EP4315406A1 - Procédé de séparation de structures d'un substrat - Google Patents

Procédé de séparation de structures d'un substrat

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Publication number
EP4315406A1
EP4315406A1 EP21716342.7A EP21716342A EP4315406A1 EP 4315406 A1 EP4315406 A1 EP 4315406A1 EP 21716342 A EP21716342 A EP 21716342A EP 4315406 A1 EP4315406 A1 EP 4315406A1
Authority
EP
European Patent Office
Prior art keywords
substrate
electromagnetic radiation
structures
thin layer
separating
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.)
Pending
Application number
EP21716342.7A
Other languages
German (de)
English (en)
Inventor
Boris Povazay
Venkata Raghavendra Subrahmanya Sarma MOKKAPATI
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.)
EV Group E Thallner GmbH
Original Assignee
EV Group E Thallner GmbH
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 EV Group E Thallner GmbH filed Critical EV Group E Thallner GmbH
Publication of EP4315406A1 publication Critical patent/EP4315406A1/fr
Pending legal-status Critical Current

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Classifications

    • 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
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L21/6835—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • 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
    • 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
    • H01L21/02002—Preparing wafers
    • 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
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67098—Apparatus for thermal treatment
    • H01L21/67115—Apparatus for thermal treatment mainly by radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68363—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used in a transfer process involving transfer directly from an origin substrate to a target substrate without use of an intermediate handle substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68368—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
    • H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
    • H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
    • H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
    • H01L2221/68381—Details of chemical or physical process used for separating the auxiliary support from a device or wafer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/005—Processes
    • H01L33/0095—Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination

Definitions

  • the present invention relates to a method and a device for separating structures from a substrate. Furthermore, the invention relates to a method and a device for transferring structures from a first substrate to a second substrate.
  • the structures to be separated from the substrate are, in particular, components isolated from a thin layer or the thin layer as such.
  • the thin layer or the isolated structures were produced in particular on the substrate, preferably grown on the substrate.
  • the thin layer and the structures are therefore used synonymously in the further course of the text.
  • the structure to be separated is consequently disclosed in each case in connection with an isolated structure or a thin layer.
  • the prior art deals with the ablation of thin layers or isolated structures from a substrate using electromagnetic radiation. It is thus customary for a laser to act, in particular from a rear side of a substrate that is transparent to electromagnetic radiation, on a boundary region in order to bring about a detachment of the thin layer from this substrate. In this case, the thin layer is not irradiated, but irradiated from the side of the substrate on which the thin layer is fixed.
  • This process is known in the art as a laser lift off (LLO) process.
  • An LLO process is a non-contact process with which thin to ultra-thin layers can be separated from a substrate, in particular from a growth substrate. One of the prerequisites for a separation is that the substrate is transparent to the laser radiation used.
  • an absorbing layer is provided between the substrate and the thin layer, so that the release takes place by the laser acting on this so-called release layer.
  • the laser radiation is first guided through the substrate from the rear side of the substrate and then hits the release layer or the thin layer. Due to the interaction of the laser radiation with the absorbing layer, ablation takes place through a physical and/or chemical reaction.
  • photochemical, photothermal or combined separation processes are conceivable. It is also conceivable that the thin layer itself has a high absorption capacity for the laser radiation and that an absorbing layer is dispensed with. In this case, the processes take place in a boundary area or at an interface of the substrate and the thin layer. Furthermore, plasma is very often used to improve the detachment of the thin film from the substrate.
  • the adhesion forces between the substrate and the thin layer are significantly weakened by the procedure mentioned.
  • gas formation between the substrate and the thin layer also contributes to a weakening of the adhesion forces.
  • Gas is mainly generated when using an additional absorbing layer between the substrate and the thin layer.
  • LLO processes typically the transparency properties of the substrate and the absorption properties of the interface between the Exploited substrate and the thin layer or the thin layer itself.
  • GaN gallium nitride/sapphire
  • the very thin gallium nitride (GaN) layer is grown on a sapphire substrate.
  • the ablation is performed with UV radiation.
  • GaN absorbs the UV radiation used very strongly, while the sapphire substrate is very transparent in this wavelength range. Furthermore, the photochemical reaction takes place
  • 2GaN- 2Ga+N2 takes place, in which nitrogen gas is produced, which promotes the ablation due to its volume expansion.
