as the basis for a quality classification of the suitability of the semiconductor for device fabrication.
  • a suitable light source preferably a laser, and in particular a high-intensity laser
  • the quality classification step comprises performing a numerical analysis of the collected photoluminescence signal, comparing the result of that numerical analysis with a predetermined acceptable photoluminescence specification such as a predetermined range of photoluminescence known to be associated with satisfactory quality, and making a quality classification of the semiconductor structure based thereon.
  • the method comprises determining an average photoluminescence intensity, comparing the average with a predetermined acceptable specification range of photoluminescence, and making a quality classification of the semiconductor structure as above based thereon.
  • the average may be a whole area average based on mean photoluminescence intensity emitted across the area of the structure, or local area average wherein the area of the structure is divided into a two dimensional array of subregions, a mean photoluminescence intensity is determined for each subregion, the mean for each subregion is compared with a predetermined acceptable photoluminescence specification, and a quality classification as above is based thereon.
  • This can be advantageous since the response attributable to an isolated defect could be swamped in a whole area average even though that defect was sufficiently serious to justify a quality rejection. At an appropriate subregion size it is possible to ensure that such a response can still be detected.
  • the photoluminescence technique produces a much more rapid response than prior art TXRF techniques. It samples across the whole wafer area and produces an average result based upon that whole wafer and is accordingly more representative of the condition of the whole wafer than the TXRF technique, where sampling is in effect concentrated on specific arbitrary sample areas. Its speed and accuracy make it a much more effective and practical quality control method than prior art techniques.
  • the invention thus comprises a quality control metric for processing of incoming structures of semiconductors such as silicon prior to device fabrication thereupon, to be incorporated as part of a device fabrication process, comprising the steps of sequentially testing a series of such incoming structures in accordance with the foregoing first aspect of the invention, passing a structure exhibiting a photoluminescence response within the predetermined acceptable specification range of photoluminescence on to a device fabrication stage, rejecting a structure exhibiting a photoluminescence response outside the predete ⁇ riined acceptable specification range of photoluminescence from the device fabrication stage.
  • rejected structures are passed for other action such as discard or remedial treatment, for example by cleaning. This is conveniently followed by retest and accept/reject as above.
  • Additional predetermined photoluminescence parameter ranges might be determined and used to make additional decisions about rejected structures. For example a range may be determined (in particular at photoluminescence levels closely above and/or below those of the acceptable specification range) in which remedial action is to be followed, with structures outside even this remedial range being discarded immediately.
  • the photoluminescence technique produces a spatially resolved PL map at a resolution determined by the characteristics of the high-intensity beam of light.
  • This can be exploited by further preferred features of the present method, but for the fundamental objective of the invention as a simple and rapid quality test for a whole wafer during processing an average PL intensity result over the whole wafer area is obtained.
  • This can be related to a predetermined acceptable specification range developed in association with studies using slower analysis methods (eg TXRF). It has been surprisingly found, as described in detail below, that a close correlation can be demonstrated between defect data obtained from the near-surface-based PL technique of the present invention and prior art methods conventionally used.
  • the light beam is so controlled, and in particular beam power and/or wavelength and/or spot size so controlled, as to identify defects at a selective depth in said semiconductor structure, so as to collect PL information from a suitable near-surface depth, for example from the upper 12 ⁇ m of the semiconductor structure.
  • a suitable near-surface depth for example from the upper 12 ⁇ m of the semiconductor structure.
  • smaller depths may be appropriate, down to for example 5 ⁇ m or even 1 ⁇ m.
  • the present invention is a defect-monitoring tool that can be used to monitor surface contamination and other surface structural defects such as stacking faults and edge slip. Because this technique measures the surface region it will detect near-surface defects and contamination accurately. These defects are most determinative in their impact on device quality and performance. This further enhances the accuracy and reliability of the technique.
  • a predetermined acceptable specification range of average photoluminescence is first determined and then used as a reference for the results for any given wafer for quality control purposes.
  • the predetermined specification range will include a minimum and/or maximum photoluminescence value.
  • the photoluminescence signal can be affected in different ways depending upon the particular chemical species comprised in the impurity. Accordingly, the specification range will preferably comprise a minimum and a maximum photoluminescence value.
  • a quality control decision is taken depending upon whether the measured result lies within the predetermined specification range to accept structures for device fabrication when within the range, and to reject when outside the range. Rejected items may be discarded or subjected to remedial action such as additional cleaning etc.
