阅读说明：本技术 半导体元件及其制作方法 (Semiconductor element and manufacturing method thereof ) 是由 林文凯 盛义忠 薛胜元 康智凯 于 2018-01-18 设计创作，主要内容包括：本发明公开一种半导体元件及其制作方法,该半导体元件主要包含第一主动区、第二主动区以及第三主动区沿着第一方向延伸于一基底上、第一栅极线沿着第二方向延伸并交错第一主动区、第二主动区及第三主动区、第一单扩散隔离结构沿着第二方向延伸并设于第一主动区的第一栅极线正下方、第二单扩散隔离结构设于第二主动区的第一栅极线正下方以及第三单扩散隔离结构设于第三主动区的第一栅极线正下方。(The invention discloses a semiconductor element and a manufacturing method thereof, wherein the semiconductor element mainly comprises a first active area, a second active area and a third active area which extend on a substrate along a first direction, a first grid line which extends along a second direction and is staggered with the first active area, the second active area and the third active area, a first single diffusion isolation structure which extends along the second direction and is arranged under the first grid line of the first active area, a second single diffusion isolation structure which is arranged under the first grid line of the second active area and a third single diffusion isolation structure which is arranged under the first grid line of the third active area.)

1. A semiconductor device, comprising:

the first active region, the second active region and the third active region extend on the substrate along a first direction;

a first gate line extending along a second direction and crossing the first active region, the second active region and the third active region; and

the first single diffusion isolation structure extends along the second direction and is arranged right below the first gate line of the first active region.

2. The semiconductor device as defined in claim 1, further comprising shallow trench isolation surrounding said first active region and said second active region.

3. The semiconductor device as defined in claim 2, wherein the first single diffusion isolation structure is disposed in the shallow trench isolation.

4. The semiconductor device as defined in claim 2, wherein the first single diffusion isolation structure and the shallow trench isolation comprise the same material.

5. The semiconductor device as defined in claim 2, wherein the first single diffusion isolation structure and the shallow trench isolation comprise different materials.

6. The semiconductor device as claimed in claim 1, further comprising a second single diffusion isolation structure disposed directly below the first gate line in the second active region.

7. The semiconductor device as claimed in claim 1, further comprising a third single diffusion isolation structure disposed directly below the first gate line in the third active region.

8. The semiconductor device as defined in claim 1, wherein the first active region edge is cut to be flush with the first gate line edge.

9. The semiconductor device of claim 1, further comprising:

a second gate line extending along the second direction and crossing the second active region and the third active region; and

and a fourth single diffusion isolation structure extending along the second direction and disposed right below the second gate line between the second active region and the third active region.

10. The semiconductor device as claimed in claim 9, wherein the fourth single diffusion isolation structure is disposed under the second gate line crossing the second active region and under the second gate line between the second active region and the third active region.

11. The semiconductor device as claimed in claim 10, wherein the fourth single diffusion isolation structure is disposed under the second gate line crossing the second active region, under the second gate line between the second active region and the third active region, and under the second gate line crossing the third active region.

Technical Field

The present invention relates to a method for fabricating a semiconductor device, and more particularly, to a method for forming a single diffusion isolation (SDB) structure directly under a gate line.

Background

In recent years, as Field Effect Transistors (FETs) continue to shrink in size, the development of planar field effect transistor (planar) devices has faced the limit of fabrication processes. To overcome the limitation of the manufacturing process, it is becoming a mainstream trend to replace planar transistor devices with non-planar (non-planar) field effect transistor devices, such as Fin field effect transistor (Fin FET) devices. The three-dimensional structure of the finfet device can increase the contact area between the gate and the fin structure, and thus can further increase the control of the gate on the carrier channel region, thereby reducing the Drain Induced Barrier Lowering (DIBL) effect faced by the small-sized device and suppressing the Short Channel Effect (SCE). Furthermore, since the finfet device has a wider channel width for the same gate length, a doubled drain driving current can be obtained. Furthermore, the threshold voltage (threshold voltage) of the transistor device can be adjusted by adjusting the work function of the gate.

In the conventional fin field effect transistor device fabrication process, after shallow trench isolation is formed around the fin structure, a portion of the fin structure and the shallow trench isolation are usually removed by etching to form a recess, and then an insulator is filled to form a single diffusion isolation structure and separate the fin structure into two parts. However, there are still many problems in the matching of the single diffusion isolation structure and the metal gate in the current manufacturing process, and therefore how to improve the conventional finfet manufacturing process and structure is an important issue in the current technology.

Disclosure of Invention

The invention discloses a semiconductor element, which mainly comprises a first active area, a second active area and a third active area, wherein the first active area, the second active area and the third active area extend on a substrate along a first direction, a first grid line extends along a second direction and is staggered with the first active area, the second active area and the third active area, a first single diffusion isolation structure extends along the second direction and is arranged under the first grid line of the first active area, a second single diffusion isolation structure is arranged under the first grid line of the second active area, and a third single diffusion isolation structure is arranged under the first grid line of the third active area.

Drawings

FIG. 1 is a top view of a semiconductor device in accordance with one embodiment of the present invention;

FIG. 2 is a cross-sectional view of the semiconductor device of FIG. 1 along line AA';

fig. 3 is a schematic cross-sectional view of the semiconductor device of fig. 1 along a direction of a tangent line BB'.

Description of the main elements

12 substrate 14 active (active) region

16 active region 18 active region

20 fin 22 shallow trench isolation

24-bump 26 single diffusion isolation structure

28 single diffusion isolation structure 30 single diffusion isolation structure

32 single diffusion isolation structure 34 single diffusion isolation structure

36 single diffusion isolation structure 38 single diffusion isolation structure

40 single diffusion isolation structure 42 single diffusion isolation structure

44 single diffusion isolation structure 46 gate line

48 gate line 50 gate line

52 gate line 54 gate line

56 gate line 58 gate line

60 gate line 62 gate line

64 gate line 66 gate line

68 Gate line 70 Gate line

72 gate dielectric layer 74 gate material layer

76 dummy isolation structure

Detailed Description

Referring to fig. 1 to fig. 3, fig. 1 is a top view of a semiconductor device according to a preferred embodiment of the present invention, fig. 2 is a schematic cross-sectional view of the semiconductor device along a cut line AA 'in fig. 1, and fig. 3 is a schematic cross-sectional view along a cut line BB' in fig. 1. As shown in fig. 1-3, a substrate 12, such as a silicon substrate or a silicon-on-insulator (SOI) substrate, is provided, and at least one active region, such as active region 14, active region 16, and active region 18, is defined on the substrate 12, wherein each active region preferably extends along a first direction (e.g., an X direction) on the substrate 12. A plurality of fins 20 are then formed on the substrate 12 in each of the active regions 14, 16, 18 and shallow trench isolations 22 surrounding the fins 20. In the present embodiment, the number of the fin structures 20 disposed in each of the active regions 14, 16, and 18 is four for example, but the number thereof can be arbitrarily adjusted according to the product requirements, and is not limited thereto.

In accordance with a preferred embodiment of the present invention, fin structure 20 is preferably formed by a Sidewall Image Transfer (SIT) technique, which generally includes: a layout pattern is provided to a computer system and is properly calculated to define a corresponding pattern in a photomask. Subsequently, a plurality of patterned sacrificial layers with equal distance and equal width are formed on the substrate through photoetching and etching processes, so that the respective appearances of the sacrificial layers are in a strip shape. Then, deposition and etching processes are sequentially performed to form spacers on the sidewalls of the patterned sacrificial layer. The sacrificial layer is then removed and an etching process is performed under the spacer to transfer the spacer pattern into the substrate, followed by a fin cut process (fin cut) to obtain a desired patterned structure, such as a patterned stripe fin. It is noted that, in general, the fin structure or bump 24 may remain partially on the surface of the substrate 12 outside the active regions 14, 16, 18 after the fin structure cutting process is performed, and may preferably have a height substantially lower than the height of the fin structure 20 in the active regions 14, 16, 18 but slightly higher than the surface of the substrate 12.

In addition, the fin structure 20 may be formed by forming a patterned mask (not shown) on the substrate 12, and then transferring the pattern of the patterned mask to the substrate 12 to form the fin structure 20 through an etching process. Alternatively, the fin structure 20 may be formed by first forming a patterned hard mask layer (not shown) on the substrate 12, and growing a semiconductor layer, such as a silicon germanium semiconductor layer, on the substrate 12 exposed by the patterned hard mask layer by an epitaxial process, wherein the semiconductor layer serves as the corresponding fin structure 20. These embodiments for forming the fin structure are all within the scope of the present invention.

A Shallow Trench Isolation (STI) 22 is then formed around the fin structure 20 or around the active regions 14, 16, 18 from the top view of fig. 1. In the present embodiment, the shallow trench isolation 22 is formed by first forming a silicon oxide layer on the substrate 12 and completely covering the fin structure 20 by a Flowable Chemical Vapor Deposition (FCVD) process. A portion of the silicon oxide layer is removed by an etching or Chemical Mechanical Polishing (CMP) process, such that the remaining silicon oxide layer is cut to be even with or slightly higher than the surface of the fin structure 20 to form the shallow trench isolation 22, wherein the active regions 14, 16 and the fin structure 20 of the active region 18 preferably protrude from the shallow trench isolation 22, and the shallow trench isolation 22 completely covers the bump 24.

A plurality of single-diffusion isolation structures are then formed on the substrate 12, such as single-diffusion isolation structures 26, 28 at the head and tail ends of the active region 14, single-diffusion isolation structures 30, 32 beside the active region 14, single-diffusion isolation structures 34, 36, 38 in the active region 16, single-diffusion isolation structures 42, 44 in the active region 18, and a single-diffusion isolation structure 40 extending from the active region 16 to the active region 18.

In the present embodiment, the method for forming the single-diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 may first perform a photolithography and etching process to remove the fin structures 20 in the active regions 14, 16, 18 along a second direction (e.g., Y direction) to form grooves (not shown) extending along the Y direction, and then fill the grooves with dielectric material to form the single-diffusion isolation structures. It should be noted that, although the single diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 are formed by etching the fin structure 20 after the shallow trench isolation 22 is formed in the present embodiment, the present invention is not limited to this sequence, and other embodiments of the present invention may choose to first etch the aforementioned recesses for defining the single diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, and then fill the recesses and the surrounding of the fin structure 20 with a dielectric material, thereby forming the single diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 and the shallow trench isolation 22 at the same time. In other words, the timing of the single-diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 in the present embodiment can be selected after the shallow trench isolation 22 is fabricated or formed together with the shallow trench isolation 22, and these variations are within the scope of the present invention.

In addition, the single-diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, and 44 disclosed in the present embodiment may be selected from the same materials or different materials as the isolation structure 22, and both may be selected from the group consisting of silicon oxide and silicon nitride, for example. For example, in the present embodiment, the shallow trench isolation 22 is preferably made of silicon oxide and the single diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 are preferably made of silicon nitride, but not limited to this combination of materials, such as the shallow trench isolation 22 and the single diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 are all made of silicon oxide, and these variations are within the scope of the present invention.

Gate lines 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70 or gate structures are then formed on fin structure 20 across active regions 14, 16, 18 and shallow trench isolation 22. In the present embodiment, the gate lines 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70 are fabricated by performing a pattern transfer process using a gate first (gate first) fabrication process, a high-k first (high-k first) fabrication process of a gate last (gate last) fabrication process, and a high-k dielectric layer (not shown) of a gate last fabrication process as masks according to the fabrication process requirements, a portion of gate material layer 74 and a portion of gate dielectric layer 72 are removed in a single etch or a sequential etch step, the patterned photoresist is then stripped to form gate lines 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, each comprised of a patterned gate dielectric layer 72 and a patterned gate material layer 74, on shallow trench isolations 22 and fin structure 20.

As seen in fig. 1, each gate line 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70 preferably extends along the same second direction (e.g., the Y direction) as the single diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 and interleaves the active regions 14, 16, 18 and the fin structure 20, wherein each single diffusion isolation structure 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 is located directly below each gate line 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 7, for example, single diffusion isolation structure 26 is located directly below gate line 48, single diffusion isolation structures 32, 42 are located directly below gate line 50, single diffusion isolation structure 34 is located directly below gate line 50, single diffusion isolation structures 28, 36, 44 are located directly below gate line 60, single diffusion isolation structures 30, 38 are located directly below gate line 64, and single diffusion isolation structure 40 is located directly below gate line 68.

In addition, in the present embodiment, dummy isolation structures 76 may be further disposed in the active regions 14, 16, 18, the fin structures 20 and the outermost periphery of the shallow trench isolations 22 of the gate lines 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, wherein no gate line passes through the dummy isolation structures 76, the dummy isolation structures 76 are preferably completed in the same step as the single diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, and the dummy isolation structures 76 and the shallow trench isolations 22 preferably comprise different materials, for example, the shallow trench isolations 22 of the present embodiment preferably comprise silicon oxide and the dummy isolation structures 76 preferably comprise silicon nitride.

In terms of the relationship among the single diffusion isolation structure, the active region and the gate line, the single diffusion isolation structure 30 is disposed under the gate line 64 and does not intersect any active region and the fin structure 20, the single diffusion isolation structure 38 is disposed under the same gate line 64 and intersects the active region 16 and the fin structure 20, and the single diffusion isolation structure 40 extends from one edge of the active region 16 to one edge of the active region 18 and is disposed under the gate line 68 and intersects the active regions 16 and 18 and the fin structure 20. In other words, the single-diffused isolation structures 40 are disposed directly under the gate lines 68 of the staggered active areas 16, directly under the gate lines 68 between the active areas 16 and 18, and directly under the gate lines 68 of the staggered active areas 18.

In addition, as seen in the cross-sections of fig. 2 and 3, the top surfaces of the single diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 are preferably aligned with the top surface of the shallow trench isolation 22, but the bottom surfaces of the single diffusion isolation structures 26, 28, 30, 32, 34, 36, 38, 40, 42, 44 may have different profiles and/or different depths than the bottom surface of the shallow trench isolation 22 depending on whether the single diffusion isolation structures interleave the fin structure 20. For example, as shown in fig. 2, the bottom of the single diffusion isolation structure 30 is preferably slightly lower than the bottom of the adjacent shallow trench isolation 20 and is planar because it does not intersect any active region 14, 16, 18 or fin structure 20, while the bottom of the single diffusion isolation structure 38 is preferably jagged because it etches the fin structure 20 down when a recess is formed to remove a portion of the fin structure 20 by etching as described above.

A subsequent mos transistor fabrication process may then be performed, such as by forming spacers around gate lines 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, forming source/drain regions and/or epitaxial layers in fin structure 20 and/or substrate 12 on either side of the spacers, and selectively forming a metal silicide (not shown) on the surface of the source/drain regions and/or epitaxial layers. Since the fabrication of mos transistors is well known in the art, further description is omitted here.

The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in the claims of the present invention should be covered by the present invention.