Metal-insulator-metal capacitor structure of image sensor and manufacturing method thereof

Abstract

The present invention relates to a metal-insulator-metal (MIM, Metal-Insulator-Metal) capacitor structure of an image sensor and a method for manufacturing the same, and more particularly, to a metal-insulator-metal capacitor structure of an image sensor and a method for manufacturing the same, which can be formed by connecting N (Ngt; 1; a metal-insulator-metal (MIM) capacitor structure of an image sensor and a method of manufacturing the same, which increase capacitance per unit area by using a capacitor structure (N = natural number) and thereby improve noise.

Description

TECHNICAL FIELD

[0001] The present invention relates to a Metal-Insulator-Metal (MIM) capacitor structure of an image sensor and a manufacturing method thereof, and more particularly, to a Metal-Insulator-Metal (MIM) capacitor structure of an image sensor which can increase a capacitance per unit area by connecting N (N>1; N=natural number) capacitors in parallel by means of forming a stacked capacitor and thereby improve noise, and a manufacturing method thereof. BACKGROUND

[0002] An image sensor is a device for converting an optical image from an object into an electrical signal. As the image sensor described above, as an image capturing device for generating an image in a mobile phone camera or the like, it can be classified into a Charge Coupled Device (CCD) image sensor and a Complementary Metal Oxide Semiconductor (CMOS) image sensor according to a manufacturing process and an application method. Among them, the Complementary Metal Oxide Semiconductor (CMOS) image sensor is widely used in general semiconductor chip manufacturing processes because of its excellent integration competitiveness, economy, and connection convenience with peripheral chips.

[0003] A Metal-Insulator-Metal (MIM) capacitor structure is an analog capacitor applied to a pixel array side of a Complementary Metal Oxide Semiconductor (CMOS) device as described above. The Metal-Insulator-Metal (MIM) capacitor structure as described above has a small specific resistance and no parasitic capacitance due to a depletion layer inside, and thus is mainly applied to high-performance semiconductor devices.

[0004] A Metal-Insulator-Metal (MIM) capacitor is generally configured in a structure in which electrodes and dielectric films are repeatedly stacked, and in order to electrically connect each electrode to a metal wiring through a contact, it is designed to be gradually narrowed in an area when stacked upward. Therefore, since the area is limited, it is inevitably limited in obtaining a required level of capacitance.

[0005] PRIOR ART DOCUMENT

[0006] PATENT DOCUMENT

[0007] Korean Patent Publication No. 10-2009-0022042 "Metal-Insulator-Metal (MIM) Capacitor and a Manufacturing Method Thereof" SUMMARY

[0008] The present application is aimed at solving the problems of the prior art as described above, and the object of the present application is to provide a metal-insulator-metal (MIM) capacitor structure of an image sensor which can form a plurality of stacked capacitors in a limited area, thereby increasing the capacitance per unit area through a plurality of capacitor structures connected in parallel and thereby improving noise, and a manufacturing method thereof.

[0009] Further, the object of the present application is to provide a metal-insulator-metal (MIM) capacitor structure of an image sensor which can have at least one side of a fourth capacitor metal layer extended outwardly compared to a corresponding side of a third capacitor metal layer, thereby increasing the capacitance by means of an increase in the area of the fourth capacitor metal layer, and a manufacturing method thereof.

[0010] Further, the object of the present application is to provide a metal-insulator-metal (MIM) capacitor structure of an image sensor which can increase the capacitance by a fourth capacitor metal layer together with a third capacitor metal layer through a bent portion of the fourth capacitor metal layer, and a manufacturing method thereof.

[0011] In order to achieve the objects as described above, the present application can be implemented by the embodiments as described below.

[0012] In one embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application includes a first capacitor metal layer, a first intermetallic insulating film on the first capacitor metal layer, a second capacitor metal layer on the first intermetallic insulating film, a second intermetallic insulating film on the second capacitor metal layer, covering the second capacitor metal layer, and a third capacitor metal layer on the second intermetallic insulating film, at least one side of the third capacitor metal layer being extended longer on one side compared to a corresponding side of the second capacitor metal layer.

