Trench isolation structure for improving dislocation and manufacturing method thereof

Abstract

The invention provides a trench isolation structure for improving dislocation, which comprises a substrate, a trench is formed on the substrate, and a strained silicon layer is formed on the surface of the trench; a linear liner oxide layer is formed on the surface of the strained silicon layer in the groove; and the high-density plasma oxide layer is used for filling the residual groove. The strained silicon layer is used for resisting the internal stress of the high-density plasma oxide layer, and the strained silicon layer can bear the subsequent high-temperature process to keep the internal stress.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a trench isolation structure for improving dislocations and a manufacturing method thereof. Background Art

[0002] The problem of dislocations at the bottom of trenches in Trench Isolation caused by the HDP CVD (High-Density Plasma Chemical Vapor Deposition) process. The main reason for the dislocations is that during subsequent high-temperature processes, the high-density plasma oxide expands and contracts due to thermal expansion and contraction, resulting in tensile stress on the substrate and causing the formation of dislocations.

[0003] To solve the above problems, a novel trench isolation structure for improving dislocations and a manufacturing method thereof need to be proposed. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a trench isolation structure for improving dislocations and a manufacturing method thereof, which are used to solve the problem that the high-density plasma-filled oxide expands and contracts due to thermal expansion and contraction in the prior art, resulting in tensile stress on the substrate and causing dislocations.

[0005] To achieve the above purpose and other related purposes, the present invention provides a trench isolation structure for improving dislocations, including:

[0006] A substrate, on which a trench is formed, and a strained silicon layer is formed on the surface of the trench;

[0007] A linear pad oxide layer is formed on the surface of the strained silicon layer in the trench;

[0008] A high-density plasma oxide layer filling the remaining trench.

[0009] Preferably, the substrate is a silicon substrate.

[0010] Preferably, the strained silicon layer includes: a germanium-silicon epitaxial layer formed on the surface of the trench; a silicon layer formed on the surface of the germanium-silicon epitaxial layer.

[0011] Preferably, the strained silicon layer includes: a silicon layer formed on the surface of the trench; a stress layer formed by in-situ carbon doping of the silicon layer.

[0012] The present invention also provides a manufacturing method of the above trench isolation structure for improving dislocations, including:

[0013] Step 1: Provide a substrate, form a trench on the substrate, and form a strained silicon layer on the surface of the trench;

[0014] Step 2: Form a linear pad oxide layer on the surface of the strained silicon layer in the trench;

[0015] Step 3: Form a high-density plasma oxide layer that fills the remaining trenches by means of deposition and polishing.

[0016] Preferably, the substrate in Step 1 is a silicon substrate.

[0017] Preferably, the trenches are formed in Step 1 by means of photolithography and dry etching.

[0018] Preferably, the method for forming the strained silicon layer in Step 1 includes: forming a germanium-silicon epitaxial layer on the surface of the trenches; forming a silicon layer on the germanium-silicon epitaxial layer; patterning the germanium-silicon epitaxial layer and the silicon layer so that they remain in the trenches.

[0019] Preferably, the method for forming the strained silicon layer in Step 1 includes: forming a silicon layer on the surface of the trenches; introducing internal stress by in-situ carbon doping of the silicon layer; patterning the silicon layer so that it remains in the trenches.

[0020] Preferably, the polishing method in Step 3 is chemical mechanical planarization polishing.

[0021] As described above, the trench isolation structure for improving dislocations and its manufacturing method according to the present invention have the following beneficial effects:

[0022] The strained silicon layer in the present invention is used to relieve the stress of the high-density plasma oxide layer, and the strained silicon layer can withstand subsequent high-temperature processes while maintaining internal stress. Description of the Drawings

[0023] Figure 1 Schematic diagram of a trench isolation structure shown as the prior art;

[0024] Figure 2 Schematic diagram of the process flow of the present invention;

[0025] Figure 3 Schematic diagram of the trench formation of the present invention;

[0026] Figure 4 Schematic diagram of the strained silicon layer formation of the present invention;

[0027] Figure 5 Schematic diagram of the linear pad oxide layer of the present invention;

[0028] Figure 6 Schematic diagram of the high-density plasma oxide layer of the present invention. Detailed Embodiments

[0029] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0030] Please refer to Figure 6 , the present invention provides a trench isolation structure for improving dislocations, including:

[0031] A substrate 101, on which a trench 102 is formed, and a strained silicon layer 103 is formed on the surface of the trench 102;

[0032] Strained silicon technology refers to the technology that makes silicon atoms strained by using the stress generated by the lattice constant mismatch or the difference in thermal expansion of different materials during the process. According to the different strains, strained silicon can be divided into two types: compressive strained silicon (the distance between silicon atoms shrinks) and tensile strained silicon (the distance between silicon atoms expands). The stress generated by compressive strain is called compressive stress or compression stress, and the stress generated by tensile strain is called tensile stress or tension stress. The strained silicon layer 103 can be formed by methods such as chemical vapor deposition and physical vapor deposition. The strained silicon layer 103 in the present invention is used to mitigate the stress of the high-density plasma oxide layer 105, and the strained silicon layer 103 can withstand subsequent high-temperature processes while maintaining internal stress.

[0033] In some embodiments, the substrate 101 is a silicon substrate 101.

[0034] In some embodiments, the strained silicon layer 103 includes: a germanium-silicon epitaxial layer formed on the surface of the trench 102, so as to generate strain on the silicon layer; a silicon layer formed on the surface of the germanium-silicon epitaxial layer.

[0035] In some embodiments, the strained silicon layer 103 includes: a silicon layer formed on the surface of the trench 102; a stress layer formed by carbon doping of the silicon layer. Carbon doping is the same as the GeSi growth method, and Ge atoms or C (carbon) atoms are doped simultaneously during the epitaxial growth of Si to introduce internal stress.

[0036] In other embodiments, the strained silicon layer 103 can also use other known strained materials.

[0037] A linear pad oxide layer 104 is formed on the surface of the strained silicon layer 103 in the trench 102;

[0038] A high-density plasma oxide layer 105 that fills the remaining trench 102.

[0039] Please refer to Figure 2, the present invention also provides a manufacturing method of the above trench 102 isolation structure for improving dislocations, including:

[0040] Step 1: Provide a substrate 101, form a trench 102 on the substrate 101, to form a structure as shown in Figure 3 , and form a strained silicon layer 103 on the surface of the trench 102, to form a structure as shown in Figure 4 ;

[0041] The strained silicon technology refers to the technology that makes silicon atoms strained by using the stress generated by the lattice constant mismatch of different materials or the difference in thermal expansion of materials during the process. According to different strains, strained silicon can be divided into two types: compressive strained silicon (the distance between silicon atoms shrinks) and tensile strained silicon (the distance between silicon atoms expands). The stress generated by compressive strain is called compressive stress, and the stress generated by tensile strain is called tensile stress. The strained silicon layer 103 can be formed by methods such as chemical vapor deposition and physical vapor deposition. The strained silicon layer 103 in the present invention is used to mitigate the stress of the high-density plasma oxide layer 105, and the strained silicon layer 103 can withstand subsequent high-temperature processes and maintain internal stress.

[0042] In some embodiments, the substrate 101 in Step 1 is a silicon substrate 101.

[0043] In some embodiments, the trench 102 is formed by using photolithography and dry etching methods in Step 1.

[0044] In some embodiments, the formation method of the strained silicon layer 103 in Step 1 includes: forming a germanium-silicon epitaxial layer on the surface of the trench 102; forming a silicon layer on the germanium-silicon epitaxial layer, so as to generate strain in the silicon layer; patterning the germanium-silicon epitaxial layer and the silicon layer to retain them in the trench 102.

[0045] In some embodiments, the formation method of the strained silicon layer 103 in Step 1 includes: forming a silicon layer on the surface of the trench 102; introducing internal stress by in-situ carbon doping during the formation of the silicon layer; patterning the silicon layer to retain it in the trench 102. Carbon doping is the same as the GeSi growth method, and Ge atoms or C (carbon) atoms are doped simultaneously during the epitaxial growth of Si to introduce internal stress.

[0046] In other embodiments, the strained silicon layer 103 can also use other known strained materials.

[0047] Step 2: Form a linear pad oxide layer 104 on the surface of the strained silicon layer 103 in the trench 102. The linear pad oxide layer 104 can be formed by thermal oxidation or chemical vapor deposition and physical vapor deposition methods, to form a structure as shown in Figure 5 ;

[0048] Step 3: Form a high-density plasma oxide layer 105 that fills the remaining trenches 102 by means of deposition and grinding, that is, form the high-density plasma oxide layer 105 by using a high-density plasma chemical vapor deposition process, and then grind the high-density plasma oxide layer 105 onto the substrate 101 to form a structure as shown in Figure 6 the figure.

[0049] In some embodiments, the grinding method in Step 3 is chemical mechanical planarization grinding.

[0050] It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The types, quantities, and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0051] In summary, the strained silicon layer in the present invention is used to mitigate the stress of the high-density plasma oxide layer, and the strained silicon layer can withstand subsequent high-temperature processes and maintain internal stress. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0052] The above embodiments only illustrate the principle and its effects of the present invention by way of example, and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A trench isolation structure for improving dislocation, characterized in that: include: A substrate, a groove is formed on the substrate, and a strained silicon layer is formed on the surface of the groove; A linear liner oxide layer is formed on the surface of the strained silicon layer in the groove; A high density plasma oxide layer fills the remaining trenches.

2. The dislocation-improving trench isolation structure according to claim 1, characterized in that: The substrate is a silicon substrate.

3. The dislocation-improving trench isolation structure according to claim 1, characterized in that: The strained silicon layer includes: a germanium silicon epitaxial stress layer formed on the surface of the groove; and a silicon layer formed on the surface of the germanium silicon epitaxial layer.

4. The dislocation-improving trench isolation structure according to claim 1, characterized in that: The strained silicon layer comprises: a silicon layer formed on the surface of the groove; and a stress layer formed by carbon doping of the silicon layer.

5. The method for manufacturing a dislocation-improving trench isolation structure according to any one of claims 1 to 4, characterized in that: At least: Step 1, providing a substrate, forming a groove on the substrate, and forming a strained silicon layer on the surface of the groove; Step 2, forming a linear liner oxide layer on the surface of the strained silicon layer in the groove; Step three: forming a high-density plasma oxide layer filling the remaining grooves by deposition and grinding methods.

6. The method for manufacturing a dislocation-improving trench isolation structure according to claim 5, characterized in that: The substrate in step one is a silicon substrate.

7. The method for manufacturing a dislocation-improving trench isolation structure according to claim 5, characterized in that: In step one, the groove is formed by photolithography and dry etching.

8. The method for manufacturing a dislocation-improving trench isolation structure according to claim 5, characterized in that: The method for forming the strained silicon layer in step 1 includes: forming a germanium silicon epitaxial layer on the surface of the groove; forming a silicon layer on the germanium silicon epitaxial layer; and patterning the germanium silicon epitaxial layer and the silicon layer so that they remain in the groove.

9. The method for manufacturing a dislocation-improving trench isolation structure according to claim 5, characterized in that: The method for forming the strained silicon layer in step 1 includes: forming a silicon layer on the surface of the groove; in-situ carbon doping the silicon layer to introduce internal stress; and patterning the silicon layer so that it remains in the groove.

10. The method for manufacturing a dislocation-improving trench isolation structure according to claim 5, characterized in that: The grinding method in step three is chemical mechanical planarization grinding.

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