阅读说明：本技术 平坦化方法 (Planarization method ) 是由 吕丽英 黎家健 吴一雷 于 2020-04-23 设计创作，主要内容包括：本发明提供了一种能够使得待加工产品的局部平坦度更均匀的平坦化方法,待加工产品开设有填充氧化物的腔体,且其包括叠设在腔体上的第一电极层、压电层和第二电极层,第一电极包括位于第一电极层周边的第一斜面部,压电层在其表面形成第二斜面部,第二电极层包括位于第二电极层周边的第三斜面部,方法包括：在第二电极层沉积第一钝化层；对第一钝化层刻蚀以在第三斜面部的外周形成衬垫,衬垫在其表面形成第四斜面部的；在第二电极层沉积第二钝化层,第二钝化层具有第一平面部、设于第一平面部外围的第五斜面部和自第五斜面部延伸的第二平面部,第一平面部沿竖直方向上的投影覆盖腔体,第五斜面部沿竖直方向的正投影落在腔体外。(The invention provides a flattening method capable of enabling local flatness of a product to be processed to be more uniform, wherein the product to be processed is provided with a cavity filled with oxide, and the flattening method comprises a first electrode layer, a piezoelectric layer and a second electrode layer which are stacked on the cavity, the first electrode comprises a first inclined plane part positioned on the periphery of the first electrode layer, a second inclined plane part is formed on the surface of the piezoelectric layer, and the second electrode layer comprises a third inclined plane part positioned on the periphery of the second electrode layer, and the method comprises the following steps: depositing a first passivation layer on the second electrode layer; etching the first passivation layer to form a pad on the outer circumference of the third slope part, the pad having a fourth slope part formed on the surface thereof; and depositing a second passivation layer on the second electrode layer, wherein the second passivation layer is provided with a first plane part, a fifth inclined plane part arranged on the periphery of the first plane part and a second plane part extending from the fifth inclined plane part, the first plane part covers the cavity along the projection in the vertical direction, and the orthographic projection of the fifth inclined plane part in the vertical direction falls outside the cavity.)

1. A flattening method is used for flattening the surface part of a product to be processed, the product to be processed is provided with a cavity filled with oxide, the product to be processed comprises a first electrode layer, a piezoelectric layer and a second electrode layer which are stacked on the cavity, the first electrode layer covers the cavity and comprises a first inclined plane part located on the periphery of the first electrode layer, the piezoelectric layer covers the first electrode layer, due to the first inclined plane part, a second inclined plane part is formed on the surface of the piezoelectric layer, the second electrode layer covers a part of the piezoelectric layer and comprises a third inclined plane part located on the periphery of the second electrode layer, and the orthographic projection of the second electrode layer along the vertical direction falls in the cavity, and the flattening method is characterized by comprising the following steps:

depositing a first passivation layer on the second electrode layer, the first passivation layer covering the second electrode layer and the piezoelectric layer;

etching the first passivation layer to enable the first passivation layer to form a gasket on the periphery of a third inclined surface part at the periphery of the second electrode layer, wherein the gasket is flush with the second electrode layer, and a fourth inclined surface part is formed on the surface of the gasket due to the third inclined surface part;

and depositing a second passivation layer on the second electrode layer, wherein the second passivation layer covers the second electrode layer, the pad and the piezoelectric layer, the second passivation layer is provided with a first plane part, a fifth inclined plane part arranged on the periphery of the first plane part and a second plane part extending from the fifth inclined plane part, the first plane part covers the cavity along the projection in the vertical direction, and the orthographic projection of the fifth inclined plane part in the vertical direction falls outside the cavity.

2. The planarization method of claim 1, wherein the second passivation layer forms the fifth bevel portion due to the presence of the fourth bevel portion, and further forms a sixth bevel portion disposed at the periphery of the second planar portion due to the presence of the second bevel portion.

3. The planarization method of claim 1, wherein after depositing the second passivation layer on the second electrode layer, the following steps are performed:

etching the second passivation layer completely until the thickness of the second passivation layer is reduced to the required thickness;

and releasing the oxide in the cavity to obtain a finished product.

4. The planarization method of claim 1, wherein after depositing the second passivation layer on the second electrode layer, the following steps are performed:

and releasing the oxide in the cavity to obtain a finished product.

5. The planarization method of claim 1, wherein the etching of the second passivation layer is performed by a full dry etch or a full wet etch.

6. The planarization method of claim 1, wherein the first passivation layer and the second passivation layer are both made of aluminum nitride.

7. The planarization method of claim 1, wherein the product to be processed is a filter.

[ technical field ] A method for producing a semiconductor device

The invention relates to the technical field of planarization processing methods, in particular to a planarization method.

[ background of the invention ]

[ summary of the invention ]

The invention aims to provide a flattening method, which is used for flattening the surface part of a product to be machined, the machining process is easier to control, and better local flatness can be realized.

The technical scheme of the invention is as follows:

a flattening method is used for flattening the surface part of a product to be machined, the product to be machined is provided with a cavity filled with oxide, the product to be machined comprises a first electrode layer, a piezoelectric layer and a second electrode layer which are stacked on the cavity, the first electrode layer covers the cavity and comprises a first inclined plane part located on the periphery of the first electrode layer, the piezoelectric layer covers the first electrode layer, due to the first inclined plane part, a second inclined plane part is formed on the surface of the piezoelectric layer, the second electrode layer covers a part of the piezoelectric layer and comprises a third inclined plane part located on the periphery of the second electrode layer, and the orthographic projection of the second electrode layer along the vertical direction falls in the cavity, and the flattening method comprises the following steps:

depositing a first passivation layer on the second electrode layer, the first passivation layer covering the second electrode layer and the piezoelectric layer;

etching the first passivation layer to enable the first passivation layer to form a gasket on the periphery of a third inclined surface part at the periphery of the second electrode layer, wherein the gasket is flush with the second electrode layer, and a fourth inclined surface part is formed on the surface of the gasket due to the third inclined surface part;

and depositing a second passivation layer on the second electrode layer, wherein the second passivation layer covers the second electrode layer, the pad and the piezoelectric layer, the second passivation layer is provided with a first plane part, a fifth inclined plane part arranged on the periphery of the first plane part and a second plane part extending from the fifth inclined plane part, the first plane part covers the cavity along the projection in the vertical direction, and the orthographic projection of the fifth inclined plane part in the vertical direction falls outside the cavity.

As a modification, the second passivation layer forms the fifth slope portion due to the presence of the fourth slope portion, and further forms a sixth slope portion provided on the periphery of the second plane portion due to the presence of the second slope portion.

As a modification, after depositing a second passivation layer on the second electrode layer, the following steps are performed:

etching the second passivation layer completely until the thickness of the second passivation layer is reduced to the required thickness;

and releasing the oxide in the cavity to obtain a finished product.

As a modification, after depositing a second passivation layer on the second electrode layer, the following steps are performed:

and releasing the oxide in the cavity to obtain a finished product.

As a modification, the overall etching of the second passivation layer is performed by overall dry etching or overall wet etching.

As a modification, the first passivation layer and the second passivation layer are made of aluminum nitride material.

As an improvement, the product to be processed is a filter.

The invention has the beneficial effects that: the planarization method of the present invention widens the actual width of the second electrode layer using the pad since the first passivation layer is previously deposited to form the pad at the outer circumference of the third inclined surface portion of the second electrode layer before the second passivation layer is deposited, and thus, when the second passivation layer is deposited, only a thin second passivation layer needs to be deposited, so that the orthographic projection of the fifth inclined plane part of the second passivation layer along the vertical direction falls outside the cavity, even the thickness of the second passivation layer is just the required thickness, thus, the purpose of flattening the surface part (first plane part) of the product to be processed can be realized without carrying out subsequent treatment on the second passivation layer, the method is simple to operate, high in practicability, easy to control in the implementation process, capable of achieving better local flatness, not limited by materials of products to be processed, and wide in application range.

[ description of the drawings ]

FIG. 1 is a flow chart of a planarization method according to an embodiment of the present invention;

FIGS. 2 and 3 are schematic process diagrams of a planarization method according to an embodiment of the invention;

FIG. 4 is a flow chart of a planarization method according to another embodiment of the present invention;

fig. 5 and 6 are schematic process diagrams of a planarization method according to another embodiment of the invention.

[ detailed description ] embodiments

The invention is further described with reference to the following figures and embodiments.

It should be noted that all directional indicators (such as upper, lower, left, right, front, back, inner, outer, top, bottom … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components in a specific posture (as shown in the figure), and if the specific posture is changed, the directional indicator is changed accordingly.

It will also be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.