Cutting method and cutting device, chip

Abstract

Embodiments of the present application provide a cutting method, a cutting device and a chip. The cutting method comprises: step S11, providing a wafer to be cut, the wafer to be cut comprising a cutting region and chip regions located on both sides of the cutting region along a first direction; a front surface of the cutting region is provided with a functional layer, the functional layer comprising a metal material or a reflective material; step S12, etching the functional layer along the front surface of the cutting region to form an etching groove extending along a second direction; the etching groove does not penetrate through the wafer to be cut; step S13, forming micro-cracks and / or modification layers in the inside of the remaining cutting region based on a laser hidden cutting technology; and step S14, mechanically stretching a back surface of the wafer to be cut, so that the micro-cracks and the modification layers generate expansion cracks under the action of tension to separate the wafer to be cut into a plurality of chips.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and to, but is not limited to, a cutting method and cutting apparatus, and a chip. Background Technology

[0002] Currently, as integrated circuits develop towards high performance and miniaturization, the thickness of wafers is constantly decreasing and the width of the dicing channels is continuously shrinking, which places higher demands on wafer dicing processes.

[0003] In related technologies, although laser slicing technology can improve the precision of cutting, when there is a thick metal layer (such as copper, aluminum, gold, etc.) or a highly reflective blocking layer on the wafer surface, most of the laser energy cannot penetrate the metal layer to enter the wafer, resulting in a low chip splitting rate or even failure to separate the chips. Especially in the cutting of ultra-thin wafers, it is very easy to cause chip edge damage or microcracks, which seriously restricts the wafer cutting yield. Summary of the Invention

[0004] This application provides a cutting method, a cutting device, and a chip.

[0005] The technical solution of this application embodiment is implemented as follows: In a first aspect, embodiments of this application provide a cutting method, the method comprising: Step S11: Provide a wafer to be diced, the wafer to be diced includes a dicing area and chip areas located on both sides of the dicing area along a first direction; a functional layer is provided on the front side of the dicing area, the functional layer including a metal material or a reflective material; Step S12: Etch the functional layer along the front side of the cutting area to form an etching trench extending in the second direction; the etching trench does not penetrate the wafer to be cut. Step S13: Based on laser hidden cutting technology, microcracks and / or modified layers are formed inside the remaining cutting area; Step S14: Mechanically stretch the back side of the wafer to be cut, so that the modified layer and the microcracks generate propagating cracks under tension, so as to separate the wafer to be cut into multiple chips. Wherein, the first direction is parallel to the plane where the wafer to be cut is located, the second direction is perpendicular to the plane where the wafer to be cut is located, and the front and the back are two surfaces opposite to the second direction.

[0006] In some embodiments, step S12 specifically includes: Based on laser grooving technology, the functional layer is heated and vaporized along the front side of the cutting area to form an etched groove extending in the second direction. The ratio of the dimension of the etched trench in the second direction to the dimension of the cutting area along the second direction ranges from 5:50 to 15:50.

[0007] In some embodiments, the size of the cutting region along the second direction is less than or equal to 50 micrometers, and / or the size of the cutting region along the first direction is less than or equal to 15 micrometers.

[0008] In some embodiments, step S13 specifically includes: Based on the laser concealed cutting technology, a first pulsed laser is focused at at least one preset depth along the second direction in the cutting area to generate local stress at the preset depth, forming the microcrack; and / or, Based on the laser slicing technology, a first pulse laser is focused on at least one preset depth in the cutting area along the second direction, so as to cause a non-melting phase transition in the material lattice at the preset depth to form the modified layer.

[0009] In some embodiments, the first pulsed laser is focused at three predetermined depths along the second direction of the cutting region; The three preset depths are 1 / 3T, 2 / 3T, and 3 / 3T, respectively, where T is the dimension of the cutting area along the second direction.

[0010] In some embodiments, a spherical energy profile is formed at the focal point of the first pulsed laser based on a lens or holographic element; The power of the first pulsed laser ranges from 2.0W to 3.5W, the width of the modified layer is less than or equal to 2 micrometers, and the heat-affected zone of the first pulsed laser is less than 0.5 micrometers.

[0011] In some embodiments, step S13 further includes: Mechanical vibration with the same vibration frequency (10-100kHz) is applied to the wafer to be cut and the first pulsed laser.

[0012] In some embodiments, after performing step S11, the method further includes: Step S11a: Based on plasma cleaning, remove contaminants and oxide layers from the front side of the wafer to be cut; Step S11b: Based on in-situ optical detection, measure the detection parameters of the functional layer; the detection parameters include the thickness, reflectivity and roughness of the functional layer.

[0013] In some embodiments, an adhesive film is provided on the back side of the wafer to be cut, and step S14 specifically includes: A radial outward tension and a tangential rotational tension are applied to the adhesive film on the back side of the wafer to be cut, causing the modified layer and the microcracks to generate propagating cracks extending along the second direction under the action of tension.

[0014] Secondly, embodiments of this application provide a chip, which is prepared by any of the cutting methods described above.

[0015] Thirdly, embodiments of this application provide a cutting device, the device comprising: A separation module is used to carry a wafer to be diced, the wafer to be diced including a dicing area and chip areas located on both sides of the dicing area along a first direction; a functional layer is provided on the front side of the dicing area, the functional layer including a metal material or a reflective material; An etching module is used to etch the functional layer along the front side of the cutting area to form an etching trench extending in a second direction; the etching trench does not penetrate the wafer to be cut. A segmentation module is used to form microcracks and / or a modified layer inside the remaining cut area based on laser stealth cutting technology; The separation module is also used to mechanically stretch the back side of the wafer to be cut, so that the modified layer and the microcracks generate extended cracks under tension, so as to separate the wafer to be cut into multiple chips. Wherein, the first direction is parallel to the plane where the wafer to be cut is located, the second direction is perpendicular to the plane where the wafer to be cut is located, and the front and the back are two surfaces opposite to the second direction.

[0016] In some embodiments, the etching module and the segmentation module are disposed in the same device. The etching module is specifically used to heat and vaporize the functional layer along the front side of the cutting area based on laser grooving technology to form an etching groove extending in a second direction.

[0017] In some embodiments, the segmentation module further includes: A lens or holographic element is used to form a spherical energy profile at the focal point of the first pulse laser.

[0018] In some embodiments, the segmentation module further includes: A piezoelectric ceramic vibrator or ultrasonic transducer is used to apply mechanical vibration to the first pulsed laser.

[0019] In some embodiments, the separation module further includes: A piezoelectric element, located on the back side of the wafer to be cut, is used to generate mechanical vibrations on the wafer at the same frequency as the first pulsed laser.

[0020] In some embodiments, the apparatus further includes: A preprocessing module is used to remove contaminants and oxide layers from the front side of the wafer to be cut by plasma cleaning; and to measure the detection parameters of the functional layer by in-situ optical detection; the detection parameters include the thickness, reflectivity and roughness of the functional layer.

[0021] In some embodiments, the separation module is specifically used to apply radial outward tension and tangential rotational tension to the adhesive film on the back side of the wafer to be cut, so that the modified layer and the microcracks generate extended cracks extending along the second direction under the action of tension.

