CN111211039B - Method for forming trench isolation structure - Google Patents
Method for forming trench isolation structure Download PDFInfo
- Publication number
- CN111211039B CN111211039B CN201910048694.9A CN201910048694A CN111211039B CN 111211039 B CN111211039 B CN 111211039B CN 201910048694 A CN201910048694 A CN 201910048694A CN 111211039 B CN111211039 B CN 111211039B
- Authority
- CN
- China
- Prior art keywords
- layer
- oxygen
- trench
- substrate
- containing insulating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/71—Manufacture of specific parts of devices defined in group H01L21/70
- H01L21/76—Making of isolation regions between components
- H01L21/762—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers
- H01L21/76224—Dielectric regions, e.g. EPIC dielectric isolation, LOCOS; Trench refilling techniques, SOI technology, use of channel stoppers using trench refilling with dielectric materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02107—Forming insulating materials on a substrate
- H01L21/02296—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer
- H01L21/02318—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer post-treatment
- H01L21/02321—Forming insulating materials on a substrate characterised by the treatment performed before or after the formation of the layer post-treatment introduction of substances into an already existing insulating layer
Abstract
The invention provides a method for forming a trench isolation structure. The groove is filled with the oxygen-containing insulating layer, and boron ions are further implanted to form boron oxide, so that the boron oxide-containing oxygen-containing insulating layer can be used for forming the insulating material of the groove isolation structure, the insulating property of the insulating material of the groove isolation structure is equivalently improved, and the improvement of the isolation property and the groove filling capability of the groove isolation structure is facilitated.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a trench isolation structure and a forming method thereof.
Background
With the development of semiconductor technology, the size of semiconductor devices tends to decrease and the density thereof also increases gradually, and especially in the process technology of Very Large Scale Integration (VLSI), the insulation and isolation between adjacent devices are especially important with the increase of the Integration Scale of various devices. Typically, electrical isolation between adjacent components may be achieved using trench isolation structures, wherein conventional methods for forming trench isolation structures generally include the following steps.
First, referring to fig. 1a specifically, a substrate 10 is provided, and a mask layer 12 is formed on the substrate 10, so that a trench 10a is formed in the substrate 10 by using the mask layer 12 as a mask.
A second step, shown in particular with reference to fig. 1b, consists in depositing a layer 20 of insulating material on said substrate, and in filling said trench 10a with said layer 20 of insulating material. In which the insulating material layer 20 may be formed by a High Density Plasma (HDP) process to improve the filling performance of the insulating material layer 20 in the trench 10 a.
It will be appreciated that the layer of insulating material 20 also covers the top surface of the substrate and, to ensure that the trench is filled with the layer of insulating material 20, results in a greater thickness of the layer of insulating material 20 covering the top surface of the substrate and a greater recess 20a in the portion of the layer of insulating material 20 corresponding to the region of the trench relative to the portion of the layer of insulating material 20 not corresponding to the region of the trench, as shown in figure 1 b.
In addition, in forming the insulating material layer 20, the insulating material layer 20 is usually deposited by a chemical vapor deposition process (for example, a high density plasma process may be used to improve the filling performance of the trench), and the high temperature process may cause the insulating material layer 20 to have a large internal stress.
A third step, shown in particular with reference to fig. 1c, of etching the insulating-material layer 20 so as to remove the portions of the insulating-material layer 20 remote from the trenches. I.e. leaving portions of the insulating-material layer 20 close to the trenches. Thus, most of the insulating material layer 20 can be removed to reduce the polishing amount in the subsequent chemical mechanical polishing process.
Obviously, at this time, a relatively large thickness of the insulating material layer 20 still remains on the substrate surface, which will be removed by a chemical mechanical polishing process in a subsequent step.
A fourth step, specifically referring to fig. 1d, is to perform a Chemical Mechanical Polishing (Chemical Mechanical Polishing) process to remove the insulating material layer protruding from the trench.
It should be noted that, in the conventional forming method, although a high-density plasma process may be used to improve the filling performance of the insulating material layer for the trench, on the basis, a relatively large thickness of the insulating material layer is deposited on the surface of the substrate, so that the surface of the substrate presents an extremely uneven surface, which may cause dishing (dishing) of the surface after chemical mechanical polishing (cmp) to occur more easily, so that the surface after polishing has a poor flatness, which may adversely affect the subsequent process (e.g., may affect the accuracy of the subsequent photolithography process).
In addition, when the trench isolation structure is formed, a high temperature process is inevitably adopted, and the high temperature process can cause a large internal stress to be generated in the insulating material layer filled in the trench, thereby affecting the isolation performance of the trench isolation structure. Particularly, as the semiconductor technology is developed, the size of the devices is continuously reduced, and the distance between adjacent devices tends to be reduced, so how to further improve the isolation performance of the trench isolation structure is particularly important.
Disclosure of Invention
The invention aims to provide a method for forming a trench isolation structure, so as to improve the isolation performance of the trench isolation structure.
To solve the above technical problem, the present invention provides a method for forming a trench isolation structure, including:
providing a substrate, wherein at least one groove is formed in the substrate;
filling an oxygen-containing insulating layer in the trench of the substrate;
performing an ion implantation process to implant boron ions into the oxygen-containing insulating layer, the boron ions combining with oxygen in the oxygen-containing insulating layer to form boron oxide; and the number of the first and second groups,
and forming an insulating medium layer on the oxygen-containing insulating layer in the groove, wherein the top surface of the insulating medium layer is higher than the top surface of the substrate.
Optionally, the forming method of the trench includes:
forming a mask layer on the substrate, and forming a patterned photoresist layer on the mask layer; and the number of the first and second groups,
and sequentially etching the mask layer and part of the substrate by taking the photoresist layer as a mask to form at least one groove, wherein the groove penetrates through the mask layer and extends into the substrate, and the opening size of the groove is gradually reduced from the top of the groove to the bottom of the groove, so that the groove has an inclined side wall.
Optionally, before the ion implantation process is performed, the oxygen-containing insulating layer further covers a top surface of the mask layer, so that the oxygen-containing insulating layer has a protruding portion protruding out of the trench, and a portion of the oxygen-containing insulating layer filled in the trench constitutes a filling portion;
implanting the boron ions into the filling portion of the oxygen-containing insulating layer while performing the ion implantation process;
and after the ion implantation process is carried out, carrying out an annealing process, wherein in the process of carrying out the annealing process, the bulge covers the filling part.
Optionally, the oxygen-containing insulating layer is formed by a spin coating process;
and further comprising, after performing the annealing process: and removing the bulge of the oxygen-containing insulating layer by using a back etching process, and reserving at least part of the filling part.
Optionally, the material of the mask layer includes silicon nitride; forming a pad oxide layer on the substrate before forming the mask layer;
and when the mask layer is formed, the mask layer is covered on the substrate at intervals of the pad oxide layer.
Optionally, when the oxygen-containing insulating layer is filled into the trench, the top surface of the oxygen-containing insulating layer is higher than the top surface of the substrate;
further comprising, after performing the ion implantation process: etching the oxygen-containing insulating layer to a height position corresponding to the top surface of the substrate so as to expose the side wall of the pad oxide layer facing the groove;
and after exposing the side wall of the pad oxide layer, further comprising: and laterally etching the pad oxide layer to remove the part of the pad oxide layer close to the groove.
Optionally, after the pad oxide layer is laterally etched, the insulating dielectric layer is filled in the trench, the insulating dielectric layer is connected to the remaining oxygen-containing insulating layer, and the insulating dielectric layer does not cover the top surface of the substrate close to the trench.
Optionally, after forming the trench and before filling the oxygen-containing insulating layer, the method further includes: forming an isolation barrier layer on sidewalls and a bottom wall of the trench;
after filling the oxygen-containing insulating layer and performing the ion implantation process, blocking diffusion of ions implanted into the oxygen-containing insulating layer into the substrate with the isolation barrier layer.
Optionally, the material of the oxygen-containing insulating layer containing boron oxide includes silicon oxide and boron oxide, wherein a molar ratio of the silicon oxide to the boron oxide is between 15: 1-40: 1.
it is still another object of the present invention to provide a trench isolation structure, including:
a substrate having at least one trench therein;
an oxygen-containing insulating layer containing boron oxide filled in the trench of the substrate; and
an insulating dielectric layer on the oxygen-containing insulating layer in the trench, and a top surface of the insulating dielectric layer is higher than a top surface of the substrate.
Optionally, the trench isolation structure further includes:
a pad oxide layer formed on the top surface of the substrate and not covering the top surface of the substrate near the trench.
Optionally, the trench isolation structure further includes:
an isolation barrier layer formed on sidewalls and a bottom wall of the trench to space the oxygen-containing insulating layer and the substrate with the isolation barrier layer.
In the method for forming the trench isolation structure, the oxygen-containing insulating layer containing boron oxide can be finally formed by forming the oxygen-containing insulating layer and further implanting boron ions to form the insulating material of the trench isolation structure. The boron oxide has better insulating property, namely, the insulating property of the insulating material of the trench isolation structure is improved, so that the isolating property of the trench isolation structure can be correspondingly improved.
Furthermore, in the method for forming the trench isolation structure provided by the present invention, after the oxygen-containing insulating layer containing boron oxide is formed, the oxygen-containing insulating layer may be further partially removed to release internal stress of the oxygen-containing insulating layer (for example, stress generated by shrinkage of the oxygen-containing insulating layer in a high temperature process may be relieved).
Furthermore, in the method for forming the trench isolation structure provided by the present invention, the oxygen-containing insulating layer and the insulating dielectric layer are sequentially filled in the trench to jointly form the insulating material of the trench isolation structure, and at this time, when the oxygen-containing insulating layer and the insulating dielectric layer are formed, a thicker material layer can be prevented from being covered on the top surface of the substrate, so as to facilitate the subsequent removal process of the material layer covering the surface of the substrate (for example, the material layer covering the surface of the substrate can be directly removed by using a back etching process, so that the problem of surface recess caused by a chemical mechanical polishing process can be avoided).
Drawings
FIGS. 1a to 1d are schematic structural diagrams illustrating a trench isolation structure forming method in a manufacturing process thereof according to the prior art;
FIG. 2 is a flow chart illustrating a method for forming a trench isolation structure according to an embodiment of the present invention;
fig. 3a to 3i are schematic structural views illustrating a method for forming a trench isolation structure in a manufacturing process according to an embodiment of the invention.
Wherein the reference numbers are as follows:
10-a substrate; 10 a-a trench;
12-a mask layer;
20-a layer of insulating material; 20 a-a recess;
100-a substrate;
100 a-trench; 100 b-the top surface of the substrate;
110-pad oxide layer;
120-mask layer;
130-liner oxide layer;
140-an isolation barrier layer;
150-an oxygen-containing insulating layer; 151-insulating quality changing layer;
160-a layer of insulating dielectric material; 161-insulating dielectric layer;
PR1 — first photoresist layer; PR 2-second photoresist layer.
Detailed Description
The core idea of the present invention is to provide a method for forming a trench isolation structure, so as to form an oxygen-containing insulating layer containing boron oxide in a trench, so as to improve the insulating property of the insulating material of the trench isolation structure, thereby improving the isolation property of the trench isolation structure. Therefore, with the development of semiconductor technology, the trench isolation structure formed can be applied to the space between adjacent devices with gradually reduced space.
The trench isolation structure and the method for forming the same according to the present invention will be described in further detail with reference to the accompanying drawings and embodiments. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
Fig. 2 is a schematic flow chart of a method for forming a trench isolation structure according to an embodiment of the present invention, and fig. 3a to 3i are schematic structural diagrams of the method for forming a trench isolation structure according to an embodiment of the present invention during a manufacturing process thereof.
In step S100, referring to fig. 3a to 3b, a substrate 100 is provided, and at least one trench 100a is formed in the substrate 100. The substrate 100 is, for example, a silicon substrate or a silicon-on-insulator substrate, and the aspect ratio of the trench 100a is, for example, greater than or equal to 8: 1.
The method for forming the trench 100a includes the following steps, for example.
First, referring to fig. 3a, a mask layer 120 is formed on the substrate 100, and a patterned first photoresist layer PR1 is formed on the mask layer 120. The patterned first photoresist layer PR1 is correspondingly formed with a trench pattern to be formed later. And, the pattern of the first photoresist layer PR1 can be defined by using a photolithography process.
It should be noted that, when the substrate is etched to form the trench, the first photoresist layer PR1 and the mask layer 120 are used together to perform a masking function, so that the formed trench has a sloped sidewall.
Further, the material of the mask layer 120 includes silicon nitride (SiN). Based on this, in this embodiment, before forming the mask layer 120, the method further includes: a Pad Oxide layer (Pad Oxide)110 is formed on the substrate 100. That is, when the mask layer 120 is formed, the pad oxide layer 110 is covered on the substrate 100 at a corresponding interval of the mask layer 120.
It will be appreciated that when a masking layer of silicon nitride is used, the direct deposition of silicon nitride on a silicon substrate results in a greater stress being applied to the substrate due to the greater stress of silicon nitride. In this embodiment, a pad oxide layer 110 is disposed between the mask layer 120 and the substrate 100, so that the pad oxide layer 110 is used as a buffer layer to implement stress buffering. In addition, the pad oxide layer can also be used for isolating and protecting the substrate, so that the surface of the substrate is prevented from being polluted when the mask layer is removed subsequently.
In a second step, referring to fig. 3b, the mask layer 120 and a portion of the substrate 100 are sequentially etched using the first photoresist layer PR1 as a mask to form a trench 100 a. The trench 100a penetrates the mask layer 120 and extends into the substrate 100, and the opening size of the trench 100a gradually decreases from the top of the trench to the bottom of the trench, so that the trench 100a has sloped sidewalls. In this embodiment, a pad oxide layer 110 is further formed on the substrate 100, so that the trench 100a correspondingly penetrates through the pad oxide layer 110.
Specifically, when the mask layer 120 and the substrate 100 are etched by using the first photoresist layer PR1 as a mask, organic products are easily generated from the material of the first photoresist layer PR1 as the etching proceeds, and the organic products are attached to the sidewalls of the formed opening, so that the consumption of the bottom of the opening is gradually reduced as the etching proceeds, and then the inclined sidewalls are formed. In this embodiment, when the substrate is etched, the mask layer 120 is also used to achieve a mask effect together, so as to improve the accuracy of the trench pattern copied into the substrate 100.
It should be noted that, in the present embodiment, by forming the trench 100a having an inclined sidewall (for example, the trench 100a has an inverted trapezoid structure), when an insulating material is subsequently filled in the trench 100a, the filling performance of the insulating material can be effectively improved, and the problem of generating a void in the insulating material layer filled in the trench 100a is avoided. In particular, with the development of semiconductor technology, the aspect ratio of the trench is increasing (for example, the aspect ratio of the trench 100a in this embodiment is greater than or equal to 8:1), so that the filling difficulty of the trench 100a is greater, and in this embodiment, the trench having an inclined sidewall is formed, and an insulation material may be filled in a subsequent step by combining with a spin coating process, so as to solve the problem of the trench having a larger aspect ratio that is difficult to fill.
In the third step, the first photoresist layer PR1 is removed, for example, the first photoresist layer PR1 may be removed by an ashing process.
In a preferred embodiment, after etching the substrate 100 to form the trench 100a, the method further includes: a thermal oxidation process is performed to form a liner oxide layer 130 on the sidewalls and bottom wall of the trench 100 a.
Referring specifically to fig. 3c, in the present embodiment, the substrate 100 is a silicon substrate, so that the liner oxide layer 130 can be formed on the inner surface of the substrate corresponding to the trench 100a in a self-aligned manner through a thermal oxidation process.
That is, when the trench 100a is etched and formed by using an etching process, etching damage is generally generated on the sidewall and the bottom wall of the trench 100 a. Based on this, the liner oxide layer 130 can be formed to repair the etching damage of the inner surface of the trench (including the sidewall and the bottom wall of the trench). In addition, by forming the liner oxide layer 130, the profile of the sharp corner of the trench 100a can be further modified, for example, the sharp corner at the bottom of the trench 100a can be rounded, so that the problem that the sharp corner of the trench 100a is easily broken down due to electric field concentration at the sharp corner can be alleviated.
With continuing reference to fig. 3c, in this embodiment, after forming the trench 100a, the method further includes: an isolation barrier layer 140 is formed on the inner surface of the trench 100 a. In this way, ions subsequently implanted into the oxygen-containing insulating layer may be blocked by the isolation barrier layer 140, thereby preventing the implanted ions from diffusing into the substrate 100.
With continued reference to fig. 3c, in this embodiment, the isolation barrier layer 140 covers the liner oxide layer 130. And, the isolation barrier layer 140 may be made of silicon nitride, for example.
In step S200, referring specifically to fig. 3d, an oxygen-containing insulating layer 150 is filled in the trench 100a of the substrate 100.
In this embodiment, the oxygen-containing insulating layer 150 is filled in the trench 100a and further covers the top surface of the mask layer 120. And, the oxygen-containing insulating layer 150 may be formed using a spin coating process. Further, the oxygen-containing insulating layer 150 is, for example, Spin-On-Glass (GOS), and the Spin-On-Glass includes, for example, a Spin-On material of a polyoxysilane.
That is, the oxygen-containing insulating layer 150 is formed by using a spin coating process, which not only ensures the filling performance of the oxygen-containing insulating layer 150 in the trench 100a, but also prevents voids from being generated in the oxygen-containing insulating layer 150; the oxygen-containing insulating layer 150 formed by the spin coating process does not duplicate the pattern structure of the substrate, so that the oxygen-containing insulating layer 150 has a flat surface, thereby facilitating the subsequent processing of the oxygen-containing insulating layer 150.
For example, when the portion of the oxygen-containing insulating layer 150 covering the surface of the mask layer needs to be removed in the subsequent process, the portion can be removed by a chemical mechanical polishing process, and at this time, since the oxygen-containing insulating layer 150 has a flat surface, the problem that the surface of the first insulating oxide 150 after polishing is recessed can be effectively solved. And, when the oxygen-containing insulating layer 150 is formed by using the spin coating process, the thickness of the portion of the formed oxygen-containing insulating layer 150 covering the top surface of the mask layer 120 is smaller, and at this time, the oxygen-containing insulating layer can be directly processed by using the etch back process without using the chemical mechanical polishing process, so that the problem of the surface of the oxygen-containing insulating layer being recessed due to using the chemical mechanical polishing process can be avoided.
It should be noted that after the oxygen-containing insulating layer 150 is formed by using a spin coating process, the oxygen-containing insulating layer may be directly partially removed, so that the remaining oxygen-containing insulating layer is filled in the trench 100 a. Alternatively, the oxygen-containing insulating layer may be partially removed after performing the ion implantation process.
In step S300, referring specifically to fig. 3e, an ion implantation process is performed to implant boron ions into the oxygen-containing insulating layer 150 and combine the boron ions with oxygen (O) in the oxygen-containing insulating layer 150 to form boron oxide.
That is, boron ions (B +) are implanted to form boron oxide, and boron oxide has better insulating property, so that the insulating property of the insulating material filled in the trench 100a can be correspondingly improved, and the isolation property of the formed trench isolation structure can be further improved.
In this embodiment, after the formation of the oxygen-containing insulating layer 150 and before the ion implantation process is performed, a portion of the oxygen-containing insulating layer 150 covering the top surface of the mask layer is still remained, i.e., the oxygen-containing insulating layer 150 protrudes from the trench 100a, and it can be considered that a portion of the oxygen-containing insulating layer 150 protruding from the trench 100a constitutes a protruding portion and a portion of the oxygen-containing insulating layer 150 filled in the trench 100a constitutes a filling portion. In this embodiment, when the ion implantation process is performed, the boron ions (B +) are implanted only into the filling portion of the oxygen-containing insulating layer 150, and boron ions are not implanted or are implanted to a small amount into the protruding portion of the oxygen-containing insulating layer 150. That is, the boron ions (B +) are implanted into a deeper position of the oxygen-containing insulating layer 150, so that the boron ions are prevented from overflowing under the barrier of the protrusion when the high temperature annealing is performed subsequently.
As shown in fig. 3e, in the present embodiment, boron ions are implanted only into the filling portion of the oxygen-containing insulating layer 150, so that the material of the filling portion of the oxygen-containing insulating layer 150 is changed to form the insulating material changed layer 151. For example, the material of the insulating property-change layer 151 includes silicon oxide and boron oxide. The proportion of silicon oxide and boron oxide in the insulating quality-changed layer 151 can be increased by controlling the content of implanted boron ions, for example, the molar ratio of silicon oxide to boron oxide in the insulating quality-changed layer 151 is 15: 1-40: 1. specifically, the molar amount of silicon oxide may be 94% to 98%, and the molar amount of boron oxide may be 2% to 6%, specifically, the molar amount of silicon oxide is 96%, and the molar amount of boron oxide is 4%.
In addition, before performing the ion implantation process, the method may further include: a patterned second photoresist layer PR2 is formed on the oxygen-containing insulating layer 150, the patterned second photoresist layer PR2 having an opening therein corresponding to the trench 100 a. Thus, when the ion implantation process is performed, ions can be implanted into the portion of the oxygen-containing insulating layer 150 corresponding to the trench region under the mask action of the second photoresist layer PR2 without implanting ions into the portion of the oxygen-containing insulating layer 150 covering the top surface of the mask layer 120.
The pattern of the second photoresist layer PR2 corresponding to the ion implantation process may be the same as the pattern of the first photoresist layer PR1 corresponding to the trench. At this time, the pattern of the second photoresist layer PR2 and the pattern of the first photoresist layer PR1 can be defined by using the same photolithography mask.
In this embodiment, after the performing the ion implantation process, the method further includes: an annealing process is performed to assist the combination of the boron ions (B +) and the oxygen (O) in the oxygen-containing insulating layer 150, so that boron oxide (B) may be further formed2O3)。
It should be noted that, the annealing process is usually performed at a higher temperature, and the boron ions implanted into the oxygen-containing insulating layer 150 have a higher activation energy, and the isolation barrier layer 140 is formed on the inner surface of the trench 100a in the present embodiment, so that the boron ions with higher activation energy can be effectively blocked from migrating into the substrate 100; and, as mentioned above, no boron ions or only a small amount of boron ions are implanted into the protrusion of the oxygen-containing insulating layer 150, and at this time, under the cover of the protrusion, the boron ions can be effectively prevented from overflowing from the surface of the oxygen-containing insulating layer 150.
In addition, in this embodiment, after performing an ion implantation process to form boron oxide in the oxygen-containing insulating layer, the method further includes: step S400, partially removing the oxygen-containing insulating layer 150. For example, the protrusion of the oxygen-containing insulating layer 150 is removed, and at least a portion of the filling portion in the trench (i.e., at least a portion of the insulating property-changed layer 151 in the oxygen-containing insulating layer 150) remains.
As described above, since the oxygen-containing insulating layer 150 is formed by the spin coating process, it has a flat surface, and the thickness of the oxygen-containing insulating layer 150 is thin, so that the oxygen-containing insulating layer 150 can be partially removed by directly using the etch back process in this embodiment. Of course, in other embodiments, a planarization process may be performed by using a chemical mechanical polishing process to remove the portion of the oxygen-containing insulating layer 150 covering the mask layer 120, and at this time, since the surface of the oxygen-containing insulating layer 150 is flat, the problem of the surface of the oxygen-containing insulating layer after planarization being recessed can be greatly alleviated.
Also, internal stress of the oxygen-containing insulating layer can be released by partially removing the oxygen-containing insulating layer. Specifically, after the high temperature annealing process is performed, a large internal stress may be generated in the oxygen-containing insulating layer 150 (for example, an internal stress due to shrinkage of the oxygen-containing insulating layer), and at this time, the internal stress in the remaining oxygen-containing insulating layer can be relieved by partially removing the oxygen-containing insulating layer.
In a preferred embodiment, specifically referring to fig. 3f, after the oxygen-containing insulating layer is partially removed by an etching back process to remove the protruding portion protruding out of the trench, a portion of the oxygen-containing insulating layer in the trench may be further removed (i.e., the insulating variable layer 151 is partially removed), at this time, the top surface of the remaining oxygen-containing insulating layer is correspondingly made lower than the top of the trench (in this embodiment, the top surface of the insulating variable layer 151 is lower than the top surface of the mask layer 120). In this manner, the internal stress of the oxygen-containing insulating layer in the trench (i.e., the internal stress in the insulating property-changed layer 151) can be further released.
In this embodiment, when the oxygen-containing insulating layer is etched, the etching is performed at least to a height position corresponding to the top surface of the substrate, so as to expose the sidewall of the pad oxide layer 110 facing the trench 100 a. That is, the portions of the oxygen-containing insulating layer corresponding to the mask layer 120 and the pad oxide layer 110 are removed. Of course, the top surface of the oxygen-containing insulating layer remaining after etching may be made not higher than the surface of the substrate, that is, the top surface of the insulating modification layer 151 remaining after etching may be made not higher than the top surface of the substrate 100.
In this manner, i.e., corresponding to the removal of a larger portion of the insulating variable layer 151 in the trench (e.g., the depth of the trench 100a that makes the height of the insulating variable layer 151 after etching 70% to 80%), the internal stress of the insulating variable layer 151 remaining in the trench is greatly relieved. Moreover, by exposing the sidewall of the pad oxide layer 110, it is beneficial to laterally etch the pad oxide layer 110 in the subsequent process.
With continued reference to fig. 3f, after exposing the sidewalls of the pad oxide layer 110, the method further includes: step S500, the pad oxide layer 110 is laterally etched to remove a portion of the pad oxide layer 110 close to the trench.
That is, the substrate 110 is not covered with the pad oxide layer near the top surface 100b of the trench, and the substrate 110 is exposed near the top surface 100b of the trench in this embodiment, so that the problem of electric field concentration generated at the top corner formed between the sidewall of the trench 100a and the top surface of the substrate can be effectively alleviated. At this time, it can be considered that the sidewalls of the pad oxide layer 110 are recessed with respect to the sidewalls of the trench.
Referring next to fig. 3g and 3h, in step S600, an insulating dielectric layer 161 is filled on the oxygen-containing insulating layer in the trench 100a, the insulating dielectric layer 161 is connected to the remaining oxygen-containing insulating layer (i.e., the remaining insulating modification layer 151), and the top surface of the insulating dielectric layer 161 is higher than the top surface of the substrate. The material of the insulating dielectric layer 161 includes, for example, silicon oxide.
In this embodiment, the substrate is exposed near the top surface 100b of the trench by partially removing the pad oxide layer. Further, the insulating dielectric layer 161 may be left uncovered on the top surface 100b of the substrate 100 near the trench. That is, the insulating dielectric layer 161 does not fill the recess on the trench sidewall.
It should be appreciated that, at this time, the insulating dielectric layer 161 may be formed, for example, by a chemical vapor deposition process with a lower filling property, for example, the insulating dielectric layer 161 may be formed by a deposition process with a lower filling property than a high density plasma chemical vapor deposition process (HDP CVD), so as to ensure that the insulating dielectric layer 161 does not fill the recess on the sidewall of the trench, so that the insulating dielectric layer 161 does not cover the top surface of the substrate and is not connected to the pad oxide layer 110.
The filling method of the insulating dielectric layer 161 includes the following steps, for example.
Step one, specifically referring to fig. 3g, forming an insulating dielectric material layer 160 on the substrate 100, wherein the insulating dielectric material layer 160 fills the trench 100a and does not fill the recess on the trench sidewall, and the insulating dielectric material layer 160 further covers the top surface of the mask layer 120;
it should be noted that before the insulating medium material layer 160 is formed, the trench 100a is filled with an oxygen-containing insulating layer (i.e., the insulating quality-changing layer 151), and as described above, the height of the insulating quality-changing layer 151 remaining in the trench is, for example, 70% to 80% of the depth of the trench 100a, so that the depth of the empty space in the trench 100a corresponding to the upper side of the insulating quality-changing layer 151 is lower (for example, only 20% to 30% of the depth of the trench). Then, when the insulating dielectric material layer 160 is formed to fill the empty space of the trench 100a, the thickness of the insulating dielectric layer formed on the top surface of the mask layer 120 is also correspondingly smaller.
Step two, specifically referring to fig. 3h, removing a portion of the insulating dielectric material layer 160 covering the top surface of the mask layer 120, and leaving a portion of the insulating dielectric material layer filled in the trench 100a to form the insulating dielectric layer 161.
As described above, in the present embodiment, the thickness of the portion of the insulating dielectric material layer covering the top surface of the mask layer 120 is smaller, so that the insulating dielectric material layer can be partially removed by directly using the etch-back process to form the insulating dielectric layer 161 filled in the trench.
Optionally, referring specifically to fig. 3i, the mask layer may be further removed.
Based on the above forming method, the present invention further provides a trench isolation structure, which can be specifically shown in fig. 3i, where the trench isolation structure includes:
a substrate 100 having a trench formed therein; and the number of the first and second groups,
an oxygen-containing insulating layer containing boron oxide (i.e., corresponding to the insulating property-change layer 151 in the above-described embodiment) which is filled in the trench of the substrate 100; and
an insulating dielectric layer on the oxygen-containing insulating layer in the trench, and a top surface of the insulating dielectric layer is higher than a top surface of the substrate.
That is, the insulating material filled in the trench contains boron oxide, and the boron oxide has a better insulating property (for example, compared with silicon oxide, boron oxide has a better insulating property), so that the isolation performance of the formed trench isolation structure can be effectively improved. When the trench isolation structure is applied to a specific semiconductor device, the problem of mutual interference between adjacent devices can be effectively avoided.
Specifically, the material of the oxygen-containing insulating layer containing boron oxide includes, for example, silicon oxide and boron oxide, wherein a molar ratio of the silicon oxide to the boron oxide is 15: 1-40: 1. specifically, the content of the silicon oxide is, for example, 94% to 98%, and the content of the boron oxide is, for example, 2% to 6%.
Further, the trench isolation structure further includes: a pad oxide layer 110 formed on the top surface of the substrate 100, and the pad oxide layer 110 does not cover the top surface 100b of the substrate near the trench. Therefore, the problem of electric field concentration at the vertex angle of the groove can be effectively avoided.
With continued reference to fig. 3i, in this embodiment, the trench isolation structure further includes: and an insulating dielectric layer 161 formed on the oxygen-containing insulating layer (i.e., corresponding to the insulating property-changing layer 151 in the above-described embodiment) and protruding with respect to the top surface of the substrate. In this embodiment, the insulating dielectric layer 161 further protrudes from the top surface of the pad oxide layer 110. The material of the insulating dielectric layer 161 includes, for example, silicon oxide.
That is, the insulating material of the trench isolation structure includes an oxygen-containing insulating layer and an insulating dielectric layer 161 which are stacked. As described in the above embodiments, when forming the stacked oxygen-containing insulating layer and the insulating dielectric layer 161, it is necessary to partially remove the oxygen-containing insulating layer, so that the internal stress of the oxygen-containing insulating layer can be effectively released, and then the insulating dielectric layer 161 is combined to form the insulating material of the trench isolation structure. Therefore, the insulating property of the insulating material in the trench isolation structure can be improved by utilizing the oxygen-containing insulating layer containing boron oxide, and the stress of the insulating material in the trench isolation structure can be effectively relieved.
In a preferred embodiment, the trench isolation structure further includes: and the liner oxide layer 130 is formed on the side wall and the bottom wall of the groove, so that the liner oxide layer 130 is used for repairing the etching damage of the inner surface (including the side wall and the bottom wall) of the groove and further modifying the sharp-angled appearance of the groove.
In a preferred embodiment, the trench isolation structure further includes: an isolation barrier layer 140, the isolation barrier layer 140 covering the liner oxide layer 130. By providing the isolation barrier layer 140, diffusion of implanted boron ions into the substrate 100 when forming the oxygen-containing insulating layer containing boron oxide can be effectively prevented.
In summary, according to the method for forming the trench isolation structure provided by the present invention, the boron ions are implanted into the oxygen-containing insulating layer to form the oxygen-containing insulating layer containing boron oxide, and the oxygen-containing insulating layer is used to form the insulating material of the trench isolation structure, so that the insulating property of the insulating material of the trench isolation structure can be effectively improved, and the isolation property of the trench isolation structure can be correspondingly improved.
In addition, in the forming method provided by the invention, after the high-temperature process, the oxygen-containing insulating layer is further partially removed to release the internal stress of the oxygen-containing insulating layer, so that the problem that the formed trench isolation structure has larger stress is avoided. Meanwhile, based on the fact that the grooves are filled with insulating materials for many times (namely, the grooves are filled with the oxygen-containing insulating layers and the insulating medium layers in sequence), when the surface of the substrate is flattened, the back etching process can be directly utilized, compared with the chemical mechanical polishing process, the back etching process can effectively avoid the problem that the flattened surface is sunken, and the quality of the formed groove isolation structure is further improved.
The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.
Claims (7)
1. A method for forming a trench isolation structure, comprising:
providing a substrate, wherein at least one groove is formed in the substrate, and the forming method of the groove comprises the following steps: forming a mask layer on the substrate, and forming a patterned photoresist layer on the mask layer; and sequentially etching the mask layer and part of the substrate by taking the patterned photoresist layer as a mask to form at least one groove, wherein the groove penetrates through the mask layer and extends into the substrate, and the opening size of the groove is gradually reduced from the top of the groove to the bottom of the groove so that the groove has an inclined side wall;
filling an oxygen-containing insulating layer in the groove of the substrate, wherein the oxygen-containing insulating layer also covers the top surface of the mask layer, so that the oxygen-containing insulating layer is provided with a protruding part protruding out of the groove, and the part of the oxygen-containing insulating layer filled in the groove forms a filling part;
performing an ion implantation process to implant boron ions into the filling portion in the oxygen-containing insulating layer, the boron ions combining with oxygen in the oxygen-containing insulating layer to form boron oxide;
performing an annealing process, wherein the bulge covers the filling part in the process of performing the annealing process; and the number of the first and second groups,
and forming an insulating medium layer on the oxygen-containing insulating layer in the groove, wherein the top surface of the insulating medium layer is higher than the top surface of the substrate.
2. The method of forming a trench isolation structure as claimed in claim 1, wherein the oxygen-containing insulating layer is formed by a spin-on process;
and further comprising, after performing the annealing process: and removing the bulge of the oxygen-containing insulating layer by using a back etching process, and reserving at least part of the filling part.
3. The method of claim 1, wherein the mask layer comprises silicon nitride; forming a pad oxide layer on the substrate before forming the mask layer;
and when the mask layer is formed, the mask layer is covered on the substrate at intervals of the pad oxide layer.
4. The method of claim 3, wherein a top surface of the oxygen-containing insulating layer is higher than a top surface of the substrate when the oxygen-containing insulating layer is filled into the trench;
further comprising, after performing the ion implantation process: etching the oxygen-containing insulating layer to a height position corresponding to the top surface of the substrate so as to expose the side wall of the pad oxide layer facing the groove;
and after exposing the side wall of the pad oxide layer, further comprising: and laterally etching the pad oxide layer to remove the part of the pad oxide layer close to the groove.
5. The method of claim 4, wherein the insulating dielectric layer is filled in the trench after the pad oxide layer is laterally etched, the insulating dielectric layer is connected with the remaining oxygen-containing insulating layer, and the insulating dielectric layer does not cover the top surface of the substrate near the trench.
6. The method of claim 1, further comprising, after forming the trench and before filling the oxygen-containing insulating layer: forming an isolation barrier layer on sidewalls and a bottom wall of the trench;
after filling the oxygen-containing insulating layer and performing the ion implantation process, blocking diffusion of ions implanted into the oxygen-containing insulating layer into the substrate with the isolation barrier layer.
7. The method of claim 1, wherein the boron oxide-containing insulating layer comprises silicon oxide and boron oxide, and a molar ratio of the silicon oxide to the boron oxide is between 15: 1-40: 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910048694.9A CN111211039B (en) | 2019-01-18 | 2019-01-18 | Method for forming trench isolation structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910048694.9A CN111211039B (en) | 2019-01-18 | 2019-01-18 | Method for forming trench isolation structure |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111211039A CN111211039A (en) | 2020-05-29 |
| CN111211039B true CN111211039B (en) | 2020-11-20 |
Family
ID=70787948
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910048694.9A Active CN111211039B (en) | 2019-01-18 | 2019-01-18 | Method for forming trench isolation structure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111211039B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111883417B (en) * | 2020-07-27 | 2021-07-06 | 长江存储科技有限责任公司 | Manufacturing method of three-dimensional memory |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7118988B2 (en) * | 1994-08-15 | 2006-10-10 | Buerger Jr Walter Richard | Vertically wired integrated circuit and method of fabrication |
| US7329618B2 (en) * | 2005-06-28 | 2008-02-12 | Micron Technology, Inc. | Ion implanting methods |
| KR100910462B1 (en) * | 2007-09-07 | 2009-08-04 | 주식회사 동부하이텍 | Semiconductor device and method for fabricating the same |
| CN102709226A (en) * | 2012-06-21 | 2012-10-03 | 上海华力微电子有限公司 | Shallow groove isolation formation method and semiconductor device manufacturing method |
| CN104347471A (en) * | 2013-07-29 | 2015-02-11 | 中芯国际集成电路制造(上海)有限公司 | Preparation method of semiconductor device |
| CN104465487A (en) * | 2013-09-23 | 2015-03-25 | 中芯国际集成电路制造(上海)有限公司 | Method for manufacturing shallow trench isolation structure |
| CN104091779B (en) * | 2014-07-25 | 2017-02-15 | 上海华力微电子有限公司 | Shallow trench isolation structure forming method |
| CN104157601B (en) * | 2014-08-20 | 2017-03-15 | 上海华力微电子有限公司 | The method for forming fleet plough groove isolation structure |
-
2019
- 2019-01-18 CN CN201910048694.9A patent/CN111211039B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN111211039A (en) | 2020-05-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100226488B1 (en) | Isolation structure of semiconductor device and manufacturing method thereof | |
| TW201017815A (en) | Self-aligned trench formation | |
| US6825544B1 (en) | Method for shallow trench isolation and shallow trench isolation structure | |
| KR100841050B1 (en) | Method for forming a isolation layer in semiconductor device | |
| CN113345834A (en) | Low-voltage device and manufacturing method thereof | |
| US7358145B2 (en) | Method of fabricating shallow trench isolation structure | |
| US20060223280A1 (en) | Method for manufacturing semiconductor device and semiconductor device | |
| CN111211039B (en) | Method for forming trench isolation structure | |
| US7154159B2 (en) | Trench isolation structure and method of forming the same | |
| KR100500942B1 (en) | Fabricating method for trench isoaltion layer using bottom anti reflection coating | |
| KR101200509B1 (en) | Method for fabricating semiconductor device with partial silicon on insulator structure | |
| KR20070004341A (en) | Method for fabricating flash memory device | |
| KR100562268B1 (en) | Method for fabricating device isolation barrier of semiconductor device | |
| KR100671661B1 (en) | Method of forming isolation film in semiconductor device | |
| KR20120090544A (en) | Semiconductor device and method for manufacturing the same | |
| KR20000045299A (en) | Method for manufacturing semiconductor device | |
| KR20040049871A (en) | Formation method of trench oxide in semiconductor device | |
| KR20110047820A (en) | Method for manufacturing semiconductor device using organic layer and oxide stacked hardmask | |
| KR20010082901A (en) | Method for fabricating isolation film in semiconductor device | |
| KR100808590B1 (en) | Isolation layer of semiconductor device and method of forming the same | |
| KR100620171B1 (en) | Method for manufacturing shallow trench isolation in semiconductor device | |
| CN115172259A (en) | Active region vertex angle forming method and semiconductor structure | |
| CN115911128A (en) | Power semiconductor device and preparation method thereof | |
| KR101095066B1 (en) | Method for manufacturing semiconductor device | |
| KR20060134320A (en) | Trench isolation layer and method of fabricating the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 230012 No.88, xifeihe Road, comprehensive bonded zone, Xinzhan District, Hefei City, Anhui Province Patentee after: Hefei crystal integrated circuit Co.,Ltd. Address before: 230012 No.88, xifeihe Road, comprehensive bonded zone, Xinzhan District, Hefei City, Anhui Province Patentee before: HEFEI JINGHE INTEGRATED CIRCUIT Co.,Ltd. |
|
| CP01 | Change in the name or title of a patent holder |