[0013] In another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application includes a first capacitor metal layer, a first intermetallic insulating film on the first capacitor metal layer, a second capacitor metal layer on the first intermetallic insulating film, a second intermetallic insulating film on the second capacitor metal layer, covering the second capacitor metal layer, and a third capacitor metal layer on the second intermetallic insulating film, the third capacitor metal layer having a larger area than the second capacitor metal layer.

[0014] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application includes a first capacitor metal layer, a first intermetallic insulating film on the first capacitor metal layer, a second capacitor metal layer on the first intermetallic insulating film, a second intermetallic insulating film on the second capacitor metal layer, covering the second capacitor metal layer, and a third capacitor metal layer on the second intermetallic insulating film, all sides of the third capacitor metal layer being extended longer on one side compared to corresponding sides of the second capacitor metal layer.

[0015] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized in that the third capacitor metal layer includes a bent portion that extends downward in a manner that at least one side of the third capacitor metal layer surrounds at least a portion of a corresponding side of the second capacitor metal layer.

[0016] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized in that the bent portion has an up-and-down length that overlaps a corresponding side of the second capacitor metal layer in a lateral direction.

[0017] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized in that the bent portion is separated from a side of the second capacitor metal layer facing it by the second intermetallic insulating film.

[0018] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized in that it further includes an upper metal layer connected to the first, second, and third capacitor metal layers.

[0019] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized in that it includes a first capacitor metal layer; a first intermetallic insulating film on the first capacitor metal layer; a second capacitor metal layer on the first intermetallic insulating film; a second intermetallic insulating film on the second capacitor metal layer; a third capacitor metal layer on the second intermetallic insulating film; a third intermetallic insulating film on the third capacitor metal layer, covering the third capacitor metal layer; and a fourth capacitor metal layer on the third intermetallic insulating film, at least one side of the fourth capacitor metal layer being longer than a corresponding side of the third capacitor metal layer.

[0020] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized in that the second capacitor metal layer has a width smaller than that of the first capacitor metal layer.

[0021] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized in that the third capacitor metal layer has a width smaller than that of the second capacitor metal layer.

[0022] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application is characterized in that at least one side of the fourth capacitor metal layer surrounds one side surface of the third capacitor metal layer.

[0023] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application is characterized in that the fourth capacitor metal layer has a portion which extends downward from a bottom of one side surface and faces an adjacent one side surface of the third capacitor metal layer.

[0024] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application is characterized in that the fourth capacitor metal layer surrounds all side surfaces of the third capacitor metal layer.

[0025] In still another embodiment of the present application, a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application is characterized in that it further includes a plurality of upper metal layers which are spaced apart from each other on the fourth capacitor metal layer, and each capacitor metal layer is electrically connected to each upper metal layer through a respective contact.

[0026] In still another embodiment of the present application, a manufacturing method of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application is characterized in that it includes the steps of: evaporating a first insulating film on a first insulating film, evaporating a second metal layer on the first insulating film, evaporating a second insulating film on the second metal layer, and evaporating a third metal layer on the second insulating film; forming a first capacitor metal layer by etching the third metal layer; evaporating a third insulating film on the second insulating film so as to cover the first capacitor metal layer, and evaporating a fourth metal layer on the third insulating film; and forming a second capacitor metal layer on the third insulating film by etching the fourth metal layer, one side surface of the second capacitor metal layer being longer than one side surface of the first capacitor metal layer.

[0027] In still another embodiment of the present application, a manufacturing method of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application is characterized in that a step is formed on the third insulating film.

[0028] In still another embodiment of the present application, a manufacturing method of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application is characterized in that the second capacitor metal layer is formed in a structure which surrounds one side surface of the first capacitor metal layer.

[0029] In still another embodiment of the present application, the method of manufacturing a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized by further comprising: a step of forming a first intermetallic insulating film, a second intermetallic insulating film, and a third capacitor metal layer by etching the second insulating film, the third insulating film, and the second metal layer.

[0030] In still another embodiment of the present application, the method of manufacturing a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized by further comprising: a step of forming a third intermetallic insulating film and a fourth capacitor metal layer by etching the first insulating film and the first metal layer.

