Processing scribing method of glass-silicon bonding structure

Abstract

The invention discloses a processing scribing method of a glass-silicon bonding structure, and the method comprises the steps: carrying out the irradiation modification of a preset region of the glass-silicon bonding structure through a laser beam, and obtaining a modified region; the modified area penetrates through a glass layer and a silicon wafer layer of the glass-silicon bonding structure along the thickness direction of the glass-silicon bonding structure; performing chemical wet etching on the modified glass-silicon bonding structure, so that preset cutting channels are respectively formed in the glass layer and the silicon wafer layer in the modified area; and ultrasonic waves are transmitted to the bonding layer of the modified area along the preset cutting channel through a liquid medium, and splitting is carried out. According to the method, the glass-silicon bonding structure is split by adopting a composite process of laser modification, chemical wet etching and ultrasonic-assisted splitting, so that the qualification rate and the stability of scribing processing are improved.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor processing, and specifically relates to a method for dicing glass-silicon bonded structures. Background Technology

[0002] As the semiconductor industry continues to grow its demand for larger wafers, packaging technology has gradually upgraded to the Wafer Level Chip Scale Packaging (WLCSP) stage. This advanced packaging method requires first completing high-precision bonding and packaging of glass and silicon wafers, followed by device functional testing. Then, a dicing process is used to separate the wafers into individual single-chip devices. This process places higher demands on the precision, efficiency, and compatibility with multilayer bonding structures of the dicing technology. Currently, several technical systems have been developed for dicing glass and silicon flat panels, mainly including mechanical scribing, high-energy-density beam melting / vaporization, laser-induced thermal cracking, and combined methods. The combined methods often combine mechanical methods or high-energy-density beam melting with laser-induced thermal cracking. However, these existing technologies have significant limitations in application scope, processing quality, and process adaptability, making it difficult to meet the dicing requirements of glass / silicon multilayer bonding devices. Although mechanical scribing is widely used for scribing flat glass due to its low cost and mature technology, it directly compresses the material during processing, resulting in material breakage and transverse cracks in the processing area. The flatness of the cut surface is poor, which cannot meet the scribing accuracy requirements of glass-silicon bonding structures and can easily cause damage to the bonding interface or device failure.

[0003] In high-energy-density beam melting / gasification methods, conventional and short-pulse laser direct melting and gasification methods are further subdivided into integral cutting and ablation grooving-fracture methods. The former, due to the concentrated laser energy, is prone to generating an excessively large heat-affected zone, leading to defects such as microcracks, residual stress, and recast layers on the material surface. Although the latter has slightly improved the control of the heat-affected zone, the aforementioned defects are still not eliminated, making it difficult to avoid damage to multilayer materials with glass-silicon bonded structures. While ultrashort-pulse laser direct cutting can reduce heat-affected defects to some extent, the required equipment is expensive, and there is a contradiction between processing efficiency and processing quality. At the same time, the problem of residual stress inside the material after processing is prominent, making it unsuitable for large-scale mass production scenarios. Improved technologies such as laser stealth cutting, multi-focus stealth cutting, and Bessel beam direct cutting, although improving the processing effect by optimizing the laser focus distribution and controlling the lateral width of the heat-affected zone of a single modified layer to a few tens of micrometers, still cannot completely eliminate the heat-affected zone, and the cross-sectional roughness is large, making it easy for the edge to chip near the cutting path during dicing. Laser-induced thermal cracking uses laser as the primary heat source (microwaves, hot air, etc. can also be used). It is a green processing technology that does not require material removal and is suitable for brittle materials such as glass, silicon, ceramics, and diamond. It has the potential advantages of high speed and high quality. However, the feasibility of this technology depends heavily on the physical properties of the materials: silicon, as an anisotropic material, requires less energy to fracture along its main cleavage plane, while glass, as an amorphous material, has lower brittleness and higher fracture toughness than single-crystal silicon, requiring stronger thermal stress to achieve fracture. The significant differences in the physical properties of the two materials in glass-silicon multilayer bonded plates make it difficult for laser-induced thermal cracking to simultaneously meet the fracture conditions of both types of materials, thus failing to achieve efficient and precise dicing processing.

[0004] In existing technologies, the combination of laser stealth dicing and laser-induced thermal cracking can achieve dicing of glass-silicon multilayer bonded wafers with high processing efficiency and can complete bidirectional orthogonal trajectory dicing to separate single devices. However, this combined process still has obvious drawbacks: on the one hand, it requires the construction of a multi-laser beam coupling system, which is costly and has a complex process flow; on the other hand, the lateral width of the modified area of ​​the glass layer stealth dicing exceeds 40μm, the quality of the diced cross-section is generally poor, and defects such as heat-affected zones and microcracks still exist, which significantly reduces the long-term reliability of the device and cannot meet the requirements of high-precision packaging.

[0005] In summary, existing dicing techniques generally suffer from insufficient processing accuracy, high defect rate, high equipment cost, and complex processes when processing glass-silicon multilayer bonding devices, making it difficult to meet the mass production requirements of wafer-level chip packaging. Summary of the Invention

[0006] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention proposes a method for dicing glass-silicon bonded structures.

[0007] To achieve the above objectives, according to one aspect of the present invention, a method for processing and dicing a glass-silicon bonded structure is provided, comprising the following steps: A laser beam is used to irradiate and modify a predetermined region of a glass-silicon bonded structure to obtain a modified region. The modified region penetrates the glass layer and silicon wafer layer of the glass-silicon bonded structure along the thickness direction. The glass layer of the modified region forms a loose nanoscale SiO2 network structure, and the silicon wafer layer of the modified region forms local defects and nano-gap. The modified glass-silicon bonded structure was subjected to chemical wet etching, which resulted in the formation of pre-defined cuts in the glass layer and silicon wafer layer of the modified region. Ultrasonic waves are transmitted through a liquid medium along the predetermined cutting path to the bonding layer of the modified region for fragmentation.

[0008] According to the above method, the irradiation modification specifically includes: The laser beam is focused to form a short focal depth spot, and the glass-silicon bond structure is irradiated in a stepwise manner from the side away from the laser source to the side facing the laser source along the thickness direction. During irradiation modification, the corresponding energy density and step spacing are adopted according to the material properties of the glass and silicon wafer.

[0009] According to the above method, the irradiation modification specifically includes: A multifocal beam or a Bessel beam is used to scan a preset area; the depth of focus of the multifocal beam or Bessel beam can cover the entire preset area of ​​the glass-silicon bonded structure along the thickness direction of the glass-silicon bonded structure.

[0010] According to the above method, the wavelength of the laser beam is 515-1064nm, the pulse width is 0.2-50ps, the repetition frequency is 50-500kHz, the energy density acting on the glass layer is 0.1-5J / cm², and the energy density acting on the silicon wafer layer is 0.5-10J / cm².

[0011] According to the above method, the chemical wet etching specifically includes acid etching and alkaline etching, with a cleaning step between the acid and alkaline etching processes to remove residual etching solution; wherein, Acid etching is used to etch the glass layer in the modified area, while alkaline etching is used to etch the silicon wafer layer in the modified area.

[0012] According to the above method, the acid corrosion specifically includes: The modified glass-silicon bonded structure was placed in an etching bath containing an acidic etching solution; The etching temperature is 18℃-60℃, and the etching time is 30s-60min. During etching, the acidic etching solution is stirred at a speed of 200-300r / min to ensure that the acidic etching solution is in full contact with the glass layer.

[0013] According to the above method, the alkaline corrosion specifically includes: The glass-silicon bonded structure, after acid etching and cleaning, is placed in an etching tank containing an alkaline etching solution; The etching temperature is 40℃-95℃, and the etching time is 1min-60min; a circulating pump and a bubbler are used to assist etching.

[0014] According to the above method, the cleavage specifically includes: The glass-silicon bonded structure after chemical wet etching was fixed in an ultrasonic bath; Injecting liquid medium into the ultrasonic pool; Turn on the ultrasonic generator, set the frequency to 20kHz-200kHz, the power to 50W-500W, the power density to 0.5W / cm²-5W / cm², and the action time to 1-10 minutes.

[0015] Using the above method, when the thickness of the glass-silicon bonded structure is ≥500μm, the frequency of the ultrasonic generator is set to 20kHz-50kHz; when the thickness of the glass-silicon bonded structure is <500μm, the frequency of the ultrasonic generator is set to 50kHz-200kHz.

[0016] According to another aspect of the present invention, a standalone semiconductor device having a glass-silicon bonding structure is provided, which is obtained by a dicing method for processing the glass-silicon bonding structure.

[0017] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: 1. A composite process combining laser modification, chemical wet etching, and ultrasonic-assisted dicing is employed to dice glass-silicon bonded structures, improving the yield and stability of the dicing process. Laser modification creates a loose, nanoscale SiO2 network in the glass layer and localized defects and nanoscale gaps in the silicon layer, without compromising the material's surface integrity. During chemical wet etching, the etching rate in the modified area is 5-8 times higher than in the unmodified area, resulting in a uniform and gentle etching process that avoids physical damage and thermal stress. Ultrasonic-assisted dicing concentrates vibration energy on a pre-defined dicing path, achieving "directional fracture along the modified area." The fracture surface is the material's intrinsic fracture surface, fundamentally ensuring structural integrity, resulting in extremely low roughness and a smooth surface.

[0018] 2. By using a multifocal beam or Bessel beam, and equipped with a scanning galvanometer or a three-dimensional displacement platform, irradiation modification can be achieved by scanning a preset area in one go, which improves processing efficiency.

[0019] 3. Due to the different absorption of materials, setting the corresponding laser beam energy density according to the different material properties of glass and silicon wafers is more conducive to the modification of glass and silicon wafer layers. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a laser-modified region provided in an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of a chemical wet etching process provided in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of laser processing provided in an embodiment of the present invention.

[0023] Figure 4 This is another schematic diagram of laser processing provided in an embodiment of the present invention.

[0024] Figure 5 This is another schematic diagram of laser processing provided in an embodiment of the present invention.

[0025] Figure 6 This is a flowchart of the method provided in an embodiment of the present invention.

[0026] In the picture: 1-Glass layer, 2-Silicon wafer layer, 3-Bonding layer, 4-Laser device, 401-Objective lens, 402-Laser beam, 403-Multifocal forming device, 404-Multifocal beam, 405-Bessel forming device, 406-Bessel beam, 5-Laser modification path, 501-First preset cleaving path, 502-Second preset cleaving path. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] This invention provides a method for dicing glass-silicon bonded structures, aiming to improve the yield and stability of dicing by employing a composite process of laser modification, chemical wet etching, and ultrasonic-assisted dicing.

[0030] According to one aspect of the present invention, this embodiment provides a method for dicing and processing glass-silicon bonded structures, such as... Figure 6 As shown, it includes the following steps: S1, Laser Modification: A laser beam is used to irradiate and modify a predetermined region of the glass-silicon bonded structure to obtain a modified region. The modified region penetrates the glass layer and silicon wafer layer of the glass-silicon bonded structure along the thickness direction. The glass layer of the modified region forms a loose nanoscale SiO2 network structure, and the silicon wafer layer of the modified region forms local defects and nano-gap.

[0031] like Figure 1 As shown, the glass-silicon bonded structure is obtained by bonding a glass layer 1 and a silicon wafer layer 2, with a bonding layer 3 formed between them. In this invention, a laser device 4 emits a laser beam along the thickness direction of the glass-silicon bonded structure to irradiate and modify a predetermined area. The resulting laser modification path 5 penetrates both the glass layer 1 and the silicon wafer layer 2 of the glass-silicon bonded structure along its thickness direction.

[0032] In some embodiments, the laser device 4 may also be disposed on one side of the silicon wafer layer 2.

[0033] The irradiation modification can be achieved in the following two ways: The method is the same Figure 3 As shown, in the laser device 4, the laser beam 402 is focused by the objective lens 401 to form a short focal depth spot. It then progressively irradiates and modifies the glass-silicon bonded structure from the side facing away from the laser source towards the side facing the laser source, along the thickness direction, until traces of laser modification are visible on the upper surface of the glass layer 1. During the irradiation modification of each layer, a two-dimensional displacement platform moves at high speed to scan the laser beam within a preset area.

[0034] During irradiation modification, the corresponding energy density and step spacing are adopted according to the material properties of the glass and silicon wafer.

[0035] The laser beam 402 has a wavelength of 515-1064nm, a pulse width of 0.2-50ps, a repetition frequency of 50-500kHz, an energy density of 0.1-5J / cm² applied to the glass layer, and an energy density of 0.5-10J / cm² applied to the silicon wafer layer.

