Cutting structure
By introducing laser cutting grooves and multi-area cutting methods into the chip cutting structure, and combining laser cutting and blade cutting, the problems of mechanical damage and thermal damage in the existing technology are solved, thereby improving the cutting yield and quality.
Patent Information
- Application Number
- CN202422957841.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2034-11-29
AI Technical Summary
Existing chip cutting methods are prone to mechanical damage, laser thermal damage and defects, and may contaminate the chip, affecting the cutting yield.
A cutting structure is adopted, including a substrate to be cut and a laser cutting groove. By defining a cutting path, a laser cutting area and a blade cutting area on the substrate, and using the laser cutting groove to remove part of the metal in advance, the separation is completed by blade cutting. This combines the advantages of laser cutting and blade cutting, reducing mechanical damage and thermal impact.
It effectively reduces mechanical damage and laser thermal damage, improves the yield of the cutting process, reduces chip surface damage caused by metal debris, and improves the overall cutting quality.
Smart Images
Figure CN223515241U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the field of semiconductor technology relates to a cutting structure. BACKGROUND
[0002] Wafer dicing is an inevitable link in the chip manufacturing process, and the prepared wafer needs to be divided into single chip die according to the preset size before chip packaging. At present, the process methods for chip cutting mainly have two kinds:
[0003] (1) Mechanical cutting, that is, using diamond blades to rotate at high speed in wafer cutting channels to obtain chips. Pure blade cutting is the most commonly used cutting method in the chip cutting field, and its advantage lies in simple and convenient operation, but with the development of the increasing thickness of the metal layer part of the chip and the complication of the pattern structure, the blade cutting also exposes corresponding shortcomings, such as the increasing thickness of the low dielectric constant (LowK) layer in the CMOS image sensor (CMOS Image Sensor, abbreviated as CIS) chip, the metal debris generated in the cutting process is easy to wrap on the diamond blade, reducing the cutting ability and causing serious edge collapse and side crack. In addition, the metal debris continuously thrown out in the blade cutting process will fall on the wafer surface, causing damage to the chip surface and reducing the final yield of the whole process.
[0004] (2) Laser cutting is a new type of chip cutting method with high precision and non-contact, which uses continuous equal-amplitude pulse waves emitted by a laser generator to ablate and gasify the metal in the cutting channel, so as to achieve the purpose of chip separation. The advantage of laser cutting is that it is non-contact with the chip surface, and no mechanical stress is introduced in the cutting process, which can effectively avoid the generation of defects such as chipping / cracking / peeling in blade cutting. However, the disadvantage of laser cutting is that the heat effect (HAZ) caused by ablation process on the chip will cause the chip strength to weaken and internal defects to occur. In addition, CIS chips have high cleanliness requirements for the surface, and laser ablation may produce molten particles on the chip sidewall, which may fall on the chip surface during packaging and cause failure.
[0005] Therefore, how to provide a cutting structure to have less mechanical damage, laser heat damage and defects after chip cutting has become an important technical problem to be solved by the technical personnel in the field.
[0006] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely describing the technical scheme of the present application and facilitating the understanding of those skilled in the art. The above technical scheme cannot be considered as known to those skilled in the art only because it is described in the part of the background of the present application. Practical new type content
[0007] In view of the above-mentioned defects of the prior art, the purpose of the present application is to provide a cutting structure for introducing a new cutting method, solving the problem that the existing cutting method is easy to cause mechanical damage or heat effect and easy to pollute the chip and cause failure.
[0008] To achieve the above-mentioned purpose and other related purposes, the present application provides a cutting structure, comprising:
[0009] The substrate to be cut includes a first surface and a second surface arranged oppositely, and is defined with a cutting path region, a laser cutting region, a first blade cutting region and a second blade cutting region. The first blade cutting region is arranged in the cutting path region, and the width of the first blade cutting region is smaller than the width of the cutting path region. The laser cutting region is arranged in the first blade cutting region, and the width of the laser cutting region is smaller than the width of the first blade cutting region. The second blade cutting region is arranged in the laser cutting region, and the width of the second blade cutting region is smaller than the width of the laser cutting region.
[0010] The laser cutting groove is located in the laser cutting region, and the laser cutting groove is opened from the first surface and extends in the direction of the second surface. The depth of the laser cutting groove is smaller than the thickness of the substrate to be cut.
[0011] Optionally, the substrate to be cut includes a substrate layer and a metal interconnection layer arranged in sequence in the direction in which the second surface points to the first surface. The laser cutting groove extends at least into the metal interconnection layer.
[0012] Optionally, the laser cutting groove extends into the substrate layer.
[0013] Optionally, the substrate to be cut includes a first substrate and a second substrate arranged in sequence and bonded to each other in the direction in which the second surface points to the first surface. The first substrate includes a first substrate layer and a first metal interconnection layer arranged in sequence in the direction in which the second surface points to the first surface. The second substrate includes a second metal interconnection layer and a second substrate layer arranged in sequence in the direction in which the second surface points to the first surface. The laser cutting groove penetrates the second substrate layer and extends at least into the second metal interconnection layer.
[0014] Optionally, the laser cutting groove extends into the first metal interconnection layer or the first substrate layer.
[0015] Optionally, the second substrate layer has a thickness less than that of the first substrate layer.
[0016] Optionally, the to-be-cut substrate is provided with a test structure in the cutting lane area, the test structure comprising at least one metal layer, and the laser cutting groove at least penetrates one of the metal layers.
[0017] Optionally, a boundary of the test structure does not exceed the laser cutting area.
[0018] Optionally, the to-be-cut substrate comprises a plurality of CIS chips, and the cutting lane area is arranged between two adjacent CIS chips, the CIS chip comprising a device structure area and a sealing ring structure area located at a periphery of the device structure area, or further comprising a virtual structure area located at a periphery of the sealing ring structure area, the sealing ring structure area being provided with a metal sealing ring structure, and the virtual structure area being provided with a virtual metal structure, a distance between a side of the virtual metal structure facing the nearest cutting lane area and an edge of the nearest cutting lane area being greater than 0.
[0019] Optionally, a center line of the first blade cutting area coincides with a center line of the laser cutting groove.
[0020] As described above, the cutting structure of the present application comprises a to-be-cut substrate and a laser cutting groove, the to-be-cut substrate comprising a first surface and a second surface arranged oppositely and defining a cutting lane area, a laser cutting area, a first blade cutting area and a second blade cutting area, the first blade cutting area being arranged in the cutting lane area, the laser cutting area being arranged in the first blade cutting area and having a width less than that of the first blade cutting area, the second blade cutting area being arranged in the laser cutting area and having a width less than that of the laser cutting area, and the laser cutting groove being located in the laser cutting area and opening from the first surface and extending towards the second surface, the depth of the laser cutting groove being less than the thickness of the to-be-cut substrate. The cutting structure of the present application has the laser cutting groove, the metal in the cutting lane area is reduced as much as possible, which is beneficial to reduce mechanical damage caused by subsequent blade cutting, and since the first blade cutting area having a width greater than that of the laser cutting area is defined, it is also beneficial to eliminate the adverse effects introduced by laser cutting, thereby effectively improving the yield of the cutting process. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 A structural schematic diagram of the cutting structure of the present application in an embodiment is shown.
[0022] Figure 2 A process flow chart of a chip cutting method is shown.
[0023] Figure 3 The chip cutting method shown is provided with a structure diagram of a substrate to be cut in an embodiment. Figure 2
[0024] Figure 4 The chip cutting method shown is provided with a structure diagram of a substrate to be cut in another embodiment. Figure 2
[0025] Figure 5 The chip cutting method shown is provided with a diagram of ablation of the material in the laser cutting area by the laser generator emitting continuous equal-amplitude pulse waves in an embodiment. Figure 2
[0026] Figure 6 The chip cutting method shown is provided with a diagram of the structure obtained after forming the laser cutting groove in an embodiment. Figure 2
[0027] Figure 7 The chip cutting method shown is provided with a diagram of blade cutting in an embodiment. Figure 2
[0028] Figure 8 The chip cutting method shown is provided with a diagram of the width of the first blade and the width of the laser cutting groove in an embodiment. Figure 2
[0029] Figure 9 The chip cutting method shown is provided with a diagram of the structure obtained after forming the first blade cutting groove in an embodiment. Figure 2
[0030] Figure 10 The chip cutting method shown is provided with a diagram of the structure obtained after forming the second blade cutting groove in an embodiment. Figure 2
[0031] Figure 11 The chip cutting method shown is provided with a diagram of the width of the first blade, the width of the second blade and the width of the laser cutting groove used in a comparative example.
[0032] Figure 12 The chip cutting method shown is provided with a diagram of the relative positions of the first blade, the second blade and the substrate to be cut in a comparative example. Figure 11
[0033] Figure 13 The chip cutting method shown is provided with a diagram of the relative positions of the first blade, the second blade and the substrate to be cut in a comparative example.
[0034] Figure 14 A schematic view of the resulting structure after two blade cuts to separate the dies.
[0035] Figure 15 A chipping defect is shown.
[0036] Figure 16 A peeling defect is shown.
[0037] Figure 17 A void defect is shown.
[0038] Figure 18 A peeling defect is shown.
[0039] Figure 19 A topography view of a die sidewall using a die cutting method with the cutting structure of the present application is shown.
[0040] Figure 20 A topography view of a die sidewall using a pure blade cutting method is shown.
