TWI220769B - Planarization process - Google Patents

Abstract

A planarization process is described. A substrate having a film thereon is provided. A deposition process is performed for covering on the film and filling the opening with a deposition material. Then, a polishing process is performed to remove the partial material and remain other material in the opening and on the film. The deposition process is performed again to deposit the material on the material having been formed. The polishing process is performed again to remove the material until the surface of the film is exposed and also remain some material in the opening. If the surface of the material is not planar, repeating the deposition and the polishing processes until the surface of the material become planar. Since the planarization process includes repeating the deposition and the polishing processes, the issue that the surface of the material is not planar after polishing can be resolved.

Description

1220769

----- Case No. 92119805 V. Description of the invention (1) TECHNICAL FIELD The present invention relates to a semiconductor process, and in particular to a planarization process.疋 关于 β about a current process for filling backfill openings in very large scale integrated circuits (VLSI) is achieved using chemical vapor deposition (Chemical Vapor DepOsitiQL), but this deposition method still cannot fill the material only into the shovel = 2 opening, so it must first deposit a layer thicker than the depth of the opening, and then perform a planarization step to remove the material outside the opening. ^ For the purpose of flattening, chemical mechanical polishing (CMP) is the technology of global planarization that is the king of conventional grinding methods. Generally speaking, 'in the process of chemical mechanical grinding, it uses a slurry with suspended abrasive particles (siurry) and abrasives with appropriate elasticity and hardness, in The wafer surfaces are moved relative to each other to achieve the purpose of flattening. In other words, when the polishing pad is moved on the wafer in a pressing manner, the wafer surface and the abrasive particles in the polishing liquid will contact each other to cause friction, which causes wear and tear on the wafer surface, so that its surface is gradually flat. Figures 1A to 1D are schematic cross-sectional views showing the flow of a conventional metal inlaying process. The metal inlaying process is one of the applications for backfilling openings. Please refer to FIG. 1A. First, a semiconductor substrate 100 is provided. Some semiconductor elements (not shown) have been formed in the substrate 100. Next, a dielectric layer 102 is formed over the substrate 100.

11292twf1.ptc Page 7 1220769 Case No. 92119805 Λ_a. Revision V. Description of Invention (2) Then, referring to Figure 1B, a traditional photolithography technique is used to form a patterned light on the dielectric layer 〇2 A resist layer (not shown), and then the dielectric layer 102 is etched through a patterned photoresist layer to form a patterned dielectric layer 102a, and the patterned dielectric layer 1 0 2 a has an opening 1 0 4. Then, the photoresist layer is peeled. After that, referring to FIG. 1C, a metal deposition process is performed to gradually fill the metal layer 106 in the opening 104. Next, referring to FIG. 1D, a chemical mechanical polishing method is performed to remove the metal layer 106 other than the opening 104, and the metal layer 106 in the opening 104 is retained. However, in the above-mentioned process, because of the opening 104, It is relatively wide. When the metal layer 106 is formed by CVD to fill the opening 104, the surface of the metal film layer 106 will not show a flat surface. In the subsequent chemical mechanical polishing, due to its abrasive contact, The force on the surface cannot be evenly distributed, so the effect of complete flatness cannot be achieved. Especially, the metal layer 106a will appear in a shallow dish shape (as shown in FIG. 1D) after the opening is polished. In addition, if the opening to be backfilled is relatively narrow, although for a single opening, the surface of the metal layer will not have a shallow dish-type defect after grinding, there will still be grinding for multiple consecutive openings. Non-uniform erosion (as shown in Figure 2). In addition, the current accumulation of component processes is getting higher and higher, and the number of layers stacked on the wafer surface is increasing. These stacked patterned film layers will make the wafer surface more uneven and increase. Difficulty of completely flattening the polishing. Summary of the Invention

11292twf1.ptc Page 8 1220769 _ Case number 92119805 V. Description of the invention (3) Revision In view of this, the object of the present invention is to provide a flattening process to solve the problem that conventional flattening cannot be achieved.

The present invention provides a planarization process. This process first provides a substrate, a film has been formed on the substrate, and at least one opening has been formed in the film. Next, a deposition process is performed to deposit a material on the film and fill the opening. Thereafter, a grinding process is performed to remove a portion of the material, while retaining the material located in the opening and on the film. Then, the deposition process is performed again to continue depositing the material on the remaining material. Next, the grinding process is performed again to remove the material until the surface of the film is exposed, leaving the material in the opening. After that, if the surface of the material in the opening is not completely flat, repeat the deposition and grinding of the material until the surface of the material is completely flat. Since the planarization process of the present invention performs multiple depositions and multiple grindings to replace single depositions and single grindings in the conventional technology, repeated depositions and grindings are used to reduce the above-mentioned non-uniform polishing situation, thereby solving the problem. It is known that the problem of polishing that cannot be completely flattened is known. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below in conjunction with the accompanying drawings to make a detailed description as follows: Embodiment 3 FIG. A flowchart of a planarization process according to a preferred embodiment of the present invention, and FIGS. 4A to 4E are schematic cross-sectional views illustrating a planarization process of FIG. 3. Please refer to Figure 3 and Figure 4A at the same time. The flattening process is first performed.

11292twf1.ptc Page 9 1220769 said correction = 20, in this step, 0 is to provide a substrate 300, substrate 3 = diaphragm film 3 0 2 ′ and at least -opening 3 04 has been formed in the film 3 02. Recovery: 04 series? The fork contacts a window opening, a trench, or a double inlaid opening, and y 3 2 is, for example, an " electrical layer. It is worth mentioning that the following description explains the present invention with an earlier port f. However, the present invention is not limited to a single opening. For example, if there are a plurality of openings in a film, the present invention can be used for planarization purposes. . Then, referring to FIG. 3 and FIG. 4B at the same time, step 002 is performed; this step 202 is to perform a deposition process to deposit the material 306 on the film 3 02 and fill the opening 3 0 4. The deposition process is, for example, chemical vapor deposition, and the reaction gas end depends on the deposited material, and the deposited material is, for example, a dielectric material, a conductor material, or a semiconductor material, and the dielectric material is, for example, dioxide Silicon, phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), silicon nitride, etc., the conductor material is, for example, tungsten, copper or polycrystalline silicon, and the semi-metal material is, for example, silicon. Wherein, if the deposited material 306 is a metal material, a barrier layer (such as titanium / titanium nitride) is formed on the surface of the film and the opening between step 2000 and step 202 to form Prevent metal from diffusing

After that, please refer to FIG. 3 and FIG. 4C at the same time, and perform step 204, step 204 is to perform a grinding process to remove a portion of the material 300, and the bottom is located in the opening 304 and the film 302. The above material 306a, of which the polishing process example is a chemical mechanical polishing process. In this step 204, since the opening 304 is relatively wide, when the material 306 is deposited by CVD to fill the opening 304, the surface of the material 306 will not appear flat (as shown in FIG. 4B). Show),

1220769

V. Description of the invention (5) In the subsequent chemical mechanical polishing, 'the force on the grinding contact surface cannot be evenly distributed, so it will not be able to achieve a complete flattening effect, especially in the part of the opening 3 04 whose material is 306a The surface will present shallow openings 308 (as shown in Figure 4C).

Then, referring to FIG. 3 and FIG. 4D at the same time, perform step 206. This step 206 is to perform a deposition process again to continue depositing material 3 6b on the remaining material 3 06 a. The deposition process is, for example, chemical vapor deposition, and the reaction gas end depends on the deposited material, and the deposited material 3 0 6 b is the same material as the deposited material 3 06 a. In this step 206, the shallow dish-shaped opening 3 0 8 of the material 3 6 a can be filled by depositing the material 3 0 6 b (as shown in FIG. 4D). Next, please refer to FIG. 3 and FIG. 4E at the same time, and perform step 208. At this step, 208 is the grinding process again to remove the materials 3 〇 6 a, 〇 6 b, straight, the surface of the film 302 The bare part is exposed, and the 3 06 c 'located in the opening 300 is retained, wherein the polishing process is, for example, a chemical mechanical polishing process. Since f 2 in step 2 0 8, the material 3 0 6b is deposited in the shallow dish-shaped opening 3 0 8. This type of opening σ 3 0 8 is much smaller than the opening 3 0 4 in step 2 0 0. When chemical mechanical polishing is performed, 'the problem of uneven force on the polishing contact surface 1 can be solved', so the effect of complete planarization can be achieved (as shown in Figure 4E).

F ′ in the example, please continue to refer to FIG. 12 and FIG. 4E. In a preferred embodiment, port 3 〇 04 ′ can be selectively performed in step 21o.

1 0 6 的 材料 3〇6 (: The surface is not completely flat yet, then repeat step 2 What material deposition and step 2 08 grinding until the surface of the material is completely flat. 1220769 _ Case No. 92119805 5. Description of the invention (6) The correction is therefore known from the above. In the present invention, at least two deposition and grinding steps are performed. The shallow dish-shaped opening on the surface of the material is gradually reduced by repeated deposition and grinding to reduce the conventional grinding unevenness. The invention can achieve the effect of complete planarization. In addition, the multiple deposition and multiple polishing steps of the present invention can also be applied to a planarization process with multiple openings, so that each of the multiple openings is filled. The material has excellent flatness. Of course, the flattening process of the present invention is more suitable for today's high-leveling flattening processes.

Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes and retouch without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application.

11292twf1.ptc Page 12 1220769 Case No. 92119805 Revised diagrams Brief description Figures 1A to 1D are not intended to be used to understand the flow profile of a metal damascene process. Figure 2 is a conventional method using chemical machinery A schematic cross-sectional view of the structure obtained by the grinding method; FIG. 3 is a flowchart of a planarization process according to a preferred embodiment of the present invention; and FIG. 4A to FIG. 4E are a planarization process of FIG. Schematic cross-section. Explanation of the graphical symbols 1 00, 3 0 0: substrate 10 02, 102a: dielectric layers 104, 304, 308: openings 106, 106a: metal layer 3 0 2: thin film 3 0 6, 3 0 6 a, 3 0 6 b, 3 0 6 c: material

11292twfl.ptc Page 13

Claims (1)

1220769 Six Emperor 9805 Amends the scope of the patent application1. A Pingyuanhua cake, including: (a) providing a substrate, a film has been formed on the substrate, and at least a hukou is formed; ， 瓜 "，… ", Erlu thin dagger open / or have at least one opening, (b) perform a deposition system, deposit a material to cover it, and fill the opening; film (C)-grinding Process to remove a portion of the material, the material located in the opening and on the film; reserve-(d) perform the deposition process again to continue depositing the material while remaining; and / on the material-- e) The grinding process is performed again to remove the exposed surface of the material, and the material located in the opening is retained. The flattening process as described in item i of the patent scope of the patent application / more (F) 'Right in step (), the opening t is in the upper and middle + flattening process described in item 1 of the patent scope, f ~ + step = (f), if in step (e), the If the material in the opening is more stable, repeat steps (d) to (e) until the opening The surface ^ ^ is not completely flat. The material λ in the net mouth is made by a priest ... The surface is completely flat deposited 3 The flattening process 4 described in item 1 of the scope of the chemical process 4 The chemical vapor deposition process. Grinding Process 2: The flattening process 5 described in item 1 of 2 is described in the chemical mechanical polishing process.. It is selected from the flattening process described in item 1 of Qiao F ;; The driving material is selected from the group consisting of -dielectric material & 3-〇6 · The conductor material of the patented patent includes _ 2 Ϊ C. The flattening process described above, where _ t Conductor material and a semiconductor material ^ 1220769 11292twf1.ptc Page 15