Production monitoring method of groove edge coverage rate

Abstract

The invention provides a production monitoring method for the edge coverage rate of a groove, and the method comprises the steps: providing a front-layer structure which is provided with at least one groove, and the width of the groove is a first key size; a current-layer material layer is formed on the front-layer structure on the periphery of the groove and the surface of the groove, and the unfilled residual groove is in a shape with a wide lower part and a narrow upper part from bottom to top when being observed from a section angle; obtaining the thickness of the current material layer; obtaining a second key size which is the minimum distance between the current material layers of the two side walls in the groove; obtaining the edge coverage rate of the current material layer according to the first key size, the second key size and the thickness of the current material layer; and adjusting the deposition thickness of the next material layer according to the edge coverage rate of the current material layer. According to the method, the deposition thickness of the lower-layer material can be estimated conveniently through a non-destructive and instant measurement method, and the method can be used for monitoring the production process stability of each layer of deposition machine in time on line.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to a method for monitoring the production of trench edge coverage rate. Background Art

[0002] The deep trench capacitor process includes: trench etching -> capacitor dielectric formation (such as silicon oxide layer / tetraethyl orthosilicate deposition) -> electrode formation (such as polysilicon deposition / TiN atomic layer deposition) -> capacitor dielectric formation (in a cycle).

[0003] Different operating voltages (5V - 100V) require different capacitor dielectric thicknesses to correspond. Adjusting the thickness of subsequent materials requires data reference of the sidewall step coverage rate of the trench.

[0004] What is most concerned about in the step coverage rate is the minimum edge coverage rate at the overhang, which affects the sealing generated by the deposition of the underlying material. In addition, the minimum edge coverage rate is beneficial to the increase of parasitic capacitance, but will reduce the breakdown voltage of the device. Therefore, it is very important to monitor the production stability of different thicknesses and different deposition machines.

[0005] In the prior art, there is a lack of an online production monitoring method for effectively obtaining the trench edge coverage rate. To solve the above problems, a new method for monitoring the production of trench edge coverage rate needs to be proposed. Summary of the Invention

[0006] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a method for monitoring the production of trench edge coverage rate, which is used to solve the problem that there is a lack of an effective production monitoring method for obtaining the trench edge coverage rate in the prior art.

[0007] To achieve the above purpose and other related purposes, the present invention provides a method for monitoring the production of trench edge coverage rate, including:

[0008] Step 1: Provide a front layer structure, on which there is at least one trench, and the width of the trench is the first key dimension;

[0009] Step 2: Form a current layer material layer on the front layer structure outside the trench and on the surface of the trench. From a cross-sectional perspective, the remaining unfilled trench is in a shape that is wider at the bottom and narrower at the top from bottom to top;

[0010] Step 3: Obtain the thickness of the current layer material layer; obtain the second key dimension, which is the minimum distance between the current layer material layers on the two sidewalls in the trench;

[0011] Step 4: Obtain the edge coverage rate of the current layer material layer according to the first key dimension, the second key dimension, and the thickness of the current layer material layer;

[0012] Step Five: Adjust the deposition thickness of the subsequent layer material layer according to the edge coverage rate of the current layer material layer.

[0013] Preferably, in Step One, the previous layer structure is a substrate, and the trench is formed on the substrate.

[0014] Preferably, in Step One, the previous layer structure is a previous layer trench formed on a substrate, and a previous layer thin film structure is further formed on the surfaces of the previous layer trench and the substrate, and the region between the previous layer thin film structures is defined as the trench.

[0015] Preferably, in Step One, the previous layer structure is an interlayer dielectric layer, and the trench is formed on the interlayer dielectric layer.

[0016] Preferably, in Step One, the previous layer structure is a previous layer trench formed on an interlayer dielectric layer, and a previous layer thin film structure is further formed on the surfaces of the previous layer trench and the interlayer dielectric layer, and the region between the previous layer thin film structures is defined as the trench.

[0017] Preferably, the method is used for a deep trench capacitor process, and the current layer material layer in Step Two is a capacitor dielectric layer or a capacitor electrode.

[0018] Preferably, the method is used for a high density plasma deposition process, and the current layer material layer in Step Two is a high density plasma oxide layer.

[0019] Preferably, in Step One and Step Three, a critical dimension measurement machine tool is used to obtain the first critical dimension and the second critical dimension.

[0020] Preferably, in Step Three, a film thickness measurement machine tool is used to obtain the thickness of the current layer material layer.

[0021] Preferably, the edge coverage rate of the current layer material layer in Step Four is: (the first critical dimension - the second critical dimension) / 2 / the planar deposition thickness A of the current layer material layer.

[0022] As described above, the production monitoring method for the trench edge coverage rate of the present invention has the following beneficial effects:

[0023] The present invention uses a non-destructive and instant measurement method, which is conducive to estimating the deposition thickness of the underlying material and can be used to monitor the production process stability of each deposition machine tool in real time. Description of the Drawings

[0024] Figure 1 Shown is a schematic diagram of the monitoring method of the present invention;

[0025] Figure 2Schematic diagram showing the structure after forming the current layer material layer of the present invention (where A / B / C / D are the film thicknesses at different key positions of the current layer deposited material layer). Detailed implementation manners

[0026] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand 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 implementation manners, 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.

[0027] Please refer to Figure 1 , the present invention provides a production monitoring method for trench edge coverage rate, including:

[0028] Step 1: Provide a pre-layer structure, on which there is at least one trench, and the width of the trench is the first key dimension;

[0029] In some embodiments, the pre-layer structure in Step 1 is a substrate, and the trench is formed on the substrate.

[0030] In some embodiments, the pre-layer structure in Step 1 is a pre-layer trench formed on the substrate, and a pre-layer thin film structure is further formed on the surfaces of the pre-layer trench and the substrate, and the region between the pre-layer thin film structures is defined as the trench.

[0031] In some embodiments, the pre-layer structure in Step 1 is an interlayer dielectric layer, and the trench is formed on the interlayer dielectric layer. The interlayer dielectric layer includes dielectric materials such as silicon oxide, low-k dielectric materials, other suitable dielectric materials, or combinations thereof. In some examples, the low-k dielectric materials include fluorinated silicon glass (FSG), carbon-doped silicon oxide, xerogel, aerogel, amorphous fluorocarbon, parylene, BCB (bisbenzocyclobutene), polyimide, and / or other suitable dielectric materials whose dielectric constant is generally less than that of thermal silicon oxide. For example, the formation of the interlayer dielectric layer includes deposition and CMP. Deposition can include spin coating, CVD, other suitable deposition techniques, or combinations thereof.

[0032] In some embodiments, the pre-layer structure in Step 1 is a pre-layer trench formed on the interlayer dielectric layer, and a pre-layer thin film structure is further formed on the surfaces of the pre-layer trench and the interlayer dielectric layer, and the region between the pre-layer thin film structures is defined as the trench.

[0033] It should be noted that the pre-layer structure can also be other trench structures well-known to those skilled in the art, and no specific limitation is made here.

[0034] Step 2: Please refer to Figure 2, a current layer material layer is formed on the front layer structure and the groove surface around the groove. From a cross-sectional perspective, the remaining unfilled groove has a shape that is wider at the bottom and narrower at the top from bottom to top;

[0035] In some embodiments, the method is used for a deep trench capacitor process, and the current layer material layer in step two is a capacitor dielectric layer or a capacitor electrode. The capacitor electrode can be or include, for example, metal, doped polysilicon, some other suitable (some) conductive materials, or any combination of the foregoing. The capacitor dielectric layer can be or include, for example, silicon oxide, high-k dielectric, some other suitable (some) dielectrics, or any combination of the foregoing.

[0036] In some embodiments, the method is used for a high-density plasma deposition process, and the current layer material layer in step two is a high-density plasma oxide layer.

[0037] It should be noted that the current layer material layer can also be a film layer deposited in other process grooves, and no specific limitation is made here.

[0038] Step three: Obtain the thickness of the current layer material layer; obtain a second critical dimension, which is the minimum distance between the current layer material layers on the two sidewalls in the groove;

[0039] In some embodiments, a critical dimension measurement tool (such as a scanning electron microscope tool for measuring feature size) is used in step one and step three to obtain the first critical dimension and the second critical dimension.

[0040] In some embodiments, a film thickness measurement tool (such as a laser ellipsometer or a spectroscopic ellipsometer) is used in step three to obtain the thickness of the current layer material layer.

[0041] Step four: Obtain the edge coverage rate of the current layer material layer according to the first critical dimension, the second critical dimension, and the thickness of the current layer material layer;

[0042] In some embodiments, the edge coverage rate of the current layer material layer in step four is: (the first critical dimension - the second critical dimension) / 2 / the planar deposition thickness A of the current layer material layer.

[0043] Step five: Adjust the deposition thickness of the subsequent layer material layer according to the edge coverage rate of the current layer material layer. Through a non-destructive and real-time measurement method, it is beneficial for predicting the deposition thickness of the lower layer material and can be used to monitor the production process stability of each deposition tool online in a timely manner.

[0044] 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 type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0045] In summary, the present invention uses a non-destructive and real-time measurement method, which is conducive to estimating the deposition thickness of the underlying material and can be used to monitor the production process stability of each deposition machine in real time online. Therefore, the present invention effectively overcomes various drawbacks in the prior art and has high industrial utilization value.

[0046] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended 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 made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A production monitoring method for trench edge coverage rate, characterized in that At least including: Step 1: Provide a front-layer structure with at least one groove on the front-layer structure, and the width of the groove is the first critical dimension; Step 2: Form a current-layer material layer on the front-layer structure outside the groove and on the surface of the groove. When observed from a cross-sectional perspective, the remaining unfilled groove is in a shape that is wider at the bottom and narrower at the top from bottom to top; Step 3: Obtain the thickness of the current-layer material layer; obtain the second critical dimension, which is the minimum distance between the current-layer material layers on both side walls in the groove; Step 4: Obtain the edge coverage rate of the current-layer material layer according to the first critical dimension, the second critical dimension, and the thickness of the current-layer material layer; Step 5: Adjust the deposition thickness of the back-layer material layer according to the edge coverage rate of the current-layer material layer.

2. The production monitoring method for the trench edge coverage rate according to claim 1, wherein: The front-layer structure in Step 1 is a substrate, and the groove is formed on the substrate.

3. The production monitoring method for the trench edge coverage rate according to claim 1, wherein: The front-layer structure in Step 1 is a front-layer groove formed on a substrate, and a front-layer thin film structure is also formed on the surfaces of the front-layer groove and the substrate. The area between the front-layer thin film structures is defined as the groove.

4. The production monitoring method for the trench edge coverage rate according to claim 1, characterized in that: The front-layer structure in Step 1 is an interlayer dielectric layer, and the groove is formed on the interlayer dielectric layer.

5. The production monitoring method for the trench edge coverage rate according to claim 1, wherein: The front-layer structure in Step 1 is a front-layer groove formed on an interlayer dielectric layer, and a front-layer thin film structure is also formed on the surfaces of the front-layer groove and the interlayer dielectric layer. The area between the front-layer thin film structures is defined as the groove.

6. The production monitoring method for the trench edge coverage rate according to claim 1, characterized in that: The method is used for deep trench capacitor process, and the current-layer material layer in Step 2 is a capacitor dielectric layer or a capacitor electrode.

7. The production monitoring method for the trench edge coverage rate according to claim 1, characterized in that: The method is used for high-density plasma deposition process, and the current-layer material layer in Step 2 is a high-density plasma oxide layer.

8. The production monitoring method for the trench edge coverage rate according to claim 1, characterized in that: In Step 1 and Step 3, a critical dimension measuring machine tool is used to obtain the first critical dimension and the second critical dimension.

9. The production monitoring method for the trench edge coverage rate according to claim 1, characterized in that: In Step 3, a film thickness measuring machine tool is used to obtain the planar deposition thickness of the current-layer material layer.

10. The production monitoring method for the trench edge coverage rate according to claim 1, wherein: The edge coverage rate of the current-layer material layer in Step 4 is: (the first critical dimension - the second critical dimension) / 2 / the thickness of the current-layer material layer.

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