[0036] The thickness-direction step spacing of silicon wafer layer 2 is greater than or equal to that of glass layer 1. This method can form a good laser modification path, but it requires multiple processing steps in the thickness direction.

[0037] Method 2, as Figure 4 and Figure 5 As shown, by using a multi-focus beam 404 or a Bessel beam 406 in conjunction with a scanning galvanometer or a highly stable three-dimensional displacement platform, the focal depth is covered to the thickness direction of the entire glass layer 1 and silicon wafer layer 2, and a laser modification path 5 can be formed in a single scan.

[0038] The multifocal beam 404 is formed by passing a laser beam 402 through a multifocal forming device 403, which can be implemented using a DOE+ objective lens or a spatial light modulator. The Bessel beam is formed by passing a laser beam 402 through a Bessel forming device 405, which can be implemented using an axial conical lens group or a spatial light modulator.

[0039] Similarly, the wavelength of the laser beam 402 is 515-1064nm, the pulse width is 0.2-50ps, the repetition frequency is 50-500kHz, the energy density acting on the glass layer is 0.1-5J / cm², and the energy density acting on the silicon wafer layer is 0.5-10J / cm².

[0040] S2, Chemical Wet Etching: The modified glass-silicon bonded structure is subjected to chemical wet etching, which forms preset cleavages in the glass layer and silicon wafer layer of the modified region.

[0041] Chemical wet etching specifically includes acid etching and alkaline etching, with a cleaning step between the acid and alkaline etching processes to remove residual etching solution; acid etching is used to etch the glass layer of the modified area, and alkaline etching is used to etch the silicon wafer layer of the modified area.

[0042] This application does not specify a particular order for acid etching and alkaline etching. Preferably, acid etching is performed first, followed by alkaline etching. The following description uses this as an example to further illustrate chemical wet etching in detail.

[0043] In some embodiments, chemical wet etching specifically includes: S201. Place the modified glass-silicon bonded structure in an etching bath containing acidic etching solution. The etching temperature is 18℃-60℃, and the etching time is 30s-60min. During etching, the acidic etching solution is stirred at a speed of 200-300r / min using a magnetic stirrer to ensure full contact between the acidic etching solution and the glass layer. This ensures that the glass layer reacts rapidly in the acidic solution, and the glass material in the laser-modified area dissolves preferentially, forming preliminary etching marks.

[0044] Acidic corrosive solutions can be selected from hydrofluoric acid (HF) solution, a mixture of hydrofluoric acid and nitric acid (HNO3) (HF:HNO3 volume ratio 1:1-1:10), a mixture of hydrofluoric acid and sulfuric acid (H2SO4) (HF:H2SO4 volume ratio 1:5-1:20), or buffered hydrofluoric acid (BHF, NH4F:HF mass ratio 5:1-10:1); the mass fraction of hydrofluoric acid is 1wt%-40wt%, and the mass fraction of each component in the mixture should be adjusted according to the above proportions.

[0045] S202. Remove the glass-silicon bonded structure and rinse it with deionized water 3-5 times, each rinse lasting 30-60 seconds, to remove any residual acidic corrosion solution from the surface.

[0046] S203. The glass-silicon bonded structure is placed in an etching tank containing an alkaline etching solution. The etching temperature is 40℃-95℃ and the etching time is 1min-60min. During etching, a circulating pump and a bubbler are used to assist etching, resulting in uniform etching. At the same time, the silicon wafer layer in the laser-modified area is rapidly etched, further deepening and widening the etching marks to form the preset cut.

[0047] Alkaline corrosive solutions can be potassium hydroxide (KOH) solution, sodium hydroxide (NaOH) solution, tetramethylammonium hydroxide (TMAH) solution, or lithium hydroxide (LiOH) solution; the mass fraction of KOH and NaOH solutions is 5wt%-40wt%, the mass fraction of TMAH solution is 5wt%-25wt%, and the mass fraction of LiOH solution is 10wt%-30wt%.

[0048] The final structure is as follows Figure 2 As shown, a first preset cleavage 501 is formed on the glass layer 1, and a second preset cleavage 502 is formed on the silicon wafer layer 2. A bonding layer 3 is provided between the first preset cleavage 501 and the second preset cleavage 502.

[0049] Because acidic solutions have a stronger reaction specificity with glass, acid etching first can precisely etch the modified area of ​​the glass layer to form a stable initial cleavage, providing a precise path guide for subsequent alkaline etching of the silicon wafer, ensuring precise alignment of the glass and silicon wafer cleavage, and improving the integrity and edge quality of the wafer.

[0050] In some embodiments, when the thickness of the silicon wafer layer is greater than the thickness of the glass layer, alkaline etching can be performed first, followed by cleaning and then acid etching.

[0051] S3, Ultrasonic-assisted fragmentation: Ultrasonic waves are transmitted through a liquid medium along the predetermined cutting path to the bonding layer of the modified region for fragmentation.

[0052] In some embodiments, the cleavage specifically includes: S301. The glass-silicon bonded structure after chemical wet etching is fixed in an ultrasonic bath.

[0053] In some embodiments, the glass-silicon bonded structure is fixed by a clamp to ensure stable placement in the ultrasonic bath.

[0054] S302. Inject a liquid medium into the ultrasonic tank; the liquid medium is usually deionized water.

[0055] S303. Turn on the ultrasonic generator, set the frequency of the ultrasonic generator to 20kHz-200kHz, the power to 50W-500W, the power density to 0.5W / cm²-5W / cm², and the action time to 1-10 minutes.

[0056] Low-frequency ultrasonic waves are suitable for thick bonded structures, while high-frequency waves are suitable for thin bonded structures. Specifically, when the total thickness of the glass-silicon bonded structure is ≥500μm, the frequency of the ultrasonic generator is set to 20kHz-50kHz; when the total thickness of the glass-silicon bonded structure is <500μm, the frequency of the ultrasonic generator is set to 50kHz-200kHz.

[0057] Ultrasonic waves are transmitted to the bonded layer 3 through the liquid medium, generating gentle vibrations that cause the structure to gradually separate along the pre-set cleavage path. During the cleavage process, the cleavage is observed in real time. If any deviation is detected, the ultrasonic parameters are adjusted promptly or the bonded structure is repositioned to ensure complete separation along the cleavage path.

[0058] According to another aspect of the present invention, this embodiment also provides a standalone semiconductor device having a glass-silicon bonding structure, obtained by a dicing method for processing the glass-silicon bonding structure.

[0059] The invention will be further explained below with reference to specific examples and parameters.

[0060] The glass-silicon bonded structure sample required for the experiment was made by using a 0.5 mm thick borosilicate glass sheet (BF33) and a 0.5 mm thick single crystal silicon wafer, and fabricated into a 20 mm × 20 mm glass-silicon bonded structure through an anodic bonding process.

[0061] In terms of experimental equipment, a picosecond laser with a wavelength of 532nm was used, along with a beam shaping system and a scanning galvanometer or a highly stable three-dimensional displacement platform, to generate and control the focused Bessel beam (or multifocal beam) and form a laser modification path in a preset area of ​​the sample.

[0062] Prepare high-precision ultrasonic cleaners, magnetic stirrers, and constant-temperature heating devices to meet the requirements of chemical wet etching and ultrasonic-assisted dicing. The etching solutions are prepared as follows: the acidic etching solution is a 6 wt% hydrofluoric acid (HF) solution, and the alkaline etching solution is a 30 wt% sodium hydroxide (NaOH) solution. Both etching solutions are prepared using analytical grade reagents and deionized water to ensure the stability and consistency of the etching effect.

[0063] In the laser modification step, the prepared glass-silicon bonded structure sample is fixed on a three-dimensional moving stage, and the sample position is adjusted so that the Bessel beam (or multifocal beam) can accurately irradiate the preset area of ​​the glass-silicon bonded structure. The laser is turned on, and selective irradiation modification of the glass layer and silicon wafer is performed according to the set parameters: wavelength 532nm, pulse width 10ps, repetition frequency 100kHz, energy density of 5J / cm² for the glass layer, and energy density of 3J / cm² for the silicon wafer. During the irradiation process, the laser energy and beam quality are monitored in real time to ensure the uniformity and stability of the irradiation effect.

[0064] After laser modification, a chemical wet etching step is performed. First, the bonded structure is placed in an etching bath containing an acidic etchant (25°C, 6wt% hydrofluoric acid solution). A magnetic stirrer is turned on, and the solution is stirred at 250 rpm to ensure full contact between the etchant and the glass layer. The etching time is controlled at 60 minutes. After etching, the bonded structure is removed from the acidic etchant and immediately rinsed three times with deionized water, each rinse lasting 30 seconds, to thoroughly remove any residual acidic etchant from the surface. Next, the bonded structure is placed in an etching bath containing an alkaline etchant (70°C, 30%wt% sodium hydroxide (NaOH) solution), with the circulation pump and bubbler simultaneously turned on. The etching time is 60 minutes. During the etching process, the etching progress is closely monitored to ensure that the formation of the pre-defined cuts meets expectations. Finally, an ultrasonic-assisted cleaving step is performed. The bonded structure, after chemical wet etching, is placed on a fixture in an ultrasonic bath to fix it in place. Deionized water is injected into the ultrasonic bath as the liquid medium. The ultrasonic generator is turned on, with the frequency set to 50kHz, the power to 200W, and the treatment time to 5 minutes. During the ultrasonic treatment, the cleaving process is carefully observed. If any deviation is found, the ultrasonic parameters are adjusted in time or the bonded structure is repositioned to ensure that the structure is completely separated along the preset cleaving path.

[0065] In this experiment, using the controlled single-variable method, glass-silicon bonded structure samples of the same specifications (glass layer thickness 500 μm, silicon wafer layer thickness 500 μm, bonding area 20 mm × 20 mm) were processed using traditional mechanical scribing, conventional laser direct cutting, plasma etching scribing, and the composite scribing method of the present invention, which combines laser modification, chemical wet etching, and ultrasonic-assisted scribing. After processing, the cross-sectional characteristics were quantitatively analyzed using high-precision testing equipment. The testing tools included: an atomic force microscope (AFM, testing accuracy 0.01 nm) for measuring cross-sectional roughness (Ra), a scanning electron microscope (SEM, magnification 5000x) for observing the number, length, and distribution of microcracks, and a laser confocal microscope for detecting the perpendicularity of the cross-section (deviation ≤ 0.1° is considered acceptable).

[0066] The experimental results are as follows:

[0067] As can be seen from the data in the table above, the cross-sectional roughness (Ra=52.3nm) of the scribing method of this invention is significantly better than the other three methods, only 4.8% of that of the traditional mechanical scribing method, 13.1% of that of the conventional laser direct cutting method, and 27.1% of that of the plasma etching scribing method. The scribing method of this invention uses a "non-contact" modification with a Bessel beam (or multi-focus beam) to form nano-gap voids only inside the material without destroying the integrity of the material surface; the subsequent stepwise chemical wet etching has the characteristics of "selective corrosion", and the corrosion rate of the modified area is 5-8 times that of the unmodified area. The etching process is uniform and gentle, avoiding physical damage and thermal stress; the vibration energy of the ultrasonic-assisted scribing is concentrated on the preset cutting path to achieve "directional fracture along the modified area", and the cross-section is the "intrinsic fracture surface" of the material, so the roughness is extremely low and the surface is smooth.

[0068] Microcracks are a key defect affecting the mechanical properties and service life of glass-silicon bonded structures. Experimental results show that the method of this invention completely avoids the generation of microcracks, while other methods all have microcrack problems to varying degrees. Laser modification only creates nanoscale voids within the material without stress concentration; chemical etching is a "dissolution" corrosion without mechanical or thermal stress; the vibration energy of ultrasonic dicing is mild and directional, and the fracture process proceeds along a pre-set cleavage path, avoiding the generation and propagation of cracks. SEM observation shows no visible microcracks on the cross-section, fundamentally ensuring the integrity of the structure. Edge integrity is related to the sealing performance of the structure. Mechanical scribing and conventional laser etching methods produce chipping at the edges of the diced material, while plasma etching and the dicing method of this invention both produce a melting effect on the target material, thus resulting in better edge integrity.

[0069] Comparative analysis of the cross-sectional characteristics of four dicing methods reveals that the composite dicing method of this invention, combining laser modification, chemical wet etching, and ultrasonic-assisted dicing, exhibits the best performance in key indicators such as cross-sectional roughness, microcrack control, and edge integrity. Specifically, the semiconductor device structure obtained using this invention has a cross-sectional roughness reduced to below 52.3 nm, with no visible microcracks and no edge chipping defects. This result stems from the synergistic effect of the composite process: laser modification provides precise "fracture guidance," chemical etching achieves gentle "material removal," and ultrasonic dicing completes non-destructive "structural separation." This fundamentally solves the cross-sectional defect problems caused by physical damage, thermal stress, or chemical erosion in traditional dicing methods, significantly improving the yield and stability of glass-silicon bonded structure dicing.

[0070] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0071] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0072] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for processing a glass-silicon bonded structure, the method comprising: The method comprises the following steps: ​ a glass-silicon bonding structure is irradiated and modified in a preset region by a laser beam, and a modified region is obtained; the modified region penetrates the glass layer and the silicon wafer layer of the glass-silicon bonding structure along the thickness direction of the glass-silicon bonding structure, the glass layer of the modified region forms a nano-scale SiO2 network loose structure, and the silicon wafer layer of the modified region forms local defects and nano-gaps; the glass-silicon bonding structure after modification is subjected to chemical wet etching, so that the glass layer and the silicon wafer layer of the modified region form a preset scribe lane, respectively; ultrasonic waves are transmitted to the bonding layer of the modified region along the preset scribe lane through a liquid medium, and the wafer is broken.

2. The method of claim 1, wherein: The irradiation and modification specifically comprises: a short focal depth spot is formed by focusing the laser beam, and the glass-silicon bonding structure is irradiated and modified step by step along the thickness direction of the glass-silicon bonding structure from the side away from the laser source to the side facing the laser source; During the irradiation and modification, corresponding energy density and step distance are respectively adopted according to the material properties of glass and silicon wafer.

3. The method of claim 1, wherein: The irradiation and modification specifically comprises: a multi-focus beam or a Bessel beam is used to scan in the preset region, and the focal depth of the multi-focus beam or the Bessel beam can cover the entire preset region of the glass-silicon bonding structure along the thickness direction of the glass-silicon bonding structure.

4. The method according to claim 2 or 3, wherein: The wavelength of the laser beam is 515-1064 nm, the pulse width is 0.2-50 ps, the repetition frequency is 50-500 kHz, the energy density acting on the glass layer is 0.1-5 J / cm², and the energy density acting on the silicon wafer layer is 0.5-10 J / cm².

5. The method of claim 1, wherein: The chemical wet etching specifically comprises acid etching and alkali etching, and a cleaning step is arranged between the acid etching and the alkali etching for cleaning the residual etching liquid; wherein, the acid etching is used for etching the glass layer of the modified region, and the alkali etching is used for etching the silicon wafer layer of the modified region.

6. The method of claim 5, wherein: The acid etching specifically comprises: the glass-silicon bonding structure after modification is placed in an etching tank containing an acidic etching liquid; the etching temperature is 18-60°C, the etching time is 30 seconds-60 minutes; and during etching, the acidic etching liquid is stirred at a speed of 200-300 r / min to make the acidic etching liquid fully contact with the glass layer.

7. The method of claim 5, wherein: The alkali etching specifically comprises: the glass-silicon bonding structure after acid etching and cleaning is placed in an etching tank containing an alkaline etching liquid; the etching temperature is 40-95°C, the etching time is 1 minute-60 minutes; and during etching, a circulating pump and a bubbler are used to assist etching.

8. The method of claim 1, wherein: The wafer breaking specifically comprises: the glass-silicon bonding structure after chemical wet etching is fixed in an ultrasonic tank; a liquid medium is injected into the ultrasonic tank; an ultrasonic generator is turned on, the frequency of the ultrasonic generator is set to 20-200 kHz, the power is set to 50-500 W, the power density is controlled to 0.5-5 W / cm², and the action time is 1-10 minutes.

9. The method of claim 8, wherein: When the thickness of the glass-silicon bonding structure is greater than or equal to 500 μm, the frequency of the ultrasonic generator is set to 20-50 kHz; when the thickness of the glass-silicon bonding structure is less than 500 μm, the frequency of the ultrasonic generator is set to 50-200 kHz.

10. A stand-alone semiconductor device having a glass-silicon bonded structure, characterized by: by the dicing method of the glass-silicon bonded structure according to any one of claims 1 to 9.

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