[0041] BRIEF DESCRIPTION OF DRAWINGS
[0042] 100 substrate to be cut
[0043] 101 first surface
[0044] 102 second surface
[0045] 103 base layer
[0046] 104 metal interconnect layer
[0047] 1041 dielectric layer
[0048] 1042 metal wiring layer
[0049] 105 first substrate
[0050] 1051 first base layer
[0051] 1052 first metal interconnect layer
[0052] 106 second substrate
[0053] 1061 second metal interconnect layer
[0054] 1062 second base layer
[0055] 107 test structure
[0056] 108 metal seal ring structure
[0057] 109 virtual metal structure
[0058] 110, 110a laser cutting groove
[0059] 111 first blade cutting groove
[0060] 112 second blade cutting groove
[0061] 200 laser generator
[0062] 300, 300a, 300b first blade
[0063] 400, 400a, 400b second blade
[0064] S1-S4 steps
[0065] A cutting path region
[0066] B laser cutting region
[0067] C first blade cutting region
[0068] D second blade cutting region
[0069] E device structure region
[0070] F sealing ring structure region
[0071] G virtual structure region DETAILED DESCRIPTION
[0072] The above embodiments of the present application are described with reference to specific examples. However, the present application is not limited to the above examples, and various modifications and changes can be made thereto without departing from the spirit and scope of the present application. It should be understood that the present application can be practiced with modification and change by persons having the benefit of the benefit of this disclosure without departing from the spirit and scope of the present application.
[0073] It should be emphasized that the term "comprises / comprising" when used in this specification is taken to mean the presence of stated features, integers, steps or components but not to the exclusion of one or more other features, integers, steps, components or groups thereof.
[0074] Features described and / or illustrated with respect to one embodiment can be used in the same or similar manner in one or more other embodiments, in combination with or in place of features of other embodiments, or in place of or in addition to features of the other embodiments.
[0075] As described in the detailed description of the embodiments of the present application, the schematic diagrams showing the structure of the device are partially enlarged without the general scale for the convenience of description, and the schematic diagrams are only examples, which should not limit the scope of protection of the present application. In addition, three-dimensional spatial dimensions including length, width and depth should be included in actual manufacturing.
[0076] For convenience in description, spatially relative terms such as "beneath", "below", "lower", "bottom", "above", "upper" and the like can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a layer overlies another layer, it can be the only layer between the two layers or one or more intervening layers can also be present. Moreover, when a layer is referred to as being "on" or "under" another layer, it can be directly on or under the other layer, or one or more intervening layers can also be present.
[0077] In the context of this application, a structure described as having a first feature "on" a second feature can include embodiments in which the first and second features form direct contact, as well as embodiments in which additional features are formed between the first and second features, such that the first and second features can not be in direct contact.
[0078] It should be noted that the drawings provided in the embodiments of the present application only schematically illustrate the basic concept of the present application, and only the components related to the present application are shown in the drawings, rather than being drawn according to the number, shape and size of the components in actual implementation. The shape, number and proportion of each component in actual implementation can be arbitrarily changed, and the layout pattern of the components can be more complex.
[0079] The utility model provides a kind of cutting structure, please refer to Figure 1 , it is shown as the structure schematic diagram of the cutting structure in an embodiment, including to be cut substrate 100 and laser cutting groove 110, wherein, the to be cut substrate 100 includes oppositely arranged first surface 101 and second surface 102, the to be cut substrate defines cutting path area A, laser cutting area B, first blade cutting area C and second blade cutting area D, the first blade cutting area C is arranged in the cutting path area A and the width of the first blade cutting area C is less than the width of the cutting path area A, the laser cutting area B is arranged in first blade cutting area C and the width of the laser cutting area B is less than the width of the first blade cutting area C, second blade cutting area D is arranged in the laser cutting area B and the width of the second blade cutting area D is less than the width of the laser cutting area B, the laser cutting groove 110 is located in the laser cutting area B, the laser cutting groove 110 is opened from the first surface 102 and extends to the second surface 102 direction, the depth of the laser cutting groove 110 is less than the thickness of the to be cut substrate 100.
[0080] In some embodiments, the substrate to be cut 100 comprises a base layer 103 and a metal interconnection layer 104 arranged in sequence in a direction that the second surface 102 points to the first surface 101, and the laser cutting groove 110 extends at least into the metal interconnection layer 104, for example further extends into the base layer 103.
[0081] In some embodiments, the substrate to be cut 100 comprises a first substrate and a second substrate (not shown) arranged in sequence and bonded to each other in a direction that the second surface points to the first surface 101, the first substrate comprises a first base layer and a first metal interconnection layer arranged in sequence in a direction that the second surface points to the first surface, the second substrate comprises a second metal interconnection layer and a second base layer arranged in sequence in a direction that the second surface points to the first surface, and the laser cutting groove 110 extends through the second base layer and at least into the second metal interconnection layer, for example further extends into the first metal interconnection layer or the first base layer.
[0082] In some embodiments, the thickness of the second base layer is less than the thickness of the first base layer.
[0083] In some embodiments, the substrate to be cut 100 is provided with a test structure (not shown) in the cutting lane area A, the test structure comprises at least one metal layer, and the laser cutting groove 110 extends at least through one of the metal layers.
[0084] In some embodiments, the boundary of the test structure does not exceed the laser cutting area.
[0085] In some embodiments, the substrate to be cut comprises a plurality of CIS chips, and the cutting lane area is arranged between two adjacent CIS chips, the CIS chip comprises a device structure area and a sealing ring structure area located at the periphery of the device structure area, or further comprises a virtual structure area located at the periphery of the sealing ring structure area, the sealing ring structure area is provided with a metal sealing ring structure, and the virtual structure area is provided with a virtual metal structure, and the distance between the side edge of the virtual metal structure facing the nearest cutting lane area and the edge of the nearest cutting lane area is greater than 0.
[0086] In some embodiments, the center line of the first blade cutting area coincides with the center line of the laser cutting groove.
[0087] The cutting structure of the utility model has the laser cutting groove, the metal of the cutting lane area has been reduced as far as possible, is favorable for reducing the mechanical damage caused by subsequent blade cutting, and because the first blade cutting area with the width greater than the laser cutting area is defined, it is also favorable for subsequent elimination of the adverse effects introduced by laser cutting, and effective improvement of the yield of the cutting process is realized.
[0088] A chip cutting method suitable for the cutting structure of the present application is introduced below to explain the forming process of the cutting structure of the present application and the subsequent cutting process, so as to more intuitively show the improvement of the cutting structure of the present application on the cutting quality.
[0089] Please refer to Figure 2 , which is shown as a process flow chart of a chip cutting method, including the following steps:
[0090] S1: providing a to-be-cut substrate, the to-be-cut substrate including oppositely arranged first and second surfaces, the to-be-cut substrate being defined with a cutting path region, a laser cutting region, a first blade cutting region and a second blade cutting region, the first blade cutting region being arranged in the cutting path region and the width of the first blade cutting region being smaller than the width of the cutting path region, the laser cutting region being arranged in the first blade cutting region and the width of the laser cutting region being smaller than the width of the first blade cutting region, the second blade cutting region being arranged in the laser cutting region and the width of the second blade cutting region being smaller than the width of the laser cutting region;
[0091] S2: laser cutting the to-be-cut substrate to form a laser cutting groove in the laser cutting region, the laser cutting groove being open from the first surface and extending towards the second surface, the depth of the laser cutting groove being smaller than the thickness of the to-be-cut substrate;
[0092] S3: providing a first blade, the width of the first blade being equal to the width of the first blade cutting region, aligning the edge of the first blade with the edge of the first blade cutting region, and mechanically cutting the to-be-cut substrate from the first surface to obtain a first blade cutting groove in the first blade cutting region, the depth of the first blade cutting groove being smaller than the thickness of the to-be-cut substrate and greater than the depth of the laser cutting groove;
[0093] S4: providing a second blade, the width of the second blade being equal to the width of the second blade cutting region, aligning the edge of the second blade with the edge of the second blade cutting region, and mechanically cutting the to-be-cut substrate from the bottom surface of the first blade cutting groove to obtain a second blade cutting groove in the second blade cutting region, the second blade cutting groove penetrating through the second surface.
[0094] The above steps are described in detail below in combination with the structural diagram.
[0095] First, please refer to Figure 3The following steps are performed: A substrate 100 to be cut is provided. The substrate 100 includes a first surface 101 and a second surface 102 disposed opposite to each other. The substrate to be cut defines a cutting track region A, a laser cutting region B, a first blade cutting region C, and a second blade cutting region D. The first blade cutting region C is disposed within the cutting track region A and the width of the first blade cutting region C is smaller than the width of the cutting track region A. The laser cutting region B is disposed within the first blade cutting region C and the width of the laser cutting region B is smaller than the width of the first blade cutting region C. The second blade cutting region D is disposed within the laser cutting region B and the width of the second blade cutting region D is smaller than the width of the laser cutting region B.
[0096] Specifically, the cutting area A serves as the cutting area, wherein the laser cutting area B is used to form a laser cutting groove, the first blade cutting area C is used to form a first blade cutting groove, and the second blade cutting area D is used to form a second blade cutting groove, which will be described in detail in subsequent steps.
[0097] As an example, in Figure 3 In the illustrated embodiment, the substrate 100 to be cut includes a base layer 103 and a metal interconnect layer 104 sequentially disposed in the direction from the second surface 102 to the first surface 101. The laser cutting groove formed subsequently will extend at least into the metal interconnect layer 104. For example, in a preferred embodiment, the laser cutting groove will extend into the base layer 103, thereby minimizing the amount of metal that the blade needs to remove during the subsequent first blade cutting operation, thereby reducing the generation of metal chips during the blade cutting process, reducing the load on the first blade during the cutting process, and achieving the effect of reducing the occurrence of damage during blade cutting and improving the cutting process yield.
[0098] As an example, the substrate 103 may include a silicon substrate, a germanium substrate, a germanium-silicon substrate, a silicon carbide substrate, a III-V compound substrate (such as gallium nitride, gallium arsenide, etc.), or a composite substrate such as silicon-on-insulator (SOI), germanium-on-insulator (GOI), germanium-silicon-on-insulator. The substrate 103 may be doped or undoped, and may contain doped regions of various concentrations or electrical types to achieve different functions. The required electronic components may be fabricated in the substrate 103. The types and configurations of materials of the substrate 103 are not limited to the examples listed above.
[0099] As an example, the metal interconnection layer 104 can include a dielectric layer 1041 and at least one metal wiring layer 1042 embedded in the dielectric layer 1041, when the metal interconnection layer 104 contains multiple layers of the metal wiring layer 1042, two adjacent layers of the metal wiring layer 1042 can be electrically connected by a metal via (not shown). The dielectric layer 1041 can be made of silicon oxide, low-K dielectric, or other suitable material, the low-K dielectric can be, for example, fluorine-doped silicon oxide, carbon-doped silicon oxide, etc., the metal wiring layer 1042 or the metal via can be made of, for example, copper, aluminum, tungsten, titanium, titanium nitride, gold, platinum, etc.
[0100] In some other embodiments, the substrate to be cut 100 can also be a multi-layer stacked substrate, for example, please refer to Figure 4 , which shows a structural schematic diagram of the substrate to be cut 100 in another embodiment, which adopts a double-layer stacked substrate, including a first substrate 105 and a second substrate 106 arranged in sequence and bonded to each other in the direction of the second surface 102 pointing to the first surface 101, it should be noted that, Figure 4 in the example shown, the description of the direction in Figure 3 the example shown can be used, "in the direction of the second surface 102 pointing to the first surface 101" corresponds to the understanding that the lower surface of the substrate to be cut 100 points to the direction of the upper surface; the first substrate 105 includes a first base layer 1051 and a first metal interconnection layer 1052 arranged in sequence in the direction of the second surface 102 pointing to the first surface 101, the second substrate 106 includes a second metal interconnection layer 1061 and a second base layer 1062 arranged in sequence in the direction of the second surface 102 pointing to the first surface 101, the subsequently formed laser cutting groove will penetrate the second base layer 1062 and extend at least into the second metal interconnection layer 1061, for example, in a preferred embodiment, the laser cutting groove will extend into the first metal interconnection layer 1052, in another preferred embodiment, the laser cutting groove will extend into the first base layer 1051.
[0101] As an example, the thickness of the second base layer 1062 is less than the thickness of the first base layer 1051.
[0102] As an example, the substrate to be cut 100 is provided with a test structure 107 in the cutting path area A, the test structure 107 includes at least one metal layer, and the subsequently formed laser cutting groove will at least penetrate one layer of the metal layer. For example, in a preferred embodiment, the laser cutting groove will penetrate all metal layers of the test structure 107.
[0103] As an example, the boundary of the test structure 105 does not exceed the laser cutting area B.
[0104] As an example, the substrate to be cut includes a plurality of CIS chips, and the cutting groove region A is arranged between two adjacent CIS chips, Figure 4 As an example, the CIS chip includes a device structure region E, a sealing ring structure region F arranged at the periphery of the device structure region E, and a virtual structure region G arranged at the periphery of the sealing ring structure region F in a further example. The sealing ring structure region F is provided with a metal sealing ring structure 108, and the virtual structure region G is provided with a virtual metal structure 109. The distance between the virtual metal structure 109 and the edge of the nearest cutting groove region A is greater than 0, and the virtual metal structure 109 is used to block the stress transmission to the device structure region E during cutting.
[0105] As an example, the substrate to be cut includes a plurality of CIS chips, and the cutting groove region A is arranged between two adjacent CIS chips, Figure 5 As an example, the substrate to be cut includes a plurality of CIS chips, and the cutting groove region A is arranged between two adjacent CIS chips, Figure 6 The step S2 is performed: laser cutting the substrate to be cut 100 to form a laser cutting groove 110 in the laser cutting region B, the laser cutting groove 110 is opened from the first surface 102 and extends to the second surface 102, the depth of the laser cutting groove 110 is less than the thickness of the substrate to be cut 100, and the laser cutting groove 110 is arranged in the cutting groove region A. Figure 5 As an example, the substrate to be cut includes a plurality of CIS chips, and the cutting groove region A is arranged between two adjacent CIS chips, Figure 6 As an example, the substrate to be cut includes a plurality of CIS chips, and the cutting groove region A is arranged between two adjacent CIS chips,
[0106] Specifically, the purpose of the laser cutting in this step is to remove part or all of the metal in the blade cutting region in advance, reduce or eliminate the generation of metal chips in the subsequent blade cutting process, thereby reducing the load in the subsequent blade cutting process, reducing the generation of defects such as corner collapse, cracks, and peeling caused by blade cutting, and reducing or eliminating the problem of metal debris falling on the wafer surface causing damage to the chip surface.
[0107] Specifically, the specific depth of the laser cutting groove 110 can be set according to the specific layer structure of the substrate to be cut 100, for example, for a substrate to be cut 100 in which Figure 3 As an example, the substrate to be cut includes a plurality of CIS chips, and the cutting groove region A is arranged between two adjacent CIS chips, Figure 4The laser cutting slot 110 can penetrate the second base layer 1062 and extend into the second metal interconnection layer 1061 to remove part of the metal layer, can further extend into the first metal interconnection layer 1052 to remove more metal layer, and can further extend into the first base layer 1051 to remove as much metal layer as possible.
[0108] Referring back to Figures 7 to 9 , the step S3 is performed: providing a first blade 300, the width of the first blade 300 being equal to the width of the first blade cutting area C, aligning the edge of the first blade 300 with the edge of the first blade cutting area C, and mechanically cutting the to-be-cut substrate 100 from the first surface 101 to obtain a first blade cutting slot 111 in the first blade cutting area C, the depth of the first blade cutting slot 111 being less than the thickness of the to-be-cut substrate 100 and greater than the depth of the laser cutting slot 110, wherein, Figure 7 a schematic diagram of blade cutting is shown, Figure 8 a comparison diagram of the width of the first blade 300 and the width of the laser cutting slot 110 is shown, Figure 9 a schematic diagram of the structure obtained after cutting the first blade cutting slot 111 is shown.
[0109] Specifically, after the laser cutting slot 110 is preliminarily obtained, blade cutting is performed, and the main purpose is to reduce the thermal effect (HAZ) of the ablation process of laser cutting on the chip, and prevent the chip from weakening in strength and increasing in internal defects caused by the thermal effect.
[0110] Specifically, since the metal of the first blade cutting area C has been removed to a certain extent or most of it has been removed by the previous laser cutting step, the generation of metal chips will be greatly reduced in the blade cutting process of this step, thereby reducing or eliminating the chip yield problem caused by the splashing of cutting debris, and the blade load can also be reduced, which helps to reduce the generation of defects such as corner collapse, cracks, and peeling caused by blade cutting.
[0111] Specifically, as shown in Figure 8 , since the width of the laser cutting area B is less than the width of the first blade cutting area C, and the width of the first blade 300 is equal to the width of the first blade cutting area C and the edge of the first blade 300 is aligned with the edge of the first blade cutting area C, the first blade 300 can cover the laser cutting slot 110 during the cutting process, thereby effectively removing the molten particles that may be generated on the sidewall of the laser cutting slot 110 in the laser ablation process.
[0112] As an example, the width range between the first blade kerf 111 and the sidewall of the same side of the laser kerf 110 is 5-15 microns, for example 8 microns, 10 microns, 12 microns, etc.
[0113] In some embodiments, the center line of the first blade kerf 111 coincides with the center line of the laser kerf 110, that is, the mechanical cutting with the first blade 300 is concentric cutting relative to the laser kerf 110.
[0114] Specifically, the depth of the first blade kerf 111 is less than the thickness of the to-be-cut substrate 100 and greater than the depth of the laser kerf 110, that is, in the final structure, there will be no trace of the laser kerf 110, and a pure blade cutting kerf and sidewall can be obtained, eliminating the sidewall sintering and other adverse effects introduced by laser cutting, and the first blade kerf 111 does not completely penetrate the to-be-cut substrate 100, which can prepare for the next precise cutting, so as to ensure the accuracy and quality of the cutting edge.
[0115] As an example, the distance between the plane where the bottom surface of the laser kerf 110 is located and the plane where the bottom surface of the first blade kerf 111 is located is D1, and the distance between the plane where the bottom surface of the laser kerf 110 is located and the second surface 102 is D2, wherein the range of D1 / D2 is 1 / 3-1 / 2.
[0116] Again, referring to Figure 10 , the step S4 is performed: providing a second blade 400, the width of the second blade 400 is equal to the width of the second blade cutting area D, aligning the edge of the second blade 400 with the edge of the second blade cutting area D, and mechanically cutting the to-be-cut substrate 100 from the bottom surface of the first blade kerf 111 to obtain a second blade kerf 112 in the second blade cutting area D, the second blade kerf 112 penetrates the second surface 102.
[0117] In some embodiments, the center line of the second blade kerf 112 coincides with the center line of the first blade kerf 111.
[0118] So far, the discrete chips are cut by the laser cutting step, the first blade cutting step and the second blade cutting step in sequence. Since the laser cutting removes part or all of the metal in the blade cutting area in advance, the cutting capacity of the subsequent blade cutting can be improved and the chip surface damage caused by metal debris can be reduced. In addition, the first blade with a width greater than the width of the laser cutting groove can eliminate the side wall sintering and other adverse effects introduced by the laser cutting. That is, the chip cutting method of the cutting structure of the utility model combines the advantages of laser cutting and blade cutting, while avoiding the problems caused by the two cutting methods, which is beneficial to improve the yield of the cutting process.
[0119] As an example, a pair of examples is provided, please refer to Figure 11 and Figure 12 , wherein, Figure 11 The contrast diagram of the width of the first blade 300a, the width of the second blade 400a and the width of the laser cutting groove 110a used in the pair of examples is shown, Figure 12 The schematic diagram of the structure obtained after cutting the discrete chips in the above-mentioned pair of examples is shown. In the pair of examples, since the width of the laser cutting groove 110a is greater than the width of the first blade 300a, the first blade 300a does not contact the side wall of the laser cutting groove 110a during cutting. The side wall of the laser cutting groove 110a is still retained in the final structure, so that the molten particles that may exist on the side wall of the laser cutting groove 110a may fall on the chip surface during packaging and cause failure. Figure 9 and Figure 10 As shown, in the chip cutting method of the cutting structure of the utility model, the first blade 300 can cover the laser cutting groove 110 during cutting, so that the molten particles that may be generated on the side wall of the laser cutting groove 110 during laser ablation can be effectively removed. There will be no trace of the laser cutting groove 110 in the final structure, and the groove and the side wall of the pure blade cutting can be obtained, and the side wall sintering and other adverse effects introduced by the laser cutting can be eliminated.
[0120] As an example, a pair of examples is provided, please refer to Figure 13 and Figure 14 , wherein, Figure 13 The relative position schematic diagram of the first blade 300b, the second blade 400b and the substrate to be cut used in the pair of examples of pure blade cutting is shown, Figure 14 The schematic diagram of the structure obtained after cutting the discrete chips by two times of blade cutting is shown.
[0121] Please refer to Figures 15 to 18 , which shows several defect diagrams caused by the above two pairs of examples, wherein,Figure 15 shows a chipping defect, Figure 16 shows a peeling defect, Figure 17 shows a void defect, Figure 18 shows a peeling defect.
[0122] According to an embodiment of the present application, the chip cutting method adapted to the cutting structure of the present application is implemented on a 5000 million pixel (50MP) stacked wafer. The results show that, compared with the pure blade cutting method, the cutting method adapted to the cutting structure of the present application can improve the overall yield by about 1.6%, and can reduce the damage introduced in the process by about 2%.
[0123] Specifically, by observing the side wall morphology of the working chip through optical microscope (OM) and scanning electron microscope (SEM), it is found that the chip morphology appearance using the cutting method adapted to the cutting structure of the present application has no laser mark and sintered material attachment, and basically keeps consistent with the side wall morphology of pure knife cutting. For example, please refer to Figure 19 and Figure 20 wherein, Figure 19 shows the morphology diagram of the chip side wall using the chip cutting method adapted to the cutting structure of the present application, Figure 20 shows the morphology diagram of the chip side wall using the pure knife cutting method, and it can be seen that the two are basically consistent.
[0124] Specifically, by collecting the 5S data and three-point bending strength data of the working chip using the chip cutting method with the cutting structure of the utility model and comparing them with the data of the pure knife-cut chip, it is found that the 5S data of the working chip is better than that of the pure knife-cut chip, while the chip strength remains consistent with that of the pure knife-cut chip. This result shows that using a blade width greater than the width of the laser cutting groove can eliminate the adverse effects caused by laser cutting. Among them, 5S refers to a site management method in the field of semiconductor manufacturing and chip production, which originated in Japan and is mainly used to improve and maintain the order and cleanliness of the workplace to improve efficiency and quality. 5S represents the first letters of five Japanese words: Seiri (organize), Seiton (tidy), Seiso (clean), Seiketsu (clean) and Shitsuke (discipline). These principles help reduce waste, improve production efficiency and product quality, and create a safer working environment. Three-point bending strength, also known as bending strength, refers to the maximum stress a material can withstand before breaking when bent. In the chip field, three-point bending strength is often used to evaluate the mechanical strength and reliability of chips. During testing, the sample is placed on two support points and a load is applied in the middle of the two support points to simulate the bending conditions the material may encounter in actual use. For chips, this test helps evaluate their resistance to mechanical stress during manufacturing and use, especially the bending loads that may be encountered during packaging and transportation. Through three-point bending tests, the maximum load and breaking strength of the chip material can be determined to ensure the durability and reliability of the chip.
[0125] Specifically, the back corner (back corner) data can be part of the three-point bending strength data, as the back corner is a region where stress may concentrate and is more prone to breaking. By controlling the back corner, the overall mechanical strength and reliability of the chip can be improved, resulting in better performance in three-point bending tests. Back corner is usually caused by mechanical stress during cutting, related to cutting tools, cutting speed, cutting angle, material hardness, etc. The presence of the back corner may affect the mechanical strength and electrical performance of the chip, especially during packaging and use, which may further deteriorate, leading to chip breakage or circuit damage.
[0126] As an example, the back corner of a 50MP CMOS sensor chip was used to compare the effects of two cutting methods on chip strength. Please refer to Table 1 and Table 2, where Table 1 is the back corner (back corner) data of the pure knife-cut chip, and Table 2 is the back corner (back corner) data of the chip using the chip cutting method with the cutting structure of the utility model.
[0127] Table 1 Back corner data of pure knife-cut chip
[0128]
[0129] Table 2 back break data of the chip cut by the chip cutting method adapting the cutting structure of the utility model
[0130]
[0131] It can be seen from the data in Table 1 and Table 2 that in the three thickness ranges of 30-75 microns, 75-100 microns and 100 microns or more, the back break phenomenon of the pure knife cutting chip and the chip cut by the chip cutting method adapting the cutting structure of the utility model is effectively controlled, and no back break occurs. However, for the pure knife cutting chip, the average back break value is 4.53 microns, and the maximum back break value is 25 microns. For the chip cut by the chip cutting method adapting the cutting structure of the utility model, the average back break value is 0.06 microns, and the maximum back break value is 2.5 microns. It can be seen that compared with the pure knife cutting chip, the average back break value and the maximum back break value of the chip cut by the chip cutting method adapting the cutting structure of the utility model are greatly reduced, indicating that the chip cutting method adapting the cutting structure of the utility model performs better in controlling back break.
[0132] In summary, the cutting structure of the utility model includes a to-be-cut substrate and a laser cutting groove. The to-be-cut substrate includes a first surface and a second surface arranged opposite to each other and defines a cutting path area, a laser cutting area, a first blade cutting area, and a second blade cutting area. The first blade cutting area is arranged in the cutting path area. The laser cutting area is arranged in the first blade cutting area and has a width smaller than that of the first blade cutting area. The second blade cutting area is arranged in the laser cutting area and has a width smaller than that of the laser cutting area. The laser cutting groove is located in the laser cutting area and opens from the first surface and extends towards the second surface. The depth of the laser cutting groove is smaller than the thickness of the to-be-cut substrate. The cutting structure of the utility model has a laser cutting groove, and the metal in the cutting path area is reduced as much as possible, which is beneficial to reduce mechanical damage caused by subsequent blade cutting. In addition, the first blade cutting area with a width larger than that of the laser cutting area is also beneficial to eliminate the adverse effects introduced by laser cutting, thereby effectively improving the yield of the cutting process. Therefore, the utility model effectively overcomes the shortcomings of the prior art and has high industrial utilization value.
[0133] The above embodiments only exemplarily illustrate the principles and effects of the utility model, and are not used to limit the utility model. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the utility model. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the utility model should be covered by the claims of the utility model.
Claims
1. A cutting structure, characterized by, The application relates to a cutting substrate, comprising a first surface and a second surface arranged oppositely, wherein the cutting substrate defines a cutting path region, a laser cutting region, a first blade cutting region and a second blade cutting region, the first blade cutting region is arranged in the cutting path region and the width of the first blade cutting region is smaller than the width of the cutting path region, the laser cutting region is arranged in the first blade cutting region and the width of the laser cutting region is smaller than the width of the first blade cutting region, the second blade cutting region is arranged in the laser cutting region and the width of the second blade cutting region is smaller than the width of the laser cutting region. A laser cutting groove is arranged in the laser cutting region, the laser cutting groove is open from the first surface and extends towards the second surface, and the depth of the laser cutting groove is smaller than the thickness of the cutting substrate. The cutting substrate comprises a base layer and a metal interconnection layer arranged in sequence from the second surface to the first surface, and the laser cutting groove extends into the metal interconnection layer.
2. The cutting structure of claim 1, wherein: The laser cutting groove extends into the base layer.
3. The cutting structure of claim 2, wherein: The cutting substrate comprises a first substrate and a second substrate arranged in sequence and bonded to each other from the second surface to the first surface, the first substrate comprises a first base layer and a first metal interconnection layer arranged in sequence from the second surface to the first surface, the second substrate comprises a second metal interconnection layer and a second base layer arranged in sequence from the second surface to the first surface, and the laser cutting groove extends through the second base layer and into the second metal interconnection layer.
4. The cutting structure of claim 1, wherein: The laser cutting groove extends into the first metal interconnection layer or the first base layer.
5. The cutting structure of claim 4, wherein: The thickness of the second base layer is smaller than the thickness of the first base layer.
6. The cutting structure of claim 4, wherein: The cutting substrate is provided with a test structure in the cutting path region, the test structure comprises at least one metal layer, and the laser cutting groove extends through at least one metal layer.
7. The cutting structure of claim 1, wherein: The boundary of the test structure does not exceed the laser cutting region.
8. The cutting structure of claim 7, wherein: The cutting substrate comprises a plurality of CIS chips, the cutting path region is arranged between two adjacent CIS chips, the CIS chip comprises a device structure region and a sealing ring structure region arranged at the periphery of the device structure region, or further comprises a virtual structure region arranged at the periphery of the sealing ring structure region, the sealing ring structure region is provided with a metal sealing ring structure, the virtual structure region is provided with a virtual metal structure, and the distance between the side edge of the virtual metal structure facing the nearest cutting path region and the edge of the nearest cutting path region is greater than 0.
9. The cutting structure of claim 1, wherein: The center line of the first blade cutting region coincides with the center line of the laser cutting groove.
10. The cutting structure of claim 1, wherein: