Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D62/00—Semiconductor bodies, or regions thereof, of devices having potential barriers
  • H10D62/60—Impurity distributions or concentrations
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/26—Bombardment with radiation
  • H01L21/263—Bombardment with radiation with high-energy radiation
  • H01L21/268—Bombardment with radiation with high-energy radiation using electromagnetic radiation, e.g. laser radiation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
  • H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
  • H01L21/76—Making of isolation regions between components
  • H01L21/762—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers
  • H01L21/7624—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers using semiconductor on insulator [SOI] technology
  • H01L21/76251—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers using semiconductor on insulator [SOI] technology using bonding techniques
  • H01L21/76254—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers using semiconductor on insulator [SOI] technology using bonding techniques with separation/delamination along an ion implanted layer, e.g. Smart-cut, Unibond
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
  • H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
  • H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
  • H01L21/7806—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices involving the separation of the active layers from a substrate
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10D—INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
  • H10D62/00—Semiconductor bodies, or regions thereof, of devices having potential barriers
  • H10D62/10—Shapes, relative sizes or dispositions of the regions of the semiconductor bodies; Shapes of the semiconductor bodies
  • H10D62/124—Shapes, relative sizes or dispositions of the regions of semiconductor bodies or of junctions between the regions
• • H10P34/42—
• • H10P50/00—
• • H10P54/00—
• • H10P95/11—

Definitions

• the present invention relates to a process for treating a substrate by means of a luminous flux of determined wavelength, and a corresponding substrate.
• the process well known under the registered trade mark Smart Cut is a widely used transfer technique which generally consists of implanting a dose of atomic or ionic species in a donor substrate, to create therein an embrittlement zone at a determined depth, delimiting a thin layer to be transferred, adhering the donor substrate on a support substrate or receiver substrate and prompting fracturing of the donor substrate at the level of the embrittlement zone, causing the detachment of the thin layer adhering to the receiver substrate.
• the sub-layer has the particular feature of being absorbent vis-a-vis a luminous flux of predetermined wavelength, this absorption occurring independently of temperature conditions.
• the layer to be heated has as such the particular feature of having a coefficient of absorption of the luminous flux which is low at ambient temperature and increases as this temperature rises.
• the absorbent sub ⁇ layer can then be heated by passing through the layer to be heated which is to some degree transparent to a light beam.
• This technique therefore rapidly heats localised regions of a substrate to considerable depths which would be heated improperly only if a thermal treatment was undertaken where the sole intervening mechanism would be thermal diffusion, and at the end of a particularly long heating period.
• the thickness of such a layer can typically be in the range of 0.5 - 50 micrometers.
• a first aspect of the present invention relates to a process for treating a substrate by means of a luminous flux of determined wavelength, this substrate comprising an embedded layer which is absorbent, that is, which absorbs said luminous flux independently of the temperature, this embedded layer being interleaved between a first layer, said treatment layer, and a second layer, the first semi-conductive layer having a coefficient of absorption of luminous flux which is low at ambient temperature and growing as this temperature rises, a process according to which said first layer is irradiated in the direction of said embedded layer by at least one pulse of said luminous flux, characterised in that
• said luminous flux is applied at several places of the surface of the first layer to heat regions of the embedded layer and generate in this first layer by propagation of a thermal front, opposite to said heated regions of the embedded layer, heated zones forming thermal pillars which dilate and generate constraints within the second layer, via the embedded layer, and in that
• said substrate is subjected to chemical and/or mechanical treatment of its wafer to generate incipient fracture;
• embrittlement treatment of said substrate is carried out in the first or in the second layer in the vicinity of its interface with said embedded layer, or in the embedded layer itself;
• said embrittlement treatment is selected from the following techniques: implanting of atomic species combined or not with thermal treatments, porosification, creation of an intermediate layer whereof the material has a mesh parameter different to that of the rest of said layer;
• said embedded layer is a continuous layer, without continuity solution
• said embedded layer is a discontinuous layer, that is, constituted by a collection of discrete regions ;
• the absorbent embedded layer is a doped layer, for example made of silicon
• the thickness of said second layer is preferably less than that of the first layer, their thickness ratio being between 1/2 to 1/100;
• said luminous flux is laser radiation, infrared for example, preferably of a wavelength of the order of 10.6 micrometers;
• a flux materialising in the form of at least one radiation of cylindrical or tapered form is used;
• said embedded layer in addition to being absorbent, has a thermal dilation coefficient greater than that of the material or materials of the other layers;
• At least one of said first and second layers is silicon.
• Another aspect of the invention relates to a substrate comprising an embedded layer which is absorbent, that is, which absorbs a luminous flux of determined wavelength independent of the temperature, interleaved between a first layer having a coefficient of absorption of said luminous flux which is low at ambient temperature and growing as the latter increases, and a second layer, characterised in that the thickness of said second layer is less than that of the first layer, their thickness ratio being between 1/2 and 1/100.
• Figure 1 is a schematic sectional view of a substrate comprising an embedded layer, which is suitable for being subjected to the treatment process according to the invention
• Figure 2 is a view similar to the preceding view, which illustrates the execution of said process
• Figure 3 is an enlarged view of a detail of the structure illustrated in Figure 2;
• Figure 4 is a sectional and simplified view of a variant embodiment of the substrate
• FIGS 5 and 6 are simplified views of two different embodiments of the process of the present invention.
• Figure 7 is a view of another variant of this process .
• the substrate shown in Figure 1 is suitable for being treated according to the process of the present invention.
• This substrate 1 comprises an embedded layer 3 which is interleaved between a first layer 2 and a second layer 4.
• the first layer 2 said "treatment” layer, silicon for example, has the particular feature of having a coefficient of absorption of luminous flux of predetermined wavelength, which is low at ambient temperature and growing as this temperature rises.
• this layer comprises lightly doped silicon, for example at a level of around a few 10 15 atoms/cm 3 , then this material is transparent to radiation of laser type emitting in far infrared (for example a wavelength of the order of 10.6 micrometers) .
• the above embedded layer 3 is for example a layer which is epitaxied on the layer 2.
• This layer has the particular feature of being significantly absorbent for the above luminous flux and substantially independently of the temperature.
• This layer absorbent when it is a semi-conductor, is to dope it with another atomic species for example.
• this embedded layer can for example be a layer of silicon of a micrometer in thickness doped at a level of the order of 1.10 20 atoms/cm , for example with atoms of boron, phosphorous or arsenic.
• the second layer 4 is as such a layer epitaxied on the preceding one, for example also made of silicon.
• Referenced 5 in this figure is an optional zone of the layer 4, very close to its interface I with the embedded layer, 3 which has the characteristic of being embrittled.
• This localised embrittlement treatment can be carried out in the layer 4 via its rear face 40 by well known embrittlement treatment such as implantation of atomic species combined or not with thermal treatments, or the creation of pores in this zone 5 (treatment of porosification) .
• Another example of treatment is the creation of an intermediate layer whereof the material has a mesh parameter different to that of the rest of the layer .
• the layer 4 can be created in the following manner, for example: creation of an epitaxied layer of 2 ⁇ in thickness of Si-Ge on silicon where the percentage of germanium represents more than 20% and on which another layer of silicon of 20 ⁇ has been grown by epitaxy, for example.
• the thickness of the second layer 4 is less than that of the first layer 2, their thickness ratio being preferably and typically between 1/2 and 1/100, in such a way that application of the process forming the subject of the invention is also not a result of embrittlement inside the layer 2.
• the corresponding thicknesses of the layers 2 and 4 have been referenced eB and eC in Figure 2.
• the process according to the invention consists of irradiating the first layer 2, by its front face 20, by means of a luminous flux whereof the wavelength is determined so that this flux is absorbed by the embedded layer 3, while being transparent, at least in the first instance, for the layer 2.
• the luminous flux is preferably laser radiation in the infrared field.
• infrared radiation passes through the whole layer 2 and is absorbed by the layer 3 which heats locally.
• the latter have a height eA which is a function of the energy output by the radiation luminous and of the duration of application of the latter.
• eA which is a function of the energy output by the radiation luminous and of the duration of application of the latter.
• the present applicant has disclosed the fact that due to the elevation of temperature localised of the layer 2 these thermal pillars, as shown in Figure 3, dilate and generate constraints C, especially shearing constraints, which locally deform the embedded layer 3, and are transmitted to the second layer 4, near the interface.
• the present process therefore consists of using irradiation to a level of constraints sufficient for initiating incipient fracture, in the second layer 4, in the vicinity of its interface I with the embedded layer 3. At the very least, the process generates structural defects in the layer 4, which make it fragile locally.
• each thermal pillar and its height are selected such that theoretical dilation of this thermal pillar, in the vertical direction (that is, perpendicularly) in free space (that is, taken in isolation, as if not found in the structure) would be at least equal to 4/1000 of its diameter.
• thermal pillars of diameter substantially equal to 50 ⁇ are produced.
• the temperature of each pillar is brought to a temperature of 1273°K, or a delta T of 1000°K with the ambient temperature.
• the average coefficient of dilation in this temperature range is of 2.5*E-6.
• the height eA of pillar to be made to satisfy the criterion cited above is calculated:
• optimal parameters can be optionally selected by using commercially available simulation software.
• This incipient fracture is all the easier to use, as indicated earlier, if the incipient fracture and/or the embrittlement of the substrate of the layer 4 has been carried out in the zone 5.
• the incipient fracture consists of subjecting the substrate to previous chemical and/or mechanical treatment of its wafer, for example to form an indentation there.
• irradiation in the first instance, near the indentation, then more and more closely to propagate the incipient fracture inherent to the indentation.
