Method for improving interval time of manufacturing procedures of back reflection metal grating

Abstract

The invention provides a method for improving interval time of manufacturing processes of a back reflection metal grating, which comprises the following steps of: 1, providing a substrate, and sequentially forming an interlayer dielectric layer, a barrier layer, a metal layer, a first metal hard mask layer, a first hard mask layer, a second metal hard mask layer and a second hard mask layer on the back surface of the substrate; step 2, performing first etching, and forming a plurality of grooves in the second metal hard mask layer and the second hard mask layer; 3, second etching is carried out, and a plurality of grooves are formed in the first hard mask layer; and step 4, carrying out pretreatment on the exposed first metal hard mask layer, and then carrying out third etching to form the back reflection metal grating. According to the invention, the technological process can be optimized, the final morphology defect of the metal grating is improved, the cost is reduced, and the technological window is expanded.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and specifically to a method for improving the process interval (Qtime) in the manufacturing of back-reflective metal grids. Background Technology

[0002] With the widespread application of back-illuminated image sensors in consumer electronics, they are becoming increasingly sensitive to light, have fewer noise defects, and require higher and more refined manufacturing processes.

[0003] In terms of manufacturing process, the aspect ratio of backside metal grids (BMGs) has been improved through hard metal mask technology. However, the exposure of the hard metal mask has strict requirements on Q time and is highly susceptible to fluctuations in the factory's internal environment, leading to product defects such as... Figure 1 The defects shown mean that factory production requires continuous upgrades to production lines and hardware modifications to mitigate the environmental impact on products, which seriously affects production efficiency and costs. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a method for improving the interval time of back-reflective metal grid manufacturing processes, in order to solve the problem of product defects caused by the exposure of the metal hard mask in the prior art.

[0005] To achieve the above and other related objectives, this application provides a method for improving the interval time of manufacturing processes for back-reflective metal grids, comprising:

[0006] Step 1: Provide a substrate, and sequentially form an interlayer dielectric layer, a barrier layer, a metal layer, a first metal hard mask layer, a first hard mask layer, a second metal hard mask layer, and a second hard mask layer on the back side of the substrate;

[0007] Step two, perform the first etching to form multiple trenches in the second metal hard mask layer and the second hard mask layer;

[0008] Step 3: Perform a second etching to form multiple trenches in the first hard mask layer;

[0009] Step four involves pre-treating the exposed first metal hard mask layer and then performing a third etching process to form a back-reflective metal grid.

[0010] Preferably, in step four, the polymer formed on the surface of the first metal hard mask layer by the first etching and the second etching is removed by pretreatment.

[0011] Preferably, pretreatment is performed using plasma.

[0012] Preferably, the metal layer includes an aluminum layer, and the first metal hard mask layer includes a titanium nitride layer.

[0013] Preferably, before performing the first etching, a photoresist layer with a back-reflective metal grid pattern is formed on the second hard mask layer.

[0014] Preferably, the photoresist layer is used as a mask, and after the first etching is performed, the photoresist layer is removed.

[0015] Preferably, the removal of the photoresist layer is performed on the same machine as the first etching.

[0016] Preferably, the second etching is performed using the second metal hard mask layer and the second hard mask layer as masks.

[0017] Preferably, the removal of the second hard mask layer is completed during the second etching process.

[0018] Preferably, the removal of the second metal hard mask is completed during the third etching process.

[0019] As described above, the method for improving the manufacturing process interval of back-reflective metal grids provided in this application has the following beneficial effects: 1) expanding the Q time process window; 2) reducing the cost of upgrading and modifying process equipment, as well as the investment cost of additional configurations; 3) reducing the probability of process defects occurring during the transfer process, which is conducive to improving product quality. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 The diagram shows a defect that occurs when fabricating a back-reflective metal grid according to existing technology.

[0022] Figure 2 The flowchart shown is a method for improving the manufacturing process interval of back-reflective metal grids according to an embodiment of this application;

[0023] Figures 3A-3D The diagram shown is a cross-sectional view of the device formed after each step in the method for improving the interval time of back-reflective metal manufacturing grid provided in the embodiments of this application. Detailed Implementation

[0024] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application 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 this invention.

[0025] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0028] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0029] Please see Figure 2 The document illustrates a flowchart of a method for improving the manufacturing process interval of back-reflective metal grids according to an embodiment of this application.

[0030] like Figure 2 As shown, the method for improving the manufacturing process interval of back-reflective metal grilles includes the following steps:

[0031] Step 1: Provide a substrate, and sequentially form an interlayer dielectric layer, a barrier layer, a metal layer, a first metal hard mask layer, a first hard mask layer, a second metal hard mask layer, and a second hard mask layer on the back side of the substrate;

[0032] Step two, perform the first etching to form multiple trenches in the second metal hard mask layer and the second hard mask layer;

[0033] Step 3: Perform a second etching to form multiple trenches in the first hard mask layer;

[0034] Step four involves pre-treating the exposed first metal hard mask layer and then performing a third etching process to form a back-reflective metal grid.

[0035] In step one, the substrate can be a semiconductor substrate, such as silicon (Si), germanium (Ge), SiGe substrate, silicon-on-insulator (SOI), or germanium-on-insulator (GOI). In other embodiments, the semiconductor substrate can also be a substrate comprising other elemental semiconductors or compound semiconductors, and can also be a multilayer structure, such as Si / SiGe. Those skilled in the art can select the constituent materials of the substrate according to the type of device structure formed on the substrate; therefore, the type of substrate should not limit the scope of protection of this invention.

[0036] As an example, such as Figure 3A As shown, an interlayer dielectric layer 301, a barrier layer 302, a metal layer 303, a first metal hard mask layer 304, a first hard mask layer 305, a second metal hard mask layer 306, and a second hard mask layer 307 are sequentially formed on the back side of the substrate through a deposition process.

[0037] For example, the interlayer dielectric layer 301 includes an oxide layer, the barrier layer 302 includes a Ti / TiN layer, the metal layer 303 includes an aluminum layer, the first metal hard mask layer 304 includes a titanium nitride layer, the first hard mask layer 305 includes a silicon oxynitride layer stacked from bottom to top and an oxide layer formed by a plasma-enhanced deposition process, the second metal hard mask layer 306 includes a titanium nitride layer, and the second hard mask layer 307 includes a TEOS layer.

[0038] In step two, before performing the first etching, a photoresist layer with a back-reflective metal grid pattern is formed on the second hard mask layer 307.

[0039] Using the photoresist layer as a mask, a first etching is performed, followed by the removal of the photoresist layer. For example, the removal of the photoresist layer and the first etching are performed on the same machine.

[0040] like Figure 3BAs shown, after the first etching is performed, multiple trenches are formed in the second metal hard mask layer 306 and the second hard mask layer 307.

[0041] In step three, the second etching is performed using the second metal hard mask layer 306 and the second hard mask layer 307 as masks. During the second etching process, the second hard mask layer 307 is removed.

[0042] like Figure 3C As shown, after the second etching is performed, multiple trenches are formed in the first hard mask layer 305.

[0043] In step four, a pretreatment process removes the polymer formed on the surface of the first and second etching layers of the first metal hard mask. Exemplarily, this pretreatment is performed using plasma. By performing this pretreatment, the Qtime can be increased by a factor of three.

[0044] like Figure 3D As shown, during the third etching process, the second metal hard mask layer 306 is removed.

[0045] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0046] In summary, the method for improving the manufacturing process interval of back-reflective metal grids provided in this application has the following beneficial effects: 1) expanding the Q-time process window; 2) reducing the cost of upgrading and modifying process equipment, as well as the investment cost of additional configurations; 3) reducing the probability of process defects occurring during the transfer process, which is conducive to improving product quality. Therefore, this application effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0047] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this application.

Claims

1. A method for improving the process interval time of a back-reflective metal grid manufacturing process, characterized in that, The method comprises: Step one, providing a substrate, forming an interlayer dielectric layer, a barrier layer, a metal layer, a first metal hard mask layer, a first hard mask layer, a second metal hard mask layer and a second hard mask layer on the back of the substrate in sequence; Step two, performing a first etching to form a plurality of grooves in the second metal hard mask layer and the second hard mask layer; Step three, performing a second etching to form a plurality of grooves in the first hard mask layer; Step four, after pre-treating the exposed first metal hard mask layer, performing a third etching to form the back reflective metal grid.

2. The method of claim 1, wherein, In the step four, the pre-treatment removes the polymer formed on the surface of the first metal hard mask layer by the first etching and the second etching.

3. The method of claim 2, wherein, The pre-treatment is performed by plasma.

4. The method of claim 1, wherein, The metal layer comprises a metal aluminum layer, and the first metal hard mask layer comprises a titanium nitride layer.

5. The method of claim 1, wherein, Before performing the first etching, a photoresist layer with a pattern of the back reflective metal grid is formed on the second hard mask layer.

6. The method of claim 5, wherein, After performing the first etching with the photoresist layer as a mask, the photoresist layer is removed.

7. The method of claim 6, wherein, The removal of the photoresist layer and the first etching are completed on the same machine.

8. The method of claim 1, wherein, The second etching is performed with the second metal hard mask layer and the second hard mask layer as masks.

9. The method of claim 8, wherein, During the performance of the second etching, the removal of the second hard mask layer is completed.

10. The method of claim 1, wherein, During the performance of the third etching, the removal of the second metal hard mask is completed.

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