CN115332182A - Mandrel removing method for self-aligned double-pattern structure - Google Patents
Mandrel removing method for self-aligned double-pattern structure Download PDFInfo
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- CN115332182A CN115332182A CN202211005694.9A CN202211005694A CN115332182A CN 115332182 A CN115332182 A CN 115332182A CN 202211005694 A CN202211005694 A CN 202211005694A CN 115332182 A CN115332182 A CN 115332182A
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Abstract
The invention provides a mandrel removing method of a self-aligned double-pattern structure, which comprises the steps of forming a plurality of mandrel structures on a first region and a second region; depositing a first film layer and etching to remove the first film layer on the tops of the first mandrel structure and the second mandrel structure and the first film layer on the mandrel etching stop layer, and forming a first side wall on the side wall of the first mandrel structure and the side wall of the second mandrel structure; forming an organic dielectric layer to cover the first mandrel structure and the second mandrel structure; forming a silicon-containing anti-reflection layer; exposing the silicon-containing anti-reflection layer of the first region; removing the silicon-containing anti-reflection layer and the organic dielectric layer on the first area; removing the first side wall on the first mandrel structure; removing the organic dielectric layer of the second region; depositing a second film layer to cover the first mandrel structure and the second mandrel structure; removing the second film layer on the first mandrel structure; forming a second side wall on the side wall of the first mandrel structure; removing the first mandrel structure and the second mandrel structure; and forming a combined structure of the first side walls which are arranged at intervals and the first side walls and the second side walls which are arranged at intervals.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a mandrel removing method of a self-aligned double-pattern structure.
Background
In the fabrication of integrated circuits, technology nodes are advancing, especially for process nodes of 24nm and belowIn point, the critical dimensions defined by photolithographic processes for the associated structures have reached a limit. To obtain smaller-sized structures, a self-aligned dual patterning technique is introduced (Salf Aligned Double Patterning, SADP process). Taking the later-stage SADP process as an example, amorphous silicon is used as a mandrel film layer, and the specific flow comprises the following steps: forming a film layer structure before etching; etching the mandrel structure to form the mandrel structure; depositing side walls on two sides of the mandrel structure; etching the side wall; and carrying out a mandrel removal exposure process to form a film layer before the removal etching of the side wall. And then performing a mandrel structure removal process. For certain regions, the mandrels between the side walls need to be completely removed, but for some other regions, the thickness of the side walls alone cannot completely define the critical dimension of the subsequent pattern. Therefore, in performing the process, a portion of the mandrel structure needs to be retained; and taking the residual film layer structure as a mask layer, and carrying out a subsequent metal hard mask etching process. For the mandrel material removal process step of the above process flow, the specific area requires that the step maintain a certain isotropic etch to ensure complete removal of the mandrel material therein. And the other certain region is affected by the isotropic etching, so that the appearance of side wall bending is formed in the residual mandrel material. Furthermore, the curved shape can bring further influence to the next metal hard mask etching process, causing problems such as damage and the like.
Disclosure of Invention
In view of the above drawbacks of the prior art, an object of the present invention is to provide a mandrel removing method for a self-aligned dual pattern structure, which is used to solve the problem of sidewall bending caused by isotropic and anisotropic etching for mandrel removal in different regions of the SADP process in the prior art.
To achieve the above and other related objects, the present invention provides a method for removing a mandrel from a self-aligned dual pattern structure, comprising:
the method comprises the following steps of firstly, providing a lamination layer, wherein the lamination layer is formed by stacking an etching stop layer, a metal hard mask layer and a mandrel etching stop layer from bottom to top in sequence; dividing the laminated layer into a first area and a second area along the longitudinal direction of the laminated layer;
step two, forming a plurality of mandrel structures which are arranged at intervals on the mandrel etching stop layers of the first region and the second region respectively; wherein the mandrel structure on the mandrel etching stop layer in the first region is a first mandrel structure; the mandrel structure on the mandrel etching stop layer in the second area is a second mandrel structure;
depositing a first film layer to cover the upper surface of the mandrel etching stop layer and the outer surfaces of the first mandrel structure and the second mandrel structure;
etching the first film layer to remove the first film layer on the tops of the first and second mandrel structures and the first film layer on the upper surface of the mandrel etching stop layer, and forming first side walls on the side walls of the first and second mandrel structures;
forming an organic dielectric layer, wherein the organic dielectric layer covers the mandrel etching stop layer and the first mandrel structure and the second mandrel structure; forming a silicon-containing anti-reflection layer on the organic dielectric layer; then coating photoresist on the silicon-containing anti-reflection layer;
exposing and developing to expose the silicon-containing anti-reflection layer in the first area;
seventhly, etching and removing the silicon-containing anti-reflection layer and the organic dielectric layer on the first area, and exposing the first mandrel structure;
eighthly, removing the first side wall on the first mandrel structure; ashing the residual organic dielectric layer, and further removing the organic dielectric layer covering the second region;
ninthly, depositing a second film layer, wherein the second film layer covers the mandrel etching stop layer and the upper surfaces of the first mandrel structure and the second mandrel structure and the first side walls of the first mandrel structure and the second mandrel structure;
tenth, etching the second film layer, and removing the second film layer on the upper surface of the mandrel etching stop layer, the second film layer on the upper surface of the first mandrel structure, the second mandrel structure and the second film layer on the upper surface of the first side wall of the second mandrel structure; forming a second side wall on the side wall of the first mandrel structure, and forming a second side wall attached to the first side wall of the second mandrel structure;
eleven, removing the first mandrel structure and the second mandrel structure; forming the first side walls which are arranged at intervals on the mandrel etching stop layer on the first area; forming a combined structure of first side walls and second side walls which are arranged at intervals on the mandrel etching stop layer on the second region;
and step twelve, etching the mandrel etching stop layer and the metal hard mask layer by taking the combined structure of the first side wall and the second side wall as a mask until the upper surface of the etching stop layer is etched.
Preferably, the metal hard mask layer in the first step is TiN.
Preferably, the mandrel etching stop layer in the first step is a silicon oxide layer.
Preferably, the critical dimension of the first mandrel structure in step two is smaller than the critical dimension of the second mandrel structure.
Preferably, the first film layer in step three is silicon nitride.
Preferably, the mandrel structure in step two is amorphous silicon.
Preferably, in the eighth step, the first side wall on the first mandrel structure is removed by wet etching.
As described above, the mandrel removing method of the self-aligned dual pattern structure of the present invention has the following advantages: the process requirements of the invention on the first area and the second area are the same, and only the mandrel structure material in the first area and the second area needs to be completely removed. The residual film structures after the two areas are etched are both side walls, so that the problem of side wall bending cannot occur, and the problem of defects generated in the subsequent hard metal hard mask etching process is solved.
Drawings
FIGS. 1 to 10 are schematic views showing the structure of each stage of the self-aligned double patterning mandrel removal method of the present invention;
FIG. 11 is a flow chart of a mandrel removal method for self-aligned dual pattern structures according to the present invention.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
Please refer to fig. 1 to 11. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.
The present invention provides a method for removing a mandrel with a self-aligned dual pattern structure, as shown in fig. 11, fig. 11 is a flowchart of the method for removing the mandrel with the self-aligned dual pattern structure of the present invention, the method at least includes the following steps:
the method comprises the following steps of firstly, providing a lamination layer, wherein the lamination layer is formed by stacking an etching stop layer, a metal hard mask layer and a mandrel etching stop layer from bottom to top in sequence; dividing the laminated layer into a first area and a second area along the longitudinal direction of the laminated layer;
further, the metal hard mask layer in the first step of this embodiment is TiN.
Further, the mandrel etching stop layer in the first step of this embodiment is a silicon oxide layer.
As shown in fig. 1, in the first step, a stack layer is provided, and the stack layer is formed by stacking an etching stop layer 01, a metal hard mask layer 02 and a mandrel etching stop layer 03 from bottom to top in sequence; dividing the lamination into a first area (area A) and a second area (area B) along the longitudinal direction of the lamination; the metal hard mask layer is TiN; the mandrel etching stop layer is a silicon oxide layer.
Step two, forming a plurality of mandrel structures which are arranged at intervals on the mandrel etching stop layers of the first area and the second area respectively; wherein the mandrel structure on the mandrel etching stop layer in the first region is a first mandrel structure; the mandrel structure on the mandrel etching stop layer in the second area is a second mandrel structure;
further, in the second step of this embodiment, the critical dimension of the first mandrel structure is smaller than the critical dimension of the second mandrel structure.
Further, the mandrel structure in step two of this embodiment is amorphous silicon.
As shown in fig. 1, in the second step, a plurality of mandrel structures 04 arranged at intervals are formed on the mandrel etching stop layer in the first and second regions, respectively; wherein the mandrel structure located on the mandrel etch stop layer of the first region is a first mandrel structure; the mandrel structure on the mandrel etching stop layer in the second area is a second mandrel structure; the critical dimension of the first mandrel structure is smaller than the critical dimension of the second mandrel structure. The mandrel structure is amorphous silicon.
Depositing a first film layer to cover the upper surface of the mandrel etching stop layer and the outer surfaces of the first mandrel structure and the second mandrel structure;
further, in the third step of the present invention, the first film layer is silicon nitride. As shown in fig. 2, depositing a first film 05 covering the upper surface of the mandrel etch stop layer and the outer surfaces of the first and second mandrel structures; the first film 05 is silicon nitride.
Etching the first film layer to remove the first film layer on the tops of the first and second mandrel structures and the first film layer on the upper surface of the mandrel etching stop layer, and forming first side walls on the side walls of the first and second mandrel structures; as shown in fig. 3, this step four etches the first film layer 05, so that the first film layer 05 on top of the first and second mandrel structures and the first film layer 05 on the upper surface of the mandrel etch stop layer 03 are removed, and first sidewalls 06 are formed on the sidewalls of the first and second mandrel structures.
Forming an organic dielectric layer, wherein the organic dielectric layer covers the mandrel etching stop layer and the first mandrel structure and the second mandrel structure; forming a silicon-containing anti-reflection layer on the organic dielectric layer; then coating photoresist on the silicon-containing anti-reflection layer; as shown in fig. 4, in the fifth step, an organic dielectric layer 07 is formed, where the organic dielectric layer 07 covers the mandrel etching stop layer 03 and the first and second mandrel structures 04; forming a silicon-containing anti-reflection layer 08 on the organic dielectric layer 07; a photoresist 09 is then applied over the silicon-containing anti-reflective layer 08.
Exposing and developing to expose the silicon-containing anti-reflection layer in the first area; as shown in fig. 4, that is, after development, the second region is still covered with the photoresist 09.
Seventhly, etching and removing the silicon-containing anti-reflection layer and the organic dielectric layer on the first area, and exposing the first mandrel structure; as shown in fig. 5, in this step seven, the silicon-containing antireflection layer and the organic dielectric layer on the first region are etched and removed, so that the first mandrel structure is exposed, and the organic dielectric layer 07 is still covered on the second region.
Eighthly, removing the first side wall on the first mandrel structure; ashing the rest organic dielectric layer, and further removing the organic dielectric layer covering the second region;
further, in the eighth step of this embodiment, the first sidewall on the first mandrel structure is removed by wet etching. As shown in fig. 6, in the present embodiment, the first sidewall 06 on the first mandrel structure is removed by wet etching.
Step nine, depositing a second film layer, wherein the second film layer covers the mandrel etching stop layer and the first mandrel structure, the upper surface of the second mandrel structure and the first side wall of the second mandrel structure; this step nine deposits a second film 10 covering the mandrel etch stop layer and the first mandrel structure, the upper surface of the second mandrel structure and the first sidewalls 06 of the sidewalls thereof, as shown in fig. 7.
Tenth, etching the second film layer, and removing the second film layer on the upper surface of the mandrel etching stop layer, the second film layer on the upper surface of the first mandrel structure, the second mandrel structure and the second film layer on the upper surface of the first side wall of the second mandrel structure; forming a second side wall on the side wall of the first mandrel structure, and forming a second side wall attached to the first side wall of the second mandrel structure; as shown in fig. 8, in this step ten, the second film layer is etched, and the second film layer on the upper surface of the mandrel etching stop layer, the second film layer on the upper surface of the first mandrel structure, the second mandrel structure, and the second film layer on the upper surface of the first sidewall thereof are removed; and forming a second side wall on the side wall of the first mandrel structure, and forming a second side wall 11 attached to the first side wall of the second mandrel structure.
Eleven, removing the first mandrel structure and the second mandrel structure; forming the first side walls which are arranged at intervals on the mandrel etching stop layer on the first region; forming a combined structure of first side walls and second side walls which are arranged at intervals on the mandrel etching stop layer on the second region; as shown in fig. 9, the eleventh step removes the first and second mandrel structures, and forms the first sidewalls 06 spaced apart from each other on the mandrel etching stop layer on the first region; and forming a combined structure of the first side wall 11 and the second side wall 11 which are arranged at intervals on the mandrel etching stop layer on the second region, namely, the first side wall and the second side wall on the second region are attached to each other to form the combined structure.
And step twelve, etching the mandrel etching stop layer and the metal hard mask layer by taking the combined structure of the first side wall and the first and second side walls as a mask until the mandrel etching stop layer and the metal hard mask layer are etched to the upper surface of the etching stop layer. As shown in fig. 10, in this step twelve, the mandrel etching stop layer and the metal hard mask layer are etched by using the combined structure of the first sidewall and the first and second sidewalls as a mask until the mandrel etching stop layer and the metal hard mask layer are etched to the upper surface of the etching stop layer, so as to form a mandrel etching stop layer structure 13 and a metal hard mask layer structure 12 located thereunder.
In summary, the process requirements of the present invention for the first region and the second region are the same, and only the mandrel structure material therein needs to be completely removed. The residual film structures after the two areas are etched are both side walls, so that the problem of side wall bending cannot occur, and the problem of defects generated in the subsequent hard metal hard mask etching process is solved. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Those skilled in the art can modify or change the above-described embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and scope of the present invention as defined in the appended claims.
Claims (7)
1. A mandrel removing method for a self-aligned dual pattern structure, comprising:
the method comprises the following steps of firstly, providing a lamination layer, wherein the lamination layer is formed by stacking an etching stop layer, a metal hard mask layer and a mandrel etching stop layer from bottom to top in sequence; dividing the lamination into a first area and a second area along the longitudinal direction of the lamination;
step two, forming a plurality of mandrel structures which are arranged at intervals on the mandrel etching stop layers of the first region and the second region respectively; wherein the mandrel structure on the mandrel etching stop layer in the first region is a first mandrel structure; the mandrel structure on the mandrel etching stop layer in the second area is a second mandrel structure;
depositing a first film layer to cover the upper surface of the mandrel etching stop layer and the outer surfaces of the first mandrel structure and the second mandrel structure;
etching the first film layer to remove the first film layer on the tops of the first and second mandrel structures and the first film layer on the upper surface of the mandrel etching stop layer, and forming first side walls on the side walls of the first and second mandrel structures;
fifthly, forming an organic dielectric layer, wherein the organic dielectric layer covers the mandrel etching stop layer and the first mandrel structure and the second mandrel structure; forming a silicon-containing anti-reflection layer on the organic dielectric layer; then coating photoresist on the silicon-containing anti-reflection layer;
exposing and developing to expose the silicon-containing anti-reflection layer in the first area;
seventhly, etching to remove the silicon-containing anti-reflection layer and the organic dielectric layer on the first region and exposing the first mandrel structure;
eighthly, removing the first side wall on the first mandrel structure; ashing the rest organic dielectric layer, and further removing the organic dielectric layer covering the second region;
step nine, depositing a second film layer, wherein the second film layer covers the mandrel etching stop layer and the first mandrel structure, the upper surface of the second mandrel structure and the first side wall of the second mandrel structure;
tenth, etching the second film layer, and removing the second film layer on the upper surface of the mandrel etching stop layer, the second film layer on the upper surface of the first mandrel structure, the second mandrel structure and the second film layer on the upper surface of the first side wall of the second mandrel structure; forming a second side wall on the side wall of the first mandrel structure, and forming a second side wall attached to the first side wall of the second mandrel structure;
eleven, removing the first mandrel structure and the second mandrel structure; forming the first side walls which are arranged at intervals on the mandrel etching stop layer on the first area; forming a combined structure of first and second side walls which are arranged at intervals on the mandrel etching stop layer on the second region;
and step twelve, etching the mandrel etching stop layer and the metal hard mask layer by taking the combined structure of the first side wall and the second side wall as a mask until the upper surface of the etching stop layer is etched.
2. The method for removing a mandrel from a self-aligned dual pattern structure according to claim 1, wherein: and the metal hard mask layer in the step one is TiN.
3. The method of claim 1, wherein: and the mandrel etching stop layer in the first step is a silicon oxide layer.
4. The method for removing a mandrel from a self-aligned dual pattern structure according to claim 1, wherein: and the critical dimension of the first mandrel structure in the second step is smaller than that of the second mandrel structure.
5. The method for removing a mandrel from a self-aligned dual pattern structure according to claim 1, wherein: the first film layer in the third step is silicon nitride.
6. The method for removing a mandrel from a self-aligned dual pattern structure according to claim 1, wherein: and the mandrel structure in the second step is amorphous silicon.
7. The method for removing a mandrel from a self-aligned dual pattern structure according to claim 1, wherein: and eighthly, removing the first side wall on the first mandrel structure through wet etching.
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| CN202211005694.9A CN115332182A (en) | 2022-08-22 | 2022-08-22 | Mandrel removing method for self-aligned double-pattern structure |
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| CN202211005694.9A CN115332182A (en) | 2022-08-22 | 2022-08-22 | Mandrel removing method for self-aligned double-pattern structure |
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