Laser cutting method and cutting structure

Abstract

The invention provides a laser cutting method and a cutting structure.The laser cutting method comprises the steps that a to-be-cut substrate is provided, a cutting channel area is defined on the to-be-cut substrate, and the cutting channel area is provided with a first side area and a second side area which are opposite; and forming a first groove part and a second groove part in the first side area and the second side area of the cutting channel area through laser treatment, wherein at least part of the area between the first groove part and the second groove part is not subjected to laser treatment, and the island part which is not removed is reserved. According to the invention, the laser processing frequency of the cutting channel area can be effectively reduced, so that the accumulation of heat effect caused by laser cutting is greatly reduced, the chip strength is ensured to meet the specification requirement, and meanwhile, the reduction of the laser processing frequency can effectively improve the unit time productivity of a laser station.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of semiconductor integrated circuit manufacturing, and particularly relates to a laser cutting method and a cutting structure. BACKGROUND

[0002] With the rapid development of information technology, the performance of chips is constantly rising, and the manufacturing technology and materials are constantly updated and iterated. The structure becomes more and more complex, and the device sensitivity is also higher and higher.

[0003] In the current wafer preparation process, low dielectric constant (Low-K) materials distributed between metal interconnection layers have become the industry mainstream. Due to the brittleness of Low-K materials, traditional mechanical physical blade cutting has problems such as edge damage of the cutting path, internal chip cracking, particle spatter, and cracking between chip layers. In addition, the cutting path area of high-order products has complex metal wiring design and high-density test key arrangement, which can easily cause metal and blade adhesion during blade cutting, resulting in chip edge damage and internal chip cracking, or uneven stress on the blade, causing blade damage.

[0004] It should be noted that the above introduction to the technical background is only to facilitate the clear and complete description of the technical scheme of the present application, and to facilitate the understanding of those skilled in the art. The above technical scheme cannot be considered as known to those skilled in the art merely because it is described in the background section of the present application. SUMMARY

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a laser cutting method and a cutting structure to solve the problem that the number of cycles required for laser processing is too large in the prior art, which can easily cause the strength of the chip to decrease sharply.

[0006] To achieve the above-mentioned purpose and other related purposes, the present application provides a laser cutting method, which comprises: providing a to-be-cut substrate, the to-be-cut substrate being defined with a cutting path area, the cutting path area having opposite first and second side regions; forming a first groove portion and a second groove portion in the first and second side regions of the cutting path area by laser processing, and at least part of the region between the first and second groove portions is not processed by laser and retains an unremoved island portion.

[0007] Optionally, the laser cutting method further comprises the step of cutting the cutting path area with the first and second groove portions by a cutting blade wheel, and the distance between the two outer sidewalls of the first and second groove portions is greater than the width of the cutting blade wheel.

[0008] Optionally, the substrate surface to be cut comprises a laser cutting layer, the laser cutting layer comprises a low-K dielectric layer, a metal layer, or a stack structure composed of both, and at least one of the first groove portion and the second groove portion penetrates the laser cutting layer.

[0009] Optionally, the width of the island portion ranges from 5 microns to 10 microns.

[0010] Optionally, the height of the island portion ranges from less than or equal to one half of the depth of the first groove portion or the second groove portion.

[0011] Optionally, the width of the cutting lane region is greater than 80 microns, and the top of the island portion is flush with the top of the first groove portion or the second groove portion.

[0012] Optionally, the number of times of laser processing for forming the first groove portion ranges from 1 to 8, and the number of times of laser processing for forming the second groove portion ranges from 1 to 8.

[0013] Optionally, the laser processing mode of the first groove portion is to first perform laser processing on the first side edge of the cutting lane region, and then gradually translate the laser towards the middle region of the cutting lane region until the first groove portion is formed; and the laser processing mode of the second groove portion is to first perform laser processing on the second side edge of the cutting lane region, and then gradually translate the laser towards the middle region of the cutting lane region until the second groove portion is formed.

[0014] Optionally, there is an overlap between adjacent translation steps in the process of gradually translating the laser towards the middle region of the cutting lane region to form the first groove portion; and / or there is an overlap between adjacent translation steps in the process of gradually translating the laser towards the middle region of the cutting lane region to form the second groove portion.

[0015] Optionally, the ratio of the laser overlap width between adjacent translation steps to the laser width ranges from 30% to 50%.

[0016] Optionally, the depth of the first groove portion ranges from 5 microns to 15 microns, and the depth of the second groove portion ranges from 5 microns to 15 microns.

[0017] Optionally, the width of the first groove portion is equal to the width of the second groove portion; or the width of the first groove portion is less than the width of the second groove portion; or the width of the first groove portion is greater than the width of the second groove portion.

[0018] Optionally, the laser cutting method is applicable to an image sensor, wherein the cutting lane region comprises at least one of a metal interconnection layer and a test structure.

[0019] Optionally, there is an overlap between the time period for forming the first groove portion and the time period for forming the second groove portion.

[0020] The application also provides a cutting structure, which comprises: a substrate to be cut, the substrate to be cut being defined with a cutting track area, the cutting track area having opposite first and second side areas; the first and second side areas of the cutting track area respectively form a first groove part and a second groove part, and at least part of the area between the first and second groove parts is not treated by laser and retains an unremoved island part.

[0021] Optionally, the distance between the two outer sidewalls of the first and second groove parts is greater than the width of a cutting wheel used for cutting.

[0022] Optionally, the width of the island part ranges from 5 microns to 10 microns; the height of the island part is less than or equal to half of the depth of the first or second groove part, or the top of the island part is flush with the top of the first or second groove part.

[0023] As described above, the laser cutting method of the application has the following beneficial effects:

[0024] The laser cutting method of the application can effectively reduce the number of laser treatments of the cutting track area, for example, by 3-5 times less than the conventional number of laser treatments, thereby greatly reducing the accumulation of thermal effects caused by laser cutting, ensuring that the strength of the chip meets the specification requirements, and the reduction in the number of laser treatments can effectively improve the unit time production capacity (UPH) of the laser irradiation station.

[0025] The distance between the two outer sidewalls of the first and second groove parts of the application is greater than the width of the cutting wheel, the low-K medium and metal layer on both sides where the cutting wheel falls have been removed, and sufficient cutting wheel offset space can be reserved, so that the actual effect of the laser cutting of the application is consistent with the conventional U-shaped groove, and the risk of cutting wheel or chip debris, peeling or fragmentation is greatly avoided.

[0026] The size of the island part reserved between the first and second groove parts of the application is small or / and the height is low, which can avoid the chip yield problem caused by cutting debris splashing.

[0027] The application can use a laser with a narrow beam for cutting, the energy of the laser is highly concentrated, and through multiple laser translations and processing times, accurate control of different groove widths, depths and types can be achieved, which is suitable for the regulation and control of different products.

[0028] When the application is laser cut, the groove is formed from both sides of the cutting track to the middle, so that the actual thermal effect of the laser on the side of the chip is only 1-2 times of thermal effect accumulation, which greatly weakens the influence of laser energy on the chip. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings, which are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is to be understood that the drawings are solely for purposes of illustration and are not limiting as to the scope of the present application.

[0030] Figures 1-6 The structure schematic diagram shown as each step of the laser cutting method of the embodiment of the present application, wherein, Figure 4 The structure schematic diagram shown as Figure 3 The electron microscope diagram of the structure shown, Figure 3 The cutting structure schematic diagram shown as the embodiment of the present application.

[0031] Figure 7 The chip front surface strength comparison schematic diagram shown as the W-shaped groove and the traditional U-shaped groove after cutting of the embodiment of the present application.

[0032] Figures 8-9 The structure schematic diagram shown as another laser cutting method of the embodiment of the present application, wherein, Figure 9 The structure schematic diagram shown as Figure 8 The electron microscope diagram of the structure shown.

[0033] Figure 10 The structure schematic diagram shown as another laser cutting method of the embodiment of the present application.

[0034] Element number explanation

[0035] 10 substrate layer

[0036] 11 laser cutting layer

[0037] 111 low K dielectric layer

[0038] 112 metal layer

[0039] 13 cutting track area

[0040] 14 laser beam

[0041] 15 first groove part

[0042] 16 second groove part

[0043] 17 island part

[0044] 18 cutting wheel DETAILED DESCRIPTION

[0045] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0046] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components.

[0047] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0048] In the detailed description of embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0049] For ease of description, spatial relation terms such as “below,” “under,” “lower than,” “below,” “above,” and “upper” may be used herein to describe the relationship between one element or feature shown in the accompanying drawings and other elements or features. It will be understood that these spatial relation terms are intended to include directions other than those depicted in the drawings for devices in use or operation. Furthermore, when a layer is referred to as being “between” two layers, it may be the only layer between the two layers, or there may be one or more layers in between.

[0050] In the context of this application, the structure described above the first feature may include embodiments in which the first and second features are formed in direct contact, or embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact.

[0051] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0052] like Figures 1-6 As shown, this embodiment provides a laser cutting method, which includes the following steps:

[0053] As shown in FIG. 1, first, step 1) is performed to provide a substrate to be cut, which is defined with a scribe lane region 13 having opposite first and second side regions. Figure 1

[0054] As shown in FIG. 1, the substrate to be cut can be a substrate layer 10 and a laser cutting layer 11 disposed on the substrate layer 10. The substrate layer 10 can be, for example, a silicon substrate, a germanium substrate, a germanium-silicon substrate, a silicon carbide substrate, a group III-V compound substrate (e.g., gallium nitride, gallium arsenide, etc.), or a composite substrate such as a silicon-on-insulator (SOI), a germanium-on-insulator (GOI), a germanium-silicon-on-insulator, etc. The substrate layer 10 can be doped or undoped, and can include various doped regions of different concentrations and electrical types to achieve different functions. The material type and configuration of the substrate layer 10 are not limited to the examples listed above. Figure 1

[0055] As shown in FIG. 1, the laser cutting layer 11 includes a low-K dielectric layer 111, a metal layer 112, or a stack structure composed of both. For example, the laser cutting layer 11 can be an interconnect layer of a chip, which includes alternatingly stacked low-K dielectric layers 111 and metal wiring layers. The low-K dielectric layer 111 can be, for example, silicon dioxide, silicon nitride, silicon oxynitride, etc. The metal wiring layer can be, for example, copper, aluminum, tungsten, titanium, titanium nitride, gold, platinum, etc. In one specific example, the laser cutting method is applied to an image sensor, in which the scribe lane region 13 includes at least one of a metal interconnect layer and a test structure, which can include, for example, a stack of silicon dioxide and a metal copper wiring layer. Figure 1

[0056] As shown in FIG. 1, the substrate to be cut is defined with a scribe lane region 13 having opposite first and second side regions, and the substrate to be cut can be divided into independent chips by cutting the scribe lane region 13. The width of the scribe lane region 13 can be, for example, 60-120 microns. Figure 1

[0057] As shown in FIG. 1, then, step 2) is performed to form a first groove portion 15 and a second groove portion 16 in the first and second side regions of the scribe lane region 13, respectively, by laser processing. At least a portion of the region between the first and second groove portions 15, 16 is not processed by the laser and retains an unremoved island portion 17. Figures 2-4

[0058] ​​​​​Specifically, in the embodiment, the laser action mechanism belongs to non-contact cutting, the energy density is high, the ultra-short pulse effect in time and high resolution in space have advantages of fast stress-free release processing effect on the chip, there is no huge mechanical stress caused by separate blade cutting, and defects such as particle splashing, chip edge damage and chip internal rupture can be avoided. In addition, the laser precision is high, the processing path is flexible and controllable, and the high-precision control can be performed on the slot appearance, which is beneficial to the regulation and control of the slot type, depth and profile of different types of products.

