Bonding layer of carrier wafer, preparation method of bonding layer, wafer bonding structure and photon de-bonding method

Abstract

The invention provides a bonding layer of a carrier wafer, a preparation method of the bonding layer, a wafer bonding structure and a photon de-bonding method. The bonding layer comprises a first micro-nano structure on the surface of the transparent carrier and an inorganic release material layer arranged on the surface of the first micro-nano structure; and the surface of one side, close to the transparent carrier, of the inorganic release material layer is provided with a second micro-nano structure. According to the method, the second micro-nano structure is formed on the surface of the inorganic release material layer in the carrier wafer, and interface modification is carried out, so that when a photon de-bonding method is adopted for de-bonding, the interface of the inorganic release material and the organic bonding material is free of stress and almost free of carbon scrap separation, the photothermal conversion efficiency can be effectively improved, and the service life of the device is prolonged. The photon de-bonding reutilization frequency is increased, and the cost of the photon de-bonding process is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of advanced electronic packaging, and relates to a bonding layer of a carrier wafer and a preparation method thereof, a wafer bonding structure, and a photon debonding method. Background Art

[0002] Temporary bonding technology is crucial for handling, transporting, thinning, and reconstructing device wafers. Currently, there are numerous methods for debonding thinned ultra-thin wafers from temporary carrier wafers, primarily including thermal slip, mechanical debonding, chemical debonding, laser debonding, and photonic debonding. Thermal slip and mechanical methods inevitably generate significant mechanical stress during the debonding process, resulting in a high breakage rate. The principles of thermal slip and chemical dissolution make it difficult for temporary bonding materials to meet the high-temperature and chemical resistance requirements of advanced packaging processes. Furthermore, the laser debonding process suffers from high equipment costs, unsuitability for warped wafers, power fluctuations and unevenness in the laser system, and the light absorption properties of the organic release material, all of which can cause adhesive residue and photodamage. The resulting carbon debris can even reduce chip yield. Because scanning and irradiation are achieved by controlling the laser focus, the laser debonding process is complex and requires very expensive equipment. Since laser debonding is a time-intensive rastering process, the limitation of spot size makes it difficult to further improve the debonding efficiency, especially for large-size wafer-level or panel-level bond pairs.

[0003] Photon debonding utilizes an inorganic release layer as a light-absorbing layer. Under the irradiation of a pulsed flash lamp, the inorganic release layer generates instantaneous high temperature through the photothermal conversion effect, promoting the debonding of the adhesive interface, thereby achieving the debonding of the wafer bonded pair. However, the current reflectivity of inorganic release materials in a wide spectrum (200-1200nm) is as high as over 40%. This not only results in low photothermal conversion efficiency, but also poses a major safety hazard due to the reflected high-energy pulsed light. On the other hand, the adhesion between the inorganic release material and the transparent carrier wafer is poor, making it difficult to withstand the impact of large photon energy and causing interface cracking.

[0004] Therefore, how to achieve effective debonding of wafers in a wide spectral range, improve the photothermal conversion efficiency, and reduce costs is an urgent problem that needs to be solved in current research. Summary of the Invention

[0005] In response to the shortcomings of the prior art, the present invention aims to provide a carrier wafer bonding layer and preparation method thereof, a wafer bonding structure, and a photon debonding method. The present invention forms a second micro-nanostructure on the surface of the inorganic release material layer near the carrier wafer to perform interface modification, thereby achieving stress-free and almost carbon-free separation at the interface between the inorganic release material and the organic bonding material during debonding using the photon debonding method. This effectively improves the photothermal conversion efficiency, increases the number of photon debonding reuses, and reduces the cost of the photon debonding process.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a bonding layer of a carrier wafer for photon debonding, wherein the bonding surface bonding layer comprises a first micro-nano structure on a surface of a transparent carrier and an inorganic release material layer disposed on a surface of the first micro-nano structure;

[0008] The surface of the inorganic release material layer close to the transparent carrier has a second micro-nano structure.

[0009] It should be noted that the micro-nano structure in the present invention refers to a protruding structure with a certain roughness formed on the surface, which can be nanometer-scale or micrometer-scale; and the first micro-nano structure and the second micro-nano structure in the present invention are embedded in each other.

[0010] In addition, the bonding layer in the present invention is merely a stacking structure on the surface of the carrier wafer, which can be bonded to the surface of the second wafer to form a wafer bonding structure.

[0011] The present invention arranges an inorganic release material layer with a second micro-nano structure on the surface of a transparent carrier. The inorganic release material and the second micro-nano structure cooperate with each other to jointly improve the wide-spectrum absorption performance and photothermal conversion efficiency of the bonding layer, reduce the photon debonding threshold of the same type of wafer bonding, and at the same time improve the adhesion of the inorganic release material layer to the transparent carrier; the inorganic release material layer has the advantages of high photothermal conversion efficiency, extremely low transmittance, strong high temperature resistance and chemical resistance, and repeatability. When used for photon debonding, stress-free and almost carbon-free separation is achieved at the interface between the release material layer and the bonding layer; and the number of reuses of the inorganic release material layer is increased, reducing the cost of the photon debonding process.

[0012] For the present invention, if the surface of the inorganic release material layer does not have the second micro-nano structure, during the photon debonding process, there will be low photothermal conversion efficiency and the reflected high-energy pulse light will pose a major safety hazard. At the same time, it will also affect the adhesion between the inorganic release material layer and the transparent carrier, resulting in a small number of reuses of the inorganic release material layer and a high debonding threshold.

[0013] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0014] Preferably, the roughness of the first micro-nanostructure is ≤2μm, for example 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm or 2μm, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0015] Preferably, the roughness of the second micro-nanostructure is ≤2μm, for example, 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm or 2μm, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable, preferably 50nm to 2μm.

[0016] It can be understood that the thickness of the inorganic release material layer in the present invention must be greater than the roughness of the second micro-nano structure. The roughness of the second micro-nano structure is ≤2μm, which is more conducive to forming an ultra-thin inorganic release material film and reducing the heat conduction path; the roughness of the second micro-nano structure is more preferably 50nm~2μm, that is, the roughness of the surface of the inorganic release material layer close to the transparent carrier cannot be too low, otherwise it will affect the wide-spectrum absorption performance and adhesion strength.

[0017] Preferably, the thermal expansion coefficient of the inorganic release material is 3×10 -6 ~1×10 -5 / ℃, for example 3×10 -6 / ℃、4×10 -6 / ℃、5×10 -6 / ℃、6×10 -6 / ℃、7×10 -6 / ℃、8×10 -6 / ℃、9×10 -6 / °C or 1×10 -5 / ℃, etc., but are not limited to the listed values. Other values not listed within the numerical range are also applicable.

[0018] The thermal expansion coefficient of the inorganic release material provided by the present invention is preferably 3×10 -6~1×10 -5 / ℃, which can make the thermal expansion coefficients between the transparent carrier and the inorganic release material layer have a good match, which is beneficial to reduce the damage caused by thermal mismatch during the photon debonding process.

[0019] Preferably, the inorganic release material has a temperature tolerance of ≥ 700°C, for example, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1300°C, 1400°C or 1500°C, etc., but is not limited to the listed values, and other values not listed within this numerical range are also applicable.

[0020] The inorganic release material of the present invention preferably has a temperature tolerance of ≥700° C., which can achieve excellent photon debonding effects while not affecting the subsequent high-temperature process of the wafer after debonding.

[0021] Preferably, the inorganic release material is selected from opaque materials.

[0022] In the present invention, the inorganic release material is ensured to be in an opaque state, thereby preventing the pulse light transmitted during the photon debonding process from directly irradiating the device wafer and causing damage to the wafer.

[0023] Preferably, the inorganic releasing material includes any one of non-metallic materials, metallic materials, or alloy materials, or a combination of at least two of them.

[0024] Preferably, the non-metallic material includes a carbon material.

[0025] Preferably, the metal material includes any one of W, Ta, Mo, Cr, Zr or Ti, or a combination of at least two of them.

[0026] Furthermore, when there are two metal materials, the weight ratio of the corresponding two different metal materials is between 1:10 and 10:1, for example, 1:10, 5:10, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, etc.

[0027] Preferably, the alloy material includes any one of Ti alloy, W alloy, Mo alloy or Ni alloy, or a combination of at least two of them.

[0028] More specifically, in the alloy material, the weight ratio between the two main elements is between 1:10 and 10:1, for example, 1:10, 5:10, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1.

[0029] For example, the titanium alloy includes any one of TiC, TiN or TiW or a combination of at least two of them. Preferably, in the titanium alloy material, the weight ratio of titanium to non-titanium elements is between 1:10 and 10:1, for example, 1:10, 5:10, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, etc.

[0030] For example, the W alloy includes WC, etc., and more preferably, the weight ratio of tungsten to non-tungsten elements is between 1:10 and 10:1, such as 1:10, 5:10, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, etc.

[0031] For the present invention, the inorganic release material is preferably the above-mentioned type of material, which has high opacity, low thermal expansion coefficient and high temperature resistance, and can achieve rapid thermal decomposition or thermal mismatch of the bonding material at the interface between the inorganic release material layer and the organic bonding layer during the photon debonding process.

[0032] Preferably, the absorbance of the inorganic release material layer in a preset first spectral range is ≥ 60%, for example, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100%, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0033] Further preferably, the absorbance of the inorganic release material layer in the preset second spectral range is ≥80%, such as 80%, 85%, 90%, 95% or 100%, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0034] Preferably, the transmittance of the inorganic release material layer in a preset first spectral range is ≤0.1%.

[0035] In the present invention, the inorganic release material has a high absorbance in a wide spectral range and an extremely low transmittance, which can better play its role in the photon debonding process; and considering that the spectral range of the pulsed light used in the photon debonding process of this application is preferably 200-1200nm, it is further preferred that the preset first spectral range is selected from 200-1200nm, and the preset second spectral range is selected from 400-600nm.

[0036] Preferably, the thickness of the inorganic release material layer is 0.15 to 10 μm, for example, 0.15 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm or 10 μm, etc., but is not limited to the listed values, and other values not listed within the numerical range are also applicable.

[0037] In the present invention, the thickness of the inorganic release material layer is controlled to be 0.15-10 μm, which is more conducive to forming an ultra-thin inorganic release material film and reducing the heat conduction path.

[0038] In a second aspect, the present invention provides a method for preparing a bonding layer of a carrier wafer for photon debonding as described in the first aspect, the preparation method comprising:

[0039] A first micro-nano structure is prepared on at least one side of the transparent carrier, and then an inorganic release material layer is provided on the surface of the first micro-nano structure. A second micro-nano structure is prepared on the surface of the inorganic release material layer close to the transparent carrier.

[0040] In the present invention, after the first micro-nano structure is formed on the surface of the transparent carrier, during the preparation process of the inorganic release material layer, the surface of the inorganic release material layer close to the first micro-nano structure can also form a surface with a micro-nano structure. The roughness of the corresponding micro-nano structure can be adjusted by the method to form a second micro-nano structure.

[0041] It should be noted that the present invention does not limit the preparation methods of the inorganic release material layer and the first micro-nanostructure and the second micro-nanostructure. The present invention is applicable to any method that can achieve the corresponding purpose and is reasonably known to those skilled in the art.

[0042] For example, the inorganic release material layer without any treatment can be deposited by a deposition method.

[0043] For example, the preparation methods of the first micro-nanostructure and the second micro-nanostructure are independently selected from sandblasting, plasma treatment or laser etching.

[0044] In a third aspect, the present invention provides a wafer bonding structure, comprising a first wafer, a second wafer, and a bonding structure between the first wafer and the second wafer;

[0045] The first wafer comprises a transparent carrier having a bonding layer as described in the first aspect, and the second wafer comprises a device wafer having an organic adhesive layer as a layer to be bonded;

[0046] The bonding layer and the organic adhesive layer are bonded to each other to form the bonding structure.

[0047] The wafer bonding structure provided by the present invention is bonded to each other by the bonding layer of the transparent carrier provided by the first aspect and the organic bonding layer on the surface of the device wafer, which can not only ensure the bonding effect between the transparent carrier and the device wafer, but also will not cause any damage to the device wafer during the photon debonding process.

[0048] Preferably, the bonding strength between the bonding layer and the organic bonding layer is 0.1 to 5 N / 30 mm, for example, 0.1 N / 30 mm, 0.5 N / 30 mm, 1 N / 30 mm, 1.5 N / 30 mm, 2.5 N / 30 mm, 3 N / 30 mm, 3.5 N / 30 mm, 4 N / 30 mm, 4.5 N / 30 mm or 5 N / 30 mm, etc., but is not limited to the listed values, and other values not listed within this numerical range are also applicable.

[0049] Preferably, the thickness of the organic bonding layer is 2 to 200 μm, for example, 2 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm or 200 μm, etc., but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0050] In the present invention, the thickness of the organic bonding layer is relatively thick, preferably 2 to 200 μm, which is more conducive to preventing the device wafer from being thermally damaged and covering the micro-bumps of the device layer.

[0051] Preferably, the 5% thermal decomposition temperature of the organic bonding material in the organic bonding layer is ≥300°C, for example, 300°C, 325°C, 350°C, 375°C, 400°C, 425°C, 450°C, 475°C or 500°C, etc., but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0052] It is understood that the thermal decomposition of 5% (T d , 5%) refers to the temperature at which the material loses 5% of its weight during thermal decomposition, usually determined by thermogravimetric analysis (TGA); this temperature is preferably ≥300°C, which can better meet the subsequent high-temperature process technology.

[0053] Furthermore, the present invention does not impose any special limitations on the organic bonding material in the organic bonding layer. For example, the organic bonding agent can be selected from at least one of WLP PB901, PB902, PB903, PB904, PB906 or PB916 of Shenzhen Huaxun Semiconductor Materials Co., Ltd.; in addition, the composite method between the organic bonding layer and the device wafer is also a conventional technical solution. Those skilled in the art can make adaptive selections and adjustments based on actual needs, such as spin-coating the organic bonding material on the surface of the device wafer and then pre-curing it to obtain an organic bonding layer.

[0054] It should also be noted that the bonding method of the wafer bonding structure in the present invention is also a conventional technical solution, and the present invention is applicable to all methods that can be known within a reasonable range by those skilled in the art.

[0055] Exemplarily, the present invention provides a bonding method:

[0056] The bonding layer of the first wafer and the organic adhesive layer of the second wafer are bonded to each other, and then vacuum hot-pressed to obtain a wafer bonding structure.

[0057] Optionally, the temperature of the vacuum hot pressing is 150-250°C, for example, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C or 250°C, etc., but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0058] Optionally, the pressure of the vacuum hot pressing is 1 to 10 kN, such as 1 kN, 2 kN, 3 kN, 4 kN, 5 kN, 6 kN, 7 kN, 8 kN, 9 kN or 10 kN, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0059] In a fourth aspect, the present invention further provides a photon debonding method, which is used for debonding the wafer bonding structure as described in the second aspect, and the photon debonding method comprises:

[0060] Pulsed light is used to irradiate the first wafer in the wafer bonding structure to complete debonding of the first wafer and the second wafer.

[0061] In the present invention, when a wafer bonding structure containing the bonding layer of the first aspect is used to debond a device wafer and a transparent carrier (especially for temporary debonding), a broad spectrum beam of pulsed light is emitted through the transparent carrier wafer and irradiated onto the inorganic release material layer of the bonding layer by a photon debonding method. Under the synergistic effect of the second micro-nanostructure, the inorganic release material layer has a high photothermal conversion efficiency. The photothermal conversion effect generates an instantaneous high temperature, which promotes thermal decomposition or thermal mismatch at the interface of the organic adhesive material bonded to the inorganic release material layer. This causes stress-free separation of the bonded wafer pair at the interface between the inorganic release material layer and the organic adhesive layer, thereby achieving debonding of the two wafers. After photon debonding, almost no carbonized debris appears on the surfaces of both the transparent carrier and the device wafer. In addition, the inorganic release material layer remains intact on the transparent carrier and can be reused after cleaning. At the same time, no obvious inorganic release material residue is observed on the organic adhesive layer, and the organic adhesive layer on its surface can be easily removed without damaging the device wafer surface. The photon release material can be reused, reducing the cost of the photon debonding process.

[0062] In addition, the bonding layer provided by the first aspect of the present invention is difficult to be applied to other debonding methods. If laser debonding is used, the problem of the photon release layer falling off may occur.

[0063] Preferably, the second wafer in the wafer bonding structure is first thinned, and then the first wafer in the wafer bonding structure is irradiated with pulsed light.

[0064] The bonding layer of the first aspect provided by the present invention is also suitable for the thinning process of the device wafer. The bonding layer in the transparent carrier and the organic bonding layer in the device wafer have high bonding strength and excellent bonding effect, which can realize the thinning of the device wafer first and then debonding without causing damage to the device wafer or destruction of the bonding structure.

[0065] Preferably, the thickness of the second wafer in the wafer bonding structure after thinning is ≤100μm, for example, 100μm, 95μm, 90μm, 85μm, 80μm, 75μm, 70μm, 65μm, 60μm, 55μm, 50μm, 40μm, 30μm, 20μm or 10μm, etc., but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0066] In the present invention, an ultra-thin device wafer structure can be obtained, thereby broadening the application range of the wafer.

[0067] Preferably, the spectrum range of the pulsed light is 200 to 1200 nm.

[0068] Preferably, the pulse duration of the pulse light is 50 to 5000 μs, for example, 50 μs, 100 μs, 500 μs, 1000 μs, 1500 μs, 2000 μs, 2500 μs, 3000 μs, 3500 μs, 4000 μs, 4500 μs or 5000 μs, etc., preferably 100 to 300 μs, but is not limited to the listed values, and other unlisted values within this numerical range are also applicable.

[0069] In the debonding process of the present invention, the pulse duration is short, and instantaneous high temperature can be achieved, thereby achieving the purpose of rapid debonding.

[0070] Preferably, the energy density of the pulsed light irradiated in the inorganic release material layer is ≤20 J / cm 2 , for example 1J / cm 2 , 2J / cm 2 , 3J / cm 2 , 4J / cm 2 , 5J / cm 2 , 6J / cm 2 , 7J / cm 2 , 8J / cm 2 , 9J / cm 2 , 10J / cm 2 , 11J / cm 2 , 12J / cm 2 , 13J / cm 2 , 14J / cm 2 , 15J / cm 2 , 16J / cm 2 , 17J / cm 2 , 18J / cm 2 , 19J / cm 2 or 20J / cm 2 etc., preferably 2 to 20 J / cm 2 , but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0071] Preferably, the spot overlap rate of the pulsed light is ≤5%, for example 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc., but is not limited to the listed values, and other unlisted values within the numerical range are also applicable.

[0072] It should also be noted that after irradiation, a transparent carrier having the bonding layer described in the first aspect and a device wafer having the organic bonding layer described in the third aspect are obtained respectively; the two can be stress-free separated by a suction cup; after further cleaning the transparent carrier and the device wafer, a reusable transparent carrier having the bonding layer described in the first aspect and a device wafer with the organic bonding layer removed are obtained respectively.

[0073] Compared with the prior art, the present invention has the following beneficial effects:

[0074] (1) The present invention sets an inorganic release material layer with a second micro-nano structure on the surface of the transparent carrier. The inorganic release material and the second micro-nano structure cooperate with each other to jointly improve the wide-spectrum absorption performance and photothermal conversion efficiency of the bonding layer, reduce the peeling threshold when bonding with other wafers, and at the same time improve the adhesion between the inorganic release material layer and the transparent carrier; so that the inorganic release material layer has the advantages of high photothermal conversion efficiency, extremely low transmittance, high temperature resistance and chemical resistance, and repeatability. When used for photon debonding, stress-free and almost carbon-free separation is achieved at the interface between the transparent carrier and the device wafer; and the number of repeated uses of photon debonding is increased, reducing the cost of the photon debonding process.

[0075] (2) The wafer bonding structure provided by the present invention is characterized by bonding the bonding layer of the transparent carrier provided by the first aspect to the organic bonding layer on the surface of the device wafer, which can ensure the bonding effect between the transparent carrier and the device wafer and will not cause any damage to the device wafer during the photon debonding process.

[0076] (3) In the present invention, when the wafer bonding structure containing the bonding layer of the first aspect is used to perform debonding (especially temporary debonding) of the device wafer and the transparent carrier, a broad spectrum beam of pulsed light passes through the transparent carrier wafer and irradiates the inorganic release material layer of the bonding layer by a photon debonding method. Under the synergistic effect of the second micro-nano structure, the inorganic release material layer has a very high photothermal conversion efficiency, and generates instantaneous high temperature through the photothermal conversion effect, which promotes thermal decomposition or thermal mismatch of the interface of the organic adhesive material bonded to the inorganic release material layer, so that the bonding The wafer pair undergoes stress-free separation at the interface between the inorganic release material layer and the organic bonding layer, achieving debonding of the two wafers. After photon debonding, there is almost no carbonized debris on the surface of both the transparent carrier and the device wafer. In addition, the inorganic release material layer remains intact on the transparent carrier and can be reused after cleaning. At the same time, no obvious residue of inorganic release material is observed on the organic bonding layer, and the organic bonding layer on its surface can be easily removed, and the surface of the device wafer is not damaged. The photon debonding is reused several times, reducing the cost of the photon debonding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1Schematic diagram of the process of all processes from preparation of the bonding layer to completion of debonding of the transparent carrier wafer and the device wafer in Example 1.

[0078] Figure 2 1 is a comparison chart of the reflectivity of the inorganic release material layer containing the second micro-nano structure in Example 1 and the inorganic release material layer not containing the second micro-nano structure in Comparative Example 1 within the wavelength range of 200 to 1200 nm.

[0079] Figure 3 This is a comparison chart of the transmittance of the inorganic release material layer containing the second micro-nano structure in Example 1 and the inorganic release material layer not containing the second micro-nano structure in Comparative Example 1 within the wavelength range of 200 to 1200 nm.

[0080] Figure 4 This is a sample diagram of the wafer bonding structure (wafer bonding pair) provided in Example 1.

[0081] Figure 5 Surface images of the organic bonding layer of the device wafer after separation in step (6) in Example 1 and the bonding layer (structured release layer) in the transparent carrier wafer.

[0082] Figure 6 Surface images of the device wafer after cleaning in step (7) in Example 1 and the bonding layer (structured release layer) in the transparent carrier wafer.

[0083] Among them, 1-transparent carrier wafer, 2-first micro-nano structure, 3-inorganic release material layer, 4-device wafer, 5-organic bonding layer, 6-wafer bonding structure, 7-ultra-thin wafer bonding structure, 8-pulse flash lamp, 9-light beam, 10-cleaning agent for cleaning ultra-thin device wafer, 11-single ultra-thin chip structure. DETAILED DESCRIPTION

[0084] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0085] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions.

[0086] In the description of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly indicate the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0087] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the industry.

[0088] Example 1

[0089] This embodiment provides a bonding layer of a carrier wafer for photon debonding, a wafer bonding structure including the bonding layer, and a method for photon debonding of the wafer bonding structure.

[0090] A bonding layer of a carrier wafer: the bonding layer comprises a first micro-nano structure on the surface of a transparent carrier wafer and an inorganic release material layer disposed on the surface of the first micro-nano structure; the surface of the inorganic release material layer away from the side close to the transparent carrier wafer has a second micro-nano structure;

[0091] The wafer bonding structure includes a first wafer, a second wafer and a bonding structure between the first wafer and the second wafer; the first wafer includes a transparent carrier wafer having a bonding layer, and the second wafer includes a device wafer having an organic bonding layer as the layer to be bonded; the bonding layer and the organic bonding layer are bonded to each other to form the bonding structure.

[0092] like Figure 1 As shown, this embodiment also provides a method for all processes from preparing the bonding layer to completing the debonding of the transparent carrier wafer and the device wafer:

[0093] (1) Formation of the bonding layer of the carrier wafer: A first micro-nanostructure 2 (roughness of 200 nm) is prepared on a transparent carrier wafer 1 (8 inches, thickness of 700 μm) by a plasma method, and then a 200 nm thick inorganic release material layer 3 (TiW film) is deposited. A second micro-nanostructure (roughness of 100 nm) is prepared on the surface of the inorganic release material layer 3 close to the surface of the transparent carrier wafer 1 by a plasma method. The first micro-nanostructure 2 and the inorganic release material layer 3 (including the second micro-nanostructure) form the bonding layer of the carrier wafer;

[0094] (2) Formation of an organic bonding layer on the device wafer surface: An organic bonding material (purchased from Shenzhen Huaxun Semiconductor Materials Co., Ltd., WLP PB901) was spin-coated on a device wafer 4 (8 inches, 500 μm) at the following spin-coating parameters: 1900 rpm / 30 s; then pre-cured: heated at 90°C for 10 min; then heated at 180°C for 10 min; the resulting organic bonding layer 5 (with an absorbance of less than 5% at 355 nm) had a thickness of 10 μm;

[0095] (3) Formation of wafer bonding structure 6: The bonding layer in the transparent carrier wafer 1 in step (1) and the organic bonding layer 5 in the device wafer 4 in step (2) are bonded to form a bonding structure by vacuum hot pressing bonding, wherein the temperature in the vacuum hot pressing bonding is 180° C., the pressure is 3 kN, and the holding time is 10 min; the bonding strength between the inorganic release material layer 3 and the organic bonding layer 5 in the bonding structure is 0.5 N / 30 mm as tested by a tensile testing machine;

[0096] (4) Thinning the device wafer 4: Thinning the device wafer 5 to 100 μm by wafer backside thinning technology to obtain an ultra-thin wafer bonding structure 7;

[0097] (5) Photon debonding: A pulsed flash lamp 8 (spectral range 200-1200 nm) was used to generate a photon with an energy density of 2.9 J / cm 2 The light beam 9 passes through the transparent carrier wafer 1 and irradiates the inorganic release material layer 3 with a spot overlap rate of 5%, and the pulse duration is 300 μs, thereby achieving debonding of the ultra-thin wafer bonding structure 7 at the interface between the inorganic release material layer 3 and the organic bonding layer 5;

[0098] (6) Lifting the transparent carrier wafer 1 by means of a suction cup, thereby achieving stress-free separation of the ultra-thin wafer bonding structure 7;

[0099] (7) cleaning the transparent carrier wafer 1 and the ultrathin device wafer having the bonding layer of step (1) with a cleaning agent (cleaning agent 10 for cleaning the ultrathin device wafer) to obtain a cleaned ultrathin device wafer and a reusable transparent carrier wafer 1;

[0100] (8) The cleaned ultra-thin device wafer is diced to obtain a single ultra-thin chip structure 11.

[0101] Example 2

[0102] This embodiment provides a bonding layer of a carrier wafer for photon debonding, a wafer bonding structure including the bonding layer, and a method for photon debonding of the wafer bonding structure.

[0103] The bonding layer includes a first micro-nano structure on the surface of a transparent carrier wafer and an inorganic release material layer provided on the surface of the first micro-nano structure; the surface of the inorganic release material layer away from the side close to the transparent carrier wafer has a second micro-nano structure;

[0104] The wafer bonding structure includes a first wafer, a second wafer and a bonding structure between the first wafer and the second wafer; the first wafer includes a transparent carrier wafer having a bonding layer, and the second wafer includes a device wafer having an organic bonding layer as the layer to be bonded; the bonding layer and the organic bonding layer are bonded to each other to form the bonding structure.

[0105] This embodiment also provides a method for completing all processes from preparing the bonding layer to debonding the transparent carrier wafer and the device wafer:

[0106] (1) Formation of a bonding layer of a carrier wafer: a first micro-nanostructure (roughness of 1 μm) is prepared on a transparent carrier wafer (8 inches, thickness of 700 μm) by a plasma method, and then a 5 μm thick inorganic release material layer (molybdenum alloy film) is deposited. A second micro-nanostructure (roughness of 1 μm) is prepared on the surface of the inorganic release material layer close to the surface of the transparent carrier wafer by a plasma method. The first micro-nanostructure and the inorganic release material layer (including the second micro-nanostructure) form a bonding layer of the carrier wafer;

[0107] (2) Formation of an organic bonding layer on the device wafer surface: An organic bonding material (purchased from Shenzhen Huaxun Semiconductor Materials Co., Ltd., WLP PB901) was spin-coated on a device wafer (8 inches, 500 μm) at the following spin-coating parameters: 1900 rpm / 30 s; then pre-cured: heated at 90°C for 10 min; then heated at 180°C for 10 min; the resulting organic bonding layer (with an absorbance of less than 5% at 355 nm) had a thickness of 50 μm;

[0108] (3) Formation of wafer bonding structure: The bonding layer in the transparent carrier wafer in step (1) and the organic bonding layer in the device wafer in step (2) are bonded to form a bonding structure by vacuum hot pressing bonding, wherein the temperature in the vacuum hot pressing bonding is 180° C., the pressure is 3 kN, and the holding time is 15 min; the bonding strength between the inorganic release material layer and the organic bonding layer in the bonding structure is 2.5 N / 30 mm as tested by a tensile testing machine;

[0109] (4) Thinning of device wafer: Thinning the device wafer to 80 μm by wafer backside thinning technology to obtain an ultra-thin wafer bonding structure;

[0110] (5) Photon debonding: The energy density of the photon is 6 J / cm2 by the pulse flash lamp 8. 2The light beam passes through the transparent carrier wafer with a spot overlap rate of 5% to irradiate the inorganic release material layer. The pulse duration is 300μs, thereby achieving debonding of the ultra-thin wafer bonding structure at the interface between the inorganic release material layer and the organic adhesive layer.

[0111] (6) Lifting the transparent carrier wafer by a suction cup to achieve stress-free separation of the ultra-thin wafer bonding structure;

[0112] (7) cleaning the transparent carrier wafer and the ultrathin device wafer having the bonding layer of step (1) with a cleaning agent to obtain a cleaned ultrathin device wafer and a reusable transparent carrier wafer;

[0113] (8) Slicing the cleaned ultra-thin device wafer to obtain a single ultra-thin chip structure.

[0114] Example 3

[0115] This embodiment provides a bonding layer of a carrier wafer for photon debonding, a wafer bonding structure including the bonding layer, and a method for photon debonding of the wafer bonding structure.

[0116] A bonding layer of a carrier wafer: the bonding layer comprises a first micro-nano structure on the surface of a transparent carrier wafer and an inorganic release material layer disposed on the surface of the first micro-nano structure; the surface of the inorganic release material layer away from the side close to the transparent carrier wafer has a second micro-nano structure;

[0117] The wafer bonding structure includes a first wafer, a second wafer and a bonding structure between the first wafer and the second wafer; the first wafer includes a transparent carrier wafer having a bonding layer, and the second wafer includes a device wafer having an organic bonding layer as the layer to be bonded; the bonding layer and the organic bonding layer are bonded to each other to form the bonding structure.

[0118] This embodiment also provides a method for completing all processes from preparing the bonding layer to debonding the transparent carrier wafer and the device wafer:

[0119] (1) Formation of a bonding layer of a carrier wafer: a first micro-nano structure (roughness of 2 μm) is prepared on a transparent carrier wafer (8 inches, thickness of 700 μm) by a plasma method, and then a 10 μm thick inorganic release material layer (molybdenum alloy film) is deposited. A first micro-nano structure (roughness of 2 μm) is prepared on the surface of the inorganic release material layer close to the surface of the transparent carrier wafer by a plasma method. The first micro-nano structure and the inorganic release material layer (including the second micro-nano structure) form a bonding layer of the carrier wafer;

[0120] (2) Formation of an organic bonding layer on the device wafer surface: An organic bonding material (purchased from Shenzhen Huaxun Semiconductor Materials Co., Ltd., WLP PB901) was spin-coated on a device wafer (8 inches, 500 μm) at the following spin-coating parameters: 1900 rpm / 30 s; then pre-cured: heated at 90°C for 10 min; then heated at 180°C for 10 min; the resulting organic bonding layer (with an absorbance of less than 5% at 355 nm) had a thickness of 100 μm;

[0121] (3) Formation of wafer bonding structure: The bonding layer in the transparent carrier wafer in step (1) and the organic bonding layer in the device wafer in step (2) are bonded to form a bonding structure by vacuum hot pressing bonding, wherein the temperature in the vacuum hot pressing bonding is 180° C., the pressure is 3 kN, and the holding time is 15 min; the bonding strength between the inorganic release material layer and the organic bonding layer in the bonding structure is 5 N / 30 mm as tested by a tensile testing machine;

[0122] (4) Thinning of device wafer: Thinning the device wafer to 70 μm by wafer backside thinning technology to obtain an ultra-thin wafer bonding structure;

[0123] (5) Photon debonding: A pulsed flash lamp with an energy density of 20 J / cm 2 The light beam passes through the transparent carrier wafer with a spot overlap rate of 5% to irradiate the inorganic release material layer. The pulse duration is 300μs, thereby achieving debonding of the ultra-thin wafer bonding structure at the interface between the inorganic release material layer and the organic adhesive layer.

[0124] (6) Lifting the transparent carrier wafer by a suction cup to achieve stress-free separation of the ultra-thin wafer bonding structure;

[0125] (7) cleaning the transparent carrier wafer and the ultrathin device wafer having the bonding layer of step (1) with a cleaning agent to obtain a cleaned ultrathin device wafer and a reusable transparent carrier wafer;

[0126] (8) Slicing the cleaned ultra-thin device wafer to obtain a single ultra-thin chip structure.

[0127] Example 4

[0128] The difference between this embodiment and embodiment 1 is that the inorganic release material in this embodiment is Cr metal.

[0129] The other conditions are the same as those in Example 1.

[0130] Example 5

[0131] The difference between this embodiment and embodiment 1 is that the inorganic release material in this embodiment is Al metal.

[0132] The other conditions are the same as those in Example 1.

[0133] Example 6

[0134] The difference between this embodiment and embodiment 1 is that the thickness of the inorganic release material layer in this embodiment is 5 μm, and the roughness of the second micro-nano structure is 2.5 μm.

[0135] The other conditions are the same as those in Example 1.

[0136] Example 7

[0137] The difference between this embodiment and embodiment 1 is that the roughness of the second micro-nano structure in the inorganic release material layer in this embodiment is 40 nm.

[0138] The other conditions are the same as those in Example 1.

[0139] Example 8

[0140] The difference between this embodiment and embodiment 1 is that the light absorption rate of the inorganic release material layer in this embodiment is 55% within a wide spectrum range of 200 to 1200 nm.

[0141] The other conditions are the same as those in Example 1.

[0142] Comparative Example 1

[0143] The difference between this comparative example and Example 1 is that the bonding layer in this comparative example does not contain the second micro-nano structure.

[0144] In the method, when depositing the inorganic release material layer, the surface of the first micro-sodium structure close to the transparent carrier wafer is adjusted to form a smooth plane.

[0145] The other conditions are the same as those in Example 1.

[0146] Figure 2 The comparison chart of the reflectivity of the inorganic release material layer containing the second micro-nano structure in Example 1 and the inorganic release material layer not containing the second micro-nano structure in Comparative Example 1 in the wavelength range of 200 to 1200 nm is shown. Figure 2 It can be seen that the inorganic release material layer containing the second micro-nano structure in the bonding layer of the present invention can effectively reduce the reflectivity in the wavelength range of 200-1200 nm compared with the inorganic release material layer without the second micro-nano structure.

[0147] Figure 3 The transmittance comparison chart of the inorganic release material layer containing the second micro-nano structure in Example 1 and the inorganic release material layer not containing the second micro-nano structure in Comparative Example 1 in the wavelength range of 200 to 1200 nm is shown. Figure 3 It can be seen that from Figure 2It can be seen that the inorganic release material layer containing the second micro-nano structure in the bonding layer of the present invention can effectively improve the transmittance in the wavelength range of 200-1200 nm compared with the inorganic release material layer without the second micro-nano structure.

[0148] Figure 4 This is a sample diagram of the wafer bonding structure (wafer bonding pair) provided in Example 1.

[0149] Figure 5 The surface image of the organic bonding layer of the device wafer after separation in step (6) in Example 1 and the surface image of the bonding layer (structured release layer) in the transparent carrier wafer are shown, as shown in FIG. Figure 4 As shown, after the photon debonding treatment of the present invention, no carbonized debris appears on the surface of the separated transparent carrier wafer and the device wafer; in addition, after the photon debonding, no obvious residue of inorganic release material is observed on the organic bonding layer.

[0150] Figure 6 The surface image of the device wafer after cleaning in step (7) in Example 1 and the surface image of the bonding layer (structured release layer) in the transparent carrier wafer are shown. The transparent carrier wafer containing the bonding layer in the present invention remains intact after photon debonding and can be reused after cleaning; at the same time, the organic bonding material on the surface of the device wafer can be easily removed and the device surface is not damaged.

[0151] Table 1 shows the thermal expansion coefficient and temperature tolerance of the inorganic release materials provided in Examples 1-8 and Comparative Example 1, the photothermal conversion efficiency of the inorganic release material layer containing the second micro-nano structure in Examples 1-8 and the inorganic release material layer not containing the second micro-nano structure provided in Comparative Example 1, and the reflectivity, absorbance and transmittance in the spectral range of 200 to 1200 nm.

[0152] Photothermal conversion efficiency test:

[0153] The reflectivity, absorbance and transmittance were tested using a spectrometer (UV-Vis-NIR Spectrophotometer).

[0154] Table 1

[0155]

[0156]

[0157] Table 2 shows the debonding results of Examples 1-8 and Comparative Example 1 during the photon debonding process.

[0158] Table 2

[0159]

[0160] Note: In Table 2, Schott glass is used as the basis for determining whether the inorganic release material layer is damaged after separation of the transparent carrier wafer, and silicon wafer is used as the basis for determining whether the device wafer is damaged.

[0161] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A bonding layer of a carrier wafer for photonic debonding, characterized in that The bonding layer includes a first micro-nano structure on the surface of a transparent carrier and an inorganic release material layer arranged on the surface of the first micro-nano structure; The surface of the inorganic release material layer close to the transparent carrier has a second micro-nano structure.

2. The bonding layer of a carrier wafer for photonic debonding according to claim 1, characterized in that: The roughness of the first micro-nanostructure is ≤2 μm; Preferably, the roughness of the second micro-nanostructure is ≤2 μm, preferably 50 nm to 2 μm.

3. The bonding layer of a carrier wafer for photonic debonding according to claim 1, characterized in that: The thermal expansion coefficient of the inorganic release material is 3×10 -6 ~1×10 -5 / ℃; Preferably, the inorganic release material has a temperature tolerance of ≥700°C; Preferably, the inorganic release material is selected from opaque materials; Preferably, the inorganic releasing material comprises any one of non-metallic materials, metallic materials, or alloy materials, or a combination of at least two thereof; Preferably, the non-metallic material comprises a carbon material; Preferably, the metal material includes any one or a combination of at least two of W, Ta, Mo, Cr, Zr or Ti; Preferably, the alloy material includes any one of Ti alloy, W alloy, Mo alloy or Ni alloy, or a combination of at least two of them.

4. The bonding layer of a carrier wafer for photonic debonding according to claim 1 or 3, characterized in that: The inorganic release material layer has an absorbance of ≥60% in a preset first spectral range and an absorbance of ≥80% in a preset second spectral range; Preferably, the transmittance of the inorganic release material layer in a preset first spectral range is ≤0.1%; Preferably, the thickness of the inorganic release material layer is 0.15-10 μm.

5. A method for preparing a bonding layer of a carrier wafer for photon debonding according to any one of claims 1 to 4, characterized in that: The preparation method comprises: A first micro-nano structure is prepared on at least one side of the transparent carrier, and then an inorganic release material layer is provided on the surface of the first micro-nano structure. A second micro-nano structure is prepared on the surface of the inorganic release material layer close to the transparent carrier.

6. A wafer bonding structure, characterized in that: The wafer bonding structure includes a first wafer, a second wafer, and a bonding structure between the first wafer and the second wafer; The first wafer comprises a transparent carrier having a bonding layer according to any one of claims 1 to 4, and the second wafer comprises a device wafer having an organic bonding layer as a layer to be bonded; The bonding layer and the organic adhesive layer are bonded to each other to form the bonding structure.

7. The wafer bonding structure according to claim 6, wherein: The bonding strength of the bonding layer and the organic bonding layer after bonding is 0.1 to 5 N / 30 mm; Preferably, the thickness of the organic bonding layer is 2 to 200 μm; Preferably, the 5% thermal decomposition temperature of the organic bonding material in the organic bonding layer is ≥300°C.

8. A method for photon debonding, characterized in that: The photon debonding method is used for debonding the wafer bonding structure according to claim 6 or 7, and the photon debonding method comprises: Pulsed light is used to irradiate the first wafer in the wafer bonding structure to complete debonding of the first wafer and the second wafer.

9. The method of photon debonding according to claim 8, characterized in that: First, thinning the second wafer in the wafer bonding structure is performed, and then the first wafer in the wafer bonding structure is irradiated with pulsed light; Preferably, the thickness of the second wafer in the wafer bonding structure after thinning is ≤100 μm.

10. The photon debonding method according to claim 8, characterized in that: The spectral range of the pulsed light is 200 to 1200 nm; Preferably, the pulse duration of the pulse light is 50 to 5000 μs, preferably 100 to 300 μs; Preferably, the energy density of the pulsed light irradiated in the inorganic release material layer is ≤20 J / cm 2 , preferably 2 to 20 J / cm 2 ; Preferably, the spot overlap rate of the pulse light is ≤5%.

Images