[0022] This application provides a dicing method, dicing apparatus, and chip; wherein, the dicing method includes: step S11, providing a wafer to be diced, the wafer to be diced including a dicing area and chip areas located on both sides of the dicing area along a first direction; a functional layer is provided on the front side of the dicing area, the functional layer including a metal material or a reflective material; step S12, etching the functional layer along the front side of the dicing area to form an etching trench extending along a second direction; the etching trench does not penetrate the wafer to be diced; step S13, based on laser hidden cutting technology, forming microcracks and / or a modification layer inside the remaining dicing area; step S14, mechanically stretching the back side of the wafer to be diced, causing the modification layer and microcracks to generate propagating cracks under tension, so as to separate the wafer to be diced into multiple chips.

[0023] In this embodiment, by etching away the functional layer of the cutting area, on the one hand, the blocking or reflection of the laser by the functional layer can be effectively eliminated, allowing the laser etch technology to act on the front side of the wafer to be cut and cut. This allows microcracks and / or modified layers to be generated in the interior of the cutting area in a non-contact manner, thus enabling the laser etch technology to be applied to ultra-thin wafers with narrow cutting areas. On the other hand, when separating the wafer by mechanical stretching, irregular microcracks, pits or material loss can be avoided on the sidewalls or corners of the separated chip, thereby improving production efficiency and product quality. Attached Figure Description

[0024] In the accompanying drawings (which are not necessarily drawn to scale), similar reference numerals may describe similar parts in different views. Similar reference numerals with different letter suffixes may indicate different examples of similar parts. The drawings illustrate, by way of example and not limitation, the various embodiments discussed herein.

[0025] Figure 1 A schematic flowchart illustrating the cutting method provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure during the wafer dicing process provided in the embodiments of this application. Figure 1 ; Figure 3 This is a schematic diagram of the structure during the wafer dicing process provided in the embodiments of this application. Figure 2 ; Figure 4 This is a schematic diagram of the structure during the wafer dicing process provided in the embodiments of this application. Figure 3 ; Figure 5 This is a schematic diagram of the structure during the wafer dicing process provided in the embodiments of this application. Figure 4 ; Figure 6 This is a schematic diagram of the cutting device provided in the embodiments of this application; Figure 7 Schematic diagram of the dicing apparatus and wafer to be diced provided in the embodiments of this application. Figure 1 ; Figure 8 Schematic diagram of the dicing apparatus and wafer to be diced provided in the embodiments of this application. Figure 2 ; Figure 9 Schematic diagram of the dicing apparatus and wafer to be diced provided in the embodiments of this application. Figure 3 . Detailed Implementation

[0026] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0027] In the following description, numerous details are set forth in order to provide a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, to avoid confusion with this application, some technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0028] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0029] In the following description, the terms "first," "second," and "third" are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first," "second," and "third" may be interchanged in a specific order or sequence where permissible, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein. In the drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0030] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this application.

[0031] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0032] Before introducing the embodiments of this application, let's define two directions that may be used in the following embodiments to describe the three-dimensional structure. The two directions may include the X-axis (first) and the Y-axis (second). The X-axis is parallel to the plane where the wafer to be cut is located; the Y-axis is perpendicular to the plane where the wafer to be cut is located.

[0033] This application provides a cutting method. Figure 1 This is a flowchart illustrating the cutting method provided in an embodiment of this application, as shown below. Figure 1 As shown, the cutting method includes the following steps: Step S11: Provide a wafer to be cut, which includes a cutting area and chip areas located on both sides of the cutting area along the X-axis direction; a functional layer is provided on the front side of the cutting area, which includes a metal material or a reflective material.

[0034] In this embodiment, the wafer to be diced may include multiple repeating chip regions, with adjacent chip regions separated by dicing regions; wherein, the chip regions contain actual circuits or devices, and the functional layers in the dicing regions may include marking patterns, test structure patterns, process control monitoring patterns, and other parts that do not participate in the actual circuit functions.

[0035] Furthermore, depending on the actual function, the material of the functional layer may include metallic materials (such as aluminum, copper, etc.), low-k films (low dielectric constant films), or reflective materials; the thickness and number of functional layers can be set according to actual needs and are not limited here.

[0036] Step S12: Etch the functional layer along the front side of the cutting area to form an etching trench extending along the Y-axis; the etching trench does not penetrate the wafer to be cut.

[0037] In this embodiment, the width and depth of the etching trench can be set according to the width and depth required for cutting in step S13; for example, the wider the etching trench, the larger the process window of step S13; and the deeper the etching trench, the greater the depth of functional layer removal, which is more conducive to the first pulse laser in step S13 penetrating into the interior of the wafer.

[0038] In this embodiment, the method of forming the etching trench can be set according to actual needs; for example, when the precision requirement is low, laser grooving (LG) technology can be used; and when the precision requirement is high, plasma etching can be used.

[0039] Step S13: Based on laser hidden cutting technology, microcracks and / or modified layers are formed inside the remaining cutting area.

[0040] In this embodiment, Stealth Dicing (SD) refers to focusing a laser beam into the interior of a transparent or semi-transparent material to form microcracks and / or a modified layer within the material. When an external force (such as mechanical tension) is subsequently applied, the cracks will propagate along the microcracks and / or the modified layer, thereby achieving separation of the chip region.

[0041] In this embodiment, forming microcracks and / or a modified layer inside the remaining cutting area means forming microcracks, a modified layer, or both microcracks and a modified layer inside the remaining cutting area. Specifically, when the first pulse laser (such as an ultraviolet or infrared laser) penetrates the surface of the wafer to be cut and focuses on a certain point inside, the photon energy is absorbed by the material, generating an extremely high energy density near the focal point. This energy does not melt or vaporize the material, but rather generates microcracks or lattice reconstruction (i.e., a modified layer). The "and / or" in subsequent embodiments can also be understood with reference to this.

[0042] Among these, microcracks are formed when laser energy causes local stress to exceed the material's fracture strength, creating a network of tiny cracks ranging from nanometers to micrometers in size; lattice reconstruction is the non-melting phase transition of the material's lattice (such as amorphization or dislocation multiplication), which weakens the structural strength. Additionally, the modified layer is a subsurface layer (located inside the wafer, not on the surface) with extremely small dimensions, typically 1-5 micrometers wide and less than 1 micrometer thick.

[0043] In related technologies, because the surface of the wafer to be cut has a functional layer, and the functional layer has a strong reflection or absorption effect on the first pulse laser used in laser etch, it is difficult for the first pulse laser to penetrate the functional layer from the front side of the wafer to reach the interior of the wafer. This not only forces the first pulse laser to penetrate only from the back side of the wafer, increasing process complexity, but also makes it difficult to segment the functional layer when separating chip regions, leading to chip edge damage or microcracks, which seriously restricts the wafer cutting yield. In the embodiments of this application, on the one hand, by etching away at least part of the functional layer, the blocking or reflection effect of the first pulse laser in the laser etch is reduced, allowing the first pulse laser to penetrate from the front side of the wafer to be cut, reducing process complexity; on the other hand, microcracks and / or the modified layer can extend to the upper and lower surfaces of the cutting area under the action of external force, reducing chip edge damage and improving the wafer cutting yield.