[0031] In still another embodiment of the present application, the method of manufacturing a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application, characterized in that the fourth capacitor metal layer has a width larger than that of the third capacitor metal layer.

[0032] The present application can achieve the following effects by the constitution as described above.

[0033] The present application can form a plurality of stacked capacitors in a limited area, thereby increasing the capacitance per unit area by the plurality of capacitor structures connected in parallel and thereby improving noise.

[0034] Further, the present application can make at least one side of the fourth capacitor metal layer extend outwardly compared to the corresponding side of the third capacitor metal layer, thereby increasing the capacitance by the increase in the area of the fourth capacitor metal layer.

[0035] Further, the present application can increase the capacitance by the bent portion of the fourth capacitor metal layer together with the third capacitor metal layer.

[0036] Further, it should be noted that even the effects not explicitly mentioned herein should be understood as effects recited in the specification of the present application, according to the technical features of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a plan view of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to an embodiment of the present application.

[0038] Figure 2 is a plan view of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to Figure 1 is an AA' cross-sectional view of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to the present application.

[0039] Figure 3 is a plan view of a metal-insulator-metal (MIM) capacitor structure of an image sensor according toFigure 1 Equivalent circuit diagram of a metal-insulator-metal (MIM) capacitor structure of an image sensor.

[0040] Figures 4 to 13 is a sectional view for explaining a manufacturing method of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to one embodiment of the present application.

[0041] Symbol explanation

[0042] 1: Metal-insulator-metal capacitor structure, 110: First capacitor metal layer, 111: First connection portion, 115: First intermetallic insulating film, 115a: Contact hole, 120: Second capacitor metal layer, 121: Second connection portion, 125: Second intermetallic insulating film, 125a: Contact hole, 130: Third capacitor metal layer, 130a, 130b, 130c, 130d: Side surface of third capacitor metal layer, 131: Third connection portion, 135: Third intermetallic insulating film, 135a: Contact hole, 140: Fourth capacitor metal layer, 140a, 140b, 140c, 140d: Side surface of fourth capacitor metal layer, 141: Bending portion, 150: Upper metal layer, 161: First contact, 163: Second contact, 165: Third contact, 167: Fourth contact, 170: Interlayer insulating film, 171: Contact hole, M1: First metal layer, M2: Second metal layer, M3: Third metal layer, M4: Fourth metal layer, I1: First insulating film, I2: Second insulating film, I3: Third insulating film, I4: Fourth insulating film, PR1, PR2, PR3, PR4: Photoresist film. DETAILED DESCRIPTION

[0043] Next, embodiments of the present application will be described in more detail with reference to the accompanying drawings. Embodiments of the present application can be modified into various different modes, and should not be interpreted as limiting the scope of the present application to the following embodiments, but should be interpreted with the matters recited in the claims as a basis. In addition, the following embodiments are provided only as a reference to more completely explain the present application to those having an average knowledge in the art.

[0044] Note that in the following description, when it is recited that one constitutional element (or layer) is disposed on another constitutional element (or layer), one constitutional element can be disposed directly on the other constitutional element, or there can be another constitutional element or layer between the respective constitutional elements. In addition, when it is recited that one constitutional element is disposed directly on or above another constitutional element, there will be no other constitutional element between the respective constitutional elements. Furthermore, "upper", "upper portion", "lower portion", "upper side", "lower side", or "one side" of one constitutional element represents a relative positional relationship.

[0045] Further, it should be noted that when a certain embodiment can be implemented in different ways, a certain engineering order can be executed in a different order from the order described below. For example, two consecutive described steps can be executed at the same time or in the reverse order.

[0046] Further, it should be noted that in the following, when the constituent elements of the invention are described, numbers such as "first" and "second" constitutions and the like can be described before the constituent elements, but each constituent element is independent of each other, and for example, the "second" constitution is not premised on the "first" constitution.

[0047] Figure 1 is a plan view of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to an embodiment of the present invention, and Figure 2 is a plan view of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to Figure 1 is an AA' cross-sectional view of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to

[0048] Next, referring to the drawings, a metal-insulator-metal capacitor structure 1 of an image sensor according to an embodiment of the present invention will be described in detail. The metal-insulator-metal capacitor structure 1 according to the present invention is understood to be formed on the pixel area side of the image sensor, not the logic side. Further, it should be noted that in the illustrated drawings, a case where four electrodes are formed is illustrated, but the number of formed capacitor electrodes is not particularly limited.

