Conductive structure and forming method thereof
By forming a covering layer on the conductive layer and providing a recess on the upper portion thereof, the problem of time-dependent dielectric breakdown caused by the reduction of the wire spacing is solved, thereby improving the reliability of the semiconductor device.
Patent Information
- Application Number
- CN202410270532.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-11
- Publication Date
- 2025-09-12
AI Technical Summary
As the dimensions of semiconductor structures and interconnects shrink, the distance between conductive lines decreases, leading to a serious problem of time-dependent dielectric breakdown (TDDB), which affects device reliability.
A capping layer is formed on the conductive layer, a recess of the capping layer is provided around an upper portion of the conductive layer to prevent diffusion of metal material, a conductive structure is formed to reduce time-dependent dielectric breakdown, and the conductive layer and the barrier layer are planarized by a chemical mechanical polishing process.
While reducing the wire spacing, time-dependent dielectric breakdown (TDDB) is effectively prevented, improving device reliability.
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Figure CN120637313A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a conductive structure and a method for forming the same. More specifically, the present invention relates to a conductive structure and a method for forming the same that can improve device reliability. Background Art
[0002] In recent years, the semiconductor industry has faced numerous challenges as semiconductor structures and interconnects have become increasingly smaller. For example, the shrinking distance between conductors has reduced the time-dependent dielectric breakdown (TDDB), which in turn reduces the reliability of the dielectric layer between conductors.
[0003] In view of this, there is an urgent need for a structure and a method for forming the structure that can reduce the distance between conductive lines while taking into account the time-dependent dielectric breakdown (TDDB). Summary of the Invention
[0004] An embodiment of the present invention provides a method for forming a conductive structure, comprising the following steps: providing a substrate including a conductive feature layer; forming a dielectric layer on the conductive feature layer; forming a first opening, a second opening, and a third opening in the dielectric layer; forming a barrier layer in the first opening, the second opening, and the third opening and on the dielectric layer; forming a conductive layer on the barrier layer; planarizing the conductive layer and the barrier layer formed on the dielectric layer, wherein the planarized conductive layer has a first height; removing a portion of the barrier layer to form a recess around an upper portion of the conductive layer, wherein the top surface of the barrier layer is lower than the top surface of the dielectric layer, and the recess has a depth, wherein the ratio of the depth to the first height is between 0 and 1; and forming a capping layer on the recess, the conductive layer, and the barrier layer.
[0005] In some embodiments, a first distance exists between the first opening and the second opening, and a ratio of the depth to the first distance is between 1 and 100.
[0006] In some embodiments, a second distance exists between the second opening and the third opening, and the second distance is greater than the first distance.
[0007] In some embodiments, the barrier layer formed at the bottom of the first opening has a first thickness, the barrier layer formed on the sidewall of the first opening has a second thickness, and the first thickness is greater than the second thickness.
[0008] An embodiment of the present invention provides a conductive structure, and the conductive structure includes a conductive feature layer, a dielectric layer, a first conductor component, and a covering layer. The conductive feature layer is disposed on a substrate. The dielectric layer is disposed on the conductive feature layer. The first conductor component is disposed in the dielectric layer and includes a first conductive layer, a first barrier layer, and a first covering member. The first barrier layer covers the sidewalls and bottom of a first lower portion of the first conductive layer. The first covering member surrounds the sidewalls of a first upper portion of the first conductive layer. The first upper portion has a first upper height, the first lower portion has a first lower height, and the ratio of the first upper height to the first lower height is between 0 and 1. The covering layer is disposed on the dielectric layer.
[0009] In some embodiments, the conductive structure further includes a second conductive component. The second conductive component is disposed in the dielectric layer and spaced apart from the first conductive component by a first spacing, and includes a second conductive layer, a second barrier layer, and a second cover. The second barrier layer covers the sidewalls and bottom of the second lower portion of the second conductive layer. The second cover surrounds the sidewalls of the second upper portion of the second conductive layer. The second upper portion of the second conductive layer has a second upper height that is the same as the first upper height of the first conductive layer, and a ratio of the second lower height of the second lower portion of the second conductive layer to the first spacing is between 0 and 100.
[0010] In some embodiments, the conductive structure further includes a third conductive component. The third conductive component is disposed in the dielectric layer and spaced apart from the second conductive component by a second spacing, and includes a third conductive layer, a third barrier layer, and a third cover. The third barrier layer covers the sidewalls and bottom of a third lower portion of the third conductive layer. The third cover surrounds the sidewalls of a third upper portion of the third conductive layer. The second spacing is greater than the first spacing.
[0011] In some embodiments, the first conductive layer has a height, and a ratio of the first upper portion height to the height is between 0 and 1.
[0012] In some embodiments, the first barrier layer at the bottom of the first conductive layer has a first thickness, the first barrier layer surrounding the sidewall of the first conductive layer has a second thickness, and the first thickness is greater than the second thickness.
[0013] In some embodiments, the first spacing is less than or equal to 0.13 microns. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The following examples are presented in conjunction with the accompanying drawings for a clearer understanding of the present invention. It should be noted that, in accordance with standard industry practice, various features are not drawn to scale. In fact, the dimensions of various features may be arbitrarily enlarged or reduced for clarity of discussion.
[0015] Figures 1 to 4are cross-sectional views of various stages of a method for forming a conductive structure according to some embodiments of the present invention. DETAILED DESCRIPTION
[0016] Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.
[0017] In addition, for the convenience of description, spatially related terms such as "on", "above", "below", "between" and the like may be used in the present invention to describe the relationship between one element or feature and another element as shown in the drawings) or function. In addition to the orientations depicted in the drawings, spatially related terms are intended to cover different orientations of the device in use or operation. The device can be oriented in other ways (rotated 90 degrees or in other directions), and the spatially related descriptors used in the present invention can also be interpreted accordingly. The terms "including", "having", "comprising" and the like used in the present invention are open terms, meaning including but not limited to.
[0018] In order to reduce the distance between conductive lines without causing time-dependent dielectric breakdown (TDDB) degradation or other device performance issues due to the diffusion of metal materials into the dielectric layer, embodiments of the present invention provide a conductive structure surrounding a capping layer on top of the metal material and a method for forming the same. Figures 1 to 4 , Figures 1 to 4 are cross-sectional views of various stages of a method for forming a conductive structure according to some embodiments of the present invention.
[0019] like Figure 1As shown, a substrate 102 including a conductive feature layer 110 is provided. The conductive feature layer 110 includes various conductive components, such as transistors, capacitors, inductors, or combinations thereof. Subsequently, a dielectric layer 120 is formed on the conductive feature layer 110. In some embodiments, the dielectric layer 120 includes an oxide. In some embodiments, the dielectric layer 120 is formed by a deposition process, such as a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, or other suitable processes. Next, a first opening OP1, a second opening OP2, and a third opening OP3 are formed in the dielectric layer 120. In some embodiments, a first spacing S1 is provided between the first opening OP1 and the second opening OP2, and a second spacing S2 is provided between the second opening OP2 and the third opening OP3, and the second spacing S2 is greater than the first spacing S1. In some embodiments, the first spacing S1 is less than or equal to 0.13 microns (μm). In some embodiments, the second spacing S2 is less than or equal to 0.13 microns (μm).
[0020] Next, a barrier layer 130 is formed on the dielectric layer 120 and in the first, second, and third openings OP1, OP2, and OP3. In some embodiments, the material forming the barrier layer 130 includes titanium (Ti), titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN), or a combination thereof. In some embodiments, the barrier layer 130 formed on the sidewalls of the first, second, and third openings OP1, OP2, and OP3 has a first thickness TH1, and the barrier layer 130 formed at the bottoms of the first, second, and third openings OP1, OP2, and OP3 has a second thickness TH2. The second thickness TH2 is different from the first thickness TH1, for example, the second thickness TH2 is greater than the first thickness TH1.
[0021] like Figure 2 As shown, a conductive layer 140 is formed on the barrier layer 130. In addition, in this step, the top surface of the conductive layer 140 is higher than the top surface of the barrier layer 130 formed on the dielectric layer 120. In some embodiments, the material forming the conductive layer 140 is copper (Cu), aluminum (Al), tungsten (W), or other conductive materials.
[0022] like Figure 3As shown, the conductive layer 140 is planarized and the barrier layer 130 formed on the dielectric layer 120 is removed. Subsequently, a part of the planarized barrier layer 130 is removed to form a recess RS around the upper part of the planarized conductive layer 140. Specifically, the conductive layer 140 and the barrier layer 130 formed on the dielectric layer 120 are planarized such that the top surface of the conductive layer 140, the top surface of the barrier layer 130 in the first opening OP1, the second opening OP2, and the third opening OP3 (as Figure 1 ) and the top surface of the dielectric layer 120 are coplanar. In addition, the planarized conductive layer 140 has a first height H1. In some embodiments, the conductive layer 140 and the barrier layer 130 in the first opening OP1, the second opening OP2, and the third opening OP3 (as Figure 1 ) are planarized by a Chemical-Mechanical Polishing (CMP) process.
[0023] Subsequently, a recess RS is formed around the upper part of the planarized conductive layer 140, for example, by an etching process, such that the top surface of the barrier layer 130 is lower than the top surface of the dielectric layer 120 and the top surface of the conductive layer 40. And the recess RS has a depth D. In addition, the ratio of the depth D of the recess RS to the first height H1 of the conductive layer 140 is between 0 and 1 (0 < D / H1 < 1).
[0024] As Figure 4 shown, a covering layer 150 is formed in the recess RS (as Figure 3 ) and on the conductive layer 140 and the barrier layer 130, that is, a first wire component 160A is formed in the first opening OP1 (as Figure 1 ), a second wire component 160B is formed in the second opening OP2 (as Figure 1 ), and a third wire component 160C is formed in the third opening OP3 (as Figure 1 ). In addition, the covering layer 150 in the recess RS (as Figure 3 ) formed around the upper part of the conductive layer 140 has a second height H2.
[0025] In some embodiments, the material for forming the covering layer 150 includes an oxide, such as silicon dioxide or titanium oxide. In some embodiments, the ratio of the second height H2 to the first spacing S1 is between 1 and 100 (1 < H2 / S1 < 100). Similarly, the ratio of the second height H2 to the second spacing S2 is also between 1 and 100 (1 < H2 / S2 < 100).
[0026] As Figure 4The conductive structure 100 shown includes a substrate 102, a conductive feature layer 110 disposed on the substrate 102, a dielectric layer 120 disposed on the conductive feature layer 110, a first conductive feature 160A, a second conductive feature 160B, and a third conductive feature 160C located in the dielectric layer 120, and a capping layer 150 disposed on the dielectric layer 120. In some embodiments, the conductive feature layer 110 includes various conductive features, such as transistors, capacitors, inductors, or combinations thereof. In some embodiments, the dielectric layer 120 includes an oxide.
[0027] The first conductive line member 160A and the second conductive line member 160B are separated by the dielectric layer 120 at a first spacing S1. The second conductive line member 160B and the third conductive line member 160C are separated by the dielectric layer 120 at a second spacing S2, and the second spacing S2 is greater than the first spacing S1. In some embodiments, the first spacing S1 is less than or equal to 0.13 micrometers (μm). In some embodiments, the second spacing S2 is less than or equal to 0.13 micrometers (μm).
[0028] The first conductive line component 160A, the second conductive line component 160B, and the third conductive line component 160C respectively include a conductive layer 140, a barrier layer 130, and a cover 152. The sidewalls and the bottom of the lower portion of the conductive layer 140 are covered by the barrier layer 130, and the sidewalls of the upper portion of the conductive layer 140 are surrounded by the cover 152. In addition, the top surface of the conductive layer 140 is coplanar with the top surface of the dielectric layer 120, and the top surface of the barrier layer 130 is lower than the top surface of the conductive layer 140 and the top surface of the dielectric layer 120. In some embodiments, the conductive layer 140 has a first height H1, the lower portion of the conductive layer 140 has a second height H2, and the upper portion of the conductive layer 140 has a third height H3, and the recess RS (e.g., Figure 3 The depth D of the conductive layer 140 is substantially equal to the third height H3 of the upper portion of the conductive layer 140. In some embodiments, the third height H3 is less than the second height H2, that is, the ratio of the third height H3 to the second height H2 is between 0 and 1 (0 <H3 / H2<1)。
[0029] In some embodiments, barrier layer 130 surrounding the sidewall of the lower portion of conductive layer 140 has a first thickness TH1, barrier layer 130 at the bottom of the lower portion of conductive layer 140 has a second thickness TH2, and the first thickness TH1 is less than the second thickness TH2.
[0030] In some embodiments, the conductive layer 140 is made of copper (Cu), aluminum (Al), tungsten (W), or other conductive materials. In some embodiments, the barrier layer 130 is made of titanium (Ti), titanium nitride (TiN), tantalum (Ta), tantalum nitride (TaN), or a combination thereof. In some embodiments, the cover 152 is made of an oxide, such as silicon dioxide or titanium oxide, and the material of the cover 152 is the same as that of the cover layer 150.
[0031] In summary, the conductive structure and its formation method according to the embodiments of the present invention can reduce the spacing between conductive lines while preventing the diffusion of conductive material due to high temperatures by providing a cover layer (covering member) on the barrier layer, thereby preventing the degradation of time-dependent dielectric breakdown (TDDB). Therefore, the embodiments of the present invention can improve time-dependent dielectric breakdown (TDDB) and device reliability.
[0032] Although the present invention has been described in considerable detail with reference to some embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the embodiments described herein.
[0033] The above briefly describes the features of multiple embodiments of the present invention, making it easier for those skilled in the art to understand the present invention. Anyone skilled in the art will understand that the present invention can easily serve as a basis for modification or design of other structures or processes to achieve the same purposes and / or obtain the same advantages as the embodiments of the present invention. Anyone skilled in the art will also understand that structures equivalent to the above do not depart from the spirit and scope of protection of the present invention, and can be changed, replaced, and modified without departing from the spirit and scope of the present invention.
[0034]
Explanation of symbols
[0035] 100: conductive structure
[0036] 102:Substrate
[0037] 110: conductive feature layer
[0038] 120: dielectric layer
[0039] 130: barrier layer
[0040] 140: conductive layer
[0041] 150: Covering layer
[0042] 152: Cover
[0043] 160A: First conductor component
[0044] 160B: Second wire member
[0045] 160C: Third wire member
[0046] D: Depth
[0047] H1: First Height
[0048] H2: Second height
[0049] H3: The third height
[0050] RS: Depression
[0051] OP1: First opening
[0052] OP2: Second opening
[0053] OP3: The third opening
[0054] S1: first spacing
[0055] S2: Second spacing
[0056] TH1: First thickness
[0057] TH2: Second thickness.
Claims
1. A method for forming a conductive structure, characterized in that: include: providing a substrate including a conductive feature layer; forming a dielectric layer on the conductive feature layer; forming a first opening, a second opening, and a third opening in the dielectric layer; forming a barrier layer in the first opening, the second opening, the third opening, and on the dielectric layer; forming a conductive layer on the barrier layer; planarizing the conductive layer and the barrier layer formed on the dielectric layer, wherein the conductive layer after planarization has a first height; removing a portion of the barrier layer to form a recess around an upper portion of the conductive layer and having a top surface of the barrier layer lower than a top surface of the dielectric layer, wherein the recess has a depth, and a ratio of the depth to the first height is between 0 and 1; and A covering layer is formed on the recess, the conductive layer and the barrier layer.
2. The method according to claim 1, characterized in that A first distance exists between the first opening and the second opening, and a ratio of the depth to the first distance is between 1 and 100.
3. The method according to claim 2, characterized in that A second distance is provided between the second opening and the third opening, and the second distance is greater than the first distance.
4. The method according to claim 1, wherein The barrier layer formed on the bottom of the first opening has a first thickness, the barrier layer formed on the sidewall of the first opening has a second thickness, and the first thickness is greater than the second thickness.
5. A conductive structure, characterized in that include: a conductive feature layer disposed on the substrate; a dielectric layer disposed on the conductive feature layer; The first conductive line component is disposed in the dielectric layer and includes: a first conductive layer; a first barrier layer covering the sidewalls and bottom of the first lower portion of the first conductive layer; and a first cover surrounding a sidewall of a first upper portion of the first conductive layer, wherein the first upper portion has a first upper height, the first lower portion has a first lower height, and a ratio of the first upper height to the first lower height is between 0 and 1; and The covering layer is disposed on the dielectric layer.
6. The conductive structure according to claim 5, characterized in that Further including: The second conductive component is disposed in the dielectric layer and is spaced apart from the first conductive component by a first distance, and comprises: a second conductive layer; a second barrier layer covering the sidewalls and bottom of the second lower portion of the second conductive layer; and a second cover surrounding a sidewall of the second upper portion of the second conductive layer, The second upper height of the second upper portion of the second conductive layer is the same as the first upper height of the first conductive layer, and a ratio of the second lower height of the second lower portion of the second conductive layer to the first spacing is between 0 and 100.
7. The conductive structure according to claim 6, characterized in that: Further including: A third conductive component is disposed in the dielectric layer and is spaced apart from the second conductive component by a second distance, and includes: a third conductive layer; a third barrier layer covering sidewalls and a bottom of the third lower portion of the third conductive layer; and a third cover surrounding a sidewall of the third upper portion of the third conductive layer, The second distance is greater than the first distance.
8. The conductive structure according to claim 5, characterized in that The first conductive layer has a height, and a ratio of the first upper portion height to the height is between 0 and 1.
9. The conductive structure according to claim 7, wherein: The first barrier layer at the bottom of the first conductive layer has a first thickness, the first barrier layer surrounding the sidewall of the first conductive layer has a second thickness, and the first thickness is greater than the second thickness.
10. The conductive structure according to claim 6, wherein: The first spacing is less than or equal to 0.13 microns.