[0044] It should be noted that the presence of the etched trenches reduces the thickness of the functional layer penetrating the surface during the first pulse laser incidence. Therefore, a lower laser energy can be used to achieve the required energy density within the remaining cutting area, thereby reducing the heat-affected zone (HAZ) when the first pulse laser is focused inside the wafer, and improving process stability. Furthermore, after the formation of microcracks and / or the modified layer, the main structure of the wafer to be cut remains intact and does not separate.

[0045] Step S14: Mechanically stretch the back side of the wafer to be cut, so that the modified layer and microcracks generate propagating cracks under tension, thereby separating the wafer to be cut into multiple chips.

[0046] In this embodiment of the application, during the mechanical stretching process, when the tensile stress reaches the critical fracture strength of the area where the microcracks and / or the modified layer are located, the original cracks begin to expand and extend along the Y-axis towards the surface of the cutting area, eventually penetrating the entire thickness of the cutting area, thereby dividing the wafer to be cut into multiple independent chips.

[0047] In this embodiment, the type of chip (i.e., chip region) can be set according to actual needs, such as control chip, storage chip, etc.; among which, control chip can be, for example, a central processing unit (CPU), a digital signal processor (DSP), a field programmable gate array (FPGA), etc.; storage chip can be, for example, dynamic random access memory (DRAM); non-volatile memory (e.g., NAND flash memory), etc.

[0048] In this embodiment, the stretching amount and stretching speed of mechanical stretching can be set according to the size, thickness, distribution position of the modified layer and material properties of the wafer, so as to ensure that all microcracks and modified layers inside the wafer are fully expanded, while avoiding chip splashing due to excessive mechanical stretching or stress relaxation due to excessively slow mechanical stretching.

[0049] In this embodiment, by etching away the functional layer of the cutting area, on the one hand, the blocking or reflection of the functional layer on the first pulse laser can be effectively eliminated, allowing the laser etch technology to cut from the front side of the wafer to be cut. This allows microcracks and / or a modified layer to be generated in the interior of the cutting area in a non-contact manner, thus enabling the laser etch technology to be applied to ultra-thin wafers with narrow cutting areas. On the other hand, when separating the wafer by mechanical stretching, irregular microcracks, pits, or material detachment can be avoided on the sidewalls or corners of the separated chip, thereby improving production efficiency and product quality.

[0050] Next, the dicing method for the wafer to be diced will be explained in detail. Figures 2 to 5 This is a schematic diagram of the structure during the wafer dicing process provided in an embodiment of this application.

[0051] First, perform step S11, providing, as follows Figure 2 The wafer 100 to be diced shown includes a dicing region A and chip regions B located on both sides of the dicing region A along the X-axis direction; a functional layer 120 is provided on the front side A1 of the dicing region A, and the functional layer 120 includes a metal material or a reflective material.

[0052] Here, chip region B contains actual circuits or devices used to form chip 110; the functional layer 120 in dicing region A may include parts that do not participate in the actual circuit function, such as marking patterns, test structure patterns, and process control monitoring patterns.

[0053] It should be noted that the bottom of the functional layer 120 is provided with a dielectric layer and other parts that do not participate in the function; in addition, the back side of the wafer 100 to be cut is attached and fixed by an adhesive film (not shown).

[0054] In some embodiments, after performing step S11, the cutting method further includes steps S11a to S11b.

[0055] Step S11a: Based on plasma cleaning, remove contaminants and oxide layers from the front side A1 of the wafer 100 to be cut.

[0056] In this embodiment, contaminants are, for example, photoresist residue, and oxide layers are, for example, metal oxide layers. Since contaminants or oxide layers can affect the etching process of functional layer 120 in steps S12 and / or S13, resulting in spatial non-uniformity of etching rate, etching depth, sidewall morphology, or etching damage, the surface of the wafer 100 to be cut can be cleaned to remove contaminants and oxide layers and other surface defects before steps S12 and / or S13.

[0057] In this embodiment, plasma cleaning can be low-pressure plasma cleaning using a mixture of argon and oxygen. Furthermore, the process parameters during plasma cleaning can be set according to the material and contaminant type on the surface of the wafer 100 to be cut; for example, the cleaning intensity can be controlled to avoid insufficient cleaning affecting subsequent etching, or excessive cleaning causing damage to chip region B.

[0058] In this embodiment, plasma cleaning is a dry process. Compared with wet cleaning, plasma cleaning avoids the problems of chemical residue and drying, resulting in high cleanliness of the front A1 of the wafer to be cut, which is beneficial to the uniformity of subsequent etching processes.

[0059] Step S11b: Based on in-situ optical detection, measure the detection parameters of the functional layer 120; the detection parameters include the thickness, reflectivity and roughness of the functional layer 120.

[0060] In this embodiment, in-situ optical detection can be performed by scanning with a confocal microscope or a spectrometer; thus, in-situ optical detection can provide real-time feedback on the surface state of the wafer 100 to be inspected; for example, based on the detection data, the laser parameters (such as energy density and scanning speed) of the laser grooving technology in step S12 or the focusing depth of the laser hidden cutting technology in step S13 can be dynamically adjusted.

[0061] Specifically, when the functional layer 120 is detected to be too thick, parameters such as the laser power and etching time of the laser grooving technology in step S12 can be automatically adjusted (e.g., increased); here, the thickness of the functional layer 120 is its geometric dimension along the Y-axis. Alternatively, when the reflectivity of the surface of the cutting area A is detected to be high, the laser wavelength of the laser hidden cutting technology in step S13 is optimized to reduce scattering; here, reflectivity is the ability to reflect laser wavelengths. Furthermore, when the roughness of the surface of the cutting area A is detected to be high, in order to avoid laser scattering leading to a decrease in the uniformity of the microcracks 130 and / or the modified layer 140 in step S13, the cleaning intensity can be increased or decreased according to the actual situation to reduce the roughness.

[0062] It should be noted that the above steps S11a to S11b can be performed before step S12, before step S13, or before steps S12 and S13; this application does not restrict the order of the steps.

[0063] The above pretreatment steps can increase the precision of etching, thereby improving the cutting yield. For example, in step S12, the metal in the functional layer 120 is precisely removed to prevent metal residues from blocking the first pulse laser in step S13, thereby improving the cutting yield by 5-10%. Furthermore, the "detection-optimization" feedback loop is integrated into the cutting process, and an adaptive pretreatment system is formed through real-time optimization. Compared with the fixed parameter method in related technologies, this application can precisely control the etching depth in steps S12 and S13.

[0064] Perform step S12, and etch functional layer 120 along the front side A1 of cutting area A (see reference for location). Figure 2 ), forming as Figure 3 The etching trench 121 extends along the Y-axis as shown; the etching trench 121 does not penetrate the wafer 100 to be cut.

[0065] In some embodiments, step S12 specifically includes: heating and vaporizing the functional layer 120 along the front side A1 of the cutting area A based on laser grooving technology to form an etched groove 121 extending along the Y-axis direction.

[0066] In this embodiment, the laser grooving technology employs a second-pulse laser with a high absorption rate for the functional layer 120 material. During laser irradiation, the functional layer 120 absorbs laser energy in a very short time, its temperature rapidly rises above its melting point, and it melts and vaporizes, then is blown off the surface by the auxiliary gas, thereby forming a grooving pattern. Figure 3 The etching trench 121 extends along the Y-axis as shown.

[0067] In this embodiment of the application, during the laser grooving process, the scanning speed, repetition frequency and pulse energy of the laser beam can be controlled in real time according to the detection parameters of the functional layer 120 obtained in the previous steps, and the laser focus position and energy density can be adjusted to achieve depth control of the etched trench with a precision of 121 micrometers.

[0068] The ratio of the dimension d1 of the etched trench 121 in the Y-axis direction to the dimension d2 of the cutting area A in the Y-axis direction ranges from 5:50 to 15:50. For example, the ratio (d1:d2) of the dimension of the etched trench 121 to the dimension of the cutting area A in the Y-axis direction is a value between (5:50), (10:50), (15:50), or any combination thereof.

[0069] This avoids heat buildup caused by deep laser grooving, which could damage chip 110; or, it avoids the first pulse laser in subsequent step S13 being unable to penetrate into the cutting area A due to shallow laser grooving, thus ensuring the cutting effect.

[0070] It should be noted that functional layer 120 can be partially removed; or, functional layer 120 can be completely removed (e.g., Figure 3 (as shown); or, the entire functional layer 120 is removed, and part of the material at the bottom of the functional layer 120 is removed; the depth of the etching trench 121 can be determined according to actual needs.

[0071] In this embodiment, the laser grooving technology is a dry, non-contact processing method, thus avoiding mechanical stress on the wafer 100 to be cut and preventing edge chipping or delamination that may occur with traditional mechanical cutting. Simultaneously, during the laser grooving process, the second pulse laser has an extremely short duration, and most of the heat generated is carried away by the auxiliary gas and debris, concentrating the heat in a very small area. This makes the heat-affected zone controllable and effectively prevents heat diffusion from causing performance degradation of the chip 110. Furthermore, as... Figure 3 As shown, since the functional layer 120 is completely removed in this application, the first pulse laser in the laser hidden cutting step S13 can successfully penetrate into the cutting area A.

[0072] In some embodiments, the dimension d2 of the cutting region A along the Y-axis is less than or equal to 50 micrometers, and / or the dimension d3 of the cutting region A along the X-axis is less than or equal to 15 micrometers.

[0073] For example, the dimension d2 of the cutting region A along the Y-axis can be a value between 20 micrometers, 25 micrometers, 30 micrometers, 40 micrometers, 50 micrometers, or any combination thereof. The dimension d3 of the cutting region A along the X-axis can be a value between 5 micrometers, 10 micrometers, 15 micrometers, or any combination thereof. Here, dimensions d2 and d3 determine the space available for cutting on the wafer 100 to be cut.

[0074] In this embodiment, because the diameter of the laser spot in the laser grooving technology in step S12 can be controlled within 15 micrometers, the etching trench 121 can be precisely formed within the cutting area A (less than 15 micrometers) without damaging the chip areas B on both sides. Simultaneously, due to the presence of the etching trench 121, the focused spot of the subsequent laser dicing step can also be limited to the cutting area A, further improving cutting accuracy. In other words, the cutting method in this embodiment is suitable for ultra-thin wafers with narrow cutting areas.

[0075] Furthermore, since the ratio of the dimension of the etching trench 121 in the Y-axis direction to the dimension of the cutting area A in the Y-axis direction ranges from 5:50 to 15:50, and the dimension of the cutting area A in the Y-axis direction is less than or equal to 50 micrometers, the dimension of the etching trench 121 in the Y-axis direction is less than or equal to 15 micrometers; for example, the dimension d1 of the etching trench 121 in the Y-axis direction can be a value between 5 micrometers, 10 micrometers, 15 micrometers, or any combination thereof.

[0076] Here, when the cutting area A has a thick metal layer or a highly reflective material (i.e., functional layer 120), directly using the laser slicing (SD) technique in step S13 will result in a low segmentation rate. This is because functional layer 120 blocks the effective transmission of the first pulse laser energy, preventing the microcracks formed inside from fully expanding, thus failing to achieve complete chip separation (100% separation), leading to chipping and a decrease in cutting yield. However, this application sets step S12, using a high-energy second pulse laser focused on the surface of functional layer 120 to rapidly heat and vaporize functional layer 120, thereby removing or thinning functional layer 120, creating conditions for the subsequent step S13.

[0077] Step S13 is performed, based on laser hidden cutting technology, to form a shape like this inside the remaining cutting area A. Figure 4 Microcracks 130 and / or modified layer 140.

[0078] In some embodiments, step S13 specifically includes: based on laser slicing technology, focusing a first pulsed laser at at least one preset depth along the Y-axis of the cutting area A to generate local stress at the preset depth, forming a shape such as... Figure 4The microcracks 130; and / or, based on laser stencil technology, focusing a first pulsed laser at at least a predetermined depth along the Y-axis of the cutting region A, so as to cause a non-melting phase transition in the material lattice at the predetermined depth, forming a microcrack such as... Figure 4 The modified layer 140.

[0079] In this embodiment, the wavelength of the first pulse laser used in the laser slicing technology can be determined based on the optical properties of the material (such as transmittance and absorptivity) and processing requirements (such as precision, efficiency, and thermal damage); for example, it can be an ultraviolet laser or an infrared laser. When the first pulse laser penetrates the surface of the wafer 100 to be sliced ​​and focuses on a certain point inside, the photon energy is absorbed by the material, thereby generating an extremely high energy density near the focal point in a very short time, which causes changes inside the slicing area A, forming microcracks 130 and / or a modified layer 140.

[0080] In this embodiment, the microcracks 130 are formed as follows: when the first pulsed laser is focused at a predetermined depth within the cutting region A, the instantaneous energy density at the focal point is extremely high, causing the material to be heated and rapidly expand in a very short time, generating localized thermal stress; when the localized thermal stress exceeds the fracture strength of the material, a network of nanoscale to microscale microcracks, i.e., microcracks 130, is formed. The microcracks 130 significantly reduce the mechanical strength of the region, providing a preferred path for crack propagation during subsequent mechanical stretching.

[0081] In this embodiment, the modified layer 140 is formed as follows: when the first pulsed laser is focused at a predetermined depth inside the cutting region A, the laser energy is absorbed by the material, causing a non-melting phase transition in the crystal structure; for example, monocrystalline silicon can be transformed into amorphous silicon or polycrystalline silicon, or defects such as dislocations and lattice distortions can be generated, forming the modified layer 140; wherein, the modified layer 140 is a subsurface layer (located inside the wafer, not on the surface), and its size is extremely small (typically 1-5 micrometers wide and less than 1 micrometer thick), requiring microscopic observation. The modified layer 140 significantly weakens the mechanical strength of the region, providing a preferred path for crack propagation during subsequent mechanical stretching.

[0082] It should be noted that the two changes described above can occur individually or simultaneously. For example, when the laser energy density is low, a modified layer 140 can be formed; when the laser energy density is high, microcracks 130 and the modified layer 140 can be formed simultaneously. The microcracks 130 and / or the modified layer 140 generated in step S13 can, in the subsequent mechanical stretching step, cause the cracks to propagate along the lattice weakening direction or the direction of the microcracks 130, eventually penetrating to the surface of the wafer 100 to be cut, thus achieving the separation of the chip 110.

[0083] In this embodiment, the first pulsed laser can be focused at one or more depth positions along the Y-axis of the cutting region A; for example, the first pulsed laser can be focused at one, two, three, or four depth positions along the Y-axis of the cutting region A to form microcracks 130 and / or modified layers 140 at the focused positions. Here, the multiple focused depths can be uniformly distributed or non-uniformly distributed.

[0084] In some embodiments, the first pulsed laser is focused at three preset depths along the Y-axis of the cutting region A; wherein the three preset depths are 1 / 3T, 2 / 3T and 3 / 3T, respectively, and T is the size of the cutting region A along the Y-axis.

[0085] For example, when the dimension d2 of the cutting area A along the Y-axis is 20 micrometers, the trisection points are located at 6.7 micrometers, 13.3 micrometers, and 20 micrometers from top to bottom, respectively; as another example, when the dimension d2 of the cutting area A along the Y-axis is 50 micrometers, the trisection points are located at 16.7 micrometers, 33.3 micrometers, and 50 micrometers from top to bottom, respectively; and so on.

[0086] In this embodiment, the preset depth of the trisection points divides the thickness of the cutting area A into approximately three equal parts, forming three equally parallel microcracks 130 and / or modified layers 140, which is equivalent to pre-setting "fracture guide lines" inside. This causes the mechanical tension generated during subsequent mechanical stretching to preferentially propagate the cracks along these weakened layers, avoiding stress concentration that could cause chipping at the edge of the chip 110. Furthermore, the trisection design disperses the cutting stress to multiple vertical surfaces, improving yield. In addition, compared to schemes with more preset depths, the preset depth of the trisection points can prevent excessive accumulation of laser energy, ensuring sufficient crack propagation while dispersing stress, thereby ensuring the integrity and yield of the separated wafer 100.

[0087] In some embodiments, a spherical energy profile is formed at the focal point of the first pulsed laser based on a lens or holographic element.

[0088] In this embodiment, a phase modulation optical element is added to the first pulsed laser system to perform beam shaping on the first pulsed laser, converting the Gaussian beam into a spherical energy distribution, forming a spherical energy profile at the focal point so that the energy density peak is in the center and attenuates smoothly outward, while minimizing the surrounding thermal effects.

[0089] In this embodiment, a spherical energy profile refers to a laser focal point where the energy density distribution exhibits a spherical symmetry, meaning the energy density gradually decreases radially outward from the focal center, with the same attenuation rate in all directions. Compared to a conventional Gaussian beam, a spherical energy profile results in higher energy concentration at the focal point (energy density increased by 50%) and more uniform thermal diffusion around the focal point.

[0090] Among them, optical elements that can form a spherical energy profile at the focal point of the first pulse laser include, but are not limited to: aspherical lenses, diffractive optical elements (DOE), spatial light modulators (SLM), or holographic elements.

[0091] In this embodiment, the first pulse laser with a spherical energy profile, when set at a preset depth with three equally spaced points, helps ensure the uniformity of the microcracks 130 and / or the modified layer 140. Specifically, the spherical energy profile results in a higher peak energy density at the focal point, enabling the achievement of a nonlinear absorption threshold at lower pulse energies, thereby reducing total heat input. Simultaneously, the spherical energy distribution allows for precise energy constraint, reducing damage to the wafer 100 to be cut. Furthermore, the stronger penetrating power of the spherical energy makes the laser slicing process more efficient, thereby improving cutting accuracy and yield.

[0092] In some embodiments, the power of the first pulsed laser ranges from 2.0W to 3.5W, the width of the modified layer 140 is less than or equal to 2 micrometers, and the heat-affected zone of the first pulsed laser is less than 0.5 micrometers.

[0093] Here, the value of the first pulse laser power can be 2.0W, 2.5W, 3.0W, 3.5W, or any combination of two of them.

[0094] In this embodiment of the application, by controlling the energy depth of the first pulsed laser in step S13, the size of the modified layer 140 along the X-axis can be made less than or equal to 2 micrometers; for example, 1.5 micrometers, 1.8 micrometers, etc. Furthermore, the heat-affected zone of the first pulsed laser can be controlled to be less than 0.5 micrometers; for example, 0.3 micrometers, 0.5 micrometers, etc.

[0095] In this embodiment of the application, the "heat-affected zone" refers to the area where, when the first pulse laser is focused on the interior of the material (here, the interior of the wafer) to form the modified layer 140, in addition to producing the expected modification (such as microcracks) at the focal point, the heat from the laser energy will also diffuse to the area around the focal point, causing undesirable microstructural changes (such as lattice damage, phase transitions, etc.) to occur in the nearby material. This area affected by heat is called the heat-affected zone.

[0096] By combining the steps in the embodiments of this application, such as steps S11a-S11b, S12, S13, and forming a spherical energy profile, the heat-affected zone can be controlled to be less than 0.5 micrometers. This not only makes the first pulse laser more precise, but also minimizes thermal damage to the surrounding chip area B, ensuring the electrical performance and reliability of the chip; and reduces the risk of thermal damage to the edge of the chip 110 after the wafer 100 is separated, thus improving the cutting yield.

[0097] In summary, in ultra-thin wafers with an overall thickness of less than or equal to 20 micrometers and narrow dicing widths of less than 15 micrometers, any stress or thermal damage during processing can easily lead to wafer bending, cracking, or performance failure. Therefore, the steps in this application can control and reduce the heat-affected zone (less than 0.5 micrometers) on ultra-thin wafers, thereby improving the dicing yield of ultra-thin wafers.

[0098] In some embodiments, step S13 further includes: applying mechanical vibration at the same vibration frequency to the wafer 100 to be diced and the first pulse laser; the vibration frequency is 10-100 kHz (kilohertz).

[0099] In this embodiment of the application, the vibration frequency of the wafer 100 to be cut and the first pulse laser is a value between 10kHz, 20kHz, 30kHz, 50kHz, 80kHz, 90kHz, 100kHz or any combination thereof.

[0100] In this embodiment, a piezoelectric ceramic vibrator or an ultrasonic transducer can be integrated in step S13 to synchronously apply high-frequency (e.g., 10-100 kHz) mechanical vibration to the first pulse laser. This mechanical vibration acts on the surface of the wafer 100 to be cut, assisting the first pulse laser in forming a more uniform microcrack network inside and reducing crack propagation resistance.

[0101] Specifically, a piezoelectric element can be installed under the carrier (such as a film or blue film) of the wafer to be inspected, with its vibration frequency synchronized with the first pulse laser; for example, both at 100 kHz. In this way, the vibration energy is transferred to the microcrack 130 and / or the modified layer 140 region, reducing the fracture toughness of the material and promoting the faster and more uniform propagation of the microcrack 130 at the laser focus. This can reduce the required laser energy (e.g., from 3±0.1W to 2.5±0.1W) and suppress the expansion of the heat-affected zone.

[0102] In related technologies, microcracks are formed solely by laser energy, which is susceptible to material inhomogeneity and may lead to incomplete crack propagation (especially in ultrathin wafers). However, in this embodiment, by applying mechanical vibration at the same frequency, the material can be actively "shaken," ensuring that the crack propagates along the vertical plane where the modified layer 140 is located, thereby increasing the segmentation rate of the wafer to be cut to nearly 100%. In addition, since the heat-affected zone needs to be less than 0.5 micrometers, vibration can reduce the laser dwell time, further compressing the heat-affected zone to less than 0.3 micrometers, thus enhancing the cutting yield of the "ultrathin wafer."

[0103] In step S14, the back side A2 of the wafer 100 to be cut is mechanically stretched, causing the modified layer 140 and microcracks 130 to propagate cracks under tension, such as... Figure 5 As shown, the wafer 100 to be cut is separated into multiple chips 110.

[0104] In some embodiments, a film is provided on the back side A2 of the wafer 100 to be cut. Step S14 specifically includes: applying radial outward tension and tangential rotational tension to the film on the back side A2 of the wafer 100 to be cut, so that the modified layer 140 and the microcracks 130 (location please refer to) Figure 4 Under tension, an extended crack is generated that extends along the Y-axis.

[0105] In this embodiment, the adhesive film is used to fix the back side A2 of the wafer 100 to be cut onto the support stage. The adhesive film is typically a viscoelastic polymer film, such as blue film, UV film, heat-release film, shape memory polymer, etc.

[0106] In this embodiment, a mechanical device applies radial outward tension and tangential rotational tension to the adhesive film on the back side A2 of the wafer 100 to be cut, guiding the modified layer 140 and microcracks 130 to extend and expand along the Y-axis, ultimately completely dividing the wafer 100 into multiple independent chips 110. By applying two forces, the stress field inside the cutting region A is uniformized, causing the cracks to extend along the Y-axis, avoiding stress concentration that could lead to crack skewing or chip chip breakage inside the cutting region A, thus achieving efficient cutting and complete separation of the chips 110.

[0107] Among them, radial outward tension refers to the tensile force radiating from the center to the edge along the plane of the adhesive film, and tangential rotational tension refers to the shear force or rotational force in the direction perpendicular to the radial direction within the plane of the adhesive film. In addition, this application can monitor the stress distribution based on sensors to adjust the tension in real time. The radial tension and tangential tension can be set according to actual needs.

[0108] It should be noted that radial outward tension can be applied alone, or both radial outward tension and tangential rotational tension can be applied simultaneously. In this embodiment, it is preferred to apply both tensions simultaneously to achieve a better separation effect.

[0109] In this embodiment, mechanical stretching is used to extend the crack to the surface of the cutting area A, thereby achieving a Disco Die Separator (DDS). The stretching speed, i.e., the DDS speed, directly affects the stability of crack propagation and the separation quality of the chip 110. When the stretching rate is too low, crack propagation is too slow, the stress relaxation effect is significant, reducing the separation rate and prolonging the process time, thus affecting production efficiency. Conversely, when the stretching rate is too high, the adhesive film expands too quickly, causing instantaneous stress concentration, which can easily lead to chipping at the chip edge or chip spatter, especially in high-speed stretching of ultra-thin wafers, potentially causing uncontrollable breakage.

[0110] Therefore, the stretching speed is controlled within the range of 4 mm / s to 6 mm / s, which can be a value between 4 mm / s, 5 mm / s, 6 mm / s, or any combination thereof. This allows for the reduction of stress relaxation while maintaining good separation performance.

[0111] In summary, by first etching away the metal or reflective material of the functional layer 120 on the front side A1 of the cutting area A, the obstruction of the functional layer 120 to laser slicing is eliminated. Then, based on laser slicing, microcracks 130 and / or a modified layer 140 are formed inside the remaining cutting area A. Finally, mechanical stretching is used to propagate the cracks, thereby cutting the wafer 100 to be sliced ​​into multiple chips 110. This embodiment effectively solves the problems of thick metal or high reflective layers causing laser penetration failure and low chip 110 splitting rate. At the same time, it also avoids the problems of wafer 100 cracking and poor segmentation effect, making it applicable to ultra-thin wafers with narrow cutting areas, expanding the application scenarios of laser slicing, and improving production efficiency and product quality.

[0112] In addition, this application also provides a chip 110, please refer to the following embodiments. Figure 5 , Figure 5 This is a schematic diagram of the structure of a chip 110 provided in an embodiment of this application. The chip 110 is prepared by any of the cutting methods described in the above embodiments.

[0113] In this embodiment, chip 110 is an independent unit separated from the wafer 100 to be diced. For example... Figure 5As shown, after the mechanical stretching in step S14 is completed, the wafer 100 to be cut is separated into multiple chips 110 along the cutting region A; each chip 110 includes a chip region B and a remaining part of the cutting region A; wherein, the remaining part of the cutting region A on the sidewall of the chip region B does not constitute the circuit structure in the chip 110.

[0114] In addition, since the chip 110 is formed by the cutting method in the above embodiment, the chip 110 has a complete structure, no obvious heat-affected zone, and no chipping or delamination defects on the sidewall edges of the chip 110.

[0115] It should be noted that the type of chip 110 can be set according to actual needs, such as control chips, storage chips, logic chips, sensor chips, or power chips, etc. Among them, control chips can be, for example, central processing units (CPU), digital signal processors (DSP), field programmable gate arrays (FPGA), microcontroller units (MCU), or application-specific integrated circuits (ASIC), etc.; storage chips can be, for example, dynamic random access memory (DRAM); non-volatile memory (e.g., NAND flash memory), etc.

[0116] In addition, please refer to Figures 6 to 9 This application also provides a cutting apparatus 200, which includes a separation module 210, an etching module 220, and a dicing module 230. The separation module 210 is used to carry a wafer 100 to be cut. The wafer 100 includes a cutting region A and chip regions B located on both sides of the cutting region A along the X-axis. A functional layer 120 is provided on the front surface A1 of the cutting region A, and the functional layer 120 includes a metallic material or a reflective material. The etching module 220 is used to etch along the front surface A1 of the cutting region A. The etch functional layer 120 is etched to form an etch trench 121 extending along the Y-axis direction; the etch trench 121 does not penetrate the wafer 100 to be diced; the dicing module 230 is used to form a modified layer 140 and / or microcracks 130 inside the remaining dicing area A based on laser hidden cutting technology; the separation module 210 is also used to mechanically stretch the back side A2 of the wafer 100 to be diced, so that the modified layer 140 and microcracks 130 generate extended cracks under tension, so as to separate the wafer 100 to be diced into multiple chips 110.

[0117] Here, since the cutting device 200 integrates a separation module 210, an etching module 220, and a dicing module 230, the etching module 220 first removes the metal or reflective layer on the surface of the wafer 100 to be cut, the dicing module 230 then forms microcracks 130 and / or a modified layer 140 inside the cutting area A, and finally the separation module 210 applies mechanical force to separate the wafers, thereby improving the yield and precision of wafer cutting. This not only applies to ultra-thin wafers with narrow dicing channels, but also expands the application scenarios of laser hidden cutting technology.

[0118] In the embodiments of this application, such as Figure 7 As shown, the separation module 210 is used to support and separate the wafer 100 to be cut; specifically, the separation module 210 may include a support stage, and the wafer 100 to be cut is fixed on the support stage (the position can be referred to the separation module 210) by an adhesive film; at the same time, the separation module 210 can apply radial outward tension and tangential rotational tension to the wafer 100 to be cut.

[0119] In some embodiments, the etching module and such Figure 9 The segmentation module 230 shown is disposed in the same device. The etching module is specifically used to heat and vaporize the functional layer 120 along the front side A1 of the cutting area A based on laser grooving technology, forming as shown in the figure. Figure 8 The etched trench 121 shown extends along the Y-axis.

[0120] In this embodiment, the laser grooving technology uses a second-pulse laser with a high absorption rate for the functional layer 120 material. During laser irradiation, such as Figure 7 The functional layer 120 shown absorbs laser energy in a very short time, its temperature rapidly rises above its melting point, and then melts, vaporizes, and is blown off the surface by the auxiliary gas, thus forming a layer as shown in the diagram. Figure 8 The etching trench 121 extends along the Y-axis as shown.

[0121] In this embodiment, the segmentation module 230 is specifically used to focus a first pulse laser at at least one preset depth along the Y-axis of the cutting region A based on laser slicing technology, so as to generate local stress at the preset depth and form a shape such as Figure 4 The microcracks 130; and / or, based on laser stencil technology, focusing a first pulsed laser at at least a predetermined depth along the Y-axis of the cutting region A, so as to cause a non-melting phase transition in the material lattice at the predetermined depth, forming a microcrack such as... Figure 4 The modified layer 140.

[0122] In this embodiment, the wavelength of the first pulse laser used in the laser slicing technology can be determined based on the optical properties of the material (such as transmittance and absorptivity) and processing requirements (such as precision, efficiency, and thermal damage); for example, it can be an ultraviolet laser or an infrared laser. When the first pulse laser penetrates the surface of the wafer 100 to be sliced ​​and focuses on a certain point inside, the photon energy is absorbed by the material, thereby generating an extremely high energy density near the focal point in a very short time, which causes changes inside the slicing area A, forming microcracks 130 and / or a modified layer 140.

[0123] In this embodiment of the application, the etching module and the segmentation module 230 are integrated into the same device, which means that the etching module and the segmentation module 230 can share the same laser or use two independent lasers respectively. This allows the above steps S12 and S13 to be executed continuously in the same device, resulting in better process connection and thus improving segmentation efficiency.

[0124] In some embodiments, such as Figure 9 The segmentation module 230 also includes a lens or holographic element for forming a spherical energy profile of the first pulsed laser at the focal point.

[0125] In this embodiment, the lens or holographic element is disposed in the optical path of the laser in the segmentation module 230. Specifically, the element can be any of the following: an aspherical lens, a diffractive optical element (DOE), a spatial light modulator (SLM), or a computer-generated hologram (CGH). Its function is to modulate the wavefront of the incident laser beam so that after passing through the focusing objective lens, the energy density distribution near the focal point is approximately spherically symmetric, that is, the energy attenuation rate is basically the same in all radial directions from the center of the focal point.

[0126] In this embodiment, a lens or holographic element is used to form a spherical energy profile at the focal point of the first pulsed laser. This results in a higher peak energy density at the focal point, allowing the nonlinear absorption threshold to be reached at lower pulse energies, thereby reducing total heat input. Simultaneously, the spherical energy distribution enables precise energy control, reducing thermal damage to the wafer 100 to be cut and facilitating the formation of continuous, uniform microcracks 130 and / or modified layers 140 during multi-depth focusing. Furthermore, the stronger penetrating power of the spherical energy makes the laser slicing process more efficient, thereby improving cutting accuracy and yield.

[0127] In some embodiments, the segmentation module 230 further includes a piezoelectric ceramic vibrator or an ultrasonic transducer for applying mechanical vibration to the first pulse laser.

[0128] In this embodiment, a piezoelectric ceramic vibrator or an ultrasonic transducer is located in the slicing module 230, which applies high-frequency (e.g., 10-100 kHz) mechanical vibration to the first pulse laser. This mechanical vibration acts on the surface of the wafer 100 to be sliced, assisting the first pulse laser in forming a more uniform microcrack network 130 inside, thereby reducing the resistance to crack propagation.

[0129] In some embodiments, the separation module 210 further includes a piezoelectric element located on the back side A2 of the wafer 100 to be cut, for generating mechanical vibrations in the wafer 100 to be cut at the same frequency as the first pulse laser.

[0130] In this embodiment, the vibration frequency of the wafer 100 to be cut is synchronized with the first pulse laser; for example, both are 100kHz. In this way, the vibration energy is transferred to the microcrack 130 and / or the modified layer 140 region, reducing the material's fracture toughness and promoting faster and more uniform propagation of the microcrack 130 at the laser focal point. This reduces the required laser energy (e.g., from 3±0.1W to 2.5±0.1W) and suppresses the expansion of the heat-affected zone.

[0131] In this embodiment, by applying mechanical vibration at the same frequency, the material can be actively "shaken" to ensure that the crack extends along the vertical plane where the modified layer 140 is located, thereby increasing the segmentation rate of the wafer 100 to be cut to nearly 100%. In addition, since the heat-affected zone needs to be less than 0.5 micrometers, and vibration can reduce the laser dwell time, the heat-affected zone can be further compressed to less than 0.3 micrometers, thereby enhancing the cutting yield of the "ultra-thin wafer".

[0132] In some embodiments, the dicing apparatus 200 further includes: a pretreatment module for removing contaminants and oxide layers from the front side A1 of the wafer 100 to be diced by plasma cleaning; and for measuring the detection parameters of the functional layer 120 by in-situ optical detection; the detection parameters include the thickness, reflectivity and roughness of the functional layer 120.

[0133] In this embodiment, by adding a preprocessing module, a "detection-optimization" closed loop is formed in the cutting device 200, which can increase the accuracy during etching, thereby improving the cutting yield by 5-10%. Furthermore, by integrating the "detection-optimization" feedback loop into the cutting process, an adaptive preprocessing system is formed through real-time optimization. Compared with the fixed parameter method in related technologies, this application can precisely control the etching depth.

[0134] In some embodiments, the separation module 210 is specifically used to apply radial outward tension and tangential rotational tension to the adhesive film on the back side A2 of the wafer to be cut, so that the modified layer 140 and the microcrack 130 generate extended cracks extending along the Y-axis direction under the action of tension.

[0135] In this embodiment, the separation module 210 applies radial outward tension and tangential rotational tension to the adhesive film on the back side A2 of the wafer 100 to be cut, guiding the modified layer 140 and microcracks 130 to extend and expand along the Y-axis direction. Simultaneously, the film expansion speed is controlled within the range of 4 mm / s to 6 mm / s, ultimately completely dividing the wafer 100 into multiple independent chips 110. By applying two forces, the stress field inside the cutting region A is uniformized, causing the cracks to extend along the Y-axis direction. This avoids stress concentration leading to crack skewing or chip chip breakage within the cutting region A, thus achieving efficient cutting and complete separation of the chips 110.

[0136] In summary, firstly, laser grooving (LG) technology uses a high-energy laser beam to focus on the surface of the wafer to be cut, rapidly heating and vaporizing the thicker metal barrier layer (such as the SL metal layer) in the cutting area, thus removing the metal barrier layer and creating conditions for subsequent steps. Secondly, the LG process requires precise control of depth and width to avoid thermal damage.

[0137] Next, based on Stealth Dicing (SD) technology, the first pulse of laser is focused onto the interior (rather than the surface) of the dicing area in the wafer to be diced, forming a modified layer and microcracks. SD generates internal cracks in a non-contact manner, reducing the thermal impact on the surface and ensuring that the heat-affected zone (HAZ) is less than 500 nm. This step avoids interference from the metal layer, resulting in a more uniform crack distribution.

[0138] Finally, radial tension is generated by mechanically stretching the adhesive film (such as with a DDS system), causing the cracks in the internal modified layer to propagate along the plane to the wafer surface under tension, achieving complete chip separation (100% segmentation). This step ensures chip-free edge cutting and efficient dicing.

[0139] The chip provided in this application embodiment is similar to the chip obtained in the above method embodiment or device embodiment. For technical features not disclosed in detail in this application embodiment, please refer to the above embodiments for understanding. Here, they will not be repeated.

[0140] In the several embodiments provided in this application, it should be understood that the disclosed cutting method, cutting apparatus, and chip can be implemented in a non-target manner. The apparatus embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple units or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the various components shown or discussed are coupled to each other or directly coupled.

[0141] The features disclosed in the several method or apparatus embodiments provided in this application can be arbitrarily combined without conflict to obtain new method or apparatus embodiments.

[0142] The above are merely some embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the above-described scope.

Claims

1. A cutting method, characterized in that, The method includes: Step S11: Provide a wafer to be diced, the wafer to be diced includes a dicing area and chip areas located on both sides of the dicing area along a first direction; a functional layer is provided on the front side of the dicing area, the functional layer including a metal material or a reflective material; the size of the dicing area along a second direction is less than or equal to 50 micrometers; Step S12: Etch the functional layer along the front side of the cutting area to form an etching trench extending along the second direction; the etching trench does not penetrate the wafer to be cut. Step S13: Based on laser slicing technology, a first pulsed laser is focused on the interior of the remaining cutting area to form microcracks and / or a modified layer; wherein, the power of the first pulsed laser ranges from 2.0W to 3.5W, the width of the modified layer is less than or equal to 2 micrometers, and the heat-affected zone of the first pulsed laser is less than 0.5 micrometers; the first pulsed laser is focused on three preset depths along the second direction of the cutting area; the three preset depths are 1 / 3T, 2 / 3T, and 3 / 3T, where T is the dimension of the cutting area along the second direction; mechanical vibration with the same vibration frequency is applied to the wafer to be cut and the first pulsed laser; Step S14: Mechanically stretch the back side of the wafer to be cut, so that the modified layer and the microcracks generate propagating cracks under tension, so as to separate the wafer to be cut into multiple chips. Wherein, the first direction is parallel to the plane where the wafer to be cut is located, the second direction is perpendicular to the plane where the wafer to be cut is located, and the front and the back are two surfaces opposite to the second direction.

2. The method according to claim 1, characterized in that, Step S12 specifically includes: Based on laser grooving technology, the functional layer is heated and vaporized along the front side of the cutting area to form an etched groove extending along the second direction. The ratio of the dimension of the etched trench in the second direction to the dimension of the cutting area along the second direction ranges from 5:50 to 15:

50.

3. The method according to claim 2, characterized in that, The size of the cut area along the first direction is less than or equal to 15 micrometers.

4. The method according to claim 1, characterized in that, Step S13 specifically includes: Based on the laser concealed cutting technology, the first pulsed laser is focused at three preset depths along the second direction in the cutting area to generate local stress at the preset depths, forming the microcracks; and / or, Based on the laser stealth cutting technology, the first pulsed laser is focused at three preset depths along the second direction in the cutting area, so that the material lattice at the preset depth undergoes a non-melting phase transition to form the modified layer.

5. The method according to claim 4, characterized in that, A spherical energy profile is formed at the focal point of the first pulsed laser using a lens or holographic element.

6. The method according to claim 4, characterized in that, The vibration frequency applied to the wafer to be cut and the first pulsed laser is 10-100kHz.

7. The method according to claim 1, characterized in that, After performing step S11, the method further includes: Step S11a: Based on plasma cleaning, remove contaminants and oxide layers from the front side of the wafer to be cut; Step S11b: Based on in-situ optical detection, measure the detection parameters of the functional layer; the detection parameters include the thickness, reflectivity and roughness of the functional layer.

8. The method according to claim 1, characterized in that, The back side of the wafer to be cut is provided with an adhesive film. Step S14 specifically includes: A radial outward tension and a tangential rotational tension are applied to the adhesive film on the back side of the wafer to be cut, causing the modified layer and the microcracks to generate propagating cracks extending along the second direction under the action of tension.

9. A chip, characterized in that, The chip is prepared by the dicing method as described in any one of claims 1 to 8.

10. A cutting device, characterized in that, The device includes: A separation module is used to carry a wafer to be diced, the wafer to be diced including a dicing area and chip areas located on both sides of the dicing area along a first direction; a functional layer is provided on the front side of the dicing area, the functional layer including a metal material or a reflective material; the size of the dicing area along a second direction is less than or equal to 50 micrometers; An etching module is used to etch the functional layer along the front side of the cutting area to form an etching trench extending along the second direction; the etching trench does not penetrate the wafer to be cut. A slicing module is used to focus a first pulsed laser onto the interior of the remaining slicing area based on laser slicing technology, forming microcracks and / or a modified layer; wherein the power of the first pulsed laser ranges from 2.0W to 3.5W, the width of the modified layer is less than or equal to 2 micrometers, and the heat-affected zone of the first pulsed laser is less than 0.5 micrometers; the first pulsed laser is focused on three preset depths of the slicing area along the second direction; the three preset depths are 1 / 3T, 2 / 3T, and 3 / 3T, where T is the dimension of the slicing area along the second direction; mechanical vibration with the same vibration frequency is applied to the wafer to be sliced ​​and the first pulsed laser; The separation module is also used to mechanically stretch the back side of the wafer to be cut, so that the modified layer and the microcracks generate extended cracks under tension, so as to separate the wafer to be cut into multiple chips. Wherein, the first direction is parallel to the plane where the wafer to be cut is located, the second direction is perpendicular to the plane where the wafer to be cut is located, and the front and the back are two surfaces opposite to the second direction.

11. The apparatus according to claim 10, characterized in that, The etching module and the segmentation module are disposed in the same device. The etching module is specifically used to heat and vaporize the functional layer along the front side of the cutting area based on laser grooving technology to form an etching groove extending along the second direction.

12. The apparatus according to claim 10, characterized in that, The segmentation module further includes: A lens or holographic element is used to form a spherical energy profile at the focal point of the first pulsed laser.

13. The apparatus according to claim 12, characterized in that, The segmentation module further includes: A piezoelectric ceramic vibrator or ultrasonic transducer is used to apply mechanical vibration to the first pulsed laser.

14. The apparatus according to claim 13, characterized in that, The separation module also includes: A piezoelectric element, located on the back side of the wafer to be cut, is used to generate mechanical vibrations on the wafer at the same frequency as the first pulsed laser.

15. The apparatus according to claim 10, characterized in that, The device further includes: A preprocessing module is used to remove contaminants and oxide layers from the front side of the wafer to be cut by plasma cleaning; and to measure the detection parameters of the functional layer by in-situ optical detection; the detection parameters include the thickness, reflectivity and roughness of the functional layer.

16. The apparatus according to claim 10, characterized in that, The separation module is specifically used to apply radial outward tension and tangential rotational tension to the adhesive film on the back side of the wafer to be cut, so that the modified layer and the microcracks generate extended cracks extending along the second direction under the action of tension.

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