  • the laser-matter interaction takes place in particular via the electrons. In rare cases, resonances allow direct interaction with bound states. This requires laser radiation with an exact energy. Quasi-free electrons in metals, i.e. electrons that are only very much subject to the prevailing potential, can serve as highly efficient broadband absorbers to absorb laser radiation.
  • Epitaxially grown GaN layers have a band gap of 3.3 eV, while the band gap of sapphire is around 9.9 eV.
  • a UV laser for example, can be used to penetrate the sapphire substrate and interact with the GaN or with the GaN-sapphire interface.
  • Such thin layers for example GaN layers, are usually produced on a growth substrate that has a very low transmissivity for the electromagnetic radiation used for the ablation should be used.
  • the growth substrate thus absorbs the electromagnetic radiation and this does not reach the boundary region or the interface between the thin layer and the growth substrate, so that the thin layer cannot be easily separated by means of electromagnetic radiation.
  • One way to solve the problem would be to choose a growth substrate that is transparent to the electromagnetic radiation.
  • growth substrates must be chosen on which the desired thin layers grow optimally. Consequently, when separating a particularly grown thin layer from the growth substrate, one is restricted with regard to the material of the substrate on which the thin layers or structures are provided.
  • One way of separating the thin layer from the growth substrate is to choose electromagnetic radiation with an appropriate frequency or wavelength at which the transmissivity is high enough to reach the interface between the thin layer and the growth substrate.
  • the ability of the laser to ablate the thin layer depends strongly on the frequency, so that it is very difficult to choose the optimum frequency, which on the one hand allows high transmissivity with respect to the substrate and on the other hand high ablation ability.
  • only electromagnetic radiation with a well-defined frequency is available, which cannot be varied or adjusted at will.
  • GaN LEDs GaN light emitting diodes
  • silicon is opaque in the EiV wavelength range, it is not possible to use EiV lasers to carry out the GaN ablation. Detaching a produced thin layer, in particular a GaN layer or a GaN structure, from a substrate by means of electromagnetic radiation is therefore expensive.
  • a separation process that can be carried out selectively by means of electromagnetic radiation is desired in particular for the production of electronic components.
  • the object of the present invention to provide a method and a device which at least partially eliminate, in particular completely eliminate, the disadvantages listed in the prior art.
  • the present object is achieved with the features of the independent claims.
  • Advantageous developments of the invention are specified in the dependent claims. All combinations of at least two features specified in the description, in the claims and/or in the drawings also fall within the scope of the invention. In the case of specified value ranges, values lying within the specified limits should also apply as disclosed limit values and be claimable in any combination.
  • the invention relates to a method for separating structures from a substrate, having at least the following steps, in particular in the following order, i) providing at least one structure on a first substrate, ii) irradiating a boundary region between the first substrate and the at least one Structure with electromagnetic radiation, iii) separating the at least one structure from the first substrate, wherein the electromagnetic radiation only the at least one
  • the beam path of the electromagnetic radiation thus runs from the source first through the structures to be separated and only then hits the border area.
  • the boundary area or the interface lies in the area between the structures and the first substrate. If a further layer for detachment (detachment layer) is arranged between the first substrate and the structures, the boundary region is formed by this layer.
  • the thin layer is provided on the first substrate, in particular a substrate surface.
  • the thin layer can be on the first substrate are generated.
  • the thin layer is separated into the structures in optional further steps.
  • the isolated structures are then, in particular, electronic components with a function.
  • a structure can also be formed by a thin layer, so that instead of an isolated structure, the entire thin layer can also be separated.
  • the thin layer also represents a structure.
  • the electromagnetic radiation is not radiated through the first substrate. Rather, the electromagnetic radiation is directed onto the at least one structure, with the at least one structure being at least partially transparent to the electromagnetic radiation.
  • the at least one structure can advantageously be separated from the first substrate without the radiation having to be guided through the first substrate to the boundary region.
  • the separating method is more efficient since there is no loss of energy by directing the electromagnetic radiation through the first substrate.
  • the structures can be detached from a first substrate, which consists of a material that is impermeable to the electromagnetic radiation.
  • the first substrate can advantageously be spared, since the electromagnetic radiation is only absorbed by the first substrate in the boundary region and is not radiated through the first substrate.
  • the invention relates to a device for separating structures from a substrate, at least comprising:
  • Irradiation means for irradiating a boundary region between the first substrate and the at least one structure with electromagnetic radiation
  • the irradiation means being designed in such a way that the electromagnetic radiation first penetrates the at least one structure and then impinges on the boundary area.
