TW200414487A - Method for recovering alignment mark - Google Patents

Abstract

A method for recovering an alignment mark is disclosed, by using focused ion beam (FIB) to remove metal layers and insulator layers covered on the alignment mark during manufacturing a metal-insulator-metal capacitor structure. Therefore, the cost, time, and manpower of recovering the alignment mark can be reduced.

Description

200414487 V. Description of the invention (1) The technical field to which the invention belongs: The present invention relates to a method for reproducing an alignment mark, and in particular to a method using a focused ion beam (F ocused I ο η Beam; (FIB) method to reproduce the alignment mark in a metal-insulator-metal (MIM) capacitor structure. Prior technology: In the manufacturing process of semiconductor devices, as the components become smaller and smaller, the mask pattern is also reduced. Therefore, in the photolithography process, 'in order to accurately transfer the mask pattern to the semiconductor wafer, In general, it is necessary to provide several alignment marks on the wafer for the photomask alignment so that the photomask pattern can be accurately copied to a desired position on the wafer. Metal layer-insulation layer-metal layer capacitors have a wide range of applications in semiconductor technology, such as radio frequency (RF) circuits, analog products, (Analog integrated Ci] rcuits; Analog ICs), high-power processors MicroProcessor units (MPUs), and Dynamic Random Access Memory CeUs (DRAM Cells). The metal layer-insulation layer-metal layer capacitor should be made of opaque metal on the alignment mark when the conductor is manufactured. It cannot be used for alignment of the photomask. Therefore, the general practice is to stack the layers of metal layer-insulation layer-metal layer capacitors and then remove the material layer covered on the secondary mark to reproduce the alignment mark. The objective = y reproduction alignment mark is to remove the layers of the alignment mark ° using processes such as lithography and etching until the alignment mark appears.

200414487 V. Description of the invention (2) to Figure 3, Figures 1 to 3 show the conventional reproduction alignment mark m, and the substrate 10. On the other hand, Gading has // 20 on 0: there are-group confrontation, dielectric layer m2: genus = genus / U ° 'where metal layer iii: metal layer 106 and metal layer opaque, in order to; ! 4,! 02 4 is ^ ^ ^^ iio -l ^ # Λ Λ 二 # In order to remove the material covering the alignment mark 1 02, the photoresist layer 114 is exposed and the development steps are eliminated. : Photoresist layer above the 102 layer, "i" layer: the area of the alignment mark 102 is formed as shown in Fig. 2; the i structure defines the alignment in the second resist layer 114 After marking the area of 02, use the photoresist sound 11 4 = ίϊ, and use the anisotropic dry button technique to go to / Λ11. ′ And the cores under the metal layer 110 in this part are, the two-like gas Λ 6, and the dielectric layer 104. Among them, since the dielectric layer θ1〇4 is negative, the distance between the dielectric layer 104 and the alignment mark 102 is also not equal to :, so the dielectric layer 104 may not be completely opaque to reach Purpose 'Then, use the wet type: up to two. Summary of the invention: The structure formed by the tail end of the household is shown in FIG. 3. S 2 ^ Knowing that when the alignment mark is reproduced, the cost, time, and process of using the lithography and button-engraving processes are too complicated, and it is more complicated. Reproducible method, which uses poly-ionization to provide a material layer removal of an alignment mark. Because the sub beams on the alignment mark fall exactly on the required cause by adjusting the two; 2 'can focus the material layer on the mark, effective rule 5 = can be smoothly removed and covered in the alignment ^ invention Another purpose is to provide a reproducible method that can effectively refocus the focused ion beam, capture the metal layer insulation layer-metal intercalation, and can improve the application of the element structure. Overlay between layers is aligned with 2 = 2 and 2 = 7 ^ is providing a method of using the focused ion beam to reproduce shadow half = '' No need to coat photoresist, expose photoresist and display This one: system two steps of stripping photoresist. Because Λ ′ can reduce the process cost, save the process time, and avoid the waste of human resources.

According to the above-mentioned purpose, the present invention further provides a method for realigning an alignment mark, including at least the following steps: providing a substrate, wherein the substrate includes an alignment mark on a surface of the substrate And the substrate includes a first dielectric layer and a metal layer-insulating layer-metal layer capacitor sequentially stacked on the substrate and the alignment mark on the substrate, and the metal layer- The insulating layer-metal layer capacitor includes at least a "metal layer" sequentially stacked on the above-mentioned first dielectric layer, a second dielectric layer, and a metal layer; and removing the covering on the above by using a focused ion beam. Align the second metal layer, the second dielectric layer, and the first metal layer above the note. Wherein, because the dielectric layer is a light-transmitting material, the focused ion beam described above is used.

200414487 V. Description of the invention (4) Shift: When the second metal layer, the second dielectric layer overlying the alignment mark is covered with a metal layer, one of the first dielectric layer above the alignment mark can be removed. 'You can also make the alignment mark appear without removing the first dielectric layer. : With the focused ion beam machine, the focused ion beam can be accurately landed on each material layer to be removed, and the material layer above the alignment mark can be smoothly removed to make the alignment mark reappear. Embodiments: A method for reproducing an alignment mark is disclosed, which uses a focused ion beam to remove a material layer covering the alignment mark. Therefore, the alignment mark can be easily reproduced without increasing the cost of the process and the time and labor burden, so as to achieve the purpose of restoring the alignment mark to its alignment function. In order to make this description more detailed and complete, you can refer to the following description and cooperate with the diagrams in Figures 4 and 5. Please refer to FIG. 4 ′ FIG. 4 is a schematic cross-sectional view showing a process of reproducing the alignment mark of the preferred embodiment of the present invention. First, a semiconductor substrate 200 is provided. The substrate 2GG has at least one set of alignment marks 202 on its surface for alignment when the layout pattern is transferred, so that the component layout pattern can be refined. To the desired position on the substrate. Among them, the substrate 200 may be, for example, a half body, a18 & otherwise, a dielectric layer 204 is covered on the substrate 200 to cover the alignment mark 2G2 and the alignment mark 2Q2. Material 2QQ, and on top of the dielectric layer 204 are a metal layer 206, a dielectric layer 208, and a metal layer 210 which are sequentially stacked. Among them, the metal layer 2 () 6, the dielectric layer m, and the metal layer 210 form a metal layer-insulation layer-metal layer type capacitor 212. Since the metal layer 210 and the metal layer 206 are opaque materials ’, the alignment mark 202 is opaque

I1H Page 8 200414487 V. Description of the Invention (5) The metal layer 210 and the metal layer 20 6 are shielded, and the alignment function of the alignment mark 202 cannot be provided. In order to reproduce the alignment mark 202, the present invention uses a focused ion beam machine (only the ion beam projector 214 is shown) to provide a high-energy focused ion beam 216: to remove and cover the alignment mark 2 Of the material layer. At this time, the ion beam projector 214 is adjusted so that the focused ion beam 216 emitted by the ion beam projector 214 can land on the area above the alignment mark 202. The ion beam projector 2 1 4 is then used to project the focused ion beam 2 1 6 on the metal layer 2 i above the alignment mark 2 02. The ion beam projector 214 is controlled to move back and forth in the direction 218 and the square 9 to 22 °, so that the focused ion beam 216 can be repeatedly projected on the material layer above the alignment mark 202, and the covering rod is sequentially removed. The metal layer 2H, the dielectric layer 2.8, and the metal layer 206. : ㈡2 When the material layer above Erjin 202 is aligned, the current and voltage of the focused ion beam machine can be adjusted according to the thickness and material number of each material layer to adjust the ion flux of the > subbeam 216 Amount (Flux). In this way, the removal depth and removal rate of the material layer can be effectively controlled. Among them, when the layers above the alignment mark 2 02 are removed using the focused ion beam 2 1 β, the ion beam projector 214 can be moved back and forth as described above, and the substrate 2GG can also be moved back / back. #That is, as long as the focused ion beam 216 can be moved on the material layer in the area above the selective mark 202, the present invention does not match E • ^, plus the dielectric. Therefore, as shown in FIG. 5, since the 'dielectric layer 20 8' and the dielectric layer 204 are transparent material layer 204 and the alignment mark 202, there is no intermediary material above the mark 202 The electrical layer 204 need not be completely removed:

Page 9 200414487 V. Description of the invention (6) It is not even necessary to remove and focus the dielectric layer 204. The source gas of the beam 216 can be, for example, an inert gas, preferably argon or helium. When the focused ion beam 216 is used to remove each material layer above the alignment mark 202, a special active gas, such as silicon dioxide (SiOJ, iodine ("), xenon fluoride ( XeF2), and water vapor to improve the removal rate to improve the surface flatness or increase (decrease) the removal selectivity. It is worth noting that in this embodiment, the alignment mark 2 is covered The structure above the 〇2 is a capacitor composed of a metal layer, an insulating layer, and a metal layer. However, the present invention can be used to remove the opaque material layer or the transparent material layer covering the alignment mark 002. The structure formed. For example, the covering layer is composed of a sequentially stacked dielectric layer and a metal layer: it does not have to be a metal layer-insulating layer-metal layer capacitor structure.

In summary, one of the advantages of the present invention is that the focused ion beam can accurately land on the alignment mark: material J by means of the tuning table. Therefore, the layer ′ overlying the alignment mark can be accurately and easily removed to effectively reproduce the alignment mark. 4 Another advantage of the present invention is that because the polypyramid is separated from the ancient π + age, in this way, the -beam f beam can effectively reproduce the applicability of the alignment target = process, and can also improve the element. The double-layer performance improves the process reliability and product quality: layer "layer, another invention-the advantage is that it can save the coating photoresistor H, save the system and * Γ 4 steps' so it is not only possible Decreasing the cost of working is the time for name and private use, which can also avoid the waste of human resources. Page 10 200414487 V. Description of the invention (7) As understood by those skilled in the art, the above is only a preferred implementation of the present invention. The examples are not intended to limit the scope of patent application of the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed by the present invention should be included in the scope of patent application described below.

Page 11 200414487 The diagram is briefly explained. The preferred embodiment of the present invention has been described in more detail with the following figures in the preceding description text. Among them: Figures 1 to 3 are diagrams showing conventional reproduction pairs. Sectional view of the process of quasi-marking; FIG. 4 is a schematic cross-sectional view of a process for reproducing an alignment mark of a preferred embodiment of the present invention, and FIG. 5 is a cross-sectional view of a preferred embodiment of the present invention. A cross-sectional view of the structure after the quasi-marker is reproduced. Drawing number comparison description:

100 substrate 102 alignment mark 104 dielectric layer 1 06 metal layer 108 dielectric layer 110 metal layer 112 capacitor 114 photoresist layer 200 substrate 202 alignment mark 204 dielectric layer 206 metal layer 208 dielectric layer 210 metal layer 212 Capacitance 214 ion beam cast 216 focused ion beam 2 18 square 220 direction

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Claims (1)

200414487 VI. Scope of patent application 1. A method for reproducing an alignment mark (A 1 ignment Mark) at least includes: providing a substrate, wherein the substrate includes at least one alignment mark on a surface of the substrate 'And the substrate includes at least a layer of opaque material covering the surface of the substrate and the alignment mark; and using a focused ion beam (F IB) to remove the cover over the alignment mark A layer of opaque material to expose the alignment mark. 2. The method of reproducing the alignment mark as described in the first item of the patent application, wherein the material of the opaque material layer is metal. 3. The method for reproducing the alignment mark according to item 1 of the scope of the patent application, wherein the source gas of the focused ion beam includes at least an inert gas. 4. The method for reproducing the alignment mark according to item 1 of the scope of the patent application, wherein the source gas of the focused ion beam includes at least argon (Ar). The method of reproducing the alignment mark described in item 1 of the 5.2 application patent scope, wherein the source gas of the focused ion beam includes at least helium (He). 6. The method for reproducing the alignment mark as described in the first item of the patent scope, wherein when the focused ion beam is used to remove the opaque material layer above the alignment mark, it is more useful to include the introduction of 〆 activity Gas (Active Gas) method to improve material removal rate, selection ratio, and surface flatness. 200414487 6. Scope of patent application Γ · 7 · As for the method of reproducing the alignment mark described in item 6 of the scope of patent application, in which the / tongue gas is stone dioxide ($ 丨). 8. The method for reproducing the alignment mark as described in item 6 of the scope of the patent application, wherein the active gas is a moth (12). 9. The method for reproducing the alignment mark according to item 6 in the scope of the patent application, wherein the active gas is xenon fluoride (Xe &). 10. The method for reproducing the alignment mark as described in item 6 of the scope of the patent application, wherein the active gas is water vapor. 11 · A method for reproducing an alignment mark, including at least: providing a substrate, wherein the substrate includes at least one alignment mark on a surface of the substrate, and the substrate includes at least one of sequentially stacked A light-transmitting material layer covers the surface of the substrate, the alignment mark, and a material layer; and ^ removes a ^ material layer covering the alignment mark with a focused ion beam, thereby exposing the alignment mark. The reproduction method of the opaque record is as follows: 1 · The material of the opaque material layer in the exclusive rank described in item 11 of the patent application scope is metal. τ 200414487 6. Scope of patent application 1 3. The method for reproducing the alignment mark as described in item 11 of the scope of patent application, wherein the material of the transparent material layer is a dielectric material. / ′ 14. The method for reproducing the alignment mark as described in item 丨 丨 of the scope of the patent application, wherein the source gas of the 5 ^ coke ion beam includes at least an inert gas. ， ， 15 · The source gas of the focused ion beam in the reproduction of the alignment mark described in item 丨 丨 of the patent application scope includes at least argon. 》 ’Its 1 6. The source gas of the focused ion beam in the alignment rod note described in item 丨 丨 of the patent application scope includes at least helium. The current method includes the method of using the focused ion beam as described in item 丨 丨 of the patent application to remove the overlay on the alignment and 1 ticket reproduction method, and the optical material layer at least includes removing the Align the part of the impervious layer of 椤 ^ °. The light-transmitting material 18 above is not a reproduction method using the focused ion beam to cover the n as described in item 丨 丨 of the scope of the patent application. When the light material layer is used, it can be used including , Tongue ^-the removal rate of the bad material above, the selection ratio, and the way of the flat surface of the body, to 1 in 9. This lice system is selected from silicon dioxide, iodine, # See method: Xenon, and 200414487 6. Scope of patent application, a group of steam. 2 0 — A method for reproducing an alignment mark, including at least: providing a substrate, wherein the substrate includes at least one alignment mark on one surface of the substrate, and the substrate includes at least a sequential stack A first dielectric layer and a metal layer-insulation layer-metal layer (MIM) capacitor cover the surface of the substrate and the alignment mark, and the metal layer-insulation layer-metal layer capacitor includes at least Sequentially stacking a first metal layer on the first dielectric layer, a second dielectric layer, and a second metal layer; and using a focused ion beam to remove the first metal layer overlying the alignment mark Two metal layers, the second dielectric layer, and the first metal layer. 2 1. The method for reproducing the alignment mark according to item 20 of the scope of the patent application, wherein the source gas of the focused ion beam includes at least an inert gas. 2 2. The method for reproducing the alignment mark according to item 20 of the scope of the patent application, wherein the source gas of the focused ion beam includes at least argon. 2 3. The method of reproducing the alignment mark according to item 20 of the scope of the patent application, wherein the source gas of the focused ion beam includes at least helium. 2 4. The method for reproducing the alignment mark according to item 20 of the scope of the patent application, wherein the focused metal ion beam is used to remove the second metal layer, the second dielectric layer, and the second dielectric layer. When the first metal layer is included, at least Page 16 200414487 6. Scope of patent application, except for a part of the first dielectric layer above the alignment mark. 2 5. The method for reproducing the alignment mark according to item 20 of the scope of the patent application, wherein the focused ion beam is used to remove the second metal layer, the second dielectric layer above the alignment mark, and When the first metal layer is used, a method including introducing an active gas can be used to improve the material removal rate, selection ratio, and surface flatness. 2 6. The method for reproducing the alignment mark according to item 25 of the scope of the patent application, wherein the active gas is silicon dioxide. 2 7. The method for reproducing the alignment mark as described in item 25 of the scope of patent application, wherein the active gas is iodine. 2 8. The method for reproducing the alignment mark as described in item 25 of the scope of patent application, wherein the active gas is xenon fluoride. 2 9. The method of reproducing the alignment mark as described in item 25 of the scope of patent application, wherein the active gas is water vapor. Page 17