  • the predetermined acceptable PL range will vary in accordance with the particular material and process involved and will be determined initially from existing quality control specification ranges by relating the PL responses produced by the present invention with responses in accordance with existing prior art measuring techniques.
  • the present invention provides very high throughput relative to prior art methods. For example, for a 12 inch (300 mm) wafer equivalent results can be obtained in around five minutes which would take around an hour with existing methods.
  • Photoluminescence spectroscopy is a very sensitive technique for investigating both intrinsic and extrinsic electronic transitions at impurities and defects in semiconductors.
  • silicon When silicon is excited at low temperatures with laser irradiation above the band-gap of the material, electron hole pairs are produced. These carriers can recombine in various different ways, some of which give rise to luminescence.
  • the electron hole pairs formed at low temperature can be trapped at impurities in silicon and they emit photons characteristic of this interaction, thereby giving impurity specific information in the photoluminescence spectra.
  • PL spectroscopy there are a significant number of applications of PL spectroscopy to silicon including characterisation of silicon after different processing steps, characteristic of device fabrication for example implantation, oxidation, plasma etching, the detection of point defect complexes and the presence of dislocations.
  • One of the most important applications includes the non-destructive measurement of shallow donors and acceptors such as arsenic, boron and phosphorous. Notably, this technique enables the measurement of the concentration of these shallow donors and acceptors.
  • measurements need to be carried out at liquid helium temperatures. It is known throughout the industry that at room temperature the PL signal is significantly weakened and very little useful spectral information can be obtained.
  • a room temperature technique is accordingly preferred, such as in particular that described by International patent application W098/11425, which describes a non-destructive technique which makes practical the detection of electrically active defects in semi-conductor structures based on room temperature PL.
  • the patent application discloses a PL technique which has industrial application in that it enables the image to be produced within minutes and which has a further added advantage in producing micro imaging of small individual defects particularly near to the surface of the wafer, where the device is fabricated.
  • the technique provides information concerning defects in a semiconductor or silicon structure at a rate appropriate to industrial use and in particular enables us to visualise defects in the upper regions of the semiconductor or silicon structure and in particular near to the surface of same.
  • the technique exploits enhanced non-radiative recombination of electron hole pairs at defects in a semiconductor or silicon structure with a view to enhancing contrast in a PL image of said semiconductor or silicon structure so as to enhance the viewing of defects in same.
  • the preferred PL technique for use in the present invention is therefore that in W098/11425, incorporated herein by reference.
  • the success of the room temperature PL method disclosed therein is, in part, due to the probing volume probed by the laser being small, spatial resolution preferably 0.1 to 20 ⁇ m, ideally 2 to 5 ⁇ m, and with a peak or average power density of between 10 4 to 10 9 watts/cm 2 , so that localised defects have much greater effect on the measured PL intensity and is also believed, in part, because since the excitation is focused the injected carrier density is high. This greatly increases the probability of non-radiated recombination at the defect and hence physical location of the defect.
  • the present invention in certain preferred embodiments described in more detail below exploits this by preparing a spatial map, and more preferably still a spatial image, of the defects of which the PL response is representative.
  • a high-intensity laser is meant to include, without limitation, a high power density laser i.e.. where regardless of the power of the laser the emittance is focused.
  • a pulsed laser excitation source is used and ideally luminescence data is measured and/or the luminescence images collected as a function of time. This means that both depth and spatial resolution are improved and can be used to obtain information on the carrier capture cross sections of the defects. Time resolved measurements can also be used to measure the effective carrier lifetime and obtain lifetime maps.
  • the PL technique of the present invention generates a spatially resolved PL map across the area of the wafer.
  • this data map is then processed to provide an average PL level across the whole wafer, which is compared with the reference to make the quality control decision. If the method is to be used for a simple accept/ reject quality control decision as a test prior to passing structures on for manufacture then only the averaged PL level is of concern, and the resolution of the map produced by the method is immaterial. Resolutions of the order of 7 mm are adequate. At this level of resolution, processing times are reduced, and test throughput rates maximised. For example it can take just five minutes to obtain a satisfactory accept/ reject result from a 12 inch (300 mm) wafer.
  • the method further comprises the step of generating such a map and/or such an image. In these circumstances, it can be appropriate to work to mapping/imaging resolutions of 0.5 mm or less.
  • the method further comprises storing the spatially resolved PL map on suitable data storage means and/or transmitting digitised data derived from the spatially resolved map through suitable processing means for onward processing and/or displaying the spatially resolved image on suitable display means.
  • the basic technique identifies an averaged PL intensity on which to base the accept/ reject decision. Spatially resolved information is especially useful in relation to rejected structures.