  • the irradiation means are preferably lasers which emit electromagnetic radiation of a specific wavelength.
  • the irradiation agents can also be regarded as release agents.
  • the device has additional mechanical separating means for separating the structures from the first substrate. A method for separating structures can be carried out particularly advantageously with the device for separating structures. The advantages mentioned above also apply in connection with the device for separating structures.
  • the invention relates to a method for transferring structures, in particular for transferring electronic components, from a first substrate to a second substrate, the structures being separated from the first substrate using the method for separating structures.
  • the structures provided on the first substrate can be transferred particularly efficiently to the second substrate.
  • the first substrate is advantageously protected and absorbs the electromagnetic radiation essentially only in the border area.
  • the invention relates to a device for transferring structures, in particular for transferring electronic components, from the first substrate to a second substrate, the structures provided on the first substrate being separable with the device for separating structures from the first substrate.
  • the transfer of the structures can advantageously be carried out efficiently with the device.
  • the at least one structure is separated selectively.
  • the border area is irradiated with electromagnetic radiation, this can advantageously be introduced in a locally limited manner on the corresponding border area of the at least one structure.
  • the first substrate will therefore only absorb the electromagnetic radiation in the boundary area of the structure.
  • the method thus protects the first substrate, since the electromagnetic radiation is introduced only in selected areas of the boundary area.
  • individual structures provided on the first substrate can be separated selectively, so that a broader field of application for the method for separation is made possible. For example, defective structures cannot be separated from the first substrate in a targeted manner, or only certain structures with certain properties can be detached from the first substrate in a targeted manner.
  • the at least one structure has a thickness between 0 gm and 1000 gm, preferably between 0 gm and 500 gm, even more preferably between 0 gm and 200 gm, most preferably between 0 gm and 150 gm, most preferably between 0 gm and 100 gm.
  • the thin layer or structure can thus be particularly protected and efficiently irradiated by the electromagnetic radiation.
  • the at least one structure is produced, preferably grown, on the first substrate before the separation from the first substrate.
  • the first substrate is preferably a growth substrate on which the thin layer or the isolated structures are produced directly, preferably grown.
  • a growth layer is applied to the first substrate, on which the thin layer or the structures are produced and are thus provided for the separating method.
  • the growth layer can also act as a release layer at the same time. If the thin layer or the at least one structure is produced on the substrate, it can advantageously be separated from the first substrate using the method for separating, without the first substrate having to be designed to be permeable to electromagnetic radiation.
  • irradiation means emit the electromagnetic radiation and are directed at the at least one structure.
  • the irradiation means are preferably lasers. These are particularly preferably pulsed and focused, so that the electromagnetic radiation can advantageously be introduced locally.
  • the electromagnetic radiation passes through the at least one structure and is virtually not absorbed by it.
  • the irradiation means are directed at the at least one structure.
  • further layers or other elements are penetrated by the electromagnetic radiation before it first hits the at least one structure and then the boundary area.
  • coatings can be applied to a side of the structures facing away from the first substrate, so that the separate structures can be applied or fixed better on another surface.
  • the first substrate is made of silicon.
  • the first substrate thus essentially consists of silicon. Surprisingly, it turned out that structures of substrates based on silicon can be separated particularly easily and efficiently using the separation method.
  • the at least one structure is made of gallium nitride (GaN).
  • the method for separating thin layers or structures made of gallium nitride is particularly preferred.
  • the method for separating by means of electromagnetic radiation in particular in the UV range, can be carried out particularly efficiently and easily with structures made of gallium nitride.
  • the at least one structure made of gallium nitride can be separated from the first substrate in a particularly gentle manner.
  • the electromagnetic radiation is largely not absorbed when penetrating the structures made of GaN, so that the method for cutting is predestined for structures made of gallium nitride.
  • a wavelength of the electromagnetic radiation is between 300 nm and 2000 nm, preferably between 310 nm and 1800 nm, more preferably between 320 nm and 1600 nm, most preferably between 340 nm and 1400 nm, am most preferably between 370 nm and 1250 nm.
  • the method can be carried out particularly efficiently in the range of these wavelengths.
  • the wavelength is particularly preferably adapted to the material of the structures or the thin layers, so that they largely do not absorb the electromagnetic radiation.
  • the first substrate which is preferably a growth substrate, is thus advantageously protected.
  • the use of short-wave electromagnetic radiation, in particular UV radiation, in particular with pulse times in the picosecond to nanosecond range can promote plasma generation in the interface. In this way, a particularly defect-free and gentle separation of the structures is made possible.
  • a transmissivity of the at least one structure for the electromagnetic radiation is greater than 10%, preferably greater than 25%, more preferably greater than 50%, most preferably greater than 75%, most preferably greater than 90% is.
  • the at least one structure or the thin layer is heated as little as possible, so that errors due to heat or radiation input in the structure are reduced.
  • a transmissivity of the first substrate for the electromagnetic radiation is less than 90%, preferably less than 75%, more preferably less than 50%, most preferably less than 25%, most preferably less than 10 % is.
  • the border area can advantageously be influenced locally. Penetration of the electromagnetic radiation into the first substrate can advantageously be prevented, so that the first substrate is protected and can consequently be used more often to provide or to produce the structures.
  • Another advantageous embodiment of the invention provides that an intensity of the electromagnetic radiation between 100 mWatt and 10 kWatt, preferably between 1 Watt and 1 kWatt, even more preferably between 5 watts and 500 watts, most preferably between 7 watts and 250 watts, most preferably between 10 watts and 100 watts.
  • an intensity of the electromagnetic radiation between 100 mWatt and 10 kWatt, preferably between 1 Watt and 1 kWatt, even more preferably between 5 watts and 500 watts, most preferably between 7 watts and 250 watts, most preferably between 10 watts and 100 watts.
  • the second substrate is transparent to the electromagnetic radiation and is arranged between the irradiation means and the at least one structure during the irradiation in step ii).
  • a transfer method can be carried out particularly efficiently if the second substrate is designed to be largely transparent to the electromagnetic radiation.
  • the irradiation means can advantageously be arranged in a space-saving manner on that side of the second substrate which is remote from the first substrate.
  • the structures can also be transferred to the second substrate.
  • electromagnetic radiation in particular laser radiation
  • the ablation or the separation of the thin layer is therefore possible from the side opposite the substrate.
  • the laser radiation therefore does not reach the interface through the substrate as in the prior art, but through the thin layer or the structure.
  • the method thus enables the structures to be separated without the rear side of the substrate having to be accessible. Furthermore, this enables a more cost-effective production of grown or produced thin layers or structures (e.g. GaN-based power components), since these can also be produced on non-transparent substrates.
  • grown or produced thin layers or structures e.g. GaN-based power components
  • silicon substrates have a small band gap, so electromagnetic radiation in the UV and visible wavelength ranges is absorbed. Therefore, in the prior art, lasers with a wavelength in the infrared range are required for the ablation.
  • the thin layer In the proposed method for separating structures, in particular for GaN, there is a thin layer on a substrate with high absorption in the wavelength range of the electromagnetic radiation used.
  • the thin layer must be at least partially transparent to the electromagnetic radiation that is used to ablate the thin layer.
  • GaN with a band gap of about 3.3 eV is transparent in the UV wavelength range.
  • a GaN layer/structure on silicon is thus initially irradiated by electromagnetic radiation and penetrated by it. The silicon behind it then absorbs the electromagnetic Radiation in the border area. The absorption then leads to the ablation of the thin layer or the structure.
  • GaN thermally decomposes to pure metallic gallium and nitrogen gas between approximately 710°C and 980°C. This temperature can be reached locally by laser radiation, in particular if a plasma is also generated in the interface by the laser radiation. A short pulse duration can locally limit the effect of heat. Furthermore, the dissociation can be influenced by doping the substrate.
  • the method advantageously allows the use of any substrate, in particular a growth substrate, for producing the thin layer.
  • a growth substrate for producing the thin layer.
  • the use of silicon as a growth substrate is made possible, which represents a cheaper alternative to sapphire substrates.
  • the thin films can be fabricated on opaque substrates that are cheaper, more readily available, larger, or more powerful.
  • the ablation can advantageously be performed with electromagnetic radiation that is at higher frequencies.
  • a selective separation of individual structures or layer areas is made possible.
  • electromagnetic radiation can be used, which penetrates the thin layer but heats it only insignificantly.
  • the thin layer or the structure created from it is therefore less stressed.
  • the damage to the growth substrate is minimized and reduced particularly advantageously by the sequence of irradiation, since the Growth substrate is not irradiated, but if the radiation is only absorbed in the border area.
  • the proposed method can advantageously also be used for other materials or other thin layers on other first substrates/growth substrates, as long as electromagnetic radiation can be generated which penetrates the thin layer and is absorbed by the growth substrate.
  • the growth substrate and an optional second (transfer or product) substrate onto which the thin film or structures are transferred are damaged less and can therefore be used more often.
  • the method thus describes a new possibility of separating a thin layer or structures that were produced from this thin layer from a first substrate. Since the structures also arise from a thin layer and are only correspondingly separated by further process steps, for the sake of simplicity, in the further course of the text preferably only structure is spoken of. Structure and thin layer can be used interchangeably, although the structure as an element can be made up of more than the thin layer.
  • the thin layer is preferably produced, in particular grown, directly on the first substrate.
  • the first substrate can therefore also be referred to as a growth substrate.
  • the pulse times of the electromagnetic radiation are preferably between 1.0 picosecond and 100 picoseconds, preferably between 2.0 picoseconds and 75 picoseconds, more preferably between 3.0 picoseconds and 50 picoseconds, most preferably between 4.0 picoseconds and 25 picoseconds, most preferably around 5 picoseconds.
  • Pulses in the picosecond range are also preferred because even shorter pulses in the femtosecond range produce non-linear effects that can be disadvantageous for the method. Furthermore, thermal diffusion is largely avoided by a short pulsed effect of the electromagnetic radiation.
  • the frequency of the pulse rate means the number of pulses of electromagnetic radiation emitted per second.
  • the frequency of the pulse rate is between 10 kHz and 1000 kHz, preferably between 50 kHz and 900 kHz, more preferably between 100 kHz and 800 kHz, most preferably between 250 kHz and 700 kHz, most preferably around 500 kHz.
  • an ideal energy surface density of the electromagnetic radiation is around 10 mJ/25 pm 2 , which corresponds to 4*10 5 J/m 2 .
  • the energy surface density is therefore particularly preferably between 10 2 J/m 2 and 10 8 J/m 2 , preferably between 10 3 J/m 2 and 10 7 J/m 2 , most preferably between 10 4 J/m 2 and 10 5 J /m 2 , most preferably at about 4* 10 5 J/m 2 .
  • the thin layer has a thickness between 0 ⁇ m and 1000 ⁇ m, preferably between 0 ⁇ m and 500 ⁇ m, more preferably between 0 ⁇ m and 200 ⁇ m, most preferably between 0 ⁇ m and 150 ⁇ m, most preferably between 0 ⁇ m and 100 ⁇ m. Accordingly, the isolated structures preferably have the same thickness.
  • an absorption layer which is intended to absorb the electromagnetic radiation, is located on the growth substrate.
  • the thin layer to be separated later is produced, in particular grown, on the absorption layer.
  • the absorption layer is preferably very thin and has a maximum absorption capacity for the electromagnetic radiation of the separation process described later.
  • the border area is thus formed by the absorption layer arranged between the first substrate and the thin layer. The border area absorbs the electromagnetic radiation and specifies the location of the separation between the first substrate and the thin layer or structure.
  • the absorption layer preferably has the same crystallographic orientation as the first substrate.
  • the crystal systems and lattice system of the absorption layer and of the first substrate are identical.
  • the lattice parameters of the absorption layer and of the first substrate are identical.
  • the absorption layer can thus serve as a growth layer for the thin layer to be produced. This is particularly advantageous when this (absorption) layer has the optimal properties to serve as a growth layer and as an absorption layer.
  • the boundary area or interface is understood to be the area at which the thin layer or structure to be separated must be separated. Should the thin film be grown directly on the first substrate, the interface is between the thin film and the first substrate. Should the thin layer on a absorption layer has been grown is the interface between the thin layer and the absorption layer.
  • the absorption layer has a thickness between 0 ⁇ m and 100 ⁇ m, preferably between 0 ⁇ m and 50 ⁇ m, more preferably between 0 ⁇ m and 20 ⁇ m, most preferably between 0 ⁇ m and 10 ⁇ m, most preferably between 0 ⁇ m and 1 ⁇ m.
  • Materials on either side of the interface can be tailored to enhance absorption and/or outgassing.
  • one or more elements to be implanted in the substrate surface of the first substrate, the growth substrate and/or the thin layer itself, which elements emerge in the event of electromagnetic radiation, in particular as a gas, and support the ablation.
  • elements are implanted in the substrate surface of the first substrate, the growth substrate, which enable a particularly efficient absorption of the electromagnetic radiation, which leads to better heating of the first substrate.
  • the use of an absorption layer can be dispensed with entirely and the thin layer can be produced directly on the first substrate, the growth substrate.
  • the method is preferably carried out using electromagnetic radiation with a specific frequency, intensity and coherence.
  • electromagnetic radiation with a specific frequency, intensity and coherence.
  • any electromagnetic radiation that can penetrate the thin layer and leads to an ablation of the thin layer from the substrate can be used.
  • laser radiation will be used as an example for electromagnetic radiation.
  • the electromagnetic radiation used has a wavelength or has a frequency that does not lead to undesired absorption phenomena in the thin layer.
  • the wavelength is between 1000 pm and 10 nm, preferably between 500 pm and 25 nm, more preferably between 250 pm and 50 nm, most preferably between 100 pm and 75 nm, most preferably between 10 pm and 100 nm.
  • the preferred wavelength ranges are as follows.
  • the wavelength is between 300 nm and 2000 nm, preferably between 310 nm and 1800 nm, more preferably between 320 nm and 1600 nm, most preferably between 340 nm and 1400 nm, most preferably between 370 nm and 1250 nm.
  • Electromagnetic radiation in this wavelength range penetrates the GaN very well and is absorbed well enough by the silicon.
  • the second substrate onto which the GaN is transferred should be transparent for this wavelength.
  • the second substrate can therefore preferably accommodate GaN structures/layers and has sufficiently good transmissivity in the wavelength range used.
  • the second substrate is made of sapphire.
  • the thickness of the two substrates is between 0 ⁇ m and 2000 ⁇ m, preferably between 100 ⁇ m and 1500 ⁇ m, more preferably between 200 ⁇ m and 1300 ⁇ m, most preferably between 300 ⁇ m and 1200 ⁇ m, most preferably between 500 ⁇ m and 1000 ⁇ m. Since the first substrate is used for growth and the second substrate is used for fixation after ablation, greater thicknesses are preferable because greater thicknesses make the two substrates strong enough.
  • Relative movement can be performed between the substrate and the source of electromagnetic radiation. In a particularly preferred embodiment, all optical components are static while the substrate fixed to a substrate holder moves. The substrate holder is then designed in such a way that the electromagnetic radiation can be focused onto the interface between the first substrate and the thin layer.
  • the relative movement is meandering and/or linear and/or rotary. This type of relative motion, in which a surface is scanned along a path, is sometimes called scanning.
  • the separation of the thin layer or the structures that are made from the thin layer can be supported by mechanical separation processes from the first substrate.
  • laser radiation from a higher frequency range can be used in the improved method.
  • Laser radiation from the UV range is preferably used.
  • the GaN can be pre-structured on a carrier.
  • the number of LEDs per carrier should be as large as possible.
  • the method for transferring components can also be used for non-structured, in particular epitaxial (thin) layers.
  • the thin and grown layer is from the first substrate Cut.
  • Individual areas can be selectively separated or the electromagnetic radiation can be introduced over the entire area into the border area.
  • the method of transferring components is applicable to a variety of layers and structures. However, the transmission of GaN-based structures, e.g. like p-LEDs, power devices or pure, thin GaN layers are preferred.
  • the structures preferably grown and isolated on the first substrate are transferred to a second substrate in that electromagnetic radiation, in particular a laser, penetrates through the structures and causes ablation at the interface of the structure in order to separate the structure from the first substrate .
  • the first substrate or an absorption layer absorbs the electromagnetic radiation and leads to an ablation of the structure, in particular without defects, the electromagnetic radiation is introduced in a pulsed and focused manner, i.e.
  • the electromagnetic radiation in contrast to the prior art, not through the first substrate, the growth substrate, but through the structure, acts on the interface, through the use of short-wave electromagnetic radiation, in particular UV radiation, penetration of the electromagnetic radiation into the first substrate ,
  • the growth substrate is hindered, which leads to a protection of the growth substrate, through the use of short-wave electromagnetic radiation, in particular UV radiation, in particular by pulse times in the pico to Nanosecond range plasma generation is promoted in the interface, which leads to improved ablation and by changing the substrate surface of the first substrate, the absorption and / or an outgassing process can be improved.
  • Any system comprises the materials for a first substrate, which serves as a growth substrate, for the structures or a thin layer, and a preferred second substrate, onto which the structures or the thin layer are to be transferred.
  • a first substrate which serves as a growth substrate
  • a preferred second substrate onto which the structures or the thin layer are to be transferred.
  • possible wavelength ranges are specified and the lasers whose photon wavelength is in this wavelength range. Those skilled in the art generally know a number of lasers for the specified wavelength range.
  • Figure la a first process step of an exemplary method according to the invention
  • Figure lb a second process step of an exemplary method according to the invention
  • Figure l c a third process step of an exemplary method according to the invention
  • Figure 1d shows a fourth process step of an exemplary method according to the invention
  • Figure l e a fifth process step of an exemplary method according to the invention
  • FIG. 2 shows a diagram of the penetration depth d in silicon as a function of the wavelength l of the electromagnetic radiation used
  • FIG. 3 shows two diagrams of a transmissivity (left ordinate, solid line) and absorption (right ordinate, dashed line) as a function of wavelength for silicon (top) and for GaN (bottom).
  • transmissivity left ordinate, solid line
  • absorption right ordinate, dashed line
  • a thin layer 2 is produced directly on a first substrate 1, a growth substrate.
  • the thin layer 2 is either the structure 2 to be separated or, in an optional step, is subdivided into a plurality of structures 3 which, in particular, can be separated individually and selectively.
  • An absorption layer which in particular can also serve as a growth layer at the same time and is located on the first substrate, is not shown here.
  • the absorption of the electromagnetic radiation 5 then does not take place mainly on the first substrate 1, but mainly on the absorption layer.
  • the interface 6 is then the interface between the thin layer 2 and the absorption layer.
  • the substrate 1 and/or the absorption layer are predominantly, preferably completely, impermeable to the irradiation means.
  • FIG. 1a shows a first process step in which a thin layer 2 was produced on a first substrate 1.
  • the thin layer 2 can be produced by any method, for example by PVD or CVD methods.
  • the thin layer 2 is preferably an epitaxial layer.
  • the substrate 1 is therefore suitable for growing the desired thin layer 2 on a surface.
  • the crystallographic orientation, the lattice parameters and the material of the substrate 1 should be selected in such a way that the thin layer 2 can grow optimally, in particular epitaxially, monocrystalline and preferably with as few defects as possible.
  • the choices for a suitable substrate 1 for providing the desired thin layer 2 restricted.
  • Figure lb shows an optional second process step in which the thin layer 2 is isolated.
  • several process steps are necessary to separate the thin layer 2 . It would also be conceivable that this process step does not take place, in which case the entire thin layer 2 is transferred and forms the structure 2 to be transferred have functionality. It would be conceivable, for example, for the structures 3 to produce LEDs. Those skilled in the art know what components can be created.
  • FIG. 1c shows an optional third process step in which the structures 3 are coated, in particular oxidized.
  • the coating 4 can also take place before the second step of the separation according to FIG.
  • the coating 4 can have any number of reasons, but preferably serves to improve the bond when the structures 3 are transferred to a second substrate 1'.
  • An oxide layer in particular can improve the bond between the structures 3 and the second substrate 1'.
  • FIG. 1d shows a fourth process step in which contact is made, a so-called bond, between the structures 3 of the first substrate 1 and a second substrate 1′.
  • the two substrates 1 and 1' are preferably aligned with one another beforehand. It is also conceivable that the structures 3 are aligned relative to alignment marks on the second substrate 1'. It is also conceivable that a thermal treatment is carried out after contacting to the bond between the Structures 3 and the second substrate 1 'to improve.
  • the second substrate 1' is transparent for the electromagnetic radiation 5 used in the next process step.
  • FIG. 1e shows a fifth process step, in which the irradiation means radiate a specific electromagnetic radiation 5 through the structures 3 onto an interface between the structures 3 and the first substrate 1'.
  • the interface 6 between the first substrate 1 and the structures 3 is irradiated with the aid of the electromagnetic radiation 5, in particular a laser.
  • the electromagnetic radiation 5 radiates through the structures 3.
  • the second substrate 1' used can always be selected in such a way that it is transparent to the electromagnetic radiation used in each case.
  • the electromagnetic radiation is not radiated through the first substrate 1, which as a growth substrate has to meet very specific requirements, onto the interface 6, but penetrates the second substrate 1', which can be chosen relatively freely in terms of its physical properties, as well as a possible coating 4 and the structure 3
  • An existing coating 4 is usually very thin, so that it causes high absorption of the electromagnetic radiation in the rarest of cases. Furthermore, in most cases the coating 4 is an oxide anyway, which is permeable in a broad wavelength spectrum.
  • the electromagnetic radiation 5 used is preferably pulsed.
  • the pulsed energy leads to an ablation of the structure 3 from the first substrate 1 along the interface 6.
  • the ablation can come about through different chemical and/or physical effects. For example, it is conceivable that the thermal expansions of the materials of the structure 3 and of the first substrate 1 are different. This leads to a thermal expansion difference and thus to thermal stresses. The thermal stresses eventually lead to ablation.
  • a gas is formed in the interface 6 .
  • the structures 3 were made of a material containing nitrogen, carbon or hydrogen, the formation of nitrogen gas, carbon dioxide, carbon monoxide, hydrogen gas, and water if oxides exist in the vicinity, can lead to ablation along the interface 6 , since the gases and/or liquids formed cause an increase in pressure due to their volume expansion, which leads to an ablation of the structure 3 from the first substrate 1. It is also conceivable to generate a plasma in the interface 6, which even improves the ablation.
  • FIG. 1f shows a sixth process step, in which two structures 3 are located on the second substrate 1', while all other structures 3 remain on the first substrate 1.
  • the substrate 1' already has other structures (not shown) and the transferred structures 3 are not applied directly to the substrate surface lo' of the second substrate 1', but to the structures already located on the second substrate 1' (not shown), are transferred.
  • the electromagnetic radiation 5 used which arrives at the interface 6 and runs through a structure stack, is possibly weaker due to a plurality of structures 3 arranged one above the other. The means of irradiation must be designed accordingly.
  • FIG. 1f shows a sixth process step, in which two structures 3 are located on the second substrate 1', while all other structures 3 remain on the first substrate 1.
  • the substrate 1' already has other structures (not shown) and the transferred structures 3 are not applied directly to the substrate surface lo' of the second substrate 1', but to the structures already located on the second substrate
  • the penetration depth d in silicon can be read as a function of the wavelength l of the electromagnetic radiation used.
  • the penetration depth in the silicon can be used to optimize the range of absorption.
  • the diagram shows that the penetration depth is limited to a few micrometers when the wavelength used is less than approx. 900 nm.
  • a titanium ion-based laser for example, emits photons of this wavelength. In the wavelength range between 800 nm and 1100 nm, the penetration depth is still max. 100 pm.
  • neodymium or yttberium lasers with 1 ⁇ 1064 nm and 1 ⁇ 1043 nm could be used for this wavelength range.
  • Figure 3 shows two diagrams, one for silicon (top) and one for GaN (bottom).
  • the transmissivity (left ordinate, solid line) and absorption (right ordinate, dashed line) are plotted as a function of wavelength.
  • silicon is transparent to electromagnetic radiation with a wavelength of more than approx. 1200 nm, i.e. it absorbs almost no photons.
  • GaN is transparent to electromagnetic radiation with a wavelength longer than about 380 nm.
  • the electromagnetic radiation should penetrate the thin layer, in the present case the GaN, but be absorbed in the boundary area 6, in the present case the silicon. Accordingly, a transmission window 7 in the wavelength range between approximately 380 nm and 900 nm is appropriate for this exemplary combination.
  • an extended transmission window 7' up to approximately 1100 nm can be used.
  • the present diagrams therefore only relate to the GaN/Si system as an example. Corresponding diagrams must be analyzed for other systems in order to obtain the optimal transmission window. List of references to signs
  • Second substrate (receiver substrate, transfer substrate) lo' substrate surface Thin layer

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Abstract

L'invention concerne un procédé et un dispositif pour séparer des structures d'un substrat. L'invention concerne également un procédé et un dispositif pour transférer des structures d'un premier substrat à un second substrat.
EP21716342.7A 2021-03-30 2021-03-30 Procédé de séparation de structures d'un substrat Pending EP4315406A1 (fr)

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EP (1) EP4315406A1 (fr)
JP (1) JP2024513280A (fr)
KR (1) KR20230161413A (fr)
CN (1) CN116391264A (fr)
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DE19640594B4 (de) * 1996-10-01 2016-08-04 Osram Gmbh Bauelement
US9236271B2 (en) * 2012-04-18 2016-01-12 Globalfoundries Inc. Laser-initiated exfoliation of group III-nitride films and applications for layer transfer and patterning
US20150059411A1 (en) * 2013-08-29 2015-03-05 Corning Incorporated Method of separating a glass sheet from a carrier
CA2936523A1 (fr) * 2016-07-19 2018-01-19 G. Reza Chaji Micro dispositif selectif de transfert vers un substrat recepteur

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KR20230161413A (ko) 2023-11-27
CN116391264A (zh) 2023-07-04

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