Semiconductor device and manufacturing method thereof
By designing a material layer structure at the first corner sidewall of the trench that is close to the inside of the trench and adjusted to the minimum thickness, the problem of difficult trench sealing was solved, and a smooth sealing process was achieved.
Patent Information
- Application Number
- CN202511072748.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-31
- Publication Date
- 2025-11-07
AI Technical Summary
In semiconductor devices, the difficulty in sealing trenches is particularly evident in the sealing process of MIM capacitors in DTC structures, where the cross-sectional dimensions at the corners are larger than those in other areas, making sealing difficult.
The first corner sidewall of the trench is designed to be closer to the inside of the trench than the extension surfaces of the first and second sub-sidewalls, and the thickness of the first material layer in the cross-section is the minimum thickness. The second corner sidewall can be designed as a curved surface to adjust the distance and shape at the corner.
This avoids the formation of sharp protrusions at the corners of the trench in the first material layer, ensuring a smooth sealing process and solving the problem of difficult trench sealing.
Smart Images
Figure CN120916447A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of semiconductor integrated circuits, and in particular to a semiconductor device and a manufacturing method thereof. BACKGROUND
[0002] With the increasing demand for new energy and interconnection density, decoupling capacitors need to be used on an interposer (silicon interposer) to solve the increasingly serious EMI (Electromagnetic Interference) problem. A DTC (Deep Trench Capacitor) structure is composed of a trench with a large aspect ratio and a MIM (Metal-Insulator-Metal) capacitor. During chip manufacturing, the DTC structure is formed and then sealed to prevent the MIM capacitor from being oxidized.
[0003] However, it is difficult to seal the trench after the MIM capacitor is formed in the trench. SUMMARY
[0004] The present application aims to provide a semiconductor device and a manufacturing method thereof, which can solve the problem of difficulty in sealing the trench.
[0005] To solve the above technical problems, according to a first aspect of the present application, a semiconductor device is provided, comprising:
[0006] a substrate, a trench is formed in the substrate, the trench comprises a first sidewall, the first sidewall comprises a first sub-sidewall, a second sub-sidewall, and a first corner sidewall connecting the first sub-sidewall and the second sub-sidewall, the first corner sidewall is closer to the inside of the trench relative to the included angle formed by the first sub-sidewall and the second sub-sidewall;
[0007] a first material layer is formed at least on the first sidewall, the first material layer comprises the first sidewall and a second sidewall away from the first sidewall, and the thickness of the first material layer formed on the first corner sidewall in the cross-section is the minimum thickness of the first material layer.
[0008] Optionally, the second sidewall comprises a second corner sidewall corresponding to the first corner sidewall, the distance between the first corner sidewall and the second corner sidewall is adjusted according to the shape of the second sidewall, so that the second corner sidewall is a curved surface.
[0009] Optionally, before the first material layer is formed, the cross-section of the first corner sidewall comprises a straight line;
[0010] After the first material layer is formed, the straight line becomes a curved line.
[0011] Optionally, the straight line comprises a first straight line and a second straight line, wherein the first straight line extends along a first direction, the second straight line extends along a second direction, and the first straight line intersects the second straight line.
[0012] Optionally, the semiconductor device further comprises:
[0013] a second material layer formed on a side of the first material layer away from the substrate, the second material layer comprising a first conductive material, a second conductive material, and a dielectric layer between the first conductive material and the second conductive material arranged in sequence; and
[0014] a third material layer formed on a side of the second material layer away from the substrate and filling the trench.
[0015] Optionally, the second material layer comprises the second sidewall and a third sidewall away from the second sidewall, and the third sidewall has the same cross-sectional shape as the second sidewall.
[0016] To solve the above technical problems, according to a second aspect of the present application, a semiconductor device forming method is provided, comprising:
[0017] providing a substrate, forming a trench in the substrate, the trench comprising a first sidewall, the first sidewall comprising a first sub-sidewall, a second sub-sidewall, and a first corner sidewall connecting the first sub-sidewall and the second sub-sidewall, the first corner sidewall being closer to the inside of the trench relative to the included angle formed by the first sub-sidewall and the second sub-sidewall;
[0018] forming a first material layer on at least the first sidewall, the first material layer comprising the first sidewall and a second sidewall away from the first sidewall, and the thickness of the first material layer formed on the first corner sidewall in cross-section being the minimum thickness of the first material layer.
[0019] Optionally, the second sidewall comprises a second corner sidewall corresponding to the first corner sidewall, and the distance between the first corner sidewall and the second corner sidewall is adjusted according to the shape of the second sidewall so that the second corner sidewall is curved.
[0020] Optionally, before forming the first material layer, the first corner sidewall in cross-section comprises a straight line;
[0021] After forming the first material layer, the straight line becomes a curved line.
[0022] Optionally, the trench is formed in the substrate by a mask, the mask comprises a first pattern, and the trench in cross-section comprises a second pattern.
[0023] The first pattern is the same as the second pattern; or,
[0024] The first pattern is different from the second pattern, and the first pattern is changed to the second pattern by using OPC correction when forming the trench in the substrate by the mask.
[0025] Optionally, the first material layer is formed by a thermal oxidation process, and a material of the first material layer comprises silicon oxide.
[0026] Optionally, a second material layer is formed on a side of the first material layer away from the substrate, the second material layer comprises a first conductive material, a second conductive material and a dielectric layer between the first conductive material and the second conductive material which are sequentially stacked; and,
[0027] A third material layer is formed on a side of the second material layer away from the substrate, and the third material layer fills the trench.
[0028] Optionally, the second material layer comprises the second side wall and a third side wall away from the second side wall, and the third side wall has the same cross-sectional shape as the second side wall.
[0029] The semiconductor device and the manufacturing method thereof provided by the application form a trench in a substrate, the trench comprises a first side wall, the first side wall comprises a first sub-side wall, a second sub-side wall and a first corner side wall connecting the first sub-side wall and the second sub-side wall, the first corner side wall is closer to the inside of the trench relative to an included angle formed by the extension surfaces of the first sub-side wall and the second sub-side wall, a first material layer is formed at least on the first side wall, the first material layer comprises the first side wall and a second side wall away from the first side wall, and the thickness of the first material layer formed on the first corner side wall in the cross section is the minimum thickness of the first material layer. In the application, the first corner side wall of the trench is closer to the inside of the trench relative to the included angle formed by the extension surfaces of the first sub-side wall and the second sub-side wall, and the thickness of the first material layer formed on the first corner side wall in the cross section is the minimum thickness of the first material layer, so that the first material layer does not form a sharp protrusion at the first corner side wall of the trench, and thus the width of the opening surrounded by the first material layer at the corner is greater than the width of the remaining area after the first material layer is formed, thereby facilitating the subsequent sealing of the trench and avoiding the problem that the trench is difficult to seal.
[0030] Further, by designing the second corner sidewall as a curved surface, the distance between the first corner sidewall and the second corner sidewall can be adjusted according to the growth rate of the first material layer at the corner of the trench and the shape of the second corner sidewall, so as to obtain a designed shape of the trench. BRIEF DESCRIPTION OF DRAWINGS
[0031] Figure 1 is a cross-sectional schematic view of a trench formed in a substrate in an embodiment.
[0032] Figure 2 is a cross-sectional schematic view of a trench after a first material layer is formed in the trench in an embodiment.
[0033] Figure 3 is a scanning electron microscope photo of a trench after a first material layer is formed in an embodiment.
[0034] Figure 4 is a cross-sectional schematic view of a trench formed in a substrate in an embodiment.
[0035] Figure 5 is a cross-sectional schematic view of a trench after a first material layer is formed in an embodiment.
[0036] Figure 6 is a cross-sectional schematic view of a trench after a third material layer is formed in an embodiment.
[0037] Figure 7 is a cross-sectional schematic view of a trench in an embodiment.
[0038] Figure 8 is a cross-sectional schematic view of a trench formed in a substrate in an embodiment.
[0039] Figure 9 is a cross-sectional schematic view of a trench after a first material layer is formed in an embodiment.
[0040] Figure 10 is a cross-sectional schematic view of a trench after a third material layer is formed in an embodiment.
[0041] Figure 11 is a cross-sectional schematic view of a trench in an embodiment.
[0042] Figure 12 is a scanning electron microscope photo of a trench after a first material layer is formed in an embodiment.
[0043] Figure 13 is a flow chart of a semiconductor device forming method in an embodiment.
[0044] Reference Signs List:
[0045] Figure 1 With Figure 2 : 1 - substrate; 2 - trench; 3 - first material layer.
[0046] Figures 4 to 6 , Figures 8 to 10 : 10 - substrate; 20 - trench; 21 - first sidewall; 211 - first sub- sidewall; 212 - second sub-sidewall; 213 - first corner sidewall; 30 - first material layer; 31 - second sidewall; 313 - second corner sidewall; 40 - second material layer; 41 - first conductive material; 42 - dielectric layer; 43 - second conductive material; 50 - third material layer. DETAILED DESCRIPTION
[0047] After the trench is formed in the DTC structure, thermal oxidation is performed to form an oxide layer, then the MIM capacitor is formed on the oxide layer, the MIM capacitor does not completely fill the trench, finally ALD (Atomic Layer Deposition) process is used to form silicon oxide to seal, but in the process of filling the above-mentioned materials in the trench, the cross-sectional size of the corner is larger than that of the remaining area, which finally leads to the difficulty of sealing after filling the DTC with plate material.
[0048] Figure 1 is a cross-sectional view after forming a trench in a substrate in an embodiment, Figure 2 is a cross-sectional view after forming a first material layer in the trench in an embodiment. Please refer to Figure 1 , a substrate 1 is provided, a trench 2 is formed in the substrate 1, the cross section of the trench 2 is rectangular, the corners of the rectangle can be slightly rounded, which is determined by the process conditions of actual manufacturing. Please refer to Figure 2 , thermal oxidation is performed, a first material layer 3 (i.e. thermal oxide layer) is formed on the sidewall and bottom of the trench 2, the growth rate of the first material layer 3 at the corner of the sidewall (i.e. the two ends of the rectangle in Figure 1 ) is slower than that in the middle area of the sidewall (i.e. the middle area of the rectangle in Figure 1 ), that is, the thickness of the first material layer 3 grown at the corner is thin, after the formation of the first material layer 3, the cross-sectional size of the opening surrounded by the first material layer 3 at the corner is larger than that of the remaining area, forming a structure as shown in Figure 2 .
[0049] Figure 3 is a scanning electron microscope photo of the trench after forming the first material layer in an embodiment. Please refer to Figure 3As shown, after the first material layer 3 is formed, the cross-sectional size of the opening surrounded by the first material layer 3 at the corner is larger than that of the remaining area, and after the MIM capacitor is formed in the opening surrounded by the first material layer 3, the plate of the MIM capacitor is easy to be oxidized, and the corner also forms a water vapor condensation defect, which reduces the yield, so the trench needs to be sealed, and silicon oxide is generally formed by ALD process to seal. However, due to the cross-sectional size of the opening surrounded by the first material layer 3 at the corner is larger than that of the remaining area, after the MIM capacitor is formed, the MIM capacitor forms a sharp protrusion at the corner, so that the cross-sectional size of the opening surrounded by the MIM capacitor at the corner is larger than that of the remaining area, which further causes the ALD process to be difficult to seal.
[0050] Through further research, the present application provides a semiconductor device, comprising the following steps: a substrate, a trench is formed in the substrate, the trench comprises a first sidewall, the first sidewall comprises a first sub-sidewall, a second sub-sidewall, and a first corner sidewall connecting the first sub-sidewall and the second sub-sidewall, the first corner sidewall is closer to the inside of the trench relative to the included angle formed by the extension surfaces of the first sub-sidewall and the second sub-sidewall; a first material layer is formed at least on the first sidewall, the first material layer comprises the first sidewall and a second sidewall away from the first sidewall, and the thickness of the first material layer formed on the first corner sidewall in the cross section is the minimum thickness of the first material layer.
[0051] Correspondingly, the present application also provides a semiconductor device forming method, comprising: providing a substrate, forming a trench in the substrate, the trench comprises a first sidewall, the first sidewall comprises a first sub-sidewall, a second sub-sidewall, and a first corner sidewall connecting the first sub-sidewall and the second sub-sidewall, the first corner sidewall is closer to the inside of the trench relative to the included angle formed by the extension surfaces of the first sub-sidewall and the second sub-sidewall; forming a first material layer at least on the first sidewall, the first material layer comprises the first sidewall and a second sidewall away from the first sidewall, and the thickness of the first material layer formed on the first corner sidewall in the cross section is the minimum thickness of the first material layer.
[0052] The semiconductor device and the manufacturing method thereof provided by the application, the first corner sidewall of the trench is closer to the inside of the trench relative to the included angle formed by the first sub-sidewall and the second sub-sidewall, and the thickness of the first material layer formed on the first corner sidewall in the cross section is the minimum thickness of the first material layer, so that the first material layer is prevented from forming a sharp protrusion at the first corner sidewall of the trench, and the width of the opening surrounded by the first material layer at the corner is prevented from being greater than the width of the remaining area after the first material layer is formed, thereby facilitating the subsequent sealing of the trench and avoiding the problem of difficult sealing of the trench.
[0053] To make the objectives, advantages and features of the present application clearer, the following further describes the present application in detail in connection with the drawings and specific embodiments. It should be noted that the drawings are very simplified and not drawn to scale, and are only used to facilitate and clarify the purpose of describing the embodiments of the present application. In addition, the structures shown in the drawings are often part of the actual structures. In particular, different scales are sometimes used in the drawings to show different focuses.
[0054] As used in the present application, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in the present application, the term "or" is generally employed in its sense of "and / or" unless the content clearly dictates otherwise. As used in the present application, the term "several" is generally employed in its sense of "at least one" unless the content clearly dictates otherwise. As used in the present application, the term "at least two" is generally employed in its sense of "two or more" unless the content clearly dictates otherwise. In addition, the terms "first," "second," "third," are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first," "second," "third" can explicitly or implicitly include one or at least two features unless the content clearly dictates otherwise.
[0055] In the present application, a trench is formed in a substrate, the first corner sidewall of the trench is closer to the inside of the trench relative to the included angle formed by the first sub-sidewall and the second sub-sidewall, i.e. the first corner sidewall of the trench is contracted towards the inside of the trench, and the thickness of the first material layer formed on the first corner sidewall in the cross section is the minimum thickness of the first material layer after the first material layer is formed, thereby facilitating the subsequent sealing of the trench and avoiding the problem of difficult sealing of the trench. The following describes two embodiments.
[0056]
Embodiment One
[0057] Figure 4is a cross-sectional view of the embodiment one of the present application after forming the trench in the substrate. Figure 5 is a cross-sectional view of the embodiment one of the present application after forming the first material layer. Please refer to Figure 4 and Figure 5 The semiconductor device provided by the embodiment includes:
[0058] A substrate 10, in which a trench 20 is formed, the trench 20 includes a first sidewall 21, the first sidewall 21 includes a first sub-sidewall 211, a second sub-sidewall 212 and a first corner sidewall 213 connecting the first sub-sidewall 211 and the second sub-sidewall 212, the first corner sidewall 213 extends more close to the inside of the trench 20 relative to the included angle formed by the extension surfaces of the first sub-sidewall 211 and the second sub-sidewall 212 (see the dotted line in Figure 4 ).
[0059] A first material layer 30 is formed at least on the first sidewall 21, the first material layer 30 includes the first sidewall 21 and a second sidewall 31 away from the first sidewall 21, the thickness of the first material layer 30 formed on the first corner sidewall 213 in the cross-section is the minimum thickness of the first material layer 30. In the embodiment, the first corner sidewall 213 of the trench 20 extends more close to the inside of the trench 20 relative to the included angle formed by the extension surfaces of the first sub-sidewall 211 and the second sub-sidewall 212, that is, the width of the trench 20 at the first corner sidewall 213 is smaller than the width of the rest area, after forming the first material layer 30, the thickness of the first material layer 30 formed on the first corner sidewall 213 in the cross-section is the minimum thickness of the first material layer 30, so that after forming the first material layer 30, the width of the opening surrounded by the first material layer 30 at the position corresponding to the first corner sidewall 213 is still smaller than the width of the rest area, avoiding the formation of sharp protrusions of the first material layer 30 at the corner, thereby facilitating the subsequent sealing of the trench 20.
[0060] In the embodiment, the material of the substrate 10 can be silicon, germanium, silicon germanium, silicon carbide, gallium arsenide or indium gallium, etc., can also be silicon on insulator, germanium on insulator; or can also be other materials, such as III-V compound of gallium arsenide, etc. The substrate 10 is, for example, a silicon substrate.
[0061] In the embodiment, the cross section refers to a section parallel to the surface of the substrate 10, and the longitudinal section refers to a section perpendicular to the surface of the substrate 10. The width comparison of the trench or the opening refers to the comparison of the opening sizes of different positions of the trench or the opening in the same direction (the first direction X or the second direction Y), wherein the first direction X or the second direction Y are two different directions, and in the embodiment, the first direction X is perpendicular to the second direction Y, and in other embodiments, the first direction X and the second direction Y can not be perpendicular.
[0062] In the embodiment, the cross section or the longitudinal section of the first side wall 21 can be any shape. The first sub-side wall 211 or the second sub-side wall 212 or the first corner side wall 213 can be a plane or a curved surface or a combination of the two, and the corresponding cross section can be a straight line or a curved line or a combination of the two. In an embodiment, the cross sections of the first sub-side wall 211 and the second sub-side wall 212 are straight lines, and the cross section of the first corner side wall 213 is at least one of a straight line, a concave curve, a convex curve or a combination thereof, wherein the concave curve protrudes towards the inside of the trench 20, and the convex curve protrudes away from the inside of the trench 20. In another embodiment, the cross section of the first sub-side wall 211 is a straight line, and the cross sections of the second sub-side wall 212 and the first corner side wall 213 are curved lines.
[0063] Please refer to Figure 5 As shown in the figure, the second side wall 31 includes a second corner side wall 313 corresponding to the first corner side wall 213, and the distance between the first corner side wall 213 and the second corner side wall 313 is adjusted according to the shape of the second side wall 31, so that the second corner side wall 213 is a curved surface, thereby facilitating the subsequent sealing of the trench 20 and avoiding the problem of difficult sealing of the trench 20.
[0064] The first material layer 30 can be formed by any suitable process known to those skilled in the art, such as thermal oxidation process, atomic layer deposition process (ALD), chemical vapor deposition process (CVD), physical vapor deposition process (PVD), etc., and the material of the first material layer 30 includes but is not limited to silicon oxide, silicon nitride, silicon oxynitride and / or dielectric metal oxide. In an embodiment, the first material layer 30 is an oxide layer, and the first material layer 30 is formed by thermal oxidation of the first side wall 21 of the trench 20, and in the thermal oxidation process, part of the surface of the substrate 10 at the first side wall 21 of the trench 20 is consumed. Please refer to Figure 4 As shown in the figure, before the first material layer 30 is formed, the cross section of the first corner side wall 213 includes a straight line. Please refer to Figure 5As shown, after the first material layer 30 is formed, the straight line becomes a curve, i.e. the part of the first corner sidewall 213 at the substrate 10 is oxidized so that the cross section changes from a straight line to a curve.
[0065] In this embodiment, the cross section or longitudinal section of the second sidewall 31 can be any shape. The cross section shape of the first sidewall 21 and the second sidewall 31 can be different. In one embodiment, the cross section of the first corner sidewall 213 is a straight line, the cross section of the second corner sidewall 313 is a circular arc, the cross section of the first sidewall 21 is a combined figure composed of a square in the middle and a trapezoid or a ladder shape at the end, and the cross section of the second sidewall 31 is a combined figure composed of a square in the middle and a circular arc at the end. In another embodiment, the cross section of the first corner sidewall 213 is a circular arc, the cross section of the second corner sidewall 313 is a circular arc, and the cross section of the first sidewall 21 and the second sidewall 31 are both combined figures composed of a square in the middle and a circular arc at the end, but the curvature of the circular arc in the combined figure of the first sidewall 21 is different from the curvature of the circular arc in the combined figure of the second sidewall 31, i.e. the curvature of the circular arc in the cross section of the first corner sidewall 213 is different from the curvature of the circular arc in the cross section of the second corner sidewall 313. In yet another embodiment, the cross section of the first corner sidewall 213 is a circular arc, the cross section of the second corner sidewall 313 is a circular arc, and the cross section of the first sidewall 21 and the second sidewall 31 are both elliptical, but at least one of the major axis, the minor axis and the eccentricity of the elliptical cross section of the first sidewall 21 is different from that of the second sidewall 31. Of course, it is not limited to this.
[0066] Figure 6 Fig. 4 is a schematic view of a cross section after a third material layer is formed according to an embodiment of the present application. Please refer to Fig. 4. Figure 6 As shown, the semiconductor device further comprises: a second material layer 40, the second material layer 40 is formed on the side of the first material layer 30 away from the substrate 10, the second material layer 40 comprises a first conductive material 41, a second conductive material 43 and a dielectric layer 42 between the first conductive material 41 and the second conductive material 43 which are sequentially stacked; and a third material layer 50, the third material layer 50 is formed on the side of the second material layer 40 away from the substrate 10 and fills the trench 50.
[0067] In one embodiment, the first conductive material 41 and the second conductive material 43 comprise a metal material which can include or consist essentially of a conductive metal nitride, an elemental metal or an intermetallic alloy, including but not limited to titanium nitride, the material of the dielectric layer 42 includes but is not limited to a high-k material, and the material of the third material layer 50 includes but is not limited to silicon oxide.
[0068] The second material layer 40 includes the second sidewall 31 and a third sidewall 41 away from the second sidewall 31, the third sidewall 41 has the same cross-sectional shape as the second sidewall 21, so that the trench 20 is easily sealed when the third material layer 50 is formed. In an embodiment, the third sidewall 41 can be a scaled-down version of the second sidewall 21, i.e., the second material layer 40 is conformally formed on the side of the first material layer 30 away from the substrate 10, of course, not limited to this. Figure 7 is a schematic cross-sectional view of a trench provided by an embodiment of the present application. Referring to Figure 7 , in this embodiment, the maximum projection size of the trench 20 in the first direction X is A, the maximum projection size of the trench 20 in the second direction Y is B, the projection size of the first corner sidewall 213 in the first direction X is C, the projection size in the second direction Y is E, the projection size of the second sub-sidewall 212 in the first direction X is D, 2C+D=A, the projection size of the first sub-sidewall 211 in the second direction Y is B-2E. The sizes of C and E are adjusted based on the cross-sectional size of the opening formed by the first material layer, which needs to ensure that the subsequent trench is completely sealed. In this embodiment, the first corner sidewall 213 of the trench 20 is closer to the inside of the trench 20 relative to the included angle formed by the extension surfaces of the first sub-sidewall 211 and the second sub-sidewall 212, and the thickness of the first material layer 30 formed on the first corner sidewall 213 in the cross-sectional view is the minimum thickness of the first material layer 30, which can avoid the formation of a sharp protrusion of the first material layer 30 at the first corner sidewall 213 of the trench 20, thereby avoiding the width of the opening formed by the first material layer 30 at the corner being greater than the width of the remaining area after the formation of the first material layer 30, thereby facilitating the subsequent sealing of the trench 20 and avoiding the problem of difficult sealing of the trench 20.
[0069] Further, by designing the second corner sidewall 313 as a curved surface, the distance between the first corner sidewall 213 and the second corner sidewall 313 can be adjusted according to the growth rate of the first material layer 30 at the corner of the trench 20 and the shape of the second corner sidewall 313, thereby obtaining the designed shape of the trench 21.
[0070]
Embodiment Two
[0071] Figure 8 is a schematic cross-sectional view of the trench formed in the substrate according to an embodiment of the present application. Figure 9 is a schematic cross-sectional view of the trench formed in the substrate according to an embodiment of the present application. Figure 8 and Figure 9 , the semiconductor device provided by the present embodiment includes:
[0072] A substrate 10, a trench 20 is formed in the substrate 10, the trench 20 includes a first sidewall 21, the first sidewall 21 includes a first sub-sidewall 211, a second sub-sidewall 212 and a first corner sidewall 213 connecting the first sub-sidewall 211 and the second sub-sidewall 212, the first corner sidewall 213 is closer to the inside of the trench 20 than the included angle formed by the first sub-sidewall 211 and the second sub-sidewall 212 with respect to the extension plane (refer to the dashed line in Figure 8 ).
[0073] A first material layer 30 is formed at least on the first sidewall 21, the first material layer 30 includes the first sidewall 21 and a second sidewall 31 away from the first sidewall 21, the thickness of the first material layer 30 formed on the first corner sidewall 213 in the cross section is the minimum thickness of the first material layer 30.
[0074] The difference between this embodiment and embodiment one is that the shape of the first corner sidewall 213 is different, and the descriptions of the same parts are referred to embodiment one.
[0075] Before the first material layer 30 is formed, the cross section of the first corner sidewall 213 includes a straight line. In an embodiment, the straight line includes a first straight line and a second straight line, wherein the first straight line extends along a first direction, the second straight line extends along a second direction, and the first straight line intersects with the second straight line. In another embodiment, as shown in Figure 8 , the straight line includes a first straight line, a second straight line, a third straight line and a fourth straight line, wherein the first straight line L1 and the third straight line L3 extend along a first direction X, the second straight line L2 and the fourth straight line L4 extend along a second direction Y, the first straight line L1, the second straight line L2, the third straight line L3 and the fourth straight line L4 are sequentially connected end to end to form a step constituting the first corner sidewall 213, the first straight line L1 is also connected with the first sub-sidewall 211, and the fourth straight line L4 is also connected with the second sub-sidewall 212. In another embodiment, the straight line can also include a fifth straight line and a sixth straight line, or more straight lines.
[0076] Before the first material layer 30 is formed, the cross section of the first corner sidewall 213 can also include a curved line. In an embodiment, the curved line includes a first curved line and a second curved line, wherein the first curved line intersects with the second curved line to form a step constituting the first corner sidewall 213. In another embodiment, the curved line can include a plurality of curved lines, and the plurality of curved lines are sequentially connected end to end to form a step constituting the first corner sidewall 213. The cross section of the first corner sidewall 213 can also be at least one of a straight line, a concave curve, a convex curve or a combination thereof constituting a step.
[0077] Please refer to Figure 9 As shown in the figure, the second side wall 31 includes a second corner side wall 313 corresponding to the first corner side wall 213, the distance between the first corner side wall 213 and the second corner side wall 313 is adjusted according to the shape of the second side wall 31, so that the second corner side wall 313 is curved, thereby facilitating the subsequent sealing of the trench 20 and avoiding the problem that the trench 20 is difficult to seal.
[0078] In an embodiment, the cross section of the second corner side wall 313 is circular arc, and the cross section of the second side wall 31 is elliptical, of course, not limited to this.
[0079] In an embodiment, the first material layer 30 is an oxide layer, and the first material layer 30 is formed by thermal oxidation of the first side wall 21 of the trench 20, and part of the surface of the substrate 10 at the first side wall 21 of the trench 20 is consumed in the thermal oxidation process. Please refer to Figure 8 As shown in the figure, before the first material layer 30 is formed, the cross section of the first corner side wall 213 includes a straight line. Please refer to Figure 9 As shown in the figure, after the first material layer 30 is formed, the straight line becomes a curve, that is, part of the substrate 10 at the first corner side wall 213 is oxidized so that the cross section changes from a straight line to a curve.
[0080] Figure 10 It is a cross section schematic diagram provided by the second embodiment of the present application after the third material layer is formed. Please refer to Figure 10 As shown in the figure, the semiconductor device further includes: a second material layer 40, the second material layer 40 is formed on the side of the first material layer 30 away from the substrate 10, the second material layer 40 includes a first conductive material 41, a second conductive material 43 and a dielectric layer 42 located between the first conductive material 41 and the second conductive material 43 which are sequentially stacked; and a third material layer 50, the third material layer 50 is formed on the side of the second material layer 40 away from the substrate 10 and fills the trench 50.
[0081] In an embodiment, the first conductive material 41 and the second conductive material 43 include a metal material which can contain and / or consist essentially of conductive metal nitride, elemental metal or intermetallic alloy, including but not limited to titanium nitride, the material of the dielectric layer 42 includes but is not limited to high-k material, and the material of the third material layer 50 includes but is not limited to silicon oxide.
[0082] The second material layer 40 includes the second side wall 31 and a third side wall 41 away from the second side wall 31, the third side wall 41 has the same cross-sectional shape as the second side wall 21, so that the trench 20 is easily sealed when the third material layer 50 is formed.
[0083] Figure 11 is a schematic diagram of the cross section of the trench provided by the second embodiment of the present application. As shown in the figure, Figure 11 In the embodiment, the maximum projection size of the trench 20 in the first direction X is A, the maximum projection size of the trench 20 in the second direction Y is B, the projection size of the first corner side wall 213 in the first direction X is C, and the projection size in the second direction Y is E1, wherein the projection size of the second straight line L2 in the second direction Y is E3, the projection size of the fourth straight line L4 in the second direction Y is E2, and E2+E3=E1. The projection size of the first sub-side wall 211 in the second direction Y is B-2E1, the projection size of the second sub-side wall 212 in the first direction X is D, and 2C+D=A. The sizes of C, E2 and E3 are adjusted based on the cross-sectional size of the opening surrounded by the first material layer after the first material layer is formed, and it is necessary to ensure that the subsequent trench is completely sealed.
[0084] In the embodiment, the first corner side wall 213 of the trench 20 is closer to the inside of the trench 20 relative to the included angle formed by the extension surfaces of the first sub-side wall 211 and the second sub-side wall 212, and the thickness of the first material layer 30 formed on the first corner side wall 213 in the cross section is the minimum thickness of the first material layer 30, which can avoid the formation of a sharp protrusion of the first material layer 30 at the first corner side wall 213 of the trench 20, thereby avoiding the width of the opening surrounded by the first material layer 30 at the corner being greater than the width of the remaining area after the formation of the first material layer 30, thereby facilitating the subsequent sealing of the trench 20 and avoiding the problem of difficult sealing of the trench 20.
[0085] Further, by designing the second corner side wall 313 as a curved surface, the distance between the first corner side wall 213 and the second corner side wall 313 can be adjusted according to the growth rate of the first material layer 30 at the corner of the trench 20 and the shape of the second corner side wall 313, thereby obtaining the designed shape of the trench 21.
[0086] Figure 12 is a scanning electron microscope photo of the trench after the formation of the first material layer provided by an embodiment of the present application. Please refer to Figure 12 As shown in the figure, the opening surrounded by the first material layer after the formation of the first material layer is in the form of a circular arc at the corner, and the width of the opening surrounded by the first material layer at the corner is smaller than the width of the remaining area, thereby facilitating the subsequent sealing of the trench.
[0087] Accordingly, the present application also provides a semiconductor device forming method for forming the semiconductor device as described above. Figure 13 is a flow chart of the semiconductor device forming method provided in an embodiment of the present application. Please refer to Figure 13 As shown in the figure, the semiconductor device forming method provided by the embodiment of the present application includes the following steps:
[0088] S1: providing a substrate, forming a trench in the substrate, the trench including a first sidewall, the first sidewall including a first sub-sidewall, a second sub-sidewall and a first corner sidewall connecting the first sub-sidewall and the second sub-sidewall, the first corner sidewall extending closer to the inside of the trench relative to the included angle formed by the extension surfaces of the first sub-sidewall and the second sub-sidewall;
[0089] S2: forming a first material layer at least on the first sidewall, the first material layer including the first sidewall and a second sidewall away from the first sidewall, the thickness of the first material layer formed on the first corner sidewall in the cross section being the minimum thickness of the first material layer.
[0090] Please refer to Figure 4 and Figure 8 As shown in the figure, a substrate 10 is provided, a trench 20 is formed in the substrate 10, the trench 20 including a first sidewall 21, the first sidewall 21 including a first sub-sidewall 211, a second sub-sidewall 212 and a first corner sidewall 213 connecting the first sub-sidewall 211 and the second sub-sidewall 212, the first corner sidewall 213 extending closer to the inside of the trench 20 relative to the included angle formed by the extension surfaces of the first sub-sidewall 211 and the second sub-sidewall 212.
[0091] For example, the trench 20 is formed in the substrate 10 through a mask, the mask including a first pattern, the cross section of the trench 20 being a second pattern. In an embodiment, the first pattern is the same as the second pattern. In another embodiment, the first pattern is different from the second pattern, and the first pattern is changed to the second pattern when it is transferred to the substrate through the OPC (Optical Proximity Correction) correction when the trench 20 is formed in the substrate 10 through the mask.
[0092] The cross section of the first corner sidewall 213 includes a straight line. In an embodiment, please refer to Figure 4As shown, the first corner sidewall 213 is a straight line, one side of which is connected to the first sub-sidewall 211, and the other side of which is connected to the second sub-sidewall 212. In another embodiment, the straight line includes a first straight line and a second straight line, wherein the first straight line extends along a first direction, and the second straight line extends along a second direction, and the first straight line intersects the second straight line. Please refer to Figure 8 As shown, the straight line includes a first straight line, a second straight line, a third straight line, and a fourth straight line, wherein the first straight line L1 and the third straight line L3 extend along a first direction X, the second straight line L2 and the fourth straight line L4 extend along a second direction Y, and the first straight line L1, the second straight line L2, the third straight line L3, and the fourth straight line L4 are sequentially connected end to end to form the first corner sidewall 213, the first straight line L1 is also connected to the first sub-sidewall 211, and the fourth straight line L4 is also connected to the second sub-sidewall 212. In another embodiment, the straight line can also include a fifth straight line and a sixth straight line, or more straight lines.
[0093] Please refer to Figure 5 With Figure 9 As shown, at least a first material layer 30 is formed on the first sidewall 21, the first material layer 30 includes the first sidewall 21 and a second sidewall 31 away from the first sidewall 21, and the thickness of the first material layer 30 formed on the first corner sidewall 213 in the cross section is the minimum thickness of the first material layer 30.
[0094] The second sidewall 31 includes a second corner sidewall 313 corresponding to the first corner sidewall 213, and the distance between the first corner sidewall 213 and the second corner sidewall 313 is adjusted according to the shape of the second sidewall 31, so that the second corner sidewall 313 is a curved surface, thereby facilitating the subsequent sealing of the trench 20 and avoiding the problem that the trench 20 is difficult to seal.
[0095] In an embodiment, the first material layer 30 is formed by a thermal oxidation process, and the material of the first material layer 30 includes silicon oxide.
[0096] Please refer to Figure 6 With Figure 10 As shown, after the first material layer 30 is formed, it further includes: forming a second material layer 40 away from one side of the first material layer 30, the second material layer 40 includes a first conductive material 41, a second conductive material 43, and a dielectric layer 42 located between the first conductive material 41 and the second conductive material 43, which are sequentially stacked; and forming a third material layer 50 away from one side of the second material layer 40, the third material layer 50 fills the trench 20.
[0097] The first conductive material 41, the dielectric layer 42, the second conductive material 43 and the third material layer 50 can be formed by any suitable process known to those skilled in the art, such as atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etc. The materials of the first conductive material 41 and the second conductive material 43 include, but are not limited to, titanium nitride, the material of the dielectric layer 42 includes, but is not limited to, high-k material, and the material of the third material layer 50 includes, but is not limited to, silicon oxide.
[0098] In one embodiment, the second material layer 40 includes the second sidewall 31 and a third sidewall 41 away from the second sidewall 31, and the third sidewall 41 has the same cross-sectional shape as the second sidewall 31. For example, the third sidewall 41 has an elliptical cross-section, so that the trench 20 can be easily sealed when the third material layer 50 is formed.
[0099] In summary, the semiconductor device and the manufacturing method thereof provided by the present application include forming a trench in a substrate, the trench including a first sidewall, the first sidewall including a first sub-sidewall, a second sub-sidewall and a first corner sidewall connecting the first sub-sidewall and the second sub-sidewall, the first corner sidewall being closer to the inside of the trench relative to the included angle formed by the extension surfaces of the first sub-sidewall and the second sub-sidewall, and forming a first material layer on at least the first sidewall, the first material layer including the first sidewall and a second sidewall away from the first sidewall, and the thickness of the first material layer formed on the first corner sidewall in cross-section being the minimum thickness of the first material layer. In the present application, the first corner sidewall of the trench is closer to the inside of the trench relative to the included angle formed by the extension surfaces of the first sub-sidewall and the second sub-sidewall, and the thickness of the first material layer formed on the first corner sidewall in cross-section is the minimum thickness of the first material layer, so that the first material layer can not form a sharp protrusion at the first corner sidewall of the trench, and thus the width of the opening surrounded by the first material layer at the corner is not greater than the width of the remaining area after the first material layer is formed, which is beneficial for the subsequent sealing of the trench and avoids the problem of difficult sealing of the trench.
[0100] Further, by designing the second corner sidewall as a curved surface, the distance between the first corner sidewall and the second corner sidewall can be adjusted according to the growth rate of the first material layer at the corner of the trench and the shape of the second corner sidewall, so that the design shape of the trench is obtained.
[0101] The above description is only a description of the preferred embodiments of the present application and does not limit the scope of the present application in any way. Any modification or change made by those skilled in the art based on the above disclosure is within the scope of protection of the claims.
Claims
1. A semiconductor device, characterized by, The semiconductor device comprises: a substrate, a trench is formed in the substrate, the trench comprises a first sidewall, the first sidewall comprises a first sub-sidewall, a second sub-sidewall and a first corner sidewall connecting the first sub-sidewall and the second sub-sidewall, the first corner sidewall is closer to the inside of the trench relative to the included angle formed by the extension surfaces of the first sub-sidewall and the second sub-sidewall; a first material layer is formed at least on the first sidewall, the first material layer comprises the first sidewall and a second sidewall away from the first sidewall, the thickness of the first material layer formed on the first corner sidewall in the cross section is the minimum thickness of the first material layer.
2. The semiconductor device according to claim 1, wherein The second sidewall comprises a second corner sidewall corresponding to the first corner sidewall, the distance between the first corner sidewall and the second corner sidewall is adjusted according to the shape of the second sidewall, so that the second corner sidewall is curved.
3. The semiconductor device of claim 1, wherein: Before the first material layer is formed, the first corner sidewall in the cross section comprises a straight line; After the first material layer is formed, the straight line becomes a curved line.
4. The semiconductor device of claim 3, wherein: The straight line comprises a first straight line and a second straight line, the first straight line extends along a first direction, the second straight line extends along a second direction, and the first straight line intersects the second straight line.
5. The semiconductor device of claim 1, wherein The semiconductor device further comprises: a second material layer formed on the side of the first material layer away from the substrate, the second material layer comprises a first conductive material, a second conductive material and a dielectric layer between the first conductive material and the second conductive material which are sequentially stacked; and a third material layer formed on the side of the second material layer away from the substrate and filling the trench.
6. The semiconductor device of claim 5, wherein: The second material layer comprises the second sidewall and a third sidewall away from the second sidewall, the third sidewall has the same cross-sectional shape as the second sidewall.
7. A method of forming a semiconductor device, characterized by, The semiconductor device comprises: a substrate, a trench is formed in the substrate, the trench comprises a first sidewall, the first sidewall comprises a first sub-sidewall, a second sub-sidewall and a first corner sidewall connecting the first sub-sidewall and the second sub-sidewall, the first corner sidewall is closer to the inside of the trench relative to the included angle formed by the extension surfaces of the first sub-sidewall and the second sub-sidewall; a first material layer is formed at least on the first sidewall, the first material layer comprises the first sidewall and a second sidewall away from the first sidewall, the thickness of the first material layer formed on the first corner sidewall in the cross section is the minimum thickness of the first material layer.
8. The method according to claim 7, wherein The second sidewall comprises a second corner sidewall corresponding to the first corner sidewall, the distance between the first corner sidewall and the second corner sidewall is adjusted according to the shape of the second sidewall, so that the second corner sidewall is curved.
9. The semiconductor device forming method of claim 7, wherein: The first corner sidewall cross-section comprises a straight line before forming the first material layer; The straight line becomes a curve after forming the first material layer.
10. The semiconductor device forming method of claim 7, wherein: The trench is formed in the substrate by a mask, the mask comprising a first pattern, the trench cross-section comprising a second pattern; The first pattern is identical to the second pattern; Alternatively, The first pattern is different from the second pattern, and the first pattern is transformed to the second pattern by OPC correction when the trench is formed in the substrate by the mask.
11. The semiconductor device forming method of claim 7, wherein: The first material layer is formed by a thermal oxidation process, and the material of the first material layer comprises silicon oxide.
12. The semiconductor device forming method of claim 7, wherein: A second material layer is formed on a side of the first material layer away from the substrate, the second material layer comprising a first conductive material, a second conductive material, and a dielectric layer between the first conductive material and the second conductive material, which are sequentially stacked; And, A third material layer is formed on a side of the second material layer away from the substrate, the third material layer filling the trench.
13. The method according to claim 12, wherein The second material layer comprises the second sidewall and a third sidewall away from the second sidewall, the third sidewall having the same cross-section shape as the second sidewall.