  • a preferred more developed quality control strategy might therefore be to process each unit using the more rapid, basic technique, and to generate spatially resolved data for rejected structures only. In one embodiment, taking full advantage of the ability of the technique to produce spatially resolved data on the PL response of a semiconductor structure under test, it might be appropriate, as indicated, to work at higher resolutions. Accordingly, throughput will be slower than where the technique is used as a basis for basic accept/ reject quality control decisions only.
  • a preferred more developed quality control strategy might therefore be to process each unit using the more rapid, basic technique, and to reprocess rejected structures at higher resolution using the additional functionality offered by the collection of spatially resolved data.
  • the ability to generate a map or image allows defect location to be generally identified.
  • This can be exploited in a preferred embodiment of the invention in that the method as hereinbefore described can be used to rapidly screen semiconductor structures (5 minutes for a 300 mm wafer) and identify specimens for a full chemical analysis.
  • This embodiment of the method comprises subjecting a semiconductor structure to the test as hereinbefore described to generate a spatially resolved map of PL signals across the surface of the semiconductor structure and, at least in the case of rejected structures, using the spatially resolved map to identify the general location of contamination, and further analysing the semiconductor structure in the identified location using a specific analysis technique such as TXRF to identify the impurity.
  • the method is suitable for any basic semiconductor structure on which devices are fabricated by thermal processing in familiar manner.
  • the method is suitable for structures based on wafers of silicon and silicon alloys.
  • the devices may be fabricated from simple single layer wafers or from multilayer wafers, for example formed in an epitaxial layer on a basic silicon wafer.
  • an apparatus for quality control of structures of semiconductors such as silicon prior to device fabrication thereupon comprises a high intensity light source, preferably a laser, and in particular a high-intensity laser; means to focus a high intensity beam of light from the light source onto a surface of a semiconductor structure under test; collection means to collect photoluminescence data from across the surface of the semiconductor structure under test produced by excitation of the semiconductor structure by the light beam; analysis means to process and numerically analyse the collected data; a comparator to compare the results of the analysis with predetermined acceptable specification parameters, and a transfer means adapted to transfer the structure to a particular further processing stage determined by whether the photoluminescence signal falls within the predetermined acceptable specification range.
  • the transfer means is adapted to transfer a structure exhibiting a photoluminescence response within a predetermined acceptable specification range of photoluminescence on to a device fabrication stage, and to transfer a structure exhibiting a photoluminescence response outside a predetermined acceptable specification range of photoluminescence otherwise than to the device fabrication stage; and for example to a discard location or remedial treatment stage.
  • the apparatus may thus be incorporated into a suitable production apparatus for such devices at a point immediately prior to apparatus for device fabrication.
  • the apparatus to perform the basic method generates data based on a numerical analysis of the PL response, for example an average PL signal across the whole area or a set of local area data as described. This is compared with predetermined acceptable specification parameters.
  • the apparatus preferably further comprises means to resolve the collected PL data into a spatially resolved PL map across the area of the semiconductor structure, and optionally further comprises means to convert the resolved data into a PL image and/or image/data storage means to store the map/image, and in particular to store successive map/images for future comparison, and/or means to transmit the map/image to a suitable remote data processor and/or image display means such as a visual display screen to display an image and/or related data to a user.
  • a suitable remote data processor and/or image display means such as a visual display screen to display an image and/or related data to a user.
  • a computer program and/or a suitably programmed computer for performing some or all of the steps of the method as hereinbefore described, and in particular for performing data processing steps on collected PL data, for example to determine average PL across the wafer area and/or to spatially resolve a PL map from collected PL data and/or to compare the average with a predetermined acceptable specification range.
  • Figure 1 is an illustration of a suitable apparatus for obtaining the PL data
  • Figure 2 is a schematic illustration of how data is processed
  • Figure 3 illustrates PL signals recorded in accordance with the invention for different batches of supplied wafer
  • Figure 4 illustrates PL signals recorded in accordance with the invention for different wafers in a batch
  • Figure 5 illustrates correlation of PL data to a basic quality control accept/ reject decision
  • Figure 6 illustrates a spatially resolved PL image of a wafer
  • Figures 7 and 8 illustrate a possible numerical analysis technique in accordance with the invention.
  • the apparatus illustrated in Figure 1 essentially comprises a PL imaging microscope which: towards the right hand side, comprises a bank of lasers (3- 8); towards the bottom comprises a sample stage such as an X-Y table or R- table; towards the left hand side comprises a microprocessor (40) and a display screen (39) and in the centre of the figure there are shown various optical components for directing light through the system.
  • At least one of the lasers is a high intensity laser and ideally has a spot size of between 0.1 mm and 0.5 micron and a power density of between 10 4 to 10 9 watts/cm 2 .
  • a laser selector (16) coupled with said bank of lasers is provided so as to select one or more lasers for use and further also to select the frequency and wavelength of the lasers.
  • Conventional optics such as optical fibres (9) are used to direct light towards the collimator to (10) and laser beam expander (11).
  • An apodization plate (12) is positioned between laser beam expander (11) and beam splitter (31).
  • Beam splitter (31) directs a fraction of light from the aforementioned lasers towards sample (2) via objective (34).
  • An automatic focus controller (30) is provided and coupled to a piezo driven focusing stage (33).
  • the microscope is equipped with a conventional rotating turret (36) which is provided with at least one high numerical aperture objective for micro examination and one low numerical aperture objective for macro examination (34, 35) respectively.
  • an optical displacement measuring system 38.
  • Cabling is provided so as to connect the automatic focusing controller (30) to microprocessor (40) and also a microscope objective indexing arrangement (32) to microprocessor (40).
  • filter wheel (13) Downstream of beam splitter (31) there is provided as filter wheel (13) for laser notch filters, down stream thereof there is provided a swing-aside folding mirror (14) whose function will be described hereinafter. Aligned with said mirror (14) there is provided a filter wheel (27) for wavelength selection, and rearward thereof there is provided a zoom lenses attached to a suitable CCD 2- D array detector (29).
  • Infinity system compensating lens (37) is provided in the optical path foremost of cold mirror (17) which reflects light towards a further filter wheel (23) for wavelength selection and a focusing lenses (24) which is foremost of a detector (25) for UV and visible light.
  • Detector (25) is coupled to lock-in amplifier (26). This is used to obtain a reflected image of the surfaces.
  • Rearmost of cold mirror (17) is provided a further filter wheel (18) again for wavelength selection, and rearmost thereof a focusing lens (22) and a further aperture wheel (19) for pinhole selection which is provided foremost of a detector (21) for detecting the luminescence.
  • UV and visible region detector (25) and infrared detector (21) are coupled to lock-in amplifier (26).
  • a range of wavelengths to probe different planes in the sample is provided by several lasers (3-8).
  • the lasers can be modulated by a frequency generator (16) so that the signal emitted from the sample (2) can be isolated from background radiation by means of the detectors being synchronised to the laser modulation frequency by the lock-in amplifier (26).
  • the range of wavelengths could be produced by using a tuneable laser and/or an Optical Parametric Oscillator.
  • Each laser is connected to, and aligned with, a Multi-branch optical fibre (9) so that any or all of the lasers can illuminate the sample (2).
  • the common end of the Multi-branch optical fibre terminates in an optical system (10) which coUimates the emerging light.
  • This optical system is aligned with a beam expander (11) which matches the laser beam's diameter to that required by the microscope objectives (34,35) above the sample (2).
  • the expanded beam then passes through an apodization plate (12) which distributes the optical energy evenly over the beam area.
  • the expanded and apodized beam is reflected by a beamsplitter (31) and passes to the microscope objectives (34 and 35).
  • the beam is focused by a microscope objective (34 or 35) on to the sample.
  • this objective is selected to focus the beam to a diffraction limited spot size.
  • a rotating turret (36) operated by an indexing mechanism (32), permits the objective to be changed for the macro mode where a larger area of the sample can be illuminated.
  • the apodization plate (12) can be removed so that the spot for the micro mode can be made smaller to allow higher injection levels.
  • An optical displacement sensor (38) measures the distance to the sample and, by means of a feedback loop through the auto focus controller (30), maintains the correct spacing by means of the piezo actuated focusing stage (33).
  • the Photoluminescence signal from the sample is collected by the microscope objective (34) (in the micro mode) and transported back through the beamsplitter (31) and a notch filter in the filter wheel (13) which contains notch filters matched to the range of laser wavelengths. The notch filter removes any reflected laser light, passing only the Photoluminescence signal.
  • the folding mirror (14) is swung out of the beam allowing the signal to pass to the tube lens (37), which may be incorporated to compensate for any infinity microscope objectives which may be used, and on to the cold mirror (17).
  • This component reflects those wavelengths below a selected cut off point (approximately 700 nm) to the focusing lens (24) which focuses the signal into the detector (25).
  • a filter wheel (23) in front of the detector focusing lens (24) contains filters to isolate selected wavelength bands.
  • the portion of the Photoluminescence signal lying in the wavelength range above the cut-off point passes through the cold mirror (17) and is similarly focused by the lens (22) into the detector (21). This signal also passes through a filter wheel (18) containing filters to isolate selected wavelength bands.
  • a series of pinholes of different diameters are contained in an aperture wheel (19) positioned in front of the detector (21).
  • This aperture wheel can be moved axially by the piezo actuator (20) so that the pinholes can be positioned confocally with the desired image plane.
  • the electrical signal from the detectors (21, 25) is fed to the lock-in amplifier
  • the PL image is obtained by raster scanning the stage. Alternatively optical scanning using galvo mirrors may be employed.
  • the folding mirror (14) is swung into the beam of the Photoluminescence signal.
  • the diverted signal passes through a filter wheel (27), which contains filters to isolate selected wavelength bands, and into the zoom lens (28).
  • the zoom lens allows different magnifications to be used in imaging the illuminated spot on the sample (2) on to the CCD two dimensional array (29). This allows the illuminated area of the sample (2) to be imaged at different resolutions.
  • the electrical signal from the CCD array is fed to the central processor (40) for analysis.
  • FIG. 2 The processing of data is illustrated schematically in Figure 2.
  • a sample (101) is transferred by a handling arm (102) onto a sampling base for testing by the device of Figure 1 to generate a PL signal. This is collected by the collection apparatus of Figure 1 (shown in simplified schematic form as the device 105).
  • the figure further illustrates processing of data.
  • the PL map data is passed to a processor (107) which processes the data to determine an average PL intensity across the whole area of the sample (101).
  • control unit (110) acts directly upon the handling arm (102) which then transfers the sample (101) on to a device fabrication processing line or to a reject line for remedial action as appropriate.
  • control unit (110) could for example be a display means giving an indication to an operator, who could then operate the arm (102) by separate control means for example to make an acceptable/reject choice, to divert the sample under test for remedial processing etc.
  • a secondary processing route reflects the optional second aspect of the invention.
  • data corresponding to the PL intensity map across the surface of the sample (101) is also passed to a secondary processing unit (111) which is able to resolve the data into a digitised spatially resolved map of intensity across the surface of the sample (101).
  • the resulting map is passed to a data store (112) and to a visual display screen (113).
  • the resolved data may be used to identify defect locations. In this way the basic apparatus could be used to rapidly screen wafers. The location of contamination may be identified from the wafer map, and then the wafers could be further analysed using TXRF to identify the impurity.
  • FIG. 3 An illustration that the technique can be used to monitor incoming wafer quality is provided in Figures 3 and 4.
  • a selection of different wafers were measured from different wafer manufactures. The results are shown in Figure 3. There is a clear difference in the PL signal obtained from each supplier indicating variations in the surface defect density of surface contamination level. Further measurements were carried out on batches of wafers from each supplier. A typical example is shown in Figure 4. Wafers from the same supplier have the same average value and this was found to be a general characteristic. Therefore the Average PL can be used as a metric to determine the incoming wafer quality.
  • a PL map is collected and processed and the average PL value calculated and then compared against a pre-detennined value. This specified range is used to deteraiine the wafer quality and therefore an accept/ reject process control procedure created. This procedure is illustrated graphically in Figure 5.
  • the back surface of the wafer can be recorded as well. By comparison of the wafer maps, it will be apparent if the contamination originated on the wafer back surface. Then further action can be taken to prevent cross contamination to other process equipment of metrology tools.
  • the photoluminescence tool is used as a rapid process control tool to determine wafer quality.
  • Wafer maps are obtained and the measured PL response numerically analysed to provide a quality metric, in that a deviation of the photoluminescence response from predetermined parameters known to be associated with a semiconductor structure of satisfactory quality is used as the basis of a quality control decision.
  • this can simply be a comparison of mean response over the whole area.
  • contamination can be a very localized and the average PL signal (averaged over all measured pixels in the wafer map) may not a reliable indication of such contamination. If wafer map is sub-divided using a 2D grid, then analyzed using average PL, very localized signals could be detected.
  • a virtual grid may be applied and displayed on top of the wafer map using suitable software. This can be used to perform the analysis.
  • a local area analysis also allows better location of problem sites in the structure. For example the grid elements that have failed may be indicated, a micro scan can be launched at the same location as the grid element to allows the area of interest to be inspected in more detail, and a report of the failed elements in the wafer map analysis can be exported in suitable format.
  • the local grid method is not restricted to a numerical analysis based on mean values. Any suitable pre-defined parameters, including average intensity, PL min, Max, Standard deviation and baseline) can be used to determine regions of contamination.
  • the PL signal baseline method can be a more useful parameter to use because the variation in signal across is not uniform wafer. This technique is explained below.
  • FIG. 7a A typical wafer map is shown in figure 7a with an associated histogram of PL intensity in Figure 7b.
  • Contamination is detected in the wafer map by the deviation from the baseline value and limits can be set.
  • the PL average value in this wafer map is modified by the contamination.
  • the value to be used should represent the signal level for an uncontaminated wafer.
  • the peak value shown in Figure 8 represents the true PL value of a non-contaminated wafer. Modifying the baseline function to have a peak value would allow the customer to accurately track the contamination and with more sensitivity.
  • a suitable algorithm involves the following steps:
  • the baseline of the wafer is the PL value that corresponds to the maximum number of points.
  • Baseline variation PL value - baseline
  • the PL value is the AVG PL of each element of the grid.
  • the baseline variation must be measured for each element.

Landscapes

  • Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Pathology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Testing Or Measuring Of Semiconductors Or The Like (AREA)
  • Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)

Abstract

L'invention concerne un procédé de contrôle qualité de structures de semi-conducteurs, tel que du silicium, avant fabrication de dispositif, consistant à exposer la surface d'une structure semi-conductrice sous test à au moins un faisceau d'intensité élevée d'un rayonnement lumineux provenant d'une source adéquate, de préférence un laser, et en particulier un laser d'énergie élevée, et à collecter la photoluminescence (PL) produite par excitation de la structure semi-conductrice par le faisceau de rayonnement lumineux, à analyser numériquement la photoluminescence émise à travers la zone de la structure, à comparer les résultat à une plage de spécification acceptable déterminée de photoluminescence, à réaliser un classement qualité de la structure semi-conductrice sur la base du résultat, et en particulier à rejeter ou à sélectionner en vue d'une action palliative les structures semi-conductrices présentant une réponse de photoluminescence en dehors de la plage de spécifications acceptable déterminée. Dans le mode de réalisation préféré, le procédé est appliqué en tant que partie d'une métrique de contrôle qualité avant fabrication de dispositif. Dans un perfectionnement du procédé, on procède aussi à l'obtention d'une carte de photoluminescence à résolution spatiale. L'invention concerne aussi un appareil de mise en oeuvre de ce procédé.
PCT/GB2003/003045 2002-07-17 2003-07-14 Procede et appareil de detection Ceased WO2004008119A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2003281077A AU2003281077A1 (en) 2002-07-17 2003-07-14 Detection method and apparatus

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0216622.1 2002-07-17
GB0216622A GB0216622D0 (en) 2002-07-17 2002-07-17 Detection method and apparatus

Publications (1)

Publication Number Publication Date
WO2004008119A1 true WO2004008119A1 (fr) 2004-01-22

Family

ID=9940657

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2003/003045 Ceased WO2004008119A1 (fr) 2002-07-17 2003-07-14 Procede et appareil de detection

Country Status (4)

Country Link
AU (1) AU2003281077A1 (fr)
GB (1) GB0216622D0 (fr)
TW (1) TW200411167A (fr)
WO (1) WO2004008119A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007057011A1 (de) * 2007-11-23 2009-06-10 Pi Photovoltaik-Institut Berlin Ag Erfassungsvorrichtung und Verfahren zum Erfassen einer Beschädigung einer Solarzelle mittels Photolumineszenz
DE102010011066A1 (de) * 2010-03-11 2011-09-15 Pi4_Robotics Gmbh Photovoltaikmodul-, oder Photovoltaikzellen- oder Halbleiterbauelement-Identifikationsverfahren und Photovoltaikmodul- oder, Photovoltaikzellen- oder Halbleiterbauelement-Identifikationsvorrichtung
WO2013067573A1 (fr) * 2011-11-07 2013-05-16 Bt Imaging Pty Ltd Classification et tri de plaquette pour la fabrication de cellules photovoltaïques
KR20180010187A (ko) * 2015-05-20 2018-01-30 신에쯔 한도타이 가부시키가이샤 실리콘 에피택셜 웨이퍼의 제조방법 및 평가방법

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI391645B (zh) * 2005-07-06 2013-04-01 Nanometrics Inc 晶圓或其他工作表面下污染物及缺陷非接觸測量之差分波長光致發光

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4571685A (en) * 1982-06-23 1986-02-18 Nec Corporation Production system for manufacturing semiconductor devices
WO1998011425A1 (fr) * 1996-09-10 1998-03-19 Bio-Rad Micromeasurements Limited Dispositif et procede servant a detecter des defauts microscopiques dans des semi-conducteurs
WO1999044231A1 (fr) * 1998-02-25 1999-09-02 Shin-Etsu Handotai Europe Limited Appareil d'inspection de tranches a semi-conducteurs

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4571685A (en) * 1982-06-23 1986-02-18 Nec Corporation Production system for manufacturing semiconductor devices
WO1998011425A1 (fr) * 1996-09-10 1998-03-19 Bio-Rad Micromeasurements Limited Dispositif et procede servant a detecter des defauts microscopiques dans des semi-conducteurs
WO1999044231A1 (fr) * 1998-02-25 1999-09-02 Shin-Etsu Handotai Europe Limited Appareil d'inspection de tranches a semi-conducteurs

