US-12628625-B2 - Method for filling gap

US12628625B2US 12628625 B2US12628625 B2US 12628625B2US-12628625-B2

Abstract

A method for filling a gap includes: filling a dielectric layer in the gap so that a seam is formed in the dielectric layer, the dielectric layer including two surface portions at two opposite sides of the seam, respectively; introducing a surface modification agent into the seam such that each of the two surface portions has first functional groups and second functional groups; forming a stress layer on the dielectric layer to cover the seam, the stress layer including a material different from that of the dielectric layer; and applying an energy field to permit the two surface portions to bond with each other through reaction between the first functional groups and the second functional groups.

Inventors

Po-Hsien Cheng
Tai-Chun Huang
Chung-Ting Ko
Chia-Yu Fang
Sung-En Lin
Yu-Yun Peng

Assignees

TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.

Dates

Publication Date: 20260512
Application Date: 20230911

Claims (20)

1 . A method for filling a gap, comprising: filling a dielectric layer in the gap so that a seam is formed in the dielectric layer, the dielectric layer including two surface portions at two opposite sides of the seam, respectively; introducing a surface modification agent into the seam such that each of the two surface portions has first functional groups and second functional groups; forming a stress layer on the dielectric layer to cover the seam, the stress layer including a material different from that of the dielectric layer; and applying an energy field to permit the two surface portions to bond with each other through reaction between the first functional groups and the second functional groups.
2 . The method as claimed in claim 1 , wherein prior to introducing the surface modification agent, the seam has a width between the two surface portions ranging from 5 Å to 1 nm.
3 . The method as claimed in claim 1 , wherein the surface modification agent is introduced at a temperature ranging from room temperature to 450° C.
4 . The method as claimed in claim 1 , wherein the stress layer has a coefficient of thermal expansion different from that of the dielectric layer such that a stress is generated between the stress layer and the dielectric layer.
5 . The method as claimed in claim 1 , wherein the dielectric layer includes silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbide, silicon carbon nitride, silicon oxycarbon nitride, boron nitride, metal oxide, metal nitride, metal oxynitride, metal oxycarbide, metal carbon nitride, metal oxycarbon nitride, or combinations thereof.
6 . The method as claimed in claim 5 , wherein the stress layer includes amorphous silicon, silicon oxide, silicon nitride, silicon carbide, silicon oxynitride, silicon oxycarbide, silicon carbon nitride, silicon oxycarbon nitride, boron nitride, metal oxide, metal nitride, metal oxynitride, metal oxycarbide, metal carbon nitride, metal oxycarbon nitride, or combinations thereof.
7 . The method as claimed in claim 1 , wherein applying the energy field is performed by applying an electromagnetic field with a selective frequency such that the first functional groups on one of the two surface portions and the second functional groups on the other one of the two surface portions are capable of reacting with each other.
8 . The method as claimed in claim 7 , wherein the selective frequency ranges from 100 kHz to 100 GHz.
9 . The method as claimed in claim 1 , wherein during applying the energy field, the two surface portions are selectively heated such that a temperature at the two surface portions is higher than a temperature of the stress layer.
10 . A method for filling a gap, comprising: filling a dielectric layer in the gap by atomic layer deposition, so that a seam is formed in the dielectric layer, the dielectric layer including two surface portions at two opposite sides of the seam, respectively; introducing a surface modification agent into the seam such that each of the two surface portions has first functional groups and second functional groups; forming a stress layer on the dielectric layer to cover the seam, the stress layer including a material different from that of the dielectric layer; and applying an energy field to permit the two surface portions to bond with each other through reaction between the first functional groups and the second functional groups.
11 . The method as claimed in claim 10 , wherein both the first functional groups and the second functional groups are —OH groups, and the two surface portions are bonded with each other through dehydration of the —OH groups respectively on the two surface portions.
12 . The method as claimed in claim 10 , wherein: the first functional groups are —NH x groups, where x is 1 or 2; the second functional groups are —H groups; the two surface portions are bonded with each other through dehydrogenation of the —NH x groups on one of the two surface portions and the —H groups on the other one of the two surface portions.
13 . The method as claimed in claim 10 , wherein the surface modification agent includes gas molecules having a molecular size less than a width of the seam, and is introduced into the seam by immersing the dielectric layer in the atmosphere of the gas molecules.
14 . The method as claimed in claim 13 , wherein the surface modification agent is introduced at a pressure ranging from 1 atm to 10 atm.
15 . The method as claimed in claim 13 , wherein: the gas molecules include water steam or hydrogen peroxide; and after applying the energy field, the two surface portions are bonded together by M-O-M bonds, where M is silicon, boron, or a metal element, and O is oxygen.
16 . The method as claimed in claim 13 , wherein: the gas molecules includes ammonia or hydrozine; and after applying the energy field, the two surface portions are bonded together by M-N-M bonds, where M is silicon, boron or a metal element, and Nis nitrogen.
17 . The method as claimed in claim 10 , wherein the surface modification agent includes a plasma.
18 . The method as claimed in claim 17 , wherein a precursor gas for generating the plasma includes hydrogen gas, nitrogen gas, oxygen gas, ammonia gas, or combinations thereof.
19 . A method for filling a gap, comprising: filling a dielectric layer in the gap by atomic layer deposition, so that a seam is formed in the dielectric layer, the dielectric layer including two surface portions at two opposite sides of the seam, respectively; introducing a surface modification agent into the seam such that each of the two surface portions has first functional groups and second functional groups; and applying an energy field to permit the two surface portions to bond with each other through reaction between the first functional groups and the second functional groups.
20 . The method as claimed in claim 19 , prior to applying the energy field, further comprising: forming a stress layer on the dielectric layer to cover the seam, the stress layer having a coefficient of thermal expansion different from that of the dielectric layer such that a stress is generated between the stress layer and the dielectric layer; and removing the stress layer after applying the energy field.

Description

BACKGROUND A gap-filling process for filling a conductive material or an insulating material in a gap is often repeatedly executed in the manufacturing process of a semiconductor device. With the size miniaturization of the semiconductor device, the gap-filling process is in continuous development so as to improve the performance of the semiconductor device. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. FIG. 1 is a flow diagram illustrating a method for filling a gap in accordance with some embodiments. FIGS. 2 to 9 are schematic views illustrating intermediate stages of the method depicted in FIG. 1 in accordance with some embodiments. FIGS. 10 to 13 are schematic diagrams illustrating changes in chemical bonds on two surface portions of a dielectric layer at different stages of the method in accordance with different embodiments. DETAILED DESCRIPTION The following disclosure provides many different embodiments, or examples, for implementing different features of the disclosure. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as “on,” “above,” “top,” “bottom,” “upper,” “lower,” “over,” “beneath,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly. For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing amounts, sizes, dimensions, proportions, shapes, formulations, parameters, percentages, quantities, characteristics, or other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about” even if the term “about” is not explicitly recited with the values, amounts or ranges. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are not and need not be exact, but may be approximations and/or larger or smaller than specified as desired, may encompass tolerances, conversion factors, rounding off, measurement error, and other factors known to those of skill in the art depending on the desired properties sought to be obtained by the presently disclosed subject matter. For example, the term “about,” when used with a value, can capture variations of, in some aspects ±10%, in some aspects ±5%, in some aspects ±2.5%, in some aspects ±1%, in some aspects ±0.5%, and in some aspects ±0.1% from the specified amount, as such variations are appropriate to perform the disclosed methods or employ the disclosed compositions. In general, in the manufacturing process of a semiconductor device, a gap-filling dielectric material may be filled in a gap using a suitable deposition process, such as chemical vapor deposition, physical vapor deposition, or atomic layer deposition. In the case that the gap-filling dielectric material is filled in a gap which has a relatively high aspect ratio using flowable chemical vapor deposition, in order to improve the quality or density of the gap-filling dielectric material, a post-annealing process is typically performed at a temperature as high as 700° C. or even greater. Such post-annealing process is a relatively high thermal budget process. Under the relatively high thermal budget process, defects, such as copper out-diffusion, or germanium segregation (which may lead to increased channel resistance), may be formed in the semiconductor device. In the other case that t