A method and apparatus for laser debonding

Abstract

This invention provides a method and apparatus for laser debonding, belonging to the field of semiconductor technology. The method includes the following steps: providing a temporary bonding body for a wafer, the temporary bonding body comprising a silicon carrier, an interposer, a carbon-rich thin film, a bonding layer, and a wafer stacked together; in a vacuum environment, irradiating the temporary bonding body with an infrared pulsed laser, causing interface peeling at the carbon-rich thin film, thus completing the laser debonding between the silicon carrier and the wafer. This invention uses a carbon-rich thin film as the laser release layer, reducing costs. It possesses broad-spectrum, high-efficiency absorption characteristics in the infrared laser band, enhancing laser scattering and light-trapping effects, and improving laser energy absorption efficiency. By performing laser debonding in a vacuum environment, impurities such as microparticles generated during interface peeling can be removed from the cavity, avoiding wafer contamination and interference with the laser path, thus improving the cleanliness, stability, and overall device yield of the debonding process.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, and specifically relates to a laser debonding method and debonding device. Background Technology

[0002] Currently, infrared laser debonding technology using silicon as a temporary carrier has effectively overcome the poor equipment compatibility problem of traditional ultraviolet laser debonding using glass carriers. This technology uses a thin film with a certain absorption rate of infrared laser as a release layer. During the debonding process, the release layer absorbs laser energy and undergoes rapid vaporization and plasmaification, thereby weakening the bonding strength between the silicon carrier and the product wafer, achieving their separation, i.e., debonding.

[0003] In temporary bonding and laser debonding processes, the release layer is used as a sacrificial, one-time material. Existing technologies typically use metal thin films or metal nitride thin films as the release layer. However, metal thin films are expensive to prepare, contradicting the "sacrificial, one-time" purpose of the release layer. Furthermore, existing laser debonding processes often occur in an atmospheric environment, during which the release layer undergoes instantaneous vaporization or plasmaification, or generates particulate impurities (mainly decomposition products of the release layer material). These particulate impurities not only contaminate the product wafer (especially ultrathin wafers with intricate circuit structures) but also affect the laser path, such as by reflecting and refraction the laser beam, thus impacting the laser debonding effect, device yield, and process stability.

[0004] Therefore, how to effectively suppress or avoid particulate impurities generated during the debonding process, improve the laser debonding effect, and enhance device yield and process stability is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method and apparatus for laser debonding. This invention employs a carbon-rich thin film as the laser release layer. On one hand, it completely solves the problem of high cost associated with traditional disposable release layers, which is beneficial for large-scale industrial production. On the other hand, the carbon-rich thin film possesses broad-spectrum and highly efficient absorption characteristics in the infrared laser band. Its high-density grain boundaries and micro-defect structure enhance laser scattering and light trapping effects, thereby significantly improving laser energy absorption efficiency and effectively reducing the risk of laser transmission to the wafer. Furthermore, by performing laser debonding in a vacuum environment, impurities such as microparticles generated during the vaporization or plasmaification of the carbon-rich thin film can be rapidly removed from the cavity, fundamentally avoiding wafer contamination and interference with the laser path, significantly improving the cleanliness, stability, and overall device yield of the debonding process.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for laser debonding, the method comprising the following steps: A temporary bonding assembly for a wafer is provided, the temporary bonding assembly comprising a silicon carrier, an interposer, a carbon-rich thin film, a bonding layer, and a wafer stacked together.

[0007] In a vacuum environment, the temporary bond is irradiated with an infrared pulsed laser, which causes interfacial peeling at the carbon-rich film, thus completing the laser debonding between the silicon carrier and the wafer.

[0008] This invention employs a carbon-rich thin film as the laser release layer. On one hand, it completely solves the high cost problem of traditional single-use release layers, which is beneficial for large-scale industrial production. On the other hand, the carbon-rich thin film possesses broad-spectrum, high-efficiency absorption characteristics in the infrared laser band. Its high-density grain boundaries and micro-defect structure enhance laser scattering and light trapping effects, thereby significantly improving laser energy absorption efficiency and effectively reducing the risk of laser transmission to the wafer. Furthermore, by performing laser debonding in a vacuum environment, impurities such as microparticles generated during the vaporization or plasmaification of the carbon-rich thin film can be rapidly removed from the cavity, fundamentally avoiding wafer contamination and interference with the laser path. This significantly improves the cleanliness, stability, and overall device yield of the debonding process. Based on this laser debonding method, reusable, clean silicon carriers can be obtained, significantly reducing production costs.

[0009] In this invention, a carbon-rich thin film serves as a laser release layer. Since the carbon-rich thin film itself has a strong absorption rate for infrared lasers, under laser irradiation, the carbon-rich thin film absorbs laser energy and instantly vaporizes or plasmaizes, thereby peeling off from the bonded body and realizing laser debonding.

[0010] In this invention, the introduction of the interposer and the bonding layer not only increases the adhesion of the carbon-rich film, preventing the temporary bond from delaminating in subsequent semiconductor processes, but also acts as a barrier layer to prevent damage to the silicon carrier and wafer during subsequent cleaning.

[0011] It should be noted that the present invention does not limit the diameter of the silicon carrier. For example, a silicon carrier with a diameter of 4-12 inches can be selected, specifically 4 inches, 6 inches, 8 inches, 10 inches or 12 inches, etc.

[0012] Preferably, the transmittance of the intermediate layer to the pulsed laser in the infrared band is ≥95%, for example, it can be 95%, 96%, 97%, 98% or 99%, etc.

[0013] This invention ensures that the transmittance of the interposer to the infrared pulsed laser reaches a certain value, which can avoid excessive laser loss at the silicon carrier-interposer interface, thus preventing the debonding effect from being achieved.

[0014] Preferably, the interlayer comprises an oxide film, and more preferably a silicon dioxide film.

[0015] Preferably, the thickness of the interposer layer is 20-100nm, for example, it can be 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100nm, etc.

[0016] Preferably, the surface of the interposer is rich in silanol groups, which are configured to form chemical bonds with the silicon support.

[0017] In this invention, the silicon carrier surface itself is inert, while the deposited interlayer surface is rich in silanol groups (-Si-OH-), which will form strong chemical bonds with the functional groups in the carbon-rich material. This combination increases the adhesion of the carbon-rich film on the silicon carrier and prevents it from falling off in subsequent semiconductor processing.

[0018] Preferably, the thickness of the carbon-rich film is 50-200 nm, for example, it can be 50 nm, 100 nm, 150 nm or 200 nm.

[0019] Preferably, the carbon material contained in the carbon-rich film is composed of sp 2 The proportion of carbon atoms composed of hybrid carbon atoms to the total number of carbon atoms is >70%, for example, it can be 75%, 80%, 85%, 90% or 95%, etc., preferably >90%.

[0020] In this invention, the carbon material contained in the carbon-rich thin film is composed of sp 2 The proportion of carbon atoms composed of hybrid carbon atoms is >70% of the total number of carbon atoms. Its electronic structure is dominated by delocalized π electrons, which can make the carbon-rich thin film have an intrinsic high absorption rate for the laser band used in this invention. The absorbed photon energy can be rapidly converted into lattice thermal energy. At the same time, combined with its high absorption rate, the laser energy can be highly localized in the irradiation area to achieve precise debonding.

[0021] Preferably, the carbon-rich film has a nanoscale porous structure or an interwoven network structure.

[0022] In this invention, the nanoscale porous structure or interwoven network structure can make the thin film have a large number of grain boundary vacancies and pores, which greatly enhances light scattering, extends the optical path, and improves the apparent absorption rate of the carbon-rich thin film for laser. At the same time, it also hinders the rapid conduction of phonons (heat), so that the laser energy can be efficiently localized in the irradiation area.

[0023] Preferably, the specific surface area of ​​the carbon-rich film is >100m². 2 / g, for example, could be 105m 2 / g、110m 2 / g、115m 2 / g, 120m 2 / g、125m 2 / g、130m 2 / g or 135m 2 / g etc.

[0024] Preferably, the carbon material in the carbon-rich film includes any one or a combination of at least two of carbon nanotubes, graphene, carbon black, carbon nanofibers, or pyrolytic carbon.

[0025] Preferably, the method for preparing the carbon-rich thin film includes vacuum deposition or liquid phase spin coating.

[0026] Preferably, when the carbon-rich thin film is prepared by liquid-phase spin coating, the specific steps include: The carbon source solution is spin-coated onto the surface of the intermediate layer, and then annealed to form the carbon-rich film.

[0027] Preferably, the carbon source solution is obtained by dissolving carbon material in an organic solvent, or by dispersing carbon material as a filler with a soluble polymer in a solvent. Exemplary examples of organic solvents include toluene, chlorobenzene, or N,N-dimethylformamide.

[0028] Preferably, the annealing temperature is 100-450℃, for example, 100℃, 200℃, 300℃, 400℃ or 450℃, and the annealing time is 1-180min, for example, 1min, 30min, 60min, 90min, 120min, 150min or 180min.

[0029] Preferably, the bonding layer comprises an organic bonding adhesive or an inorganic compound film.

[0030] This invention utilizes a bonding layer to fix a wafer onto a carbon-rich thin film.

[0031] Preferably, the thickness of the bonding layer is 0.2-20 μm, for example, it can be 0.2 μm, 1 μm, 5 μm, 10 μm, 15 μm or 20 μm.

[0032] Preferably, the laser wavelength of the pulsed laser is 1-50μm, for example, it can be 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm, etc.

[0033] Preferably, the pulse width of the pulsed laser is 200fs-1μs, for example, it can be 200fs, 500fs, 1ps, 10ps, 100ps, 1ns, 10ns, 100ns, 500ns or 1μs, etc.

[0034] Preferably, the pulse energy of the pulsed laser is 10μJ-1mJ, for example, it can be 10μJ, 50μJ, 100μJ, 200μJ, 500μJ, 800μJ or 1mJ.

[0035] Preferably, the pulse frequency of the pulsed laser is 0.1-100kHz, for example, it can be 0.1kHz, 1kHz, 10kHz, 20kHz, 50kHz, 80kHz or 100kHz.

[0036] Preferably, the vacuum level of the vacuum environment is 1×10⁻⁶. -1 Pa-1×10 -5 Pa, for example, could be 1×10 -3 Pa, 7.5 × 10 -4 Pa, 5×10 -4 Pa, 2.5 × 10 -4 Pa, 1×10 -4 Pa, 5×10 -5 Pa or 1×10 -5 Pa, etc., preferably 1×10 - 3 Pa-1×10 -5 Pa.

[0037] Preferably, the method includes the following steps: (1) Deposit an intermediate layer with a thickness of 20-100 nm on the surface of the silicon carrier.

[0038] The intermediate layer has a transmittance of ≥95% for pulsed laser light in the infrared band; the intermediate layer comprises an oxide film; the surface of the intermediate layer is rich in silanol groups, which are configured to form chemical bonds with the silicon carrier.

[0039] (2) A carbon-rich film with a thickness of 50-200 nm is deposited on the surface of the intermediate layer using a liquid-phase spin coating method; wherein the carbon material contained in the carbon-rich film is composed of sp 2 The proportion of hybrid carbon atoms in the total carbon atoms is >70%; the carbon-rich film has a nanoscale porous structure or interwoven network structure; the specific surface area of ​​the carbon-rich film is >100 m². 2 / g.

[0040] The specific steps of the liquid phase spin coating method include: (a) Dissolve carbon material in an organic solvent to obtain a carbon source solution, or mix carbon material as a filler with a soluble polymer in a solvent at a mass ratio of 1:(0.5-20) (e.g., 1:0.5, 1:1, 1:5, 1:10, 1:15 or 1:20, etc.) to obtain a carbon source solution.

[0041] (b) The carbon source solution is spin-coated onto the surface of the intermediate layer at a spin-coating rate of 1000-5000 rpm (e.g., 1000 rpm, 2000 rpm, 3000 rpm, 4000 rpm or 5000 rpm, etc.) for a spin-coating time of 30-120 s (e.g., 30 s, 60 s, 90 s or 120 s, etc.), and then annealed at 100-450°C in a vacuum or inert atmosphere (e.g., nitrogen or argon, etc.) for 1-180 min to form the carbon-rich film.

[0042] The soluble polymer includes any one or a combination of at least two of polyimide, polyurethane, epoxy resin or polyvinyl alcohol.

[0043] (3) A bonding layer with a thickness of 0.2-20 μm is deposited on the surface of the carbon-rich film.

[0044] The bonding layer comprises an organic bonding adhesive or an inorganic compound film, wherein the inorganic compound film comprises a silicon oxide film.

[0045] (4) Fix the wafer on the surface of the bonding layer to obtain a temporary bond.

[0046] (5) At a vacuum degree of 1×10 -3 Pa-1×10 -5 In a vacuum environment of Pa, the temporary bond is irradiated with an infrared pulsed laser, which causes interface peeling at the carbon-rich film, thus completing the laser debonding between the silicon carrier and the wafer.

[0047] The pulsed laser has a wavelength of 1-50 μm, a pulse width of 200 fs-1 μs, a pulse energy of 10 μJ-1 mJ, and a pulse frequency of 0.1-100 kHz.

[0048] (6) Use a strong oxidizing liquid to remove the carbon-rich material remaining on the silicon carrier side and the wafer side, and then use a corrosive liquid to remove the interlayer and bonding layer to obtain a recyclable silicon carrier and product wafer.

[0049] In this invention, the strong oxidizing liquid can be, for example, piranha liquid (i.e., a mixed solution of concentrated sulfuric acid and hydrogen peroxide, with a volume ratio of, for example, 3:1 or 1:3). The corrosive liquid can be, for example, hydrofluoric acid.

[0050] In a second aspect, the present invention provides a debonding apparatus, which is used in the laser debonding method described in the first aspect, the debonding apparatus comprising: A laser generating unit, which is used to generate pulsed lasers in the infrared band.

[0051] A vacuum processing unit is provided and maintained to provide the vacuum environment required for the laser debonding.

[0052] Preferably, the vacuum processing unit includes: A vacuum chamber, the interior of which is provided with a movable stage for supporting the temporary bond.

[0053] A window plate, which is disposed on the side wall of the vacuum chamber, is used to transmit the pulsed laser.

[0054] An optical path adjustment assembly is disposed within the vacuum chamber and is used to receive the pulsed laser transmitted by the window and guide and focus it onto the temporary bond.

[0055] Preferably, the debonding device further includes a vacuum pumping system for maintaining the vacuum level of the vacuum chamber.

[0056] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0057] Compared with the prior art, the present invention has the following beneficial effects: This invention employs a carbon-rich thin film as the laser release layer. On one hand, it completely solves the high cost problem of traditional single-use release layers, which is beneficial for large-scale industrial production. On the other hand, the carbon-rich thin film possesses broad-spectrum, high-efficiency absorption characteristics in the infrared laser band. Its high-density grain boundaries and micro-defect structure enhance laser scattering and light trapping effects, thereby significantly improving laser energy absorption efficiency and effectively reducing the risk of laser transmission to the wafer. Furthermore, by performing laser debonding in a vacuum environment, impurities such as microparticles generated during the vaporization or plasmaification of the carbon-rich thin film can be rapidly removed from the cavity, fundamentally avoiding wafer contamination and interference with the laser path. This significantly improves the cleanliness, stability, and overall device yield of the debonding process. Based on this laser debonding method, reusable, clean silicon carriers can be obtained, significantly reducing production costs. Attached Figure Description

[0058] Figure 1This is a schematic diagram of the structure after step (1) in the method provided in Embodiment 1 of the present invention.

[0059] Figure 2 This is a schematic diagram of the structure after step (2) in the method provided in Embodiment 1 of the present invention.

[0060] Figure 3 This is a schematic diagram of the structure after step (3) in the method provided in Embodiment 1 of the present invention.

[0061] Figure 4 This is a schematic diagram of the structure after step (4) in the method provided in Embodiment 1 of the present invention.

[0062] Figure 5 This is a schematic diagram of the debonding device provided in Embodiment 1 of the present invention.

[0063] Among them, 1-silicon carrier; 2-intermediate layer; 3-carbon-rich thin film; 4-bonding layer; 5-silicon wafer; 6-temporary bond; 7-laser generator; 8-vacuum chamber; 9-window; 10-pulsed laser; 11-optical path adjustment component; 12-moving stage; 13-vacuum pumping system. Detailed Implementation

[0064] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0065] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0066] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0067] Example 1 This embodiment provides a laser debonding method, which includes the following steps: (1) A silicon dioxide thin film with a thickness of 60 nm was deposited on the surface of silicon carrier 1 as an intermediary layer 2 by chemical vapor deposition.

[0068] The silicon dioxide film has a transmittance of 98% for pulsed laser light in the infrared band; the surface of the interposer 2 is rich in silanol groups, which are configured to form chemical bonds with the silicon carrier 1.

[0069] Figure 1 A schematic diagram of the structure after step (1) is shown.

[0070] (2) A carbon-rich thin film 3 with a thickness of 100 nm is deposited on the surface of the intermediate layer 2 using a liquid phase spin coating method; wherein, the carbon material contained in the carbon-rich thin film 3 is composed of sp 2 The proportion of hybrid carbon atoms in the carbon-rich film 3 is 95%; the carbon-rich film 3 has a nanoscale porous structure; the specific surface area of ​​the carbon-rich film 3 is 110 m². 2 / g.

[0071] The specific steps of the liquid phase spin coating method include: (a) Carbon nanotubes were dissolved in toluene to obtain a carbon source solution.

[0072] (b) The carbon source solution is spin-coated onto the surface of the intermediate layer at a spin-coating rate of 2000 rpm for 100 s, and then annealed at 300 °C for 90 min under a nitrogen atmosphere to form the carbon-rich film 3.

[0073] Figure 2 A schematic diagram of the structure after step (2) is shown.

[0074] (3) A silicon oxide film with a thickness of 10 μm is deposited on the surface of the carbon-rich film 3 as a bonding layer 4 by chemical vapor deposition.

[0075] Figure 3A schematic diagram of the structure after step (3) is shown.

[0076] (4) Fix the silicon wafer 5 on the surface of the bonding layer 4 to obtain a temporary bond 6.

[0077] Figure 4 A schematic diagram of the structure after step (4) is shown.

[0078] (5) At a vacuum degree of 1×10 -4 In a vacuum environment of Pa, the temporary bond 6 is irradiated with an infrared pulsed laser. The irradiated side is a silicon carrier, which causes interface peeling at the carbon-rich film 3, thus completing the laser debonding between the silicon carrier 1 and the silicon wafer 5.

[0079] The pulsed laser has a wavelength of 25 μm, a pulse width of 1 ns, a pulse energy of 500 μJ, and a pulse frequency of 50 kHz.

[0080] (6) Use piranha liquid to remove the carbon-rich material remaining on the silicon carrier 1 side and the silicon wafer 5 side, and then use hydrofluoric acid to remove the intermediate layer 2 and the bonding layer 4 to obtain the recyclable silicon carrier 1 and the product silicon wafer 5.

[0081] This embodiment also provides a debonding device, which is used in the above-described laser debonding method. A schematic diagram of the debonding device is shown below. Figure 5 As shown, it includes: A laser generating device 7 is used to generate an infrared pulsed laser 10.

[0082] A vacuum processing apparatus for providing and maintaining the vacuum environment required for the laser debonding.

[0083] The vacuum processing device includes: The vacuum chamber 8 is provided with a movable stage 12 for supporting the temporary bond 6.

[0084] A window 9 is disposed on the side wall of the vacuum chamber 8 and is used to transmit the pulsed laser 10.

[0085] An optical path adjustment component 11 is disposed in the vacuum chamber 8 and is used to receive the pulsed laser 10 transmitted by the window 9 and guide and focus it onto the temporary bond 6.

[0086] The debonding device also includes a vacuum pumping system 13 for maintaining the vacuum level of the vacuum chamber 8.

[0087] Example 2 This embodiment provides a laser debonding method, which includes the following steps: (1) A silicon dioxide thin film with a thickness of 20 nm was deposited on the surface of the silicon carrier as an intermediary layer by chemical vapor deposition.

[0088] The silicon dioxide film has a transmittance of 99% for pulsed laser light in the infrared band; the surface of the interlayer is rich in silanol groups, which are configured to form chemical bonds with the silicon carrier.

[0089] (2) A carbon-rich film with a thickness of 50 nm is deposited on the surface of the intermediate layer using a liquid-phase spin coating method; wherein the carbon material contained in the carbon-rich film is composed of sp 2 The carbon atoms composed of hybrid carbon atoms account for 80% of the total carbon atoms; the carbon-rich film has a nanoscale porous structure; the specific surface area of ​​the carbon-rich film is 120 m². 2 / g.

[0090] The specific steps of the liquid phase spin coating method include: (a) Carbon nanotubes were mixed with polyimide at a mass ratio of 1:10 and dispersed in toluene to obtain a carbon source solution.

[0091] (b) The carbon source solution is spin-coated onto the surface of the intermediate layer at a spin-coating rate of 3000 rpm for 90 s, and then annealed at 100°C for 180 min under a nitrogen atmosphere to form the carbon-rich film.

[0092] (3) A silicon oxide film with a thickness of 1 μm is deposited on the surface of the carbon-rich film as a bonding layer by chemical vapor deposition.

[0093] (4) Fix a silicon wafer on the surface of the bonding layer to obtain a temporary bond.

[0094] (5) At a vacuum degree of 1×10 -4 In a vacuum environment of Pa, the temporary bonded material is irradiated with an infrared pulsed laser, with the silicon carrier on the irradiated side, so that interface peeling occurs at the carbon-rich film, and laser debonding is completed between the silicon carrier and the silicon wafer.

[0095] The pulsed laser has a wavelength of 5 μm, a pulse width of 500 fs, a pulse energy of 100 μJ, and a pulse frequency of 10 kHz.

[0096] (6) Piranha liquid is used to remove the carbon-rich material remaining on the silicon carrier side and the silicon wafer side, and then hydrofluoric acid is used to remove the interlayer and bonding layer to obtain a recyclable silicon carrier and product silicon wafer.

[0097] This embodiment also provides a debonding device, which is used in the above-described laser debonding method. The debonding device includes: A laser generating device for generating pulsed laser light in the infrared band.

[0098] A vacuum processing apparatus for providing and maintaining the vacuum environment required for the laser debonding.

[0099] The vacuum processing device includes: A vacuum chamber, the interior of which is provided with a movable stage for supporting the temporary bond.

[0100] A window plate, which is disposed on the side wall of the vacuum chamber, is used to transmit the pulsed laser.

[0101] An optical path adjustment assembly is disposed within the vacuum chamber and is used to receive the pulsed laser transmitted by the window and guide and focus it onto the temporary bond.

[0102] The debonding device also includes a vacuum pumping system for maintaining the vacuum level of the vacuum chamber.

[0103] Example 3 This embodiment provides a laser debonding method, which includes the following steps: (1) A silicon dioxide thin film with a thickness of 100 nm was deposited on the surface of the silicon carrier as an intermediary layer by chemical vapor deposition.

[0104] The silicon dioxide film has a transmittance of 95% for pulsed laser light in the infrared band; the surface of the interlayer is rich in silanol groups, which are configured to form chemical bonds with the silicon carrier.

[0105] (2) A carbon-rich film with a thickness of 200 nm is deposited on the surface of the intermediate layer using a liquid-phase spin coating method; wherein the carbon material contained in the carbon-rich film is composed of sp 2 The carbon atoms composed of hybrid carbon atoms account for 98% of the total carbon atoms; the carbon-rich film has a nanoscale porous structure; the specific surface area of ​​the carbon-rich film is 125 m². 2 / g.

[0106] The specific steps of the liquid phase spin coating method include: (a) Carbon nanotubes were dissolved in toluene to obtain a carbon source solution.

[0107] (b) The carbon source solution is spin-coated onto the surface of the intermediate layer at a spin-coating rate of 4000 rpm for 60 s, and then annealed at 450 °C under a nitrogen atmosphere for 5 min to form the carbon-rich film.

[0108] (3) A silicon oxide film with a thickness of 20 μm is deposited on the surface of the carbon-rich film as a bonding layer by chemical vapor deposition.

[0109] (4) Fix a silicon wafer on the surface of the bonding layer to obtain a temporary bond.

[0110] (5) At a vacuum degree of 1×10 -4 In a vacuum environment of Pa, the temporary bonded material is irradiated with an infrared pulsed laser, with the silicon carrier on the irradiated side, so that interface peeling occurs at the carbon-rich film, and laser debonding is completed between the silicon carrier and the silicon wafer.

[0111] The pulsed laser has a wavelength of 45 μm, a pulse width of 1 μs, a pulse energy of 1 mJ, and a pulse frequency of 100 kHz.

[0112] (6) Piranha liquid is used to remove the carbon-rich material remaining on the silicon carrier side and the silicon wafer side, and then hydrofluoric acid is used to remove the interlayer and bonding layer to obtain a recyclable silicon carrier and product silicon wafer.

[0113] This embodiment also provides a debonding device, which is used in the above-described laser debonding method. The debonding device includes: A laser generating device for generating pulsed laser light in the infrared band.

[0114] A vacuum processing apparatus for providing and maintaining the vacuum environment required for the laser debonding.

[0115] The vacuum processing device includes: A vacuum chamber, the interior of which is provided with a movable stage for supporting the temporary bond.

[0116] A window plate, which is disposed on the side wall of the vacuum chamber, is used to transmit the pulsed laser.

[0117] An optical path adjustment assembly is disposed within the vacuum chamber and is used to receive the pulsed laser transmitted by the window and guide and focus it onto the temporary bond.

[0118] The debonding device also includes a vacuum pumping system for maintaining the vacuum level of the vacuum chamber.

[0119] Example 4 The difference between this embodiment and Embodiment 1 is that the thickness of the carbon-rich film is 30 nm.

[0120] The remaining methods and parameters are consistent with those in Example 1.

[0121] Example 5 The difference between this embodiment and Embodiment 1 is that the thickness of the carbon-rich film is 230 nm.

[0122] The remaining methods and parameters are consistent with those in Example 1.

[0123] Example 6 The difference between this embodiment and Embodiment 1 is that the carbon source solution is doped with non-carbon element silicon, and the silicon atoms destroy the pure sp of carbon. 2 Networks form carbon-heteroatom bonds (mostly sp). 3 (characteristics), thereby making the carbon material contained in the carbon-rich film composed of sp 2 The proportion of carbon atoms composed of hybrid carbon atoms is 65% of the total number of carbon atoms.

[0124] The remaining methods and parameters are consistent with those in Example 1.

[0125] Example 7 The difference between this embodiment and Embodiment 1 is that the annealing temperature in step (b) is increased, causing the micropores of the carbon material to close, the structure to shrink and densify, thereby reducing the specific surface area of ​​the carbon-rich film to 90 m². 2 / g.

[0126] The remaining methods and parameters are consistent with those in Example 1.

[0127] Comparative Example 1 The difference between this comparative example and Example 1 is that the carbon-rich film is replaced with a titanium nitride film.

[0128] The remaining methods and parameters are consistent with those in Example 1.

[0129] Comparative Example 2 The difference between this comparative example and Example 1 is that the vacuum environment is replaced by an atmospheric environment.

[0130] The remaining methods and parameters are consistent with those in Example 1.

[0131] analyze: As can be seen from the comparison between Example 1 and Examples 4-5, if the thickness of the carbon-rich film is too small, the absorption of the laser band used in this invention by the film is insufficient (the absorption rate drops from ~95% to below ~70%), resulting in insufficient heat energy effectively acting on the interface layer, incomplete debonding process, uneven separation force between the product wafer and the carrier, and decreased yield. If the thickness of the carbon-rich film is too large, the excessively thick carbon layer will generate more gaseous / solid residues after ablation, increasing the difficulty of subsequent cleaning processes.

[0132] A comparison between Example 1 and Example 6 shows that if the carbon material contained in the carbon-rich film is composed of sp 2 If the proportion of hybrid carbon atoms to total carbon atoms is too low, then sp in carbon-rich films will be... 3 An excessively high proportion of hybrid or amorphous carbon structures leads to an incomplete delocalized π-electron system in the thin film, resulting in a significant reduction in intrinsic light absorption at the laser wavelength used in this invention (a decrease of approximately 20%-30% from ~95%) and a decrease in photothermal conversion efficiency; simultaneously, sp 3 Carbon bonds are more stable and are more difficult to completely vaporize during laser treatment or subsequent oxygen plasma treatment, which can easily produce non-volatile carbon residues and increase the difficulty of subsequent cleaning processes.

[0133] As can be seen from the comparison between Example 1 and Example 7, if the specific surface area of ​​the carbon-rich film is too small, the nanoporous structure in the carbon-rich film tends to become denser. The thermal conductivity of the dense structure increases, and heat is more easily diffused laterally, which leads to an increase in the laser energy threshold required for debonding and an expansion of the heat-affected zone, which is not conducive to achieving accurate debonding.

[0134] As can be seen from the comparison between Example 1 and Comparative Example 1, if the carbon-rich film is replaced with a titanium nitride film, compared with the "efficient absorption-rapid vaporization" clean stripping mechanism of the carbon-rich film, the TiN film is more likely to leave metallic titanium or titanium nitride particles at the interface after laser treatment, and its high thermal stability makes subsequent removal difficult. In addition, the preparation cost of TiN film is generally higher than that of carbon-rich film processed by solution method.

[0135] As can be seen from the comparison between Example 1 and Comparative Example 2, if the vacuum environment is replaced by an atmospheric environment, the solid particulate impurities generated by the carbon-rich thin film after laser ablation will not only contaminate the product wafer, but also contaminate the laser optical path, reduce the energy of the emitted laser, and may even cause damage to the laser lens.

[0136] It should be noted that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for laser debonding, characterized in that, The method includes the following steps: A temporary bonding assembly for a wafer is provided, the temporary bonding assembly comprising a silicon carrier, an interposer, a carbon-rich thin film, a bonding layer, and a wafer stacked together; In a vacuum environment, the temporary bond is irradiated with an infrared pulsed laser, which causes interfacial peeling at the carbon-rich film, thus completing the laser debonding between the silicon carrier and the wafer.

2. The method according to claim 1, characterized in that, The transmittance of the intermediate layer to pulsed laser light in the infrared band is ≥95%; And / or, the interlayer comprises an oxide film, preferably a silicon dioxide film; And / or, the thickness of the interposer layer is 20-100 nm; And / or, the surface of the interposer is rich in silanol groups, which are configured to form chemical bonds with the silicon support.

3. The method according to claim 1, characterized in that, The thickness of the carbon-rich film is 50-200 nm; And / or, the carbon material contained in the carbon-rich film is composed of sp 2 The proportion of hybrid carbon atoms in the total number of carbon atoms is greater than 70%. And / or, the carbon-rich film has a nanoscale porous structure or an interwoven network structure; And / or, the specific surface area of ​​the carbon-rich film is >100m². 2 / g; Preferably, the carbon material in the carbon-rich film includes any one or a combination of at least two of carbon nanotubes, graphene, carbon black, carbon nanofibers, or pyrolytic carbon. And / or, the method for preparing the carbon-rich thin film includes vacuum deposition or liquid phase spin coating.

4. The method according to claim 1, characterized in that, When the carbon-rich thin film is prepared by liquid-phase spin coating, the specific steps include: A carbon source solution is spin-coated onto the surface of the intermediate layer, and then annealed to form the carbon-rich film. The carbon source solution is obtained by dissolving carbon materials in an organic solvent, or by dispersing carbon materials as fillers in a solvent with a soluble polymer. The annealing temperature is 100-450℃, and the annealing time is 1-180min.

5. The method according to claim 1, characterized in that, The bonding layer includes an organic bonding adhesive or an inorganic compound film; And / or, the thickness of the bonding layer is 0.2-20 μm.

6. The method according to claim 1, characterized in that, The wavelength of the pulsed laser is 1-50 μm; And / or, the pulse width of the pulsed laser is 200 fs-1 μs; And / or, the pulse energy of the pulsed laser is 10 μJ-1 mJ; And / or, the pulse frequency of the pulsed laser is 0.1-100kHz; And / or, the vacuum level of the vacuum environment is 1×10⁻⁶. -1 Pa-1×10 -5 Pa.

7. The method according to claim 1, characterized in that, The method includes the following steps: (1) Deposit an interlayer with a thickness of 20-100 nm on the surface of the silicon carrier; The interposer has a transmittance of ≥95% for pulsed laser light in the infrared band; the interposer comprises an oxide film; the surface of the interposer is rich in silanol groups, which are configured to form chemical bonds with the silicon carrier; (2) A carbon-rich film with a thickness of 50-200 nm is deposited on the surface of the intermediate layer using a liquid-phase spin coating method; wherein the carbon material contained in the carbon-rich film is composed of sp 2 The proportion of hybrid carbon atoms in the total carbon atoms is >70%; the carbon-rich film has a nanoscale porous structure or interwoven network structure; the specific surface area of ​​the carbon-rich film is >100 m². 2 / g; The specific steps of the liquid phase spin coating method include: (a) Dissolve carbon material in an organic solvent to obtain a carbon source solution, or mix carbon material as a filler with a soluble polymer in a solvent at a mass ratio of 1:(0.5-20) to obtain a carbon source solution; (b) The carbon source solution is spin-coated onto the surface of the intermediate layer at a spin-coating rate of 1000-5000 rpm for 30-120 s, and then annealed at 100-450°C under vacuum or inert atmosphere for 1-180 min to form the carbon-rich film. The soluble polymer includes any one or a combination of at least two of polyimide, polyurethane, epoxy resin or polyvinyl alcohol. (3) A bonding layer with a thickness of 0.2-20 μm is deposited on the surface of the carbon-rich film; wherein the bonding layer comprises an organic bonding adhesive or an inorganic compound film, and the inorganic compound film comprises a silicon oxide film; (4) Fix the wafer on the surface of the bonding layer to obtain a temporary bond; (5) At a vacuum degree of 1×10 -3 Pa-1×10 -5 In a vacuum environment of Pa, the temporary bond is irradiated with an infrared pulsed laser to induce interfacial peeling at the carbon-rich film, thereby completing the laser debonding between the silicon carrier and the wafer. The pulsed laser has a wavelength of 1-50 μm, a pulse width of 200 fs-1 μs, a pulse energy of 10 μJ-1 mJ, and a pulse frequency of 0.1-100 kHz. (6) Use a strong oxidizing liquid to remove the carbon-rich material remaining on the silicon carrier side and the wafer side, and then use a corrosive liquid to remove the interlayer and bonding layer to obtain a recyclable silicon carrier and product wafer.

8. A debonding device, characterized in that, The debonding device is used in the laser debonding method according to any one of claims 1-7, the debonding device comprising: A laser generating unit, wherein the laser generating unit is used to generate pulsed laser in the infrared band; A vacuum processing unit is provided and maintained to provide the vacuum environment required for the laser debonding.

9. The debonding device according to claim 8, characterized in that, The vacuum processing unit includes: A vacuum chamber, wherein a movable stage for supporting the temporary bond is provided inside the vacuum chamber; A window plate, which is disposed on the side wall of the vacuum chamber, is used to transmit the pulsed laser. An optical path adjustment assembly is disposed within the vacuum chamber and is used to receive the pulsed laser transmitted by the window and guide and focus it onto the temporary bond.

10. The debonding device according to claim 9, characterized in that, The debonding device also includes a vacuum pumping system for maintaining the vacuum level of the vacuum chamber.

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