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
CARVER G E ET AL: "NON-DESTRUCTIVE OPTICAL TECHNIQUES FOR CHARACTERIZING SEMICONDUCTORMATERIALS AND DEVICES", AT & T TECHNICAL JOURNAL, AMERICAN TELEPHONE AND TELEGRAPH CO. NEW YORK, US, vol. 73, no. 2, 1 March 1994 (1994-03-01), pages 66 - 76, XP000445592, ISSN: 8756-2324 *
HIGGS V: "Characterization of Si, SiGe and SOI Structures using Photoluminescence", MAT.RES.SOC.SYMP.PROC., vol. 588, 2000, pages 129 - 140, XP009017743 *
WESTRATE S ET AL: "PHOTOLUMINESCENCE MAPPING DETECTS CU CONTAMINATION IN SI WAFERS", SOLID STATE TECHNOLOGY, COWAN PUBL.CORP. WASHINGTON, US, vol. 45, no. 2, February 2002 (2002-02-01), pages 57 - 58, XP001092608, ISSN: 0038-111X *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007057011A1 (de) * 2007-11-23 2009-06-10 Pi Photovoltaik-Institut Berlin Ag Erfassungsvorrichtung und Verfahren zum Erfassen einer Beschädigung einer Solarzelle mittels Photolumineszenz
DE102007057011B4 (de) * 2007-11-23 2011-04-28 Pi Photovoltaik-Institut Berlin Ag Erfassungsvorrichtung und Verfahren zum Erfassen einer Beschädigung einer Solarzelle mittels Photolumineszenz
DE102010011066A1 (de) * 2010-03-11 2011-09-15 Pi4_Robotics Gmbh Photovoltaikmodul-, oder Photovoltaikzellen- oder Halbleiterbauelement-Identifikationsverfahren und Photovoltaikmodul- oder, Photovoltaikzellen- oder Halbleiterbauelement-Identifikationsvorrichtung
DE102010011066B4 (de) * 2010-03-11 2020-10-22 Pi4_Robotics Gmbh Photovoltaikmodul-, oder Photovoltaikzellen- oder Halbleiterbauelement-Identifikationsverfahren und Photovoltaikmodul- oder, Photovoltaikzellen- oder Halbleiterbauelement-Identifikationsvorrichtung
WO2013067573A1 (fr) * 2011-11-07 2013-05-16 Bt Imaging Pty Ltd Classification et tri de plaquette pour la fabrication de cellules photovoltaïques
KR20180010187A (ko) * 2015-05-20 2018-01-30 신에쯔 한도타이 가부시키가이샤 실리콘 에피택셜 웨이퍼의 제조방법 및 평가방법
US20180277450A1 (en) * 2015-05-20 2018-09-27 Shin-Etsu Handotai Co., Ltd. Manufacturing method and evaluation method of silicon epitaxial wafer
US10643908B2 (en) * 2015-05-20 2020-05-05 Shin-Etsu Handotai Co., Ltd. Manufacturing method and evaluation method of silicon epitaxial wafer
US11205599B2 (en) 2015-05-20 2021-12-21 Shin-Etsu Handotai Co., Ltd. Evaluation method of silicon epitaxial wafer
KR102528848B1 (ko) 2015-05-20 2023-05-04 신에쯔 한도타이 가부시키가이샤 실리콘 에피택셜 웨이퍼의 제조방법 및 평가방법

Also Published As

Publication number Publication date
GB0216622D0 (en) 2002-08-28
TW200411167A (en) 2004-07-01
AU2003281077A1 (en) 2004-02-02

Similar Documents

Publication Publication Date Title
US7113276B1 (en) Micro defects in semi-conductors
US6911347B2 (en) Method to detect surface metal contamination
JP3843637B2 (ja) 試料作製方法および試料作製システム
US6791099B2 (en) Laser scanning wafer inspection using nonlinear optical phenomena
JP2604607B2 (ja) 欠陥分布測定法および装置
KR20190049890A (ko) 반도체 웨이퍼 검사를 위한 결함 마킹
WO2004010121A1 (fr) Procede de detection et dispositif correspondant
JP4293201B2 (ja) 試料作製方法および装置
JP2002350731A (ja) 欠陥観察方法及び欠陥観察装置
WO2004008125A1 (fr) Detection de contaminants metalliques sur une surface d'une structure a semiconducteur en fois nettoyee se basant sur des mesures de photoluminescence
WO2004008119A1 (fr) Procede et appareil de detection
KR102712716B1 (ko) 백색광과 여기광을 모두 이용한 검사 장치
JP2001007173A (ja) 少数キャリアのライフタイム測定装置
WO2004008118A1 (fr) Procede et appareil de detection
JP4367433B2 (ja) 試料作製方法および装置
JPH11281576A (ja) 結晶内のフォトルミネッセンス計測装置
CN120507290B (zh) 一种锑化物半导体缺陷原位无损检测装置和方法
US12480881B2 (en) Raman spectroscopy analysis method and microscopic Raman spectroscopy device
JPH0868757A (ja) 試料表面評価方法
US7463025B2 (en) Induced magnetic field detecting apparatus and an induced magnetic field detecting method
JPS6032133B2 (ja) 試料評価装置
CN120177491A (zh) 用于集成电路检测的短波红外光发射及荧光共焦显微系统
Kumpe et al. INVESTIGATION OF LOW RESISTIVITY AS-GROWN CZ SILICON MATERIALS BY VISIBLE AND INFRARED LIGHT SCATTERING TECHNIQUES
JP2004325460A5 (fr)
JPH11295232A (ja) 表面検査装置および方法、データ生成装置および方法

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP