Pad structure

Abstract

The present disclosure provides a pad structure comprising: a plurality of first metal wires arranged along a first direction and arranged in parallel in a second direction; a plurality of second metal wires arranged along the second direction and arranged in parallel in the first direction; a plurality of third metal regions in a polygonal shape, at least one side of which is formed by either the first metal wire or the second metal wire, and the edges of no two third metal regions touch; and a metal frame wire connecting both ends of the plurality of first metal wires and both ends of the plurality of second metal wires. The disclosed embodiments can reduce the resistance of a copper pad structure and increase the heat dissipation area.

Description

Technical Field

[0001] The present disclosure relates to the field of semiconductor manufacturing technology, and in particular to a pad structure. Background Art

[0002] A pad structure (PAD) is a conductor structure used in semiconductor manufacturing processes to lead signals from the bottom layer to the upper layer or to lead signals from the same layer to different locations. It is usually made of metal materials such as copper and aluminum.

[0003] Aluminum pad structures were once widely used due to their simple manufacturing process (they could be formed through etching). However, as device sizes decreased and structural performance became increasingly complex, aluminum's shortcomings, such as delayed response, became increasingly apparent. Copper, with its excellent conductivity and electromigration properties, became a suitable material for pad structures. Unlike aluminum, copper is too hard to be etched into a specific pattern. Instead, the pattern can only be formed by filling grooves and then subjecting the filled copper to a CMP (chemical mechanical polishing) process. During this process, if the groove area is large, the copper in the center of the groove will sag during polishing, resulting in process defects such as concavity. Therefore, when using copper to form a pad structure of a specific shape, a groove width limit (less than 2 microns) is set. A grid-like pad structure with a narrow copper wire layout in the center and copper wire lock edges around the edges is used.

[0004] In existing technology, copper pad structures have high resistance and a small heat dissipation area. When exposed to high voltage and high current (>1kV, >10A) during ESD / TLP pulse discharge testing, existing copper wires are highly likely to burn out. Furthermore, the wires of the upper and lower copper pad structures are typically electrically connected via multiple tungsten conductive structures. As technology advances, the contact size between the tungsten conductive structures and the copper wires decreases, increasing resistance, negatively impacting the performance of the multi-layered pad structure.

[0005] Therefore, a pad structure is needed that can retain the advantages of copper pads and avoid the disadvantages of copper pads.

[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the Invention

[0007] The present disclosure provides a pad structure for overcoming, at least to a certain extent, the problems of high resistance and poor heat dissipation capability of copper pad structures caused by limitations and defects of related technologies.

[0008] According to one aspect of the present disclosure, a pad structure is provided, comprising: a plurality of first metal wires arranged along a first direction and arranged in parallel in a second direction; a plurality of second metal wires arranged along the second direction and arranged in parallel in the first direction; a plurality of third metal areas in the form of polygons, at least one side of which is composed of the first metal wire or the second metal wire, and the edges of every two third metal areas are not connected; and a metal frame wire connecting both ends of the plurality of first metal wires and both ends of the plurality of second metal wires at the same time.

[0009] In an exemplary embodiment of the present disclosure, the third metal region is a quadrilateral, and four sides of the quadrilateral are respectively formed by two adjacent first metal wires and two adjacent second metal wires.

[0010] In an exemplary embodiment of the present disclosure, a distance between adjacent third metal regions is a distance between the first metal lines or a distance between the second metal lines.

[0011] In an exemplary embodiment of the present disclosure, the upper and lower pad structures are connected by multiple vertical conductive structures, and the vertical conductive structures include a first vertical conductive structure of the metal frame wire connecting the upper and lower pad structures and a second vertical conductive structure of the third metal area connecting the upper and lower pad structures.

[0012] In an exemplary embodiment of the present disclosure, the first vertical conductive structures are arranged on the metal frame line according to a preset spacing, and the two ends of the second vertical conductive structure are respectively connected to the geometric centers of the two corresponding third metal areas in the two-layer pad structure.

[0013] In an exemplary embodiment of the present disclosure, each of the third metal frame lines corresponds to a vertical conductive structure.

[0014] In an exemplary embodiment of the present disclosure, the line spacing between the first metal lines is less than 2 micrometers, and the line spacing between the second metal lines is less than 2 micrometers.

[0015] In an exemplary embodiment of the present disclosure, the line spacings between the first metal lines are the same, the line spacings between the second metal lines are the same, and the line spacings between the first metal lines are equal to the line spacings between the second metal lines.

[0016] In an exemplary embodiment of the present disclosure, the first direction is perpendicular to the second direction.

[0017] In an exemplary embodiment of the present disclosure, the first metal wire, the second metal wire, the third metal region, and the metal frame wire are all made of copper.

[0018] The pad structure provided by the embodiment of the present disclosure increases the copper material area of ​​the pad structure while meeting the CMP restriction conditions of the copper material by arranging dense narrow copper wires and arranging copper sheet areas between the narrow copper wires, thereby reducing the resistance of the pad, increasing the thermal conductivity area, and avoiding damage to the copper wires in the copper pad structure caused by high-voltage and high-current ESD / TLP pulses, thereby effectively improving the electrical conductivity and thermal conductivity of the copper pad structure.

[0019] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0021] Figure 1 Schematic diagram of a pad structure in an exemplary embodiment of the present disclosure.

[0022] Figure 2 Schematic diagram of a pad structure in another exemplary embodiment of the present disclosure.

[0023] Figure 3 Schematic diagram of a pad structure in another exemplary embodiment of the present disclosure.

[0024] Figures 4A to 4G It is a schematic diagram of the manufacturing process of the multi-layer liner structure in the embodiment of the present disclosure.

[0025] Figure 5 is another cross-sectional view of the multi-layer liner structure in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0026] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the present disclosure will be more comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or that other methods, components, devices, steps, etc. may be employed. In other cases, well-known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0027] The accompanying drawings are merely schematic illustrations of the present disclosure. Identical reference numerals in the drawings denote identical or similar components, and thus their repeated descriptions will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0028] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0029] Figure 1 Schematic diagram of the structure of the pad in the exemplary embodiment of the present disclosure.

[0030] refer to Figure 1 , the pad structure 100 may include:

[0031] A plurality of first metal wires 11 are arranged along a first direction and arranged in parallel in a second direction;

[0032] A plurality of second metal wires 12 are arranged along the second direction and parallel to the first direction;

[0033] A plurality of third metal regions 13 are polygonal in shape, at least one side of which is formed by the first metal wire 11 and the second metal wire 12, and the edges of every two third metal regions 13 are not connected;

[0034] The metal frame wire 14 connects both ends of the plurality of first metal wires 11 and both ends of the plurality of second metal wires 12 .

[0035] In the embodiment of the present disclosure, the first metal wire 11 , the second metal wire 12 , the third metal region 13 , and the metal frame wire 14 are all made of copper.

[0036] exist Figure 1 In the illustrated embodiment, the first direction is perpendicular to the second direction. The first direction is, for example, the row direction, and the second direction is, for example, the column direction. The third metal region 13 is a quadrilateral, with its four sides formed by two adjacent first metal lines 11 and two adjacent second metal lines 12. The spacing between two adjacent third metal regions 13 is equal to the spacing between two adjacent first metal lines 11 or the spacing between two adjacent second metal lines 12.

[0037] In some embodiments, the first metal lines 11 and the second metal lines 12 are arranged at equal intervals, that is, the line intervals between the first metal lines 11 are the same, and the line intervals between the second metal lines 12 are the same.

[0038] In some embodiments, the first metal wire 11 and the second metal wire 12 have the same line width and the same line spacing, the line spacing is less than 2 microns, and the line width is less than 2 microns. In some embodiments of the present disclosure, the line spacing can be more than twice the line width to form a third metal area and a non-copper area with a larger area (support point in the CMP process). Since copper is a relatively hard material, it needs to be polished flat through a CMP process after the pattern is formed. During this process, if the copper material area is too large, it will cause a depression in the center of the polishing area. The applicant found in the study that the polishing effect of the CMP process is closely related to the distribution of support points (non-copper areas). By setting dense non-copper areas ( Figure 1 The CMP process utilizes a finite element (e.g., a finite element) to create a dense support point between the third metal region 13 and the copper region 13 (between the finite element and the copper region 13). This effectively prevents central depression in the third metal region 13 (copper region) during the polishing process, thereby satisfying the CMP process's copper material restrictions while increasing the overall copper region area. This increased copper region area reduces the resistance of the entire pad structure and improves thermal conductivity, avoiding the problem of copper pad structure grid line burnout caused by high resistance, high temperature, and thin grid lines in related technologies. This effectively improves the reliability of the copper pad structure.

[0039] It is understood that in other embodiments, the line width and line spacing of the first metal lines 11 and the second metal lines 12 may also be different. Effectively, the smaller the line width and the smaller the line spacing, the denser the arrangement of the first metal lines 11 and the second metal lines 12, which can increase the overall copper distribution area, thereby reducing the resistance of the pad structure 100 and improving the thermal conductivity.

[0040] The shape, position and number of the third metal region 13 can be set according to ESD requirements or process requirements. Figure 1 The third metal region 13 may be a quadrilateral with only a portion of its sides connected to the first metal line 11 or the second metal line 12, and the shape may be any shape. Figure 1In the illustrated embodiment, the spacing between two adjacent third metal regions 13 in the same row can be the column spacing of the second metal lines 12, and the spacing between two adjacent third metal regions 13 in the same column can be the row spacing of the metal frame lines 13, that is, a third metal region 13 is provided in every other row or column. To prevent central depression caused by grinding of large-area copper connections, the third metal regions 13 can be arranged so that they do not connect to the metal frame lines 14, and the edges of every two third metal regions 13 do not touch each other.

[0041] Figure 2 FIG. 1 is a schematic diagram of the arrangement of the third metal region 13 in another embodiment of the present disclosure.

[0042] refer to Figure 2 Although different third metal regions 13 cannot be connected at their edges, when the widths of the first metal wire 11 and the second metal wire 12 are small and the areas of the third metal regions 13 are appropriately set, multiple third metal regions 13 can be connected at their corners to increase the setting density of the third metal regions 13 and increase the copper material area on the pad structure while meeting the copper material CMP width limitation.

[0043] The first metal line 11, the second metal line 12, the third metal region 13, and the metal frame line 14 can be formed in the same CMP process, that is, the grooves of these structures can be made on the dielectric layer through the same photolithography process, and then filled with copper through a metal filling process (such as plasma sputtering), and finally formed through a CMP process. Figure 1 or Figure 2 The graphic shown.

[0044] It can be understood that although the pad structure in the embodiment of the present disclosure is rectangular, in actual application the pad structure can also have various shapes, such as a combination of multiple rectangles of different sizes. The present disclosure does not limit the specific shape of the pad structure.

[0045] In an exemplary embodiment of the present disclosure, the upper and lower pads are connected via a plurality of vertical conductive structures (plug holes). Figure 3 It is a schematic diagram of the arrangement of the conductive structure in an embodiment of the present disclosure.

[0046] refer to Figure 3 The vertical conductive structures may include a plurality of first vertical conductive structures 151 connecting the metal frame lines 14 of the upper and lower pads and a plurality of second vertical conductive structures 152 connecting the third metal regions 13 of the upper and lower pads.

[0047] In an exemplary embodiment of the present disclosure, the first vertical conductive structure 151 is arranged on the edge of the metal frame line 14 according to a preset spacing, and the two ends of the second vertical conductive structure 152 are respectively connected to the geometric centers of the two third metal regions 13 at corresponding positions in the two layers of pads. In one embodiment, each third metal region 13 corresponds to a vertical conductive structure. In other embodiments, multiple vertical conductive structures can be set for a third metal region 13, in which case these vertical conductive structures may not correspond to the geometric center of the third metal region 13. There are many ways to set the vertical conductive structure, and those skilled in the art can set it according to actual needs.

[0048] The setting of the third metal area and the vertical conductive structure corresponding to the third metal area can increase the connection area of ​​the upper and lower pad structures, reduce the on-resistance, and thus overcome the defects of reducing the conductive performance of the pad structure due to the reduction in the size of the conductive structure and the pad, such as the reduction in the contact area between the conductive structure and the pad, and the increase in the resistance between the pads.

[0049] Figures 4A to 4G It is a schematic diagram of the manufacturing process of the multi-layer liner structure in one embodiment of the present disclosure.

[0050] refer to Figure 4A The pad structure 42 is provided on the upper surface of the first dielectric layer 41. The pattern of the pad structure 41 is, for example, Figure 1 or Figure 2 As shown, the material of the pad structure is copper.

[0051] refer to Figure 4B A second dielectric layer 43 is deposited on the first dielectric layer 41. The materials of the first dielectric layer 41 and the second dielectric layer 43 can be the same or different. For example, both can be compounds with a dielectric constant less than 3. This disclosure does not impose any special restrictions on this.

[0052] refer to Figure 4C A plurality of holes 44 are formed in the second dielectric layer 43 at positions corresponding to the metal frame lines of the pad structure 42 and the third metal region by processes such as coating photoresist, exposing and developing, cleaning the photoresist, and dry etching or wet etching. The depth of the holes 44 is the same as the height of the second dielectric layer 43, and the bottom surface of the holes 44 exposes the upper surface of the metal, such as the metal frame lines of the pad structure 42 and the third metal region.

[0053] refer to Figure 4D , multiple holes 44 are filled with metal tungsten at one time through general metal filling processes such as seed metal implantation and metal sputtering, and a first CMP process is performed to form multiple vertical conductive structures 45 (i.e., the first vertical conductive structure 151) at one time.

[0054] refer to Figure 4E, a third dielectric layer 46 is deposited on the second dielectric layer 43 , and the material of the third dielectric layer 46 can be the same as that of the first dielectric layer 41 .

[0055] refer to Figure 4F , the third dielectric layer 46 is subjected to processes such as coating photoresist, exposure and development, cleaning photoresist, dry etching or wet etching to form a groove 47 of a new layer of liner structure. The position of the groove 47 in the vertical direction completely corresponds to the area of ​​the liner structure 42, the depth is equal to the thickness of the third dielectric layer 46, and the bottom surface exposes all the holes 44. Although the perspective in the figure cannot be shown, it can be understood that the pattern of the groove 47 on the upper surface is the same as that of the liner structure 42. Figure 1 or Figure 2 The groove 47 is not a rectangular groove, but a one-piece groove with multiple "trench". Therefore, the remaining second dielectric layer 46 in the area around the groove 47 is not located at the same level, but has different depths relative to the viewing direction. The groove 47 includes a plurality of grooves for forming a plurality of grooves. Figure 1 The grooves of the first metal line 11, the second metal line 12, the third metal area 13, and the metal frame line 14. Figures 1 to 3 It can be understood that the area of ​​the second dielectric layer 46 that is not filled with metal is located inside the pad structure. Figure 4F The remaining second dielectric layer 46 is also located at different depths in the viewing direction and will be blocked by the filled metal later.

[0056] refer to Figure 4G , the groove 47 is filled with copper metal through a general metal filling process such as seed metal implantation and metal sputtering, and a second CMP process is performed to form a pad structure 48 that is identical in pattern to the pad structure 42 and completely corresponds in position. It should be noted that since the metal frame lines 14 of the pad structure 42 and the pad structure 48 are viewed in the figure at this time, the first metal line 11, the second metal line 12 and the third metal area 13 in each pad structure cannot be displayed. At this time, the pad structure 48 is electrically connected to the pad structure 42 through the conductive structure 45, and the electrical signal of the pad structure 42 can be led to the pad structure 48. It can be understood that Figure 4G The conductive structure 45 is Figure 3 151 is a cross-sectional view of the first conductive structure 151.

[0057] Figures 4A to 4G This is a schematic diagram showing the pad structure from the side, which cannot directly show the second vertical conductive structure 152. Therefore, the present disclosure also provides Figure 5 The schematic diagram shown.

[0058] Cut longitudinally from the center of the liner structure, the section is as follows Figure 5 Reference Figure 5The second conductive structure 152 can be arranged corresponding to the third metal region 13 , and the distance between the two second conductive structures 152 is not less than the distance between the two third metal regions 13 .

[0059] In summary, the pad structure provided by the embodiment of the present disclosure increases the conductive area in the pad structure, reduces the resistance of the copper pad structure, and improves the thermal conductivity of the copper pad structure while meeting the CMP width limitation of the copper material by setting copper wires with narrow spacing, setting a third metal area between the copper wires, and setting a conductive structure at a position corresponding to the third metal area. This overcomes the defects caused by process limitations while retaining the advantages of the copper material.

[0060] It should be noted that although several modules or units of the device for action execution are mentioned in the detailed description above, this division is not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more modules or units described above can be concretized in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided into multiple modules or units to be concretized.

[0061] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the claims.

Claims

1. A liner structure, characterized in that: include: A plurality of first metal wires are arranged along a first direction and arranged in parallel in a second direction; a plurality of second metal wires disposed along the second direction and arranged in parallel in the first direction; a plurality of third metal regions, each in a polygonal shape, at least one side of which is formed by the first metal wire or the second metal wire, and edges of no two third metal regions are connected; a metal frame wire connecting both ends of the plurality of first metal wires and both ends of the plurality of second metal wires; Wherein, the line width of the first metal line is less than 2 microns, and the line width of the second metal line is less than 2 microns; The upper and lower pad structures are connected by a plurality of vertical conductive structures, wherein the vertical conductive structures include a first vertical conductive structure connecting the metal frame wires of the upper and lower pad structures and a second vertical conductive structure connecting the third metal region of the upper and lower pad structures; Wherein, each of the third metal regions corresponds to a vertical conductive structure.

2. The pad structure according to claim 1, wherein: The third metal region is a quadrilateral, and four sides of the quadrilateral are respectively formed by two adjacent first metal wires and two adjacent second metal wires.

3. The pad structure according to claim 2, wherein: The spacing between adjacent third metal regions is the spacing of the first metal lines or the spacing of the second metal lines.

4. The pad structure according to claim 1, wherein: The first vertical conductive structures are arranged on the metal frame line according to a preset interval, and two ends of the second vertical conductive structure are respectively connected to the geometric centers of two corresponding third metal regions in the two-layer pad structure.

5. The pad structure according to claim 1, wherein: The line spacing between the first metal lines is less than 2 microns, and the line spacing between the second metal lines is less than 2 microns.

6. The pad structure according to claim 1, wherein: The line spacings between the first metal lines are the same, the line spacings between the second metal lines are the same, and the line spacings between the first metal lines are equal to the line spacings between the second metal lines.

7. The pad structure according to claim 1, wherein: The first direction is perpendicular to the second direction.

8. The liner structure according to any one of claims 1 to 7, wherein: The first metal wire, the second metal wire, the third metal region, and the metal frame wire are all made of copper.

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