• Such a “layer” is made for example by epitaxy on the entire surface of the structure, then localised etching via a mask. After the mask is removed, the second layer 4 is then epitaxied in turn.
• One alternative is to proceed with implantation, for example of arsenic according to a dose of the order of 10 16 atoms/cm 2 via a mask, then annealing at 1050°C for 3 hours.
• the layer 3 in addition to being absorbent, has a thermal dilation coefficient greater than that of the surrounding material, that is, of the material of layers 2 and 4. This boosts the capacity to form incipient fracture within the structure.
• a layer of 2.5 micrometers of silicon strongly doped by atoms of boron at a boron concentration of (10 20 atoms/cm 3 ) is formed on a silicon substrate having a thickness of around 200 micrometers, lightly doped in type n (10 15 atoms/cm 3 ) , via an epitaxy technique of CVD type.
• a layer of lightly doped silicon of type n (a few 10 15 atoms/cm 3 ) , of 20 micrometers in thickness is cultivated above this layer by epitaxy of CVD type.
• the resulting structure is then soaked for a few minutes in an aqueous solution of ethylene-diamine pyrocatechol , well known to the expert for preferably attacking the silicon doped p.
• the doped layer p is thus attacked chemically at the periphery.
• An indentation of around 2.5 micrometers in height and around ten micrometers in depth is made, on the peripheral part of the substrate (wafer) , thus creating initiation which could serve as starting point for propagation of fracture, substantially at the level of or near the doped layer.
• a laser flux CO 2 is then applied to this structure in the form of a cylindrical flux of 50 microns in diameter of pulses of 600 nanoseconds in duration and energy of 20 J/cm 2 .
• a thermal pillar of cross-section of substantially 50 micrometers and extending from the doped layer p over approximately a height of 60 micrometers is created at each pulse.
• the temperature reached, substantially homogeneous over the entire height of the pillar, is around 1400°C.
• the first thermal pillar is made near (distance less than or equal to a hundred micrometers) the indentation, so as to propagate the incipient fracture inherent to the indentation.
• thermal pillars The whole surface of the substrate then undergoes creation of thermal pillars.
• Each new thermal pillar is built at a distance sufficiently close (for example less than 100 microns) to the point where the preceding pillar was created, so the fracture can be propagated more and more closely.
• This creation of pillars can be carried out continuously, in the sense that the laser beam then emits continuously and is moved at a speed such that the laser flux waits 600 nanoseconds only at each point.
• a layer of 2.5 micrometers of If strongly doped p by boron, at a concentration of 10 20 atoms/cm 3 is formed on a substrate of If in thickness of around 200 micrometers by an epitaxy technique of CVD type.
• a layer of silicon-germanium of 2 micrometers in thickness is cultivated above this layer by epitaxy of CVD type in which, due to dynamic regulation of gaseous flux in the epitaxy machine while this layer is being made, the germanium concentration passes progressively from 5% at the base of the layer to reach 25% in the middle of the thickness of the layer to reduce again to around 5% in the upper part of the layer.
• a lightly doped layer of type n (a few 10 15 atoms/cm 3 ) of 20 micrometers in thickness is made above this layer of Si-Ge by epitaxy.
• the absorbent embedded layer is not necessarily a layer made of doped silicon. It can comprise any semi-conductive layer which has a band gap less than the energy of the photon (component of luminous flux) . It can also simply be a layer of oxide.
• the first layer is made of
• Intrinsic Si that is, without doping of around 20 micrometers in thickness, on which an absorbent layer of 10 micrometers of intrinsic Germanium (non doped) and a layer of SiGe (0.8/0.2) of 50 micrometers (second layer) are cultivated successively.
• the luminous flux is generated by a laser of wavelength equal to 1.08 micrometers.
• the first layer here is a silicon substrate of 500 micrometers in thickness, to which circuits have been transferred (by adhesion and thinning of a plate comprising circuits at its surface) .
• the circuit layer of 20 micrometers in thickness constitutes the second layer.
• a planarised layer of oxide has been formed at the surface of the circuits to enable this transfer stage.
• the first layer has also been oxidised. After assembly and thinning, the layer or layers of oxide form the absorbent layer.
• Formation of circuits can be completed after transfer to the first layer, for example by forming interconnections, contacts, etc.
• This layer of circuits (second layer) is then assembled with a final support, and a laser of wavelength of 10.6 micrometers is applied to the exposed face of the first layer, according to the invention, so as to transfer the first layer to the final support.

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• 2010
  • 2010-09-10 FR FR1057211A patent/FR2964788B1/fr not_active Expired - Fee Related
• 2011
  • 2011-09-05 WO PCT/EP2011/065259 patent/WO2012031998A1/en not_active Ceased
  • 2011-09-05 US US13/818,235 patent/US9190314B2/en not_active Expired - Fee Related
  • 2011-09-05 EP EP11751609.6A patent/EP2614519B1/en not_active Not-in-force
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• 2015
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