[0049] Referring to Figure 1 and Figure 2 , the present invention relates to a metal-insulator-metal capacitor structure 1 of an image sensor, and more particularly, to a metal-insulator-metal capacitor structure 1 of an image sensor that can increase the capacitance per unit area by connecting N (N > 1; N = a natural number) capacitor structures in parallel by forming a stacked type capacitor and thereby improve noise.

[0050] The metal-insulator-metal capacitor structure 1 of the image sensor according to one embodiment of the present application can include, at the lowermost side, a first capacitor metal layer 110 as a capacitor electrode. The first capacitor metal layer 110, which is a metal layer formed of one or more of Ti / TiN / Al / Cu, etc., as an example, can have a substantially quadrangular planar shape, but is not particularly limited thereto. Further, the first capacitor metal layer 110 is preferably formed so as to have a wider area than the second capacitor metal layer 120, the third capacitor metal layer 130, and the fourth capacitor metal layer 140 to be described later. In particular, the first capacitor metal layer 110 can have one side connected to the first contact 161 for electrical connection with the upper metal layer 150. That is, the first capacitor metal layer 110, for example, preferably has an open first connection portion 111 not overlapped with the second capacitor metal layer 120 on the upper and lower sides, for physically connecting the upper side thereof with the bottom surface of the first contact 161.

[0051] Further, a first intermetallic insulating film 115 as a dielectric film can be formed on the first capacitor metal layer 110. The first intermetallic insulating film 115 is an insulating film formed between the first capacitor metal layer 110 and the second capacitor metal layer 120, and can include various insulating substances such as SiO2, SiN, Al2O3, HfO2, TiO2, and / or TaO5, etc. The first intermetallic insulating film 115 can be formed so as to have substantially the same area as the first capacitor metal layer 110, but the scope of the present application is not limited thereto. On one side of the first intermetallic insulating film 115 as described above, a contact hole 115a for physically connecting the first contact 161 with the first connection portion 111 can be formed.

[0052] Further, the second capacitor metal layer 120 can be formed on the first intermetallic insulating film 115. The second capacitor metal layer 120 as described above, which is a metal layer formed of one or more of Ti / TiN / Al / Cu, etc., as an example, can be formed between the first intermetallic insulating film 115 and a second intermetallic insulating film 125. Further, the second capacitor metal layer 120 can have a substantially quadrangular planar shape, but is not particularly limited thereto. As described above, the second capacitor metal layer 120 is preferably formed so as to have a narrower area than the first capacitor metal layer 110, thereby forming the open first connection portion 111 in the first capacitor metal layer 110.

[0053] At this time, the second capacitor metal layer 120 can have a side of which at least a part is not covered by the third capacitor metal layer 130 on its upper side. That is, the second capacitor metal layer 120 can have an open second connection part 121 which does not overlap with the third capacitor metal layer 130 vertically, and the second capacitor metal layer 120 can be electrically connected with the upper metal layer 150 through the second contact 163 which is physically connected with the second connection part 121. In an embodiment of the present application, a plurality of second capacitor metal layers 120 and the first intermetal dielectric film 115 which is positioned under the second capacitor metal layer 120 can be alternately stacked, and contrary to this, can not be formed. For example, according to a specific situation, a plurality of first intermetal dielectric films 115 and second capacitor metal layers 120 can be alternately formed, and each of the second capacitor metal layers 120 can be configured to have a different size from each other. Or, for example, the second intermetal dielectric film 125 and the third capacitor metal layer 134 can be directly formed above the first capacitor metal layer 110.

[0054] The second intermetal dielectric film 125 is a dielectric film formed on the first capacitor metal layer 110 or the second capacitor metal layer 120, and can be formed on the bottom surface of the third capacitor metal layer 130. The second intermetal dielectric film 125 as described above can include, for example, a variety of insulating substances such as SiO2, SiN, Al2O3, HfO2, TiO2, and / or TaO5. Further, on one side of the second intermetal dielectric film 125, a contact hole 125a for physically connecting the second contact 163 with the second connection part 121 can be formed.

[0055] Further, the third capacitor metal layer 130 is formed on the second intermetal dielectric film 125, and as an example, can be a metal layer formed of one or more of Ti / TiN / Al / Cu, etc. The third capacitor metal layer 130 can be formed between the second intermetal dielectric film 125 and the third intermetal dielectric film 135.

[0056] At this time, the third capacitor metal layer 130 is preferably formed in a manner having a smaller planar area than the fourth capacitor metal layer 140. For example, the third capacitor metal layer 130 can be formed in a manner that at least one side 130a is shorter than a corresponding side 140a of the fourth capacitor metal layer 140. As an example, when the third capacitor metal layer 130 and the fourth capacitor metal layer 140 each have a quadrangular planar shape, it is preferable to be formed in a manner that a corresponding side 140a of the fourth capacitor metal layer 140 is further extended outward than a side 130a of the third capacitor metal layer 130, and more preferably in a manner that at least three sides 140a, 140b, 140c of the fourth capacitor metal layer 140 are further extended outward than corresponding three sides 130a, 130b, 130c of the third capacitor metal layer 130. For example, it can be formed in a manner that corresponding sides 140a, 140b, 140c, 140d of the fourth capacitor metal layer 140 are located on the side extended outward than all sides 130a, 130b, 130c, 130d of the third capacitor metal layer 130 except for a third connection portion 131 of the third capacitor metal layer 130. Further, at least one side 130a of the third capacitor metal layer 130 can be surrounded by at least a portion of the fourth capacitor metal layer 140, and details related thereto will be described later. The third connection portion 131 is an open side not overlapping the fourth capacitor metal layer 140 vertically, and the third capacitor metal layer 130 can be electrically connected to the upper metal layer 150 through a third contact 165 physically connected to the third connection portion 131. The term "outward" can be understood as representing a side away from the center of the metal-insulator-metal capacitor structure 1 in a horizontal direction on a plan view. Figure 1 ) on a plan view.

[0057] Further, a third intermetal dielectric film 135 as a dielectric film can be formed on the third capacitor metal layer 130. The third intermetal dielectric film 135 is an insulating film formed between the third capacitor metal layer 130 and the fourth capacitor metal layer 140, and can include various insulating substances such as SiO2, SiN, Al2O3, HfO2, TiO2, and / or TaO5, for example. Further, on one side of the third intermetal dielectric film 135, a contact hole 135a for physically connecting the third contact 165 to the third connection portion 131 can be formed.

[0058] Next, a fourth capacitor metal layer 140 can be formed on the third intermetal dielectric film 135. The fourth capacitor metal layer 140, as an example, can be a metal layer formed of one or more of Ti / TiN / Al / Cu, etc. Further, the fourth capacitor metal layer 140 can take a substantially quadrangular planar shape except for one side where the third contact 165 passes through, but is not particularly limited.

[0059] The fourth capacitor metal layer 140 as described above is preferably formed desirably in a manner having a wider area than the third capacitor metal layer 130. As described above, the fourth capacitor metal layer 140 can be formed in a manner that at least one side surface 140a is longer than the corresponding side surface 130a of the third capacitor metal layer 130. Further, the fourth capacitor metal layer 140 can have a bent portion 141 formed in a manner that at least one side surface 140a is longer than the corresponding side surface 130a of the third capacitor metal layer 130 and extends downward. The third intermetal dielectric film 135 can be formed between the bent portion 141 and the side surface of the third capacitor metal layer 130 on the side opposite to the bent portion 141. The bent portion 141 as described above can be formed in a length that the side surfaces of the third capacitor metal layer 130 overlap each other in the lateral direction. Further, the bent portion 141 can be formed on all of the side surfaces 140a, 140b, 140c, 140d of the fourth capacitor metal layer 140 or only on a part of the side surfaces, and is not particularly limited.

[0060] Further, the fourth capacitor metal layer 140 can be electrically connected to the upper metal layer 150 by means of the fourth contact 167. For example, the upper side surface of the fourth capacitor metal layer 140 can be physically connected to the bottom surface of the fourth contact 167.

[0061] Further, the first intermetal dielectric film 115 on the first capacitor metal layer 110, the second capacitor metal layer 120, the second intermetal dielectric film 125, the third capacitor metal layer 130, the third intermetal dielectric film 135, and the fourth capacitor metal layer 140 can be covered with an interlayer dielectric film 170, and the upper metal layer 150 can be formed on the upper side surface of the interlayer dielectric film 170. Further, the upper metal layer 150 can be electrically connected to each of the metal layers 110, 120, 130, 140 through the first contact 161, the second contact 163, the third contact 164, and the fourth contact 167 formed in a plurality of contact holes 171 formed in the interlayer dielectric film 170 in the vertical direction.

[0062] Figure 3 is an equivalent circuit diagram of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to Figure 1 is an equivalent circuit diagram of a metal-insulator-metal (MIM) capacitor structure of an image sensor according to

[0063] See Figures 1 to 3 According to one embodiment of the present invention described above, the metal-insulator-metal capacitor structure 1 can be constructed by stacking a second capacitor C2, comprising a first capacitor C1 including a first capacitor metal layer 110, a first intermetallic insulating film 115, and a second capacitor metal layer 120, on top of the first capacitor C1. Then, a third capacitor C3, comprising a third capacitor metal layer 130, a third intermetallic insulating film 135, and a fourth capacitor metal layer 140, is stacked on top of the first capacitor C1. This forms a plurality of capacitors connected in parallel, thereby achieving a higher capacitance (C1+C2+C3) value within a limited area. In other words, the present invention increases the capacitance per unit area.

[0064] Furthermore, in this invention, at least one side 140a of the fourth capacitor metal layer 140 is located on a side that extends outward compared to the corresponding side of the third capacitor metal layer 130, thereby also having a capacitance (C) due to the increased area of ​​the fourth capacitor metal layer 140. A The capacitance (C) between the bent portion 141 and the third capacitor metal layer 130 facing the bent portion 141 and the bent portion 141. H This method allows for the acquisition of higher capacitance (C1+C2+C). A +C H That is, in one embodiment of the present invention, the optimal metal-insulator-metal (MIM) capacitor can be obtained in the same area.

[0065] Figures 4 to 13 This is a cross-sectional view illustrating a method for manufacturing a metal-insulator-metal (MIM) capacitor structure for an image sensor according to an embodiment of the present invention.

[0066] Next, with reference to the accompanying drawings, a method for manufacturing a metal-insulator-metal (MIM) capacitor structure for an image sensor according to an embodiment of the present invention will be described in detail.

[0067] See Figure 4 First, a first metal layer M1 is deposited on an insulating film (not shown). Then, a first insulating film I1 is deposited on the first metal layer M1, a second metal layer M2 is deposited on the first insulating film I1, a second insulating film I2 is deposited on the second metal layer M2, and a third metal layer M3 is deposited on the second insulating film I2.

[0068] Next, see Figure 5The third capacitor metal layer 130 is formed on the second insulating film I2 by etching the third metal layer M3. For example, the third capacitor metal layer 130 can be formed by performing an etching process using a resist film PRl formed on the third metal layer M3 as a mask pattern. Next, the resist film PRl can be removed by performing a peeling process.

[0069] Referring to Figure 6 After the third capacitor metal layer 130 is formed, a third insulating film I3 is vapor-deposited on the second insulating film I2 so as to cover the third capacitor metal layer 130, and a fourth metal layer is vapor-deposited on the third insulating film I3.

[0070] Next, referring to Figure 7 The fourth capacitor metal layer 140 is formed on the third insulating film I3 by etching the fourth metal layer M4. For example, the fourth capacitor metal layer 140 can be formed by performing an etching process using a resist film PR2 formed on the fourth metal layer M4 as a mask pattern. Next, the resist film PR2 can be removed by performing a peeling process.

[0071] At this time, it is preferable that at least one side surface 140a of the fourth capacitor metal layer 140 be formed so as to extend further outward than a corresponding side surface 130a of the third capacitor metal layer 130. Further, it is preferable that a bent portion 141 be formed around the corresponding side surface 130a of the third capacitor metal layer 130 at at least one side surface 140a of the fourth capacitor metal layer 140. The bent portion 141 as described above can be formed by the third insulating film I3 and the facing side surfaces of the third capacitor metal layer 130 being separated from each other by a certain distance.

[0072] Referring to Figure 8 After the fourth capacitor metal layer 140 is formed, the third intermetallic insulating film 135, the second intermetallic insulating film 125, and the second capacitor metal layer 120 can be formed in this order by an etching process. For example, the third intermetallic insulating film 135, the second intermetallic insulating film 125, and the second capacitor metal layer 120 can be formed by performing an etching process on the third insulating film I3, the second insulating film I2, and the second metal layer M2 in this order using a resist film PR3 formed on the third insulating film I3 and the fourth capacitor metal layer 140 as a mask pattern. Next, the resist film PR3 can be removed by performing a peeling process.

[0073] Next, referring to Figure 9The first intermetallic insulating film 115 and the first capacitor metal layer 110 can be formed in order by performing etching. For example, the first intermetallic insulating film 115 and the first capacitor metal layer 110 can be formed by performing etching on the first insulating film I1 and the first metal layer M1 in order using the photoresist film PR4 formed on the fourth capacitor metal layer 140 and the third intermetallic insulating film 135 as a mask pattern.

[0074] Next, referring to Figure 10 The interlayer insulating film 170 is vapor-deposited so as to cover all of the structures on the first capacitor metal layer 110.

[0075] After the interlayer insulating film 170 is formed, referring to Figure 11 The contact hole 171 in the interlayer insulating film 170, the contact hole 115a in the first intermetallic insulating film 115, the contact hole 125a in the second intermetallic insulating film 125, and the contact hole 135a in the third intermetallic insulating film 135 are formed. The formation of each contact hole can be performed by forming a trench using dry etching or wet etching.

[0076] Next, referring to Figure 12 The contacts 161, 163, 165, 167 are formed in the interlayer insulating film 170. For example, the contacts 161, 163, 165, 167 can be formed by forming a metal layer (not shown) on the interlayer insulating film 170 so as to fill each of the contact holes 171, 125a, 135a. The metal layer remaining on the interlayer insulating film 170 is removed after the contacts 161, 163, 165, 167 are formed.

[0077] Finally, referring to Figure 13 The upper metal layer 150 can be formed on the interlayer insulating film 170. The upper metal layer 150 can be formed by forming a metal layer (not shown) on the interlayer insulating film 170 and then performing an etching process, and detailed description thereof will be omitted.

[0078] The above detailed description is merely an example of the present application. Furthermore, the above description is merely an example of the preferred embodiment of the present application, and the present application can be used in various combinations, modifications, and environments. That is, changes or modifications can be made within the scope and / or the range of the technical concept of the present application disclosed in the present specification and the description, and / or the range of the technical or knowledge of the industry. The above-described examples are merely an example of the best state for implementing the technical idea of the present application, but various changes can be made according to the requirements in the specific application field and use of the present application. Therefore, the present application is not limited to the embodiments disclosed in the above detailed description of the application.

Claims

1. A metal-insulator-metal capacitor structure of an image sensor, characterized by, comprises: a first capacitor metal layer; a first intermetallic insulating film on the first capacitor metal layer; a second capacitor metal layer on the first intermetallic insulating film; a second intermetallic insulating film on the second capacitor metal layer, covering the second capacitor metal layer; and a third capacitor metal layer on the second intermetallic insulating film, at least one side of the third capacitor metal layer is longer than a corresponding side of the second capacitor metal layer.

2. The metal-insulator-metal capacitor structure of an image sensor according to claim 1, wherein the third capacitor metal layer has a larger area than the second capacitor metal layer.

3. The metal-insulator-metal capacitor structure of an image sensor according to claim 1, wherein all sides of the third capacitor metal layer are longer than corresponding sides of the second capacitor metal layer.

4. The metal-insulator-metal capacitor structure of an image sensor according to claim 1, wherein the third capacitor metal layer comprises: a bent portion that extends downward around at least a portion of at least one of the corresponding sides of the second capacitor metal layer.

5. The metal-insulator-metal capacitor structure of an image sensor according to claim 4, wherein the bent portion has an up-and-down length that overlaps the corresponding side of the second capacitor metal layer in a lateral direction.

6. The metal-insulator-metal capacitor structure of an image sensor according to claim 4, wherein the bent portion is separated from the corresponding side of the second capacitor metal layer by the second intermetallic insulating film. further comprising:

7. The metal-insulator-metal capacitor structure of the image sensor of claim 4, wherein, an upper metal layer connected to the first, second, and third capacitor metal layers. comprises:

8. A metal-insulator-metal capacitor structure of an image sensor, characterized by, a first capacitor metal layer; a first intermetallic insulating film on the first capacitor metal layer; a second capacitor metal layer on the first intermetallic insulating film; a second intermetallic insulating film on the second capacitor metal layer; a third capacitor metal layer on the second intermetallic insulating film; a third intermetallic insulating film on the third capacitor metal layer, covering the third capacitor metal layer; and a fourth capacitor metal layer on the third intermetallic insulating film, at least one side of the fourth capacitor metal layer is longer than a corresponding side of the third capacitor metal layer.

9. The metal-insulator-metal capacitor structure of an image sensor according to claim 8, wherein the second capacitor metal layer has a narrower width than the first capacitor metal layer.

10. The metal-insulator-metal capacitor structure of an image sensor according to claim 9, wherein the third capacitor metal layer has a narrower width than the second capacitor metal layer. ​ ​ 11. The metal-insulator-metal capacitor structure of an image sensor according to claim 8, wherein at least one side of the fourth capacitor metal layer extends around one side surface of the third capacitor metal layer.

12. The metal-insulator-metal capacitor structure of an image sensor according to claim 11, wherein the fourth capacitor metal layer has a portion extending downward from a bottom of one side surface and facing the one side surface of the adjacent third capacitor metal layer.

13. The metal-insulator-metal capacitor structure of an image sensor according to claim 8, wherein the fourth capacitor metal layer extends around all side surfaces of the third capacitor metal layer.

14. The metal-insulator-metal capacitor structure of the image sensor of claim 8, wherein, Further comprising: a plurality of upper metal layers spaced apart from each other on the fourth capacitor metal layer, each capacitor metal layer is electrically connected to each upper metal layer by a respective contact.

15. A method of fabricating a metal-insulator-metal capacitor structure of an image sensor, characterized by, including: a step of evaporating a first insulating film on a first insulating film, evaporating a second metal layer on the first insulating film, evaporating a second insulating film on the second metal layer, and evaporating a third metal layer on the second insulating film; a step of forming a first capacitor metal layer by etching the third metal layer; a step of evaporating a third insulating film on the second insulating film in a manner to cover the first capacitor metal layer, and evaporating a fourth metal layer on the third insulating film; and a step of forming a second capacitor metal layer on the third insulating film by etching the fourth metal layer, one side surface of the second capacitor metal layer is longer than one side surface of the first capacitor metal layer.

16. The manufacturing method of a metal-insulator-metal capacitor structure of an image sensor according to claim 15, wherein the third insulating film is formed with a step.

17. The manufacturing method of a metal-insulator-metal capacitor structure of an image sensor according to claim 15, wherein the second capacitor metal layer is formed in a structure that extends around one side surface of the first capacitor metal layer.

18. The method of fabricating a metal-insulator-metal capacitor structure of an image sensor according to claim 15, wherein, Further comprising: a step of forming a first intermetallic insulating film, a second intermetallic insulating film, and a third capacitor metal layer by etching the second insulating film, the third insulating film, and the second metal layer.

19. The method of manufacturing a metal-insulator-metal capacitor structure of an image sensor according to claim 18, wherein Further comprising: a step of forming a third intermetallic insulating film and a fourth capacitor metal layer by etching the first insulating film and the first metal layer.

20. The manufacturing method of a metal-insulator-metal capacitor structure of an image sensor according to claim 19, wherein the fourth capacitor metal layer has a width larger than that of the third capacitor metal layer.

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