TW202339122A - Method for preparing memory device - Google Patents

Abstract

The present application provides a method for preparing a memory device having a word line (WL) with dual conductive materials. The method includes steps of providing a semiconductor substrate with an active area defined adjacent to a surface of the semiconductor substrate; forming a recess extending from the surface into the semiconductor substrate; disposing a first insulating layer conformal to the recess; disposing a first conductive material within the recess and surrounded by the first insulating layer; removing a portion of the first conductive material to form a first conductive member; disposing a second insulating layer within the recess and conformal to the first insulating layer and the first conductive member; and disposing a second conductive material within the recess and surrounded by the second insulating layer to form a second conductive member adjacent to the first conductive member.

Description

Preparation method of memory device

This application claims priority to U.S. Patent Application Nos. 17/695,972 and 17/696,058 (that is, the priority date is "March 16, 2022"), the contents of which are incorporated herein by reference in their entirety.

The present disclosure relates to a memory device. In particular, it relates to a memory device having one word line of dual conductive material.

Dynamic random access memory (DRAM) is a semiconductor device used to store multiple bits of data in individual capacitors within an integrated circuit (IC). DRAMs are typically formed as trench capacitor DRAM cells. An advanced method of fabricating a buried gate involves building a gate electrode of a transistor and a word line in a trench in an active area (AA) of a shallow trench isolation (STI) structure.

As semiconductor manufacturing technology has improved over the past few decades, the size of electronic components has decreased accordingly. As the size of a cell transistor decreases to several nanometers in length, leakage current may occur. Leakage current may significantly reduce the performance of these unit transistors. Therefore, it is desirable to develop improvements that address related manufacturing challenges.

An embodiment of the present disclosure provides a memory device. The memory device includes a semiconductor substrate having an active region defined adjacent a surface of the semiconductor substrate, wherein the semiconductor substrate has a recess extending from the surface into the semiconductor substrate; and a word line disposed on Within the recess; wherein the word line has a first isolation layer, a first conductive component, a second isolation layer and a second conductive component, the first isolation layer is disposed in the recess and conforms to the recess , the first conductive component is surrounded by the first isolation layer and is disposed in the recess, the second isolation layer is disposed conformally to the first isolation layer and the first conductive component, and the second conductive component is adjacent to the first conductive component. A conductive component is disposed and surrounded by the second isolation layer.

In some embodiments, a first work function of the first conductive component is substantially different from a second work function of the second conductive component.

In some embodiments, the first work function of the first conductive component is substantially greater than the second work function of the second conductive component.

In some embodiments, the first conductive component and the second conductive component include the same material.

In some embodiments, the first conductive component and the second conductive component include tungsten (W) or titanium nitride (TiN).

In some embodiments, the first isolation layer and the second isolation layer include oxide.

In some embodiments, the first conductive component is surrounded by the first isolation layer and the second isolation layer.

In some embodiments, the first conductive component and the second conductive component are separated by the second isolation layer.

In some embodiments, an upper surface of the first conductive component is substantially lower than an upper surface of the second conductive component.

In some embodiments, the upper surface of the first conductive component and the upper surface of the second conductive component are surrounded by the active region of the semiconductor substrate.

In some embodiments, a width of the upper surface of the first conductive component is substantially greater than or equal to a width of the upper surface of the second conductive component.

In some embodiments, the memory device further includes a dielectric layer disposed on the first conductive component, the second conductive component and the second isolation layer.

In some embodiments, the dielectric layer contacts the upper surface of the second conductive component.

In some embodiments, the memory device further includes a conductive plug extending through the dielectric layer and connected to the active region of the semiconductor substrate.

In some embodiments, at least a portion of the second isolation layer is disposed between the dielectric layer and an upper surface of the first conductive component.

In some embodiments, the dielectric layer includes nitride.

In some embodiments, a height of the first conductive component is substantially less than or equal to a height of the second conductive component.

Another embodiment of the present disclosure provides a memory device. The memory device includes a semiconductor substrate having an active region adjacent a surface of the semiconductor substrate, wherein the semiconductor substrate has a first recess extending from the surface into the semiconductor substrate; and a word line disposed In the first recess; wherein the word line has a first isolation layer, a first conductive component, a second isolation layer and a second conductive component, the first isolation layer is conformally disposed in the first recess and has a second recess in the first recess, the first conductive component is surrounded by the first isolation layer and is disposed in the second recess, and the second isolation layer is conformal to the second recess and the third recess. Two conductive components are disposed and have a third recess in the second recess, and the second conductive component is disposed in the third recess.

In some embodiments, the three recesses have a first width and a second width, the first width is located at a position adjacent to the first conductive component, and the second width is located at a position of the first conductive component. position and at the position with the first width.

In some embodiments, the second width is substantially different than the first width.

In some embodiments, the second width is substantially greater than the first width.

In some embodiments, a first work function of the first conductive component is substantially greater than a second work function of the second conductive component.

In some embodiments, the first work function of the first conductive component is approximately greater than 4 eV, and the second work function of the second conductive component is approximately less than 4 eV.

In some embodiments, a difference between the first work function and the second work function is approximately greater than 0.5 eV.

Another embodiment of the present disclosure provides a method of manufacturing a memory device. The preparation method includes providing a semiconductor substrate having an active region defined adjacent to a surface of the semiconductor substrate; forming a recess to extend from the surface into the semiconductor substrate; and providing a first isolation layer to conformally in the recess; disposing a first conductive material in the recess and surrounded by an isolation layer; removing a portion of the first conductive material to form a first conductive component; disposing a second isolation layer in the recess within and conformable to the first isolation layer and the first conductive component; and disposing a second conductive material in the recess and surrounded by the second isolation layer to form a second conductive component adjacent to the first conductive component. Conductive components.

In some embodiments, a first work function of the first conductive component is substantially different from a second work function of the second conductive component.

In some embodiments, the first work function of the first conductive component is substantially greater than the second work function of the second conductive component.

In some embodiments, the first conductive material is the same as the second conductive material.

In some embodiments, the preparation method further includes disposing a patterned photoresist on the first isolation layer and the first conductive material, wherein removing the portion of the first conductive component exposed through the patterned photoresist .

In some embodiments, the preparation method further includes removing the patterned photoresist after the first conductive component is formed.

In some embodiments, a portion of the second conductive component disposed on the first conductive component is removed to form the second conductive component.

In some embodiments, the preparation method further includes: disposing a dielectric layer on the first conductive component, the second conductive component and the second isolation layer; and forming a conductive plug to extend through the dielectric layer and connected to the active region of the semiconductor substrate.

In some embodiments, the second isolation layer is provided before the second conductive material is provided.

In some embodiments, the provision of the first conductive material is performed before the second conductive material is provided.

In some embodiments, the placement of the first conductive material and the placement of the second conductive material are performed separately.

In summary, because a word line includes dual conductive materials with different work functions, this difference can suppress or avoid a gate-induced drain leakage (GIDL). In some embodiments, this configuration may reduce GIDL problems because the word line includes a first conductive material with a high work function and a second conductive material with a low work function. Therefore, the performance of the memory device and a process for manufacturing the memory device are improved.

The technical features and advantages of the present disclosure have been summarized rather broadly above so that the detailed description of the present disclosure below may be better understood. Other technical features and advantages that constitute the subject matter of the patentable scope of the present disclosure will be described below. It should be understood by those of ordinary skill in the art that the concepts and specific embodiments disclosed below can be easily used to modify or design other structures or processes to achieve the same purposes of the present disclosure. Those with ordinary knowledge in the technical field to which the present disclosure belongs should also understand that such equivalent constructions cannot depart from the spirit and scope of the present disclosure as defined in the appended patent application scope.

Specific examples of components and configurations are described below to simplify embodiments of the present disclosure. Of course, these embodiments are only for illustration and are not intended to limit the scope of the present disclosure. For example, in the description, the first component is formed on the second component, which may include an embodiment in which the first and second components are in direct contact, or may include an additional component formed between the first and second components. An embodiment such that the first and second components are not in direct contact. In addition, embodiments of the present disclosure may repeat reference numbers and/or letters in many examples. These repetitions are for simplicity and clarity and do not in themselves represent a specific relationship between the various embodiments and/or configurations discussed unless otherwise specified herein.

Additionally, this disclosure may repeat element numbers and/or letters in various examples. This repetition is for simplicity and clarity and does not by itself define the relationship between the various embodiments and/or configurations discussed.

Furthermore, for ease of explanation, terms such as "beneath", "below", "lower", "above", "upper", etc. may be used in this article. Spatially relative terms are used to describe the relationship of one element or feature to another (other) element or feature shown in the figures. These spatially relative terms are intended to encompass different orientations of the elements in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

FIG. 1 is a schematic cross-sectional view illustrating a memory device according to an embodiment of the present disclosure. In some embodiments, the memory device 100 includes a plurality of unit cells arranged in rows and columns.

In some embodiments, memory device 100 includes a semiconductor substrate 101 . In some embodiments, semiconductor substrate 101 includes a semiconductor material such as silicon, germanium, gallium arsenide, or combinations thereof. In some embodiments, semiconductor substrate 101 includes bulk semiconductor material. In some embodiments, the semiconductor substrate 101 is a semiconductor wafer (eg, a silicon wafer) or a semiconductor-on-insulator (SOI) wafer (eg, a silicon-on-insulator wafer). In some embodiments, semiconductor substrate 101 is a silicon substrate. In some embodiments, semiconductor substrate 101 includes lightly doped single crystal silicon. In some embodiments, semiconductor substrate 101 is a p-type substrate.

In some embodiments, the semiconductor substrate 101 includes a plurality of active areas (AA) 101a. The active region 101a is a doped region in the semiconductor substrate 101. In some embodiments, active region 101 a extends horizontally above or directly above one of the upper surfaces of semiconductor substrate 101 . In some embodiments, the active region 101 a is disposed adjacent the upper surface of the semiconductor substrate 101 . In some embodiments, each active region 101a includes a same type of dopant. In some embodiments, each active region 101a includes a type of dopant that is different from the type of dopant included in other active regions 101a. In some embodiments, each active region 101a has a same conductivity type. In some embodiments, active region 101a includes n-type dopants.

In some embodiments, the semiconductor substrate 101 includes a first surface 101b and a second surface 101c, and the second surface 101c is disposed opposite to the first surface 101b. In some embodiments, the first surface 101b is a front side of the semiconductor substrate 101, where a plurality of electronic components or components are sequentially formed on the first surface 101b and configured to be electrically connected to an external circuit. In some embodiments, active region 101a is disposed adjacent to or below first surface 101b. In some embodiments, second surface 101c is a backside of semiconductor substrate 101 that is free of electronic components or components.

In some embodiments, the semiconductor substrate 101 includes a recess 102 extending into the semiconductor substrate 101 . In some embodiments, recess 102 extends from first surface 101 b toward second surface 101 c of semiconductor substrate 101 . In some embodiments, recess 102 tapers from first surface 101 b toward second surface 101 c of semiconductor substrate 101 . In some embodiments, recess 102 has a depth that is substantially greater than a depth of active region 101a.

In some embodiments, memory device 100 includes a word line 103 disposed within recess 102 . In some embodiments, the word line 103 includes a first isolation layer 103a, a first conductive component 103b, a second isolation layer 103c and a second conductive component 103d.

In some embodiments, the first isolation layer 103a is disposed in the recess 102 and conforms to the recess 102 . In some embodiments, at least a portion of first isolation layer 103a is surrounded by active region 101a. In some embodiments, the first isolation layer 103a covers an entire sidewall of the recess 102. In some embodiments, a portion of the first isolation layer 103a is disposed on the first surface 101b of the semiconductor substrate 101. In some embodiments, the first isolation layer 103a has a second recess 104 disposed in the recess 102.

In some embodiments, first isolation layer 103a includes a dielectric material, such as an oxide. In some embodiments, the first isolation layer 103a includes an isolation material, such as silicon oxide, silicon nitride, silicon oxynitride, the like, or combinations thereof. In some embodiments, the first isolation layer 103a includes a dielectric material with a low dielectric constant (low k value).

In some embodiments, the first conductive component 103b is surrounded by the first isolation layer 103a and is disposed within the recess 102. In some embodiments, the first conductive component 103b extends from the first surface 101b toward the second surface 101c of the semiconductor substrate 101 within the first isolation layer 103a. In some embodiments, the first conductive component 103b extends along a side wall of the first isolation layer 103a. In some embodiments, the first conductive component 103b is disposed within the second recess 104.

In some embodiments, the first conductive component 103b includes a first conductive material having a first work function. In some embodiments, the first work function of the first conductive component 103b is approximately greater than 4 eV. In some embodiments, the first work function of the first conductive component 103b ranges between approximately 1 eV and approximately 8 eV. In some embodiments, the first conductive component 103b includes a conductive material such as titanium nitride (TiN), tungsten (W), or the like.

In some embodiments, the second isolation layer 103c is disposed conformally to the first isolation layer 103a and the second conductive component 103b. In some embodiments, the second isolation layer 103c is disposed conformally to a portion of the second recess 104. In some embodiments, at least part of the second isolation layer 103c is surrounded by the active region 101a. In some embodiments, the second isolation layer 103c and the first isolation layer 103a surround the first conductive component 103b. In some embodiments, the second isolation layer 103c covers the first conductive component 103b.

In some embodiments, the second isolation layer 103c is formed along a portion of a sidewall of the first isolation layer 103a, a portion of a lower surface of the first isolation layer 103a, a portion of a sidewall of the first conductive component 103b, and the first conductive component An upper surface 103e of 103b extends. In some embodiments, a portion of the second isolation layer 103c is disposed on the first surface 101b of the semiconductor substrate 101.

In some embodiments, the second isolation layer 103c has a third recess 105 disposed in the second recess 104. In some embodiments, the third recess 105 has a first width W3 and a second width W4. The first width W3 is located at a position adjacent to the first conductive component 103b, and the second width W4 is located at a position adjacent to the first conductive component 103b. 103b and at the position having the first width W3. In some embodiments, the second width W4 is substantially different than the first width W3. In some embodiments, the second width W4 is substantially greater than the first width W3.

In some embodiments, the second isolation layer 103c includes a different material than the first isolation layer 103a. In some embodiments, the second isolation layer 103c includes the same material as the first isolation layer 103a. In some embodiments, second isolation layer 103c includes a dielectric material, such as an oxide. In some embodiments, the second isolation layer 103c includes an isolation material, such as silicon oxide, silicon nitride, silicon oxynitride, the like, or combinations thereof. In some embodiments, the second isolation layer 103c includes a dielectric material with a low dielectric constant (low k value).

In some embodiments, the second conductive component 103d is disposed adjacent to the first conductive component 103b and is surrounded by the second isolation layer 103c. In some embodiments, the second conductive component 103d extends from the first surface 101b toward the second surface 101c of the semiconductor substrate 101 within the second isolation layer 103c.

In some embodiments, the second conductive component 103d extends generally parallel to the first conductive component 103b. The second conductive component 103d and the first conductive component 103b are separated by a second isolation layer 103c. In some embodiments, the second conductive component 103d is disposed within the third recess 105. In some embodiments, the first conductive component 103b and the second conductive component 103d serve as a gate electrode.

In some embodiments, the upper surface 103e of the first conductive component 103b is substantially lower than an upper surface 103f of the second conductive component 103d. In some embodiments, the upper surface 103e of the first conductive component 103b and the upper surface 103f of the second conductive component 103d are surrounded by the active region 101a of the semiconductor substrate 101. In some embodiments, the upper surface 103f of the second conductive component 103d is substantially coplanar with a horizontal surface of the second isolation layer 103c.

In some embodiments, a width W1 of the upper surface 103e of the first conductive component 103b is substantially greater than or equal to a width W2 of the upper surface 103f of the second conductive component 103d. In some embodiments, a height H1 of the first conductive component 103b is substantially less than or equal to a height H2 of the second conductive component 103d.

In some embodiments, the second conductive component 103d includes a second conductive material having a second work function. In some embodiments, the first work function of the first conductive material 103b is substantially different than the second work function of the second conductive component 103d. In some embodiments, the first work function of the first conductive material 103b is substantially greater than the second work function of the second conductive component 103d.

In some embodiments, the second work function of the second conductive component 103d is approximately less than 4 eV. In some embodiments, the second work function of the second conductive component 103d is in the range of about 0.1 eV to about 1 eV. In some embodiments, a difference between the first work function of the first conductive material 103b and the second work function of the second conductive component 103d is approximately greater than 0.5 eV. In some embodiments, the second conductive component 103d includes a conductive material such as titanium nitride (TiN), tungsten (W), or the like. In some embodiments, the second conductive component 103d includes the same material as the first conductive component 103b.

In some embodiments, the memory device 100 further includes an insulating structure 106 disposed adjacent the word line 103 . In some embodiments, the insulating structure 106 extends into the semiconductor substrate 101 from the first surface 101 b toward the second surface 101 c of the semiconductor substrate 101 .

In some embodiments, isolation structure 106 is a shallow trench isolation (STI). In some embodiments, insulating structure 106 defines a boundary of active region 101a. In some embodiments, insulating structure 106 includes a dielectric material, such as an oxide. In some embodiments, the insulating structure 106 includes an isolation material such as silicon oxide, silicon nitride, silicon oxynitride, the like, or combinations thereof.

In some embodiments, a third conductive component 107 is surrounded by an insulating structure 106 . In some embodiments, the third conductive component 107 has a third work function that is substantially equal to the first work function of the first conductive component 103b. In some embodiments, the third work function of the third conductive component 107 is approximately greater than 4 eV. In some embodiments, the third conductive component 107 includes a conductive material such as titanium nitride (TiN), tungsten (W), or the like.

In some embodiments, a third isolation layer 108 is disposed on the third conductive component 107 and the insulating structure 106 . In some embodiments, the third isolation layer 108 includes the same material as the second isolation layer 103c. In some embodiments, third isolation layer 108 includes a dielectric material, such as an oxide. In some embodiments, the third isolation layer 108 includes an isolation material such as silicon oxide, silicon nitride, silicon oxynitride, the like, or combinations thereof.

In some embodiments, the memory device 100 further includes a dielectric layer 109 disposed on the first conductive component 103b, the second conductive component 103d, the second isolation layer 103c, the third conductive component 107 and the third isolation layer 108 . In some embodiments, the dielectric layer 109 contacts the second isolation layer 103c, the third isolation layer 108, and the upper surface 103f of the second conductive component 103d.

In some embodiments, at least a portion of the second isolation layer 103c is disposed between the dielectric layer 109 and the upper surface 103e of the first conductive component 103b. In some embodiments, dielectric layer 109 includes a dielectric material, such as nitride. In some embodiments, dielectric layer 109 acts as a gate dielectric.

In some embodiments, the memory device 100 further includes a conductive plug 110 extending through the dielectric layer 109 and connected to the active region 101 a of the semiconductor substrate 101 . In some examples, the conductive plug 110 extends through the first isolation layer 103a and the second isolation layer 103c. In some embodiments, a portion of the conductive plug 110 protrudes into the semiconductor substrate 101 or the active region 101a of the semiconductor substrate 101, so that the portion of the conductive plug 110 is covered by the semiconductor substrate 101 or the active region 101a of the semiconductor substrate 101. surrounded by. In some embodiments, conductive plug 110 includes a conductive material, such as metal. In some embodiments, conductive plug 110 includes copper, gold, silver, or the like.

Since word line 103 includes dual conductive materials with different work functions, this difference can suppress or avoid a gate-induced drain leakage (GIDL). In some embodiments, this configuration may reduce GIDL problems because word line 103 includes a first conductive component 103b having the high work function and a second conductive component 103d having the low work function. Therefore, the performance of the memory device 100 can be improved.

FIG. 2 is a schematic flowchart illustrating a method S200 for manufacturing the memory device 100 according to an embodiment of the present disclosure. 3 to 20 are schematic cross-sectional views illustrating various intermediate stages of preparing the memory device 100 according to an embodiment of the present disclosure.

The stages shown in Figures 3 to 20 are also schematically shown in the flow chart of Figure 2 . In the following discussion, the various manufacturing stages shown in FIGS. 3 through 20 are discussed with reference to the process steps shown in FIG. 2 . The preparation method S200 includes multiple steps, and the description and explanation are not considered to limit the order of the steps. The preparation method S200 includes many steps (S201, S202, S203, S204, S205, S206 and S207).

Please refer to FIGS. 3 to 5 . According to step S201 in FIG. 2 , a semiconductor substrate 101 is provided. The semiconductor substrate 101 has an active region 101 a defined adjacent to a first surface 101 b of the semiconductor substrate 101 . In some embodiments, as shown in FIG. 3 , a semiconductor substrate 101 having a first surface 101 b and a second surface 101 c is provided, and the second surface 101 c is disposed opposite the first surface 101 b. In some embodiments, as shown in FIG. 4 , a groove 111 is formed, and the groove 111 extends from the first surface 101 b toward the second surface 101 c. The fabrication technique of trench 111 involves removing portions of semiconductor substrate 101 .

In some embodiments, the semiconductor substrate 101 includes an insulating structure 106 disposed around the active region 101a. In some embodiments, the insulating structure 106 extends from the first surface 101 b toward the second surface 101 c of the semiconductor substrate 101 . In some embodiments, insulating structure 106 includes a dielectric material such as an oxide or the like. In some embodiments, as shown in FIG. 5 , the manufacturing technique of the insulating structure 106 includes disposing an insulating material into the trench 111 .

Referring to FIG. 6 , according to step S202 in FIG. 2 , a recess 102 is formed, and the recess 102 extends from the first surface 101 b into the semiconductor substrate 101 . In some embodiments, the fabrication technique of recess 102 includes removing portions of semiconductor substrate 101 . In some embodiments, these portions of semiconductor substrate 101 are removed by etching or any other suitable process. In some embodiments, recess 102 is at least partially surrounded by active region 101 a of semiconductor substrate 101 . In some embodiments, a portion of the insulating structure 106 is removed.

Please refer to FIG. 7 . According to step S203 in FIG. 2 , a first isolation layer 103 a is disposed conformally to the recess 102 . In some embodiments, the first isolation layer 103a is disposed on the first surface 101b of the semiconductor substrate 101. In some embodiments, the first isolation layer 103a covers an entire sidewall of the recess 102. In some embodiments, first isolation layer 103a includes a dielectric material, such as an oxide. In some embodiments, the first isolation layer 103a and the insulating structure 106 include the same material. In some embodiments, the manufacturing technology of the first isolation layer 103a includes deposition, oxidation or any other suitable process.

Referring to FIG. 8 , according to step S204 in FIG. 2 , a first conductive material 112 is provided. In some embodiments, first conductive material 112 is disposed within recess 102 and is surrounded by first isolation layer 103a. In some embodiments, the first conductive material 112 is also disposed in the trench 111 and surrounded by the insulating structure 106 . In some embodiments, at least a portion of the first conductive material 112 is surrounded by the active region 101 a of the semiconductor substrate 101 . In some embodiments, the manufacturing technology of the first conductive material 112 includes deposition, chemical vapor deposition (CVD), or any other suitable process.

In some embodiments, the first conductive material 112 has a first work function that is approximately greater than 4 eV. In some embodiments, the first conductive material 112 is titanium nitride (TiN), tungsten (W), or the like.

Referring to FIGS. 9 to 12 , according to step S205 in FIG. 2 , a portion of the first conductive material 112 is removed to form a first conductive component 103b. In some embodiments, as shown in Figure 9, a photoresist 114' is disposed on the first conductive material 112, the first isolation layer 103a and the insulating structure 106. In some embodiments, the manufacturing technique of the photoresist 114' includes spin coating or any other suitable process.

In some embodiments, as shown in Figure 10, after disposing the photoresist 114', a portion of the photoresist 114' is removed to form a patterned photoresist 114. In some embodiments, a portion of first conductive material 112 is exposed via patterned photoresist 114 . In some embodiments, the portion of first conductive material 112 is disposed within recess 102 and is surrounded by first isolation layer 103a.

In some embodiments, as shown in FIG. 11 , the portion of the first conductive material 112 exposed through the patterned photoresist 114 is removed. In some embodiments, the portion of first conductive material 112 exposed through patterned photoresist 114 is removed by etching or any other suitable process.

In some embodiments, as shown in FIG. 12 , after removing the portion of the first conductive material 112 exposed through the patterned photoresist 114 , the patterned photoresist 114 is removed and the first conductive component 103 b is formed. In some embodiments, an upper surface 103e of the first conductive component 103b is formed. In some embodiments, patterned photoresist 114 is removed by etching, stripping, or any other suitable process.

In some embodiments, a third conductive component 107 is also formed in the trench 111 and surrounded by the insulating structure 106 . In some embodiments, the first conductive component 103b and the third conductive component 107 are formed simultaneously or separately.

Please refer to FIG. 13. According to step S206 in FIG. 2, a second isolation layer 103c is disposed in the recess 102 and is configured conformally to the first isolation layer 103a and the first conductive component 103b. In some embodiments, the second isolation layer 103c covers the first conductive component 103b and the third conductive component 107. In some embodiments, the second isolation layer 103c is also disposed on the first surface 101b of the semiconductor substrate 101.

In some embodiments, the first conductive component 103b is surrounded by the second isolation layer 103c and the first isolation layer 103a. In some embodiments, second isolation layer 103c includes a dielectric material, such as an oxide. In some embodiments, the manufacturing technology of the second isolation layer 103c includes deposition, atomic layer deposition (ALD), or any other suitable process.

Please refer to Figures 14 and 15. According to step S207 in Figure 2, a second conductive material 113 is disposed in the recess 102 and surrounded by the second isolation layer 103c to form a second conductive element adjacent to the first conductive component 103b. Component 103d. In some embodiments, as shown in Figure 14, the second conductive material 113 is disposed on the second isolation layer 103c. In some embodiments, the manufacturing technology of the second conductive material 113 includes deposition, chemical vapor deposition (CVD), or any other suitable process.

In some embodiments, the placement of the second isolation layer 103c is performed before the second conductive material 113 is placed. In some embodiments, the provision of the first conductive material 112 is performed before the second conductive material 113 is provided. In some embodiments, the placement of the first conductive material 112 and the placement of the second conductive material 113 are performed separately.

In some embodiments, as shown in Figure 15, some portions of the second conductive material 113 are removed to form the second conductive component 103s. In some embodiments, portions of the second conductive material 113 are removed by etching or any other suitable process. In some embodiments, a portion of the second conductive material 113 disposed on the first conductive component 103b is removed to form the second conductive component 103d.

In some embodiments, a portion of the second conductive material 113 on the third conductive component 107 is removed. In some embodiments, a portion of the second conductive material 113 is removed until an upper surface 103f of the second conductive component 103d is coplanar with a surface of a horizontal portion of the second isolation layer 103c.

In some embodiments, the upper surface 103e of the first conductive component 103b is substantially lower than the upper surface 103f of the second conductive component 103d. In some embodiments, the upper surface 103e of the first conductive component 103b and the upper surface 103f of the second conductive component 103d are surrounded by the active region 101a of the semiconductor substrate 101.

In some embodiments, the second conductive material 113 has a second work function that is substantially different from the first work function of the first conductive material 112 . In some embodiments, the first work function of the first conductive material 113 is substantially greater than the second work function of the second conductive material 113 . In some embodiments, the second work function of the second conductive material 113 is approximately less than 4 eV.

In some embodiments, a difference between the first work function of the first conductive material 112 and the second work function of the second conductive material 113 is approximately greater than 0.5 eV. In some embodiments, the second conductive material 113 is titanium nitride (TiN), tungsten (W), or the like. In some embodiments, the second conductive material 113 includes the same material as the first conductive material 112 .

In some embodiments, as shown in Figure 16, after forming the second conductive component 103d, a dielectric material 109' is disposed on the second isolation layer 103c and the second conductive component 103d. In some embodiments, the fabrication technique of dielectric material 109' includes deposition, CVD, or any other suitable process. In some embodiments, dielectric material 109' is nitride or the like.

In some embodiments, as shown in Figure 17, after the dielectric material 109' is provided, a portion of the dielectric material 109' is removed to form a dielectric layer 109. In some embodiments, the portion of dielectric material 109' is removed by etching or any other suitable process. In some embodiments, a portion of second isolation layer 103c is exposed via dielectric layer 109.

In some embodiments, as shown in FIG. 18 , the portion of the second isolation layer 103c exposed through the dielectric layer 109 is removed. In some embodiments, a portion of the first isolation layer 103a exposed through the dielectric layer 109 is also removed. The removal of the portion of the second isolation layer 103c exposed through the dielectric layer 109 and the removal of the portion of the first isolation layer 103a exposed through the dielectric layer 109 are accomplished by etching or any other suitable process. In some embodiments, as shown in FIG. 19 , a portion of the semiconductor substrate 101 exposed through the dielectric layer 109 is also removed.

In some embodiments, as shown in FIG. 20 , after removing the portion of the first isolation layer 103 a exposed through the dielectric layer 109 and removing the portion of the second isolation layer 103 c exposed through the dielectric layer 109 , A conductive plug 110 is formed on the active region 101a of the semiconductor substrate 101. In some embodiments, the manufacturing technique of the conductive plug 110 includes disposing a conductive material. In some embodiments, the manufacturing technology of the conductive material includes electroplating or any other suitable process.

In some embodiments, conductive plug 110 extends through dielectric layer 109 and connects to active region 101 a of semiconductor substrate 101 . In some embodiments, the conductive plug 110 is electrically connected to the word line 103 via the active region 101 a of the semiconductor substrate 101 . In some embodiments, as shown in Figure 20, the memory device 100 of Figure 1 is formed.

An embodiment of the present disclosure provides a memory device. The memory device includes a semiconductor substrate having an active region defined adjacent a surface of the semiconductor substrate, wherein the semiconductor substrate has a recess extending from the surface into the semiconductor substrate; and a word line disposed on Within the recess; wherein the word line has a first isolation layer, a first conductive component, a second isolation layer and a second conductive component, the first isolation layer is disposed in the recess and conforms to the recess , the first conductive component is surrounded by the first isolation layer and is disposed in the recess, the second isolation layer is disposed conformally to the first isolation layer and the first conductive component, and the second conductive component is adjacent to the first conductive component. A conductive component is disposed and surrounded by the second isolation layer.

Another embodiment of the present disclosure provides a memory device. The memory device includes a semiconductor substrate having an active region adjacent a surface of the semiconductor substrate, wherein the semiconductor substrate has a first recess extending from the surface into the semiconductor substrate; and a word line disposed In the first recess; wherein the word line has a first isolation layer, a first conductive component, a second isolation layer and a second conductive component, the first isolation layer is conformally disposed in the first recess and has a second recess in the first recess, the first conductive component is surrounded by the first isolation layer and is disposed in the second recess, and the second isolation layer is conformal to the second recess and the third recess. Two conductive components are disposed and have a third recess in the second recess, and the second conductive component is disposed in the third recess.

Another embodiment of the present disclosure provides a method of manufacturing a memory device. The preparation method includes providing a semiconductor substrate having an active region defined adjacent to a surface of the semiconductor substrate; forming a recess to extend from the surface into the semiconductor substrate; and providing a first isolation layer to conformally in the recess; disposing a first conductive material in the recess and surrounded by an isolation layer; removing a portion of the first conductive material to form a first conductive component; disposing a second isolation layer in the recess within and conformable to the first isolation layer and the first conductive component; and disposing a second conductive material in the recess and surrounded by the second isolation layer to form a second conductive component adjacent to the first conductive component. Conductive components.

In summary, because a word line includes dual conductive materials with different work functions, this difference can suppress or avoid a gate-induced drain leakage (GIDL). In some embodiments, this configuration may reduce GIDL problems because the word line includes a first conductive material with a high work function and a second conductive material with a low work function. Therefore, the performance of the memory device and a process for manufacturing the memory device are improved.

Although the disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and substitutions can be made without departing from the spirit and scope of the disclosure as defined by the claimed claims. For example, many of the processes described above may be implemented in different ways and replaced with other processes or combinations thereof.

Furthermore, the scope of the present application is not limited to the specific embodiments of the process, machinery, manufacture, material compositions, means, methods and steps described in the specification. Those skilled in the art can understand from the disclosure content of this disclosure that existing or future developed processes, machinery, manufacturing, etc. that have the same functions or achieve substantially the same results as the corresponding embodiments described herein can be used according to the present disclosure. A material composition, means, method, or step. Accordingly, such processes, machines, manufacturing, material compositions, means, methods, or steps are included in the patentable scope of this application.

100:Memory components 101:Semiconductor substrate 101a: Active area 101b: First surface 101c: Second surface 102:dent 103: character line 103a: First isolation layer 103b: First conductive component 103c: Second isolation layer 103d: Second conductive component 103e: Upper surface 103f: Upper surface 104:Second depression 105:Third depression 106:Insulation structure 107:Third conductive component 108:Third isolation layer 109: Dielectric layer 109’: Dielectric material 110: Conductive plug 111:Trench 112: First conductive material 113: Second conductive material 114:Patterned photoresist 114’: Photoresist H1: height H2: height S200: Preparation method S201: Steps S202: Step S203: Step S204: Step S205: Step S206: Step S207: Step W1: Width W2: Width W3: first width W4: Second width

Aspects of the present disclosure are best understood from the following detailed description when read in conjunction with the drawings. Note that, consistent with standard industry practice, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or decreased for clarity of discussion. FIG. 1 is a schematic cross-sectional view illustrating a memory device according to an embodiment of the present disclosure. FIG. 2 is a schematic flowchart illustrating a method for manufacturing a memory device according to an embodiment of the present disclosure. 3 to 20 are schematic cross-sectional views illustrating various intermediate stages of preparing a memory device according to an embodiment of the present disclosure.

100:Memory components

101:Semiconductor substrate

101a: Active area

101b: First surface

101c: Second surface

102:dent

103: character line

103a: First isolation layer

103b: First conductive component

103c: Second isolation layer

103d: Second conductive component

103e: Upper surface

103f: Upper surface

104:Second depression

105:Third depression

106:Insulation structure

107:Third conductive component

108:Third isolation layer

109: Dielectric layer

110: Conductive plug

H1: height

H2: height

W1: Width

W2: Width

W3: first width

W4: Second width

Claims (16)

A method for preparing memory components, including: providing a semiconductor substrate having an active region defined adjacent a surface of the semiconductor substrate; forming a recess to extend from the surface into the semiconductor substrate; disposing a first isolation layer to conform to the recess; disposing a first conductive material in the recess and surrounded by an isolation layer; removing a portion of the first conductive material to form a first conductive component; disposing a second isolation layer in the recess and conforming to the first isolation layer and the first conductive component; and A second conductive material is disposed in the recess and surrounded by the second isolation layer to form a second conductive component adjacent to the first conductive component. The preparation method of claim 1, wherein a first work function of the first conductive component is substantially different from a second work function of the second conductive component. The preparation method of claim 2, wherein the first work function of the first conductive component is substantially greater than the second work function of the second conductive component. The preparation method of claim 1, wherein the first conductive material is the same as the second conductive material. The preparation method of claim 1, further comprising disposing a patterned photoresist on the first isolation layer and the first conductive material, wherein removing the portion of the first conductive component exposed through the patterned photoresist part. The preparation method of claim 5 further includes removing the patterned photoresist after the first conductive component is formed. The preparation method of claim 1, wherein a portion of the second conductive component disposed on the first conductive component is removed to form the second conductive component. The preparation method as described in claim 1 also includes: disposing a dielectric layer on the first conductive component, the second conductive component and the second isolation layer; and A conductive plug is formed to extend through the dielectric layer and connect to the active region of the semiconductor substrate. The preparation method of claim 1, wherein the second isolation layer is provided before the second conductive material is provided. The preparation method of claim 1, wherein the first conductive material is disposed before the second conductive material is disposed. The preparation method as claimed in claim 1, wherein the arrangement of the first conductive material and the arrangement of the second conductive material are performed separately. The preparation method of claim 2, wherein the first work function of the first conductive component is approximately greater than 4 eV, and the second work function of the second conductive component is approximately less than 4 eV. The preparation method as claimed in claim 2, wherein a difference between the first work function and the second work function is approximately greater than 0.5 eV. The preparation method of claim 1, wherein an upper surface of the first conductive component is substantially lower than an upper surface of the second conductive component. The preparation method of claim 14, wherein the upper surface of the first conductive component and the upper surface of the second conductive component are surrounded by the active region of the semiconductor substrate. The preparation method of claim 14, wherein a width of the upper surface of the first conductive component is substantially greater than or equal to a width of the upper surface of the second conductive component.