Chip sealing ring structure for reducing stress and warping of adapter plate

Abstract

The invention relates to a chip sealing ring structure for reducing stress and warping of an adapter plate, which comprises a rewiring layer for forming wafer chips and a cutting channel for cutting and separating the wafer chips, a sealing ring region is formed by the outer side of the rewiring layer and the inner side of the cutting channel, and a closed metal ring is embedded in the sealing ring region along the circumferential direction; the metal ring is composed of a plurality of end-to-end line segments or a plurality of end-to-end arc lines in the circumferential direction, and an included angle larger than 90 degrees is formed between every two adjacent line segments. The cross section of the metal ring comprises a plurality of metal layers which are vertically arranged at intervals, and the adjacent metal layers are connected with each other; by changing the morphology of the metal ring and transferring the single-point stress between the metal and the medium, the stress is uniformly distributed along a curve or a broken line, so that the stress and warping caused by mismatching of thermal expansion coefficients are effectively relieved, the problems of warping and cracking and layering of the sealing ring are solved, and the reliability and stability of packaging are greatly ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor chip packaging, and in particular to a chip sealing ring structure for reducing stress and warping of an adapter plate. Background Art

[0002] In 2.5D / 3D packaging technology, the warping of the organic adapter board caused by the mismatch of the coefficient of thermal expansion (CTE) between different materials is an urgent problem to be solved. It not only affects the packaging quality, but also may cause mechanical stress concentration problems, reducing the reliability and life of the product. On the organic adapter board, the sealing ring structure composed of the overlapping passivation layer and the metal layer can be used as a stress buffer structure to help alleviate stress concentration and package cracking caused by temperature changes or mechanical stress during cutting, and enhance the mechanical strength of the package.

[0003] In the existing organic adapter board design, the metal layer morphology of the sealing ring usually adopts a straight frame design, such as Figure 1 As shown, the stress will be concentrated on the interface between the metal and the medium, which will easily cause cracking and delamination of the sealing ring and cannot effectively alleviate the warping of the adapter plate.

[0004] Therefore, there is a need for a sealing ring structure design that introduces a stress release structure to absorb and disperse the interface stress, reduce the warping of the adapter plate and the cracking and delamination of the sealing ring. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a chip sealing ring structure with a reasonable structure for reducing the stress and warping of the adapter plate, thereby effectively alleviating the stress and warping caused by the mismatch of thermal expansion coefficients, solving the problems of warping and cracking and delamination of the sealing ring, and greatly ensuring the reliability and stability of the package.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A chip sealing ring structure for reducing stress and warping of an adapter plate comprises a redistribution layer constituting a wafer chip and a cutting path for cutting and separating each wafer chip, wherein an area located outside the redistribution layer and inside the cutting path constitutes a sealing ring area, wherein a closed metal ring is buried in the sealing ring area along the circumferential direction; the metal ring is constituted by a plurality of line segments connected end to end or a plurality of arcs connected end to end along the circumferential direction, and an angle greater than 90° is formed between adjacent line segments; the cross section of the metal ring comprises a plurality of metal layers with upper and lower spacing layers, and adjacent metal layers are interconnected.

[0008] As a further improvement of the above technical solution:

[0009] The sealing ring region includes a plurality of passivation layers which are layered upward from the base, and the metal ring is buried in the plurality of passivation layers.

[0010] An interconnection hole is provided on the passivation layer between adjacent metal layers, and metal is filled in the interconnection hole to interconnect adjacent metal layers.

[0011] Adjacent interconnected holes are staggered in the vertical direction, and the interconnected holes on the same vertical cross section of the metal ring are orderly arranged into two rows in the vertical direction.

[0012] The ratio of the distance between two rows of interconnection holes to the width of the metal layer is greater than 1:5.

[0013] The bottom metal layer is located above the bottom passivation layer, the bottom surface of the top metal layer is attached to the bottom surface of the top passivation layer, and there is a distance between the top surface of the top metal layer and the top surface of the top passivation layer.

[0014] The thickness of the bottom metal layer is greater than that of other metal layers, and the thicknesses of other metal layers except the bottom metal layer are the same; the thickness ratio of the bottom metal layer to other metal layers is 2:1.

[0015] The thickness of the passivation layer is thicker than the thickness of the corresponding metal layer in the layer, and the thickness of the bottom passivation layer is thicker than the thickness of other passivation layers; the thickness of the passivation layer provided with the bottom metal layer and the top metal layer is 2-3 microns thicker than the thickness of other passivation layers.

[0016] The sealing ring area is formed by repeated operations of coating, exposure, development, hard baking and curing, and electroplating of dielectric materials and metals to form a stacked structure of a passivation layer and a metal layer, forming a sealing ring area in which a metal ring is buried in the passivation layer.

[0017] The metal ring is a wavy structure composed of a plurality of arcs connected end to end along the circumferential direction, the arc directions of adjacent arcs on the straight sides are opposite, and the adjacent arcs at the corners together form an outward convex structure.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The structure of the present invention changes the metal ring morphology, introduces a stress release structure, and transfers the single-point stress between the metal and the medium, so that the stress is evenly distributed along a curve or a broken line, thereby effectively alleviating the stress concentration around the sealing ring, relieving the stress and warping caused by the mismatch of thermal expansion coefficients, solving the problems of warping, cracking and delamination of the sealing ring, and greatly ensuring the reliability and stability of the package;

[0020] The present invention also includes the following advantages:

[0021] The spring-like structure is constructed by the metal layer and the passivation layer. During the high and low temperature cycle, the deformation can be controlled within the plane, and the stress is transferred through the tension and compression within the plane to avoid warping and reduce the warping of the adapter plate, effectively preventing the cracking and delamination of the sealing ring;

[0022] By arranging a closed metal ring along the circumference of the sealing ring area, the closed ring structure can prevent water vapor and chemical substances from entering the package body, thereby enhancing the reliability of the package body. On the other hand, the metal ring can block the mechanical force generated during cutting to prevent the chip from being damaged by the mechanical force. By forming a spring-like structure in the cross section of the metal ring, the deformation can be locked in the plane during the temperature cycle, achieving stress transfer and reducing the warping of the adapter plate.

[0023] The interconnection holes are staggered in the vertical direction to form two rows, and the positions of the interconnection holes in two adjacent layers are staggered and do not completely overlap, so as to avoid stress concentration caused by direct metal stacking, which may lead to fracture of the passivation layer after solidification. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the layout of existing metal rings.

[0025] Figure 2 Schematic diagram of the layout of the metal ring of the present invention (Example 1).

[0026] Figure 3 Schematic diagram of the layout of the metal rings of the present invention (Example 2).

[0027] Figure 4 Schematic diagram of the layout of the metal rings of the present invention (Example 3).

[0028] Figure 5 It is a structural schematic diagram of the cross section of the metal ring of the present invention.

[0029] Among them: 10, cutting road; 20, metal ring; 30, redistribution layer; 40, passivation layer; 50, substrate; 21, metal layer; 22, interconnection hole. DETAILED DESCRIPTION

[0030] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0031] like Figure 2 , Figure 3 and Figure 4 As shown, the chip sealing ring structure for reducing the stress and warping of the adapter plate of this embodiment includes a redistribution layer 30 constituting a wafer chip, and a cutting path 10 for cutting and separating each wafer chip, and the area located outside the redistribution layer 30 and inside the cutting path 10 constitutes a sealing ring area, and a closed metal ring 20 is buried in the sealing ring area along the circumferential direction; the metal ring 20 is composed of a plurality of line segments connected end to end or a plurality of arcs connected end to end along the circumferential direction, and an angle greater than 90° is formed between adjacent line segments; as shown in FIG. Figure 5 As shown, the cross section of the metal ring 20 includes multiple metal layers 21 arranged in upper and lower spaced layers, and adjacent metal layers 21 are interconnected.

[0032] In this embodiment, by changing the morphology of the metal ring 20 and introducing a stress release structure, the single-point stress between the metal and the medium is transferred so that the stress is evenly distributed along a curve or a broken line, thereby effectively alleviating the stress concentration around the sealing ring, alleviating the stress and warping caused by the mismatch of thermal expansion coefficients, and solving the problems of warping and cracking and delamination of the sealing ring.

[0033] The sealing ring region includes a multi-layer passivation layer 40 which is layered upward from the substrate 50 , and the metal ring 20 is buried in the multi-layer passivation layer 40 .

[0034] In this embodiment, a spring-like structure is constructed by the metal layer 21 and the passivation layer 40. During high and low temperature cycles, the deformation can be controlled within the plane, and stress can be transferred through stretching and compression within the plane to avoid warping and reduce the warping of the adapter plate, thereby effectively preventing cracking and delamination of the sealing ring.

[0035] An interconnection hole 22 is formed on the passivation layer 40 between adjacent metal layers 21 , and metal is filled in the interconnection hole 22 to interconnect adjacent metal layers 21 .

[0036] In this embodiment, the passivation layers 40 of different layers may use the same dielectric material and be produced in the same manner, and the metal layers 21 and the interconnection holes 22 of different layers may use the same metal material and be produced in the same manner.

[0037] Adjacent interconnecting holes 22 are staggered in the vertical direction, and the interconnecting holes 22 on the same vertical cross section of the metal ring 20 are orderly arranged into two vertical rows.

[0038] In this embodiment, the interconnection holes 22 are staggered in the vertical direction to form two rows, and the positions of the interconnection holes 22 of two adjacent layers are staggered and do not completely overlap, so as to avoid stress concentration caused by direct metal stacking, which may cause the passivation layer 40 to break after solidification.

[0039] In this embodiment, adjacent interconnecting holes 22 are staggered in the vertical direction. The interconnecting holes 22 on the same vertical section are orderly arranged in two rows, that is, the interconnecting holes 22 of odd layers are aligned up and down to form a row, and the interconnecting holes 22 of even layers are aligned up and down to form a row.

[0040] The ratio of the distance between the two rows of interconnected holes 22 to the width of the metal layer 21 is greater than 1:5, thereby effectively ensuring the structural strength of the metal ring 20 and effectively ensuring its sealing performance.

[0041] The bottom metal layer 21 is located above the bottom passivation layer 40 , the bottom surface of the top metal layer 21 is attached to the bottom surface of the top passivation layer 40 , and there is a distance between the top surface of the top metal layer 21 and the top surface of the top passivation layer 40 ; thereby achieving stable and reliable embedding of the metal ring 20 in the passivation layer 40 .

[0042] The thickness of the bottom metal layer 21 is greater than that of other metal layers 21, which enhances reliability and prevents water vapor from penetrating into the package from the bottom; the thickness of other metal layers 21 except the bottom layer is the same; the thickness ratio of the bottom metal layer 21 to other metal layers 21 is 2:1.

[0043] In this embodiment, the thickness of the metal layer 21 can be adjusted according to the requirements and demands of the actual package.

[0044] The thickness of the passivation layer 40 is thicker than the thickness of the corresponding metal layer 21 in the layer, and the thickness of the bottom passivation layer 40 is thicker than the thickness of other passivation layers 40, for example, 2 times, to enhance the adhesion and reliability of the passivation layer 40 and prevent the passivation layer 40 from stratification and falling off after curing; the thickness of the passivation layer 40 provided with the bottom metal layer 21 and the top metal layer 21 is 2-3 microns thicker than the thickness of other passivation layers 40.

[0045] In this embodiment, the thickness of the passivation layer 40 and the thickness of the metal layer 21 inside it can be set to a ratio of about 2:1, thereby effectively ensuring that a stable and reliable spring-like structure is formed by the metal layer 21 combined with the passivation layer 40. Of course, in actual use, the ratio can also be adjusted according to actual needs.

[0046] In this embodiment, the second passivation layer 40 below is affected by the thickness of the internal first metal layer 21, and its thickness is slightly thicker than the other passivation layers 40 above by 2 microns; the thickness of the top passivation layer 40 is also slightly thicker by 2-3 microns to reduce the generation and expansion of cracks in subsequent cutting processes, while enhancing the protection effect on the underlying metal; except for the bottom passivation layer 40, the second passivation layer 40 below, and the top passivation layer 40, the thickness of other passivation layers 40 is the same.

[0047] The sealing ring region is formed by repeated operations of coating, exposure, development, hard baking and curing, and electroplating of dielectric materials and metals to form a stacked structure of a passivation layer 40 and a metal layer 21 , forming a sealing ring region in which the metal ring 20 is buried in the passivation layer 40 .

[0048] The metal ring 20 is a wavy structure composed of a plurality of arcs connected end to end along the circumferential direction. Adjacent arcs on the straight sides have opposite arc directions, and adjacent arcs at the corners together form an outward convex structure.

[0049] exist Figure 2 In the first embodiment shown, the metal ring 20 is formed of arcs in the circumferential direction to form a wavy structure. The outer frame line and the area outside the outer frame line are the cutting road 10 area, and the chips on the wafer can be separated from each other by cutting the cutting road 10; the inner frame line is the outer boundary of the redistribution layer 30, and the sealing ring area is between the inner and outer frame lines. The wavy metal frame line is a metal ring 20 with width and thickness.

[0050] exist Figure 3 In the second embodiment shown, the metal ring 20 is a toothed structure formed by line segments in the circumferential direction. The outer frame line and the area outside the outer frame line are the cutting road 10 area, and the chips on the wafer can be separated from each other by cutting the cutting road 10; the inner frame line is the outer boundary of the redistribution layer 30, and the sealing ring area is between the inner and outer frame lines. The toothed metal frame line is a metal ring 20 with width and thickness.

[0051] exist Figure 4 In the third embodiment shown, the metal ring 20 is formed of line segments in the circumferential direction to form a caterpillar-like structure. The outer frame line and the area outside the outer frame line are the cutting road 10 area. By cutting the cutting road 10, the chips on the wafer can be separated from each other; the inner frame line is the outer boundary of the redistribution layer 30, and the area between the inner and outer frame lines is the sealing ring area. The caterpillar-like metal frame line is a metal ring 20 with width and thickness.

[0052] In this embodiment, the angle between adjacent line segments is set to be greater than 90°, so as to avoid the photoresist residue of the seal ring passivation layer 40 after exposure and development in the process, thereby effectively ensuring the packaging effect.

[0053] In this embodiment, by arranging a closed metal ring 20 along the circumferential direction in the sealing ring area, the closed ring structure can block water vapor and chemical substances from entering the package body, thereby enhancing the reliability of the package body. On the other hand, the metal ring 20 can block the mechanical force generated during cutting to prevent the chip from being damaged by the mechanical force. By forming a spring-like structure in the cross-section of the metal ring 20, the deformation can be locked within the plane during the temperature cycle, thereby achieving stress transfer and reducing the warping of the adapter plate.

[0054] The present invention effectively alleviates stress concentration around the sealing ring, relieves stress and warping caused by mismatched thermal expansion coefficients, solves the problems of warping and cracking and delamination of the sealing ring, and greatly ensures the reliability and stability of the package.

[0055] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0056] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. A chip sealing ring structure for reducing stress and warpage of an adapter plate, comprising a redistribution layer (30) constituting a wafer chip, and a cutting path (10) for cutting and separating each wafer chip, characterized in that: The area located outside the redistribution layer (30) and inside the cutting path (10) constitutes a sealing ring area, in which a closed metal ring (20) is buried along the circumferential direction; the metal ring (20) is composed of a plurality of line segments connected end to end or a plurality of arcs connected end to end along the circumferential direction, and an angle greater than 90° is formed between adjacent line segments; the cross section of the metal ring (20) includes a plurality of metal layers (21) arranged in upper and lower spacing layers, and adjacent metal layers (21) are interconnected.

2. The chip sealing ring structure for reducing stress and warpage of an adapter plate according to claim 1, characterized in that: The sealing ring region comprises a plurality of passivation layers (40) which are layered upward from a substrate (50), and the metal ring (20) is buried in the plurality of passivation layers (40).

3. The chip sealing ring structure for reducing stress and warpage of an adapter plate according to claim 2, characterized in that: An interconnection hole (22) is provided on the passivation layer (40) between adjacent metal layers (21), and metal is filled in the interconnection hole (22) so that the adjacent metal layers (21) are interconnected.

4. The chip sealing ring structure for reducing stress and warpage of an adapter plate according to claim 3, characterized in that: Adjacent interconnected holes (22) are staggered in the vertical direction, and the interconnected holes (22) on the same vertical cross section of the metal ring (20) are orderly arranged in two vertical rows.

5. The chip sealing ring structure for reducing stress and warpage of an adapter plate according to claim 4, characterized in that: The ratio of the distance between two rows of interconnection holes (22) to the width of the metal layer (21) is greater than 1:

5.

6. The chip sealing ring structure for reducing stress and warpage of an adapter plate according to claim 2, wherein: The bottom metal layer (21) is located above the bottom passivation layer (40), the bottom surface of the top metal layer (21) is attached to the bottom surface of the top passivation layer (40), and there is a distance between the top surface of the top metal layer (21) and the top surface of the top passivation layer (40).

7. The chip sealing ring structure for reducing stress and warpage of an adapter plate according to claim 2, wherein: The thickness of the bottom metal layer (21) is greater than the thickness of other metal layers (21), and the thickness of other metal layers (21) except the bottom metal layer is the same; the thickness ratio of the bottom metal layer (21) to other metal layers (21) is 2:

1.

8. The chip sealing ring structure for reducing stress and warpage of an adapter plate according to claim 2, wherein: The thickness of the passivation layer (40) is thicker than the thickness of the corresponding metal layer (21) in the layer, and the thickness of the bottom passivation layer (40) is thicker than the thickness of other passivation layers (40); the thickness of the passivation layer (40) provided with the bottom metal layer (21) and the top metal layer (21) is 2-3 micrometers thicker than the thickness of other passivation layers (40).

9. The chip sealing ring structure for reducing stress and warpage of an adapter plate according to claim 2, wherein: The sealing ring region is formed by repeatedly coating, exposing, developing, hard baking and curing, and electroplating the dielectric material and the metal to form a stacked structure of a passivation layer (40) and a metal layer (21), forming a sealing ring region in which the metal ring (20) is buried in the passivation layer (40).

10. The chip sealing ring structure for reducing stress and warpage of an adapter plate according to claim 1, wherein: The metal ring (20) is a wavy structure consisting of a plurality of arcs connected end to end along the circumferential direction, the arc directions of adjacent arcs located on the straight sides are opposite, and the adjacent arcs located at the corners together form an outward convex structure.

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