[0059] In one embodiment, the laser processing mode of the first slot part 15 is to first perform laser processing on the first side edge of the cutting path area 13, and then gradually translate the laser towards the middle area of the cutting path area 13 until the first slot part 15 is formed; the laser processing mode of the second slot part 16 is to first perform laser processing on the second side edge of the cutting path area 13, and then gradually translate the laser towards the middle area of the cutting path area 13 until the second slot part 16 is formed. When cutting by laser, the cutting path is slotted from both sides to the middle, and a preliminary isolation slot is formed between the cutting path area 13 and the chip area at the beginning, thereby reducing the thermal influence of subsequent laser processing on the chip area. The actual thermal influence of the laser on the side edge of the chip is only 1-2 times of thermal effect accumulation, which greatly weakens the influence of laser energy on the chip.

[0060] In one embodiment, there is an overlap between adjacent translation steps in the process of gradually translating the laser towards the middle area of the cutting path area to form the first slot part 15; and / or there is an overlap between adjacent translation steps in the process of gradually translating the laser towards the middle area of the cutting path area to form the second slot part 16. In one implementation, the number of laser processing times can be reduced by reducing the overlap. For example, the ratio of the laser overlap width between adjacent translation steps to the laser width is 30%-50%, specifically, the ratio of the laser overlap width between adjacent translation steps to the laser width can be 35.5%, 36.5%, 37.5%, 38.5%, compared with the ratio of the laser overlap width to the laser width of about 60% in the traditional way, the present application reduces the number of laser processing times by increasing the translation step and reducing the overlap width between adjacent translation steps.

[0061] In one embodiment, the number of laser processing times to form the first slot part 15 is 1-8 times, for example, 1 time, 2 times or 3 times, and the number of laser processing times to form the second slot part 16 is 1-8 times, for example, 1 time, 2 times or 3 times.

[0062] In one embodiment, a single laser beam 14 can be used to sequentially form the first groove 15 and the second groove 16. Alternatively, the formation time periods of the first groove 15 and the second groove 16 can overlap. For example, two laser beams 14 can be used, moving from both sides of the cutting channel region 13 towards the center to simultaneously form the first groove 15 and the second groove 16, thereby further shortening the laser cutting time and improving production efficiency, such as using a laser machine in pure narrow beam mode. In a specific example, the formation time periods of the first groove 15 and the second groove 16 overlap, meaning that they start and complete cutting simultaneously.

[0063] In one embodiment, the width of the island 17 ranges from 5 micrometers to 10 micrometers. For example... Figure 3 As shown, in one embodiment, the height of the island 17 can be less than or equal to half the depth of the first groove 15 or the second groove 16. For example, in this case, the width of the kerf region 13 is less than or equal to 80 micrometers. Because the present invention does not require the complete removal of material from the kerf region 13, but retains an island 17 of a certain width to form a W-shaped trench, compared to the traditional U-shaped trench which requires the complete removal of material from the kerf region 13, the present invention can effectively reduce the number of laser treatments required for the kerf region 13, such as reducing the number of laser treatments by 3 to 5 times compared to traditional methods. This greatly reduces the accumulation of heat effects caused by laser cutting, ensuring that the chip strength meets specifications. Simultaneously, the reduction in the number of laser treatments can effectively increase the uptime (UPH) of the laser cutting station. Furthermore, the island 17 retained between the first groove 15 and the second groove 16 is smaller in size and / or lower in height, which can avoid chip yield problems caused by flying cutting debris.

[0064] In one embodiment, at least one of the first groove 15 and the second groove 16 penetrates the laser cutting layer 11. Preferably, both the first groove 15 and the second groove 16 penetrate the laser cutting layer 11 to further reduce debris from subsequent cutting and adhesion to the cutting wheel 18. In a specific example, the depth of the first groove 15 ranges from 5 micrometers to 15 micrometers, such as 8 micrometers or 12 micrometers, and the depth of the second groove 16 ranges from 5 micrometers to 15 micrometers, such as 8 micrometers or 12 micrometers. The specific depth can be set according to the actual thickness of the laser cutting layer 11 and is not limited to the examples listed here.

[0065] like Figures 5-6 As shown, the final step is step 3), which involves cutting the cutting channel area 13 with the first groove 15 and the second groove 16 using the cutting blade 18. The distance between the two outer side walls of the first groove 15 and the second groove 16 is greater than the width of the cutting blade 18. The number of cutting blades 18 can be selected according to actual needs; two are shown in the figure.

[0066] As shown in Figure 5 cutting wheel 18 penetrates the entire substrate to be cut, and then slides along the extension direction of the cutting path region 13, through multiple cutting, finally divides the substrate to be cut into multiple independent chips.

[0067] The distance between the two outer side walls of the first groove part 15 and the second groove part 16 of the present application is greater than the width of the cutting wheel 18, the low-K medium and metal layer 112 on both sides where the cutting wheel 18 falls have been removed, the cutting wheel 18 does not contact the chip edge on both sides of the cutting path region 13, and by controlling the distance between the two outer side walls of the first groove part 15 and the second groove part 16, enough cutting wheel 18 offset space can be reserved, so that the actual effect of the laser cutting of the present application is consistent with the traditional U-shaped groove, and the risk of cutting wheel 18 or chip chipping, peeling or cracking is greatly avoided.

[0068] In a pair of examples, in order to realize high-quality separation of chips from wafers to single-die bare chips, reduce chip edge damage and internal chip cracking, etc. The bare chip separation process adopts laser pre-slotting to assist in separation, the specific steps are as follows:

[0069] A certain width of groove is pre-opened in the cutting path by laser, and the low-K material and metal material in the cutting path region are removed;

[0070] Then the remaining silicon base is separated in the groove by using a blade, so as to realize the purpose of bare chip separation.

[0071] Among them, the introduction of laser cutting process, in the process of ablation of low-K material and metal material, there is a certain heat effect, namely HAZ (Heat Affect Zone), which has a great influence on the face up strength of the chip. Chip strength is one of the key indicators of product reliability quality, especially for CIS chip packaging modules belonging to non-plastic encapsulation form, high-end mobile phone chip strength displacement requirement is greater than 3000, the traditional laser cutting process often difficult to meet the above requirements.

[0072] The conventional laser cutting trench is generally preferred to be a U-shaped groove, that is, the low-K material and the metal material in the cutting path are completely removed, and the subsequent blade only cuts the remaining silicon base in the U-shaped groove. The advantage of this is that it avoids the risk that the residual low-K material and metal material may still be contacted by the blade to cause debris and cracking, and maximally avoids the occurrence of defects such as particle splashing, chip edge damage and chip internal cracking. At the same time, the cutting load of the blade is maximally reduced. For example, for a CIS chip, the U-shaped groove is also beneficial to the cutting yield, and reduces the yield problem caused by cutting debris splashing onto the photosensitive surface.

[0073] However, the U-shaped groove generally needs to be processed by laser multiple times to completely modify the groove shape. The more times the laser beam acts, the greater the cumulative effect of the heat influence on the chip, and the greater the influence on the strength of the chip. Especially when the metal layer is thick and the required groove width is wide, the number of required laser processing times is large, and the strength of the chip will decrease sharply, and the separation of the bare chip will face great challenges.

[0074] For example, in a stack structure, the CIS wafer includes a silicon substrate, a device layer (corresponding to a logic chip) and a pixel layer (corresponding to a pixel chip) stacked in sequence, and the laser cutting layer 11 is the pixel layer and the device layer of the CIS wafer. The width of the cutting path region 13 is 70 microns, the depth of the first groove part 15 and the second groove part 16 formed by the laser cutting method of the present application is 9 microns to 10 microns, to form a W-shaped trench, the island part 17 in the W-shaped trench has a width of 4 microns to 6 microns and a height of 4 microns to 6 microns, and a laser with a narrow beam is used for cutting. The first groove part 15 and the second groove part 16 are cut simultaneously from both sides to the center, and each is processed by laser for 5 times. Compared with the U-shaped trench with the same width, the number of laser processing times is reduced by 5 times. The verification results are shown in Figure 7 As shown, the front strength of the CIS chip is increased from about 2800 of the traditional U-shaped trench to about 3400 of the W-shaped trench of the present application, the cutting yield is not affected, there is no problem such as debris and internal cracking of the chip, and the product specifications and production requirements are met.

[0075] As shown in Figure 8 and Figure 9 In another embodiment, when the width of the cutting path region 13 is greater than 80 microns, the top of the island part 17 can also be kept flush with the top of the first groove part 15 or the second groove part 16. The present example forms the first groove part 15 or the second groove part 16 on both sides of the cutting blade wheel 18, which can avoid the contact between the cutting blade wheel 18 and the side edge of the chip, and avoid the damage to the side edge of the chip or the internal cracking of the chip. At the same time, since the retained island part 17 is large, compared with the traditional U-shaped trench, the number of laser processing times can be reduced to a greater extent, the accumulation of thermal effects is greatly reduced, and the production efficiency is greatly improved.

[0076] As shown in FIG. 1, in one embodiment, the width of the first slot part 15 is equal to the width of the second slot part 16; or, the width of the first slot part 15 is less than the width of the second slot part 16; or, the width of the first slot part 15 is greater than the width of the second slot part 16, to meet the chip symmetrical cutting requirement or special chip asymmetrical cutting requirement. Figure 10 As shown in FIG. 2, in another embodiment, the width of the first slot part 15 is equal to the width of the second slot part 16; or, the width of the first slot part 15 is less than the width of the second slot part 16; or, the width of the first slot part 15 is greater than the width of the second slot part 16, to meet the chip symmetrical cutting requirement or special chip asymmetrical cutting requirement. Figure 10 As shown in FIG. 3, in an example, the width of the first slot part 15 is less than the width of the second slot part 16, according to the actual cutting requirement.

[0077] As shown in FIG. 4, in another embodiment, the width of the first slot part 15 is greater than the width of the second slot part 16, according to the actual cutting requirement. Figure 3 As shown in FIG. 5, the present embodiment further provides a cutting structure, wherein the cutting structure of the present embodiment can be cut by the laser cutting method described above, and further, the subsequent cutting can be performed by a cutter wheel. The related similar features refer to the description in the above content, which will not be described here. In the present embodiment, the cutting structure comprises: a to-be-cut substrate, the to-be-cut substrate is defined with a cutting path region, the cutting path region has opposite first and second side regions; the first and second side regions of the cutting path region form the first slot part 15 and the second slot part 16, respectively, and there is at least a part of the region between the first slot part 15 and the second slot part 16 which is not processed by laser and retains an unremoved island part 17.

[0078] In one embodiment, the distance between the two outer side walls of the first slot part 15 and the second slot part 16 is greater than the width of the cutting cutter wheel used for cutting.

[0079] In one embodiment, the width of the island part 17 ranges from 5 microns to 10 microns; the height of the island part 17 ranges from less than or equal to one half of the depth of the first slot part or the second slot part, or the top of the island part 17 is flush with the top of the first slot part 15 or the second slot part 16.

[0080] As described above, the laser cutting method of the present application has the following beneficial effects:

[0081] The laser cutting method of the present application can effectively reduce the number of laser processing of the cutting path region 13, such as reducing 3-5 times than the conventional laser processing, thereby greatly reducing the accumulation of heat effect caused by laser cutting, ensuring that the chip strength meets the specification requirements, and the reduction of the number of laser processing can effectively improve the unit time production capacity (UPH) of the laser irradiation station.

[0082] The distance between the two outer walls of the first groove part 15 and the second groove part 16 is greater than the width of the cutting wheel 18, the low-k medium and the metal layer 112 on both sides of the cutting wheel 18 have been removed, and enough cutting wheel 18 offset space can be reserved, so that the actual effect of the laser cutting of the application is consistent with the traditional U-shaped groove, and the risk of cutting wheel 18 or chip debris, peeling or fragmentation is greatly avoided.

[0083] The size of the island part 17 reserved between the first groove part 15 and the second groove part 16 is small or / and the height is low, which can avoid the chip yield problem caused by cutting debris splashing.

[0084] The application can use a laser with a narrow beam for cutting, the energy of the laser is highly concentrated, and through multiple laser translations and processing time, accurate control of different groove widths, groove depths and groove types can be achieved, which is suitable for the regulation and control of different products.

[0085] When the application is laser cut, the groove is cut from both sides of the cutting path to the middle, so that the actual heat effect of the laser on the side of the chip is only 1-2 times of heat accumulation, which greatly weakens the influence of laser energy on the chip.

[0086] Therefore, the application effectively overcomes the various shortcomings in the prior art and has high industrial utilization value.

[0087] The above embodiments only exemplarily illustrate the principles and effects of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the application should be covered by the claims of the application.

Claims

1. A laser cutting method, characterized by, The laser cutting method comprises: providing a substrate to be cut, the substrate to be cut being defined with a cutting track region having opposite first and second side regions; forming first and second groove portions in the first and second side regions of the cutting track region by laser processing, and leaving an unremoved island portion in at least a part of a region between the first and second groove portions.

2. The laser cutting method according to claim 1, characterized in that, Further comprising a step of cutting the cutting track region with the first and second groove portions by a cutting wheel, a spacing between two outer side walls of the first and second groove portions being greater than a width of the cutting wheel.

3. The laser cutting method of claim 1, wherein: The substrate to be cut has a laser cutting layer, the laser cutting layer comprising a low-K dielectric layer, a metal layer, or a laminated structure composed of both, and at least one of the first and second groove portions penetrating the laser cutting layer.

4. The laser cutting method of claim 1, wherein: The island portion has a width ranging from 5 microns to 10 microns; and / or, the first groove portion has a depth ranging from 5 microns to 15 microns, and the second groove portion has a depth ranging from 5 microns to 15 microns; and / or, the first groove portion has a width equal to that of the second groove portion, or the first groove portion has a width smaller than that of the second groove portion, or the first groove portion has a width greater than that of the second groove portion.

5. The laser cutting method of claim 1, wherein: The island portion has a height less than or equal to one half of a depth of the first or second groove portion.

6. The laser cutting method of claim 1, wherein: The cutting track region has a width greater than 80 microns, and a top of the island portion is flush with a top of the first or second groove portion.

7. The laser cutting method of claim 1, wherein: The first groove portion is formed by laser processing for 1 to 8 times, and the second groove portion is formed by laser processing for 1 to 8 times.

8. The laser cutting method of claim 1, wherein: The first groove portion is formed by laser processing in a manner that a first side edge of the cutting track region is first processed by laser, and then laser is translated step by step towards a middle region of the cutting track region until the first groove portion is formed; and the second groove portion is formed by laser processing in a manner that a second side edge of the cutting track region is first processed by laser, and then laser is translated step by step towards the middle region of the cutting track region until the second groove portion is formed.

9. The laser cutting method of claim 8, wherein: Adjacent step lengths have an overlap in the process of forming the first groove portion by translating laser towards the middle region of the cutting track region; and / or, adjacent step lengths have an overlap in the process of forming the second groove portion by translating laser towards the middle region of the cutting track region.

10. The laser cutting method of claim 9, wherein: A ratio of a laser overlap width between adjacent step lengths to a laser width is 30% to 50%.

11. The laser cutting method of claim 1, wherein: The laser cutting method is applicable to an image sensor, wherein the cutting track region comprises at least one of a metal interconnection layer and a test structure.

12. The laser cutting method according to any one of claims 1 to 11, characterized in that: The first groove portion and the second groove portion have an overlap between time periods of formation.

13. A cutting structure, characterized by The laser cutting method comprises: providing a substrate to be cut, the substrate to be cut being defined with a cutting track region having opposite first and second side regions; and forming first and second groove portions in the first and second side regions of the cutting track region by laser processing, and leaving an unremoved island portion in at least a part of a region between the first and second groove portions.

14. The cutting structure of claim 13, wherein: The distance between the two outer walls of the first groove portion and the second groove portion is greater than the width of a cutting blade used for cutting.

15. The cutting structure of claim 13, wherein: The width of the island portion ranges from 5 microns to 10 microns; the height of the island portion is less than or equal to one-half of the depth of the first groove portion or the second groove portion, or the top of the island portion is flush with the top of the first groove portion or the second groove portion.

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