JP2006351761A - Solid-state image pickup element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a solid-state image pickup element by which a pad opening can be formed after forming an organic material layer without damaging the organic material layer, and a residue on an electrode pad can be removed by ashing after forming the organic material layer. <P>SOLUTION: The method for manufacturing a solid-state image pickup element includes an inorganic material layer forming process for forming an inorganic material layer including an n-type silicon substrate 1, a photodiode 2, a transfer electrode 3, a BPSG film 4, a passivation film 5, and the electrode pad; an organic material layer forming process for forming an organic material layer composed of a planarizing film 7, a color filter 8, a planarizing film 9, and a micro lens 11 on the inorganic material layer; a protection film forming process (Figure 3(b)) for forming an optically transparent protection film 11 to protect the organic material layer from damage caused by the ashing on the organic material layer; and a protection film removing process (Figure 3(d)) for exposing the electrode pad 6 by removing the protection film at the upper part of the electrode pad 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device including an inorganic material layer including an electrode pad and an organic material layer formed thereon, and a manufacturing method thereof.

  In general, a solid-state imaging device (for example, a CCD type solid-state imaging device) has a large number of photoelectric conversion elements, a vertical transfer unit that transfers charges generated by the photoelectric conversion elements in a vertical direction, and charges transferred from the vertical transfer unit. A horizontal transfer unit that transfers in the horizontal direction, an output amplifier unit that outputs a signal corresponding to the charges transferred from the horizontal transfer unit, a pixel unit in which a color filter, a microlens, and the like are formed, a peripheral circuit, an electrode pad, and the like Is formed on one chip of the semiconductor substrate.

  FIG. 4 is a schematic cross-sectional view showing a manufacturing process of a conventional CCD solid-state imaging device. FIG. 4 shows a cross section in which the pixel portion and the pad portion are combined.

  First, the photodiode 2 is formed in the n-type silicon substrate 1 of the pixel portion, and the transfer electrode 3 made of polysilicon or the like for transferring the charges accumulated in the photodiode 2 is formed on the n-type silicon substrate 1 of the pixel portion. A peripheral circuit (not shown) made of polysilicon or the like is formed on the n-type silicon substrate 1 in the pad portion. Next, after forming a light shielding film (not shown) made of tungsten or the like that shields the transfer electrode 3 from light, an interlayer insulating film 4 such as a BPSG film is formed and reflowed.

  Next, an electrode pad 6 made of aluminum or the like is formed on the interlayer insulating film 4 on the peripheral circuit of the pad portion, and an insulating film (passivation film) 5 made of P-SiN is formed thereon. Next, the insulating film 5 on the electrode pad 6 is removed by etching to form an opening, and the electrode pad 6 is exposed (FIG. 4A). Since the layer from the silicon substrate 1 to the electrode pad 6 is composed of an inorganic material, this layer is referred to as an inorganic material layer.

  Next, a planarizing film 7 made of a transparent resin or the like is formed on the exposed surfaces of the insulating film 5 and the electrode pad 6, and the planarizing film 7 on the electrode pad 6 is removed by etching to form an opening. Is exposed again (FIG. 4B). Next, RGB color filters 8 are formed by photolithography above each photodiode 2 on the planarizing film 7 of the pixel portion (FIG. 4C). In this photolithography process, the exposed surface of the electrode pad 6 is exposed to the developer, or a residue of the color filter material is generated on the exposed surface.

  Next, a planarizing film 9 made of a transparent resin or the like is formed on the color filter 8, the planarizing film 7, and the exposed surface of the electrode pad 6, and the planarizing film 9 on the electrode pad 6 is removed by etching. Then, the electrode pad 6 is exposed again (FIG. 4D). Next, a microlens 10 for condensing light on each photodiode 2 is formed above each photodiode 2 on the planarizing film 9 in the pixel portion to complete the manufacture of the solid-state imaging device (FIG. 4 ( e)). In this microlens formation step, the exposed surface of the electrode pad 6 is exposed to a photolithography developer, or a residue of microlens material is generated on the exposed surface. Since the layers from the insulating film 5 to the microlens 10 are made of an organic material, this layer is called an organic material layer.

  As a document describing the electrode pad, there is, for example, Patent Document 1.

JP 7-31418 A

  As described above, in the conventional manufacturing method, since the electrode pad is exposed to the developer, the surface morphology is deteriorated, or a residue of an organic material such as a color filter material or a microlens material is generated on the surface of the electrode pad. , Causing bonding defects.

  In order to remove the residue, it is effective to perform an ashing process on the exposed surface of the electrode pad 6 after forming the microlens. However, depending on the ashing conditions, the organic material layer may be damaged. Setting is difficult. For example, if the condition is set to sufficiently remove the residue, the organic material layer is damaged by ashing, and if the condition is set so as not to damage the organic material layer, the dilemma cannot be removed sufficiently. Will occur.

  On the other hand, the microlens 10 is formed on the electrode pad 6 without forming an opening. After the microlens 10 is formed, the insulating film 5, the planarizing film 7, and the planarizing film 9 on the electrode pad 6 are removed by etching. Thus, by exposing the electrode pad 6, problems such as corrosion and residue of the electrode pad can be avoided. However, when the insulating film 5, the flattening film 7, and the flattening film 9 on the electrode pad 6 are collectively removed by etching, high energy is required, so that the resist mask for forming the opening is cured by etching. As a result, ashing is required to remove the resist mask. As described above, since ashing damages the organic material layer, it is difficult to adopt a method of forming an opening at the end.

  The present invention has been made in view of the above circumstances, and without damaging the organic material layer, a pad opening is formed after the organic material layer is formed, or residues on the electrode pads are formed after the organic material layer is formed. An object of the present invention is to provide a method for manufacturing a solid-state imaging device that can be removed by ashing.

  The solid-state imaging device of the present invention is a solid-state imaging device composed of an inorganic material layer including an electrode pad and an organic material layer formed thereon, and is formed on the organic material layer. A light-transmissive protective film that protects the material layer from damage due to ashing, and an opening formed in the organic material layer above the electrode pad.

  According to this configuration, the manufacturing method of applying a pad opening after forming the organic material layer or removing the residue on the electrode pad by ashing after forming the organic material without damaging the organic material layer is applied. Can do. For this reason, there is almost no residue in the electrode pad, and the reliability can be improved.

  In the solid-state imaging device of the present invention, the protective film is a glass film.

  In the solid-state imaging device of the present invention, the glass film is an organic SOG film.

  In the solid-state imaging device of the present invention, the glass film is an inorganic SOG film.

  The solid-state imaging device manufacturing method of the present invention is a solid including an inorganic material layer forming step of forming an inorganic material layer including an electrode pad, and an organic material layer forming step of forming an organic material layer on the inorganic material layer. A method for manufacturing an image pickup device, comprising: a protective film forming step of forming a light transmissive protective film for protecting the organic material layer from damage due to ashing on the organic material layer; and the protective film above the electrode pad And removing the protective film to expose the electrode pad.

  According to this method, it is possible to form a pad opening after forming the organic material layer without damaging the organic material layer, or to remove residues on the electrode pad by ashing after forming the organic material layer. . For this reason, it becomes possible to manufacture a solid-state imaging device having almost no residue on the electrode pad.

  The solid-state imaging device manufacturing method of the present invention includes an organic material layer removing step of removing the organic material layer formed above the electrode pad in the formation process of the organic material layer, and the organic film after removing the protective film. And an ashing process for removing residues generated on the electrode pad by ashing in the course of forming the material layer.

  According to this method, since the organic material layer is protected by the protective film, the residue on the electrode pad generated in the process of forming the organic material layer can be removed by ashing, and the solid-state imaging device with high reliability Can be manufactured.

  In the method for manufacturing a solid-state imaging device of the present invention, in the protective film removing step, the organic material layer formed above the electrode pad is removed together with the protective film using a resist mask, and the organic material layer And an ashing step of removing the resist mask by ashing after removing the protective film.

  According to this method, since the organic material layer is protected by the protective film, the electrode pad can be exposed after the organic material layer is formed, and a residue is generated on the electrode pad during the formation of the organic material layer. However, a highly reliable solid-state imaging device can be manufactured.

  In the method for manufacturing a solid-state imaging device of the present invention, the protective film is a glass film.

  In the method for manufacturing a solid-state imaging device of the present invention, the glass film is an organic SOG film.

  In the method for manufacturing a solid-state imaging device of the present invention, the glass film is an inorganic SOG film.

  According to the present invention, it is possible to form a pad opening after forming the organic material layer without damaging the organic material layer, or to remove a residue on the electrode pad by ashing after the organic material layer is formed. It becomes.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a CCD solid-state imaging device for explaining an embodiment of the present invention. In FIG. 1, the cross section which combined the pixel part and pad part of the solid-state image sensor was shown. In FIG. 1, the same components as those shown in FIG.
The solid-state imaging device shown in FIG. 1 is a light-transmissive protective film that protects the organic material layer from damage due to ashing on the microlens 10 and the planarizing film 9 in the configuration of the solid-state imaging device shown in FIG. The only difference is that 11 is formed. The protective film 11 is a glass film such as an organic SOG (Spin On Glass) film or an inorganic SOG film.

  According to the solid-state imaging device configured as shown in FIG. 1, since the protective film 11 for protecting the organic material layer is provided, the organic material layer is formed on the electrode pad 6 without damaging the organic material layer. It is possible to apply a manufacturing method in which an opening is formed in the substrate or a residue on the electrode pad is removed by ashing after the organic material layer is formed. Therefore, there is almost no residue on the exposed surface of the electrode pad 6, and it is possible to provide a good element free from bonding defects.

Hereinafter, a first example of the method for manufacturing the solid-state imaging device shown in FIG. 1 will be described.
FIG. 2 is a schematic cross-sectional view showing a first manufacturing process example of the CCD solid-state imaging device shown in FIG. FIG. 2 shows a cross section in which the pixel portion and the pad portion are combined. In FIG. 2, the same components as those in FIG.
First, an inorganic material layer and an organic material layer having a configuration excluding the protective film 11 shown in FIG. 1 are formed in the same process as shown in FIG. 4 (FIG. 2A). Next, a protective film 11 is formed by spin coating on the exposed surfaces of the microlens 10, the planarizing film 9, and the electrode pad 6 (FIG. 2B). Next, a resist material is formed on the protective film 11 and patterned to form a resist pattern R (FIG. 2C). Next, anisotropic etching is performed using the resist pattern R as a mask, the protective film 11 formed on the electrode pad 6 is removed, an opening is formed on the electrode pad 6, and the electrode pad 6 is exposed again. Next, the resist pattern R and the organic material residue on the exposed surface of the electrode pad 6 are removed by ashing (FIG. 2D) to obtain a solid-state imaging device having the configuration shown in FIG. In this method, since the anisotropic etching used for removing the protective film 11 does not have to be performed with high energy, the resist pattern R may be peeled off with a remover. In this case, after removing the resist pattern R, the residue may be removed by ashing using the protective film 11 as a mask.

  According to the above method, the ashing process for removing the residue on the exposed surface of the electrode pad 6 is performed after the organic material layer is covered with the protective film 11, and therefore the residue can be sufficiently removed under the ashing condition. Even when the conditions are set, it is possible to prevent the organic material layer (in particular, the organic material layer of the pixel portion) from being damaged. Therefore, it is possible to eliminate the residue of the electrode pad 6 while maintaining the performance of the organic material layer in the same manner as in the past, and it is possible to provide a good solid-state imaging device free from bonding defects.

Hereinafter, a second example of the method for manufacturing the solid-state imaging device shown in FIG. 1 will be described.
FIG. 3 is a schematic cross-sectional view showing a second manufacturing process example of the CCD solid-state imaging device shown in FIG. FIG. 3 shows a cross section in which the pixel portion and the pad portion are combined. 3, the same components as those in FIG. 1 are denoted by the same reference numerals.
First, up to the electrode pad 6 is formed in the same process as in the prior art, the insulating film 5 is formed on the interlayer insulating film 4 and the electrode pad 6, the planarizing film 7 is formed on the insulating film 5, and the pixel portion is flattened. A color filter 8 is formed on the conversion film 7, a planarization film 9 is formed on the color filter 8 and the planarization film 7, and a microlens 10 is formed on the planarization film 9 in the pixel portion (FIG. 3A). )). That is, in the process shown in FIG. 4, up to the microlens 10 is formed without forming an opening on the electrode pad 6.

  Next, the protective film 11 is formed on the microlens 10 and the planarizing film 9 by spin coating (FIG. 3B). Next, a resist material is formed on the protective film 11 and patterned to form a resist pattern R (FIG. 3C). Next, anisotropic etching is performed using the resist pattern R as a mask, and the insulating film 5, the planarizing film 7, the planarizing film 9, and the protective film 11 formed on the electrode pad 6 are collectively removed, and the electrode An opening is formed on the pad 6 to expose the electrode pad 6. Since the anisotropic etching at the time of opening formation needs to be performed with high energy, the resist pattern R is cured by this etching, and it is difficult to remove and remove with a remover. Therefore, in this method, the hardened resist pattern R is removed by ashing (FIG. 3D) to obtain a solid-state imaging device having the configuration shown in FIG. Since the protective film 11 is formed on the organic material layer, the organic material layer is not damaged by this ashing.

  According to the above method, after forming the organic material layer, the opening can be formed on the electrode pad 6 without damaging the organic material layer. By forming an opening on the electrode pad 6 after forming the organic material layer, it is possible to prevent the surface of the electrode pad 6 from being exposed to a developer or the generation of organic material residues on the surface of the electrode pad. Therefore, it is possible to provide a good solid-state imaging device free from bonding failure. In addition, since the process of forming the opening on the electrode pad is not required in the process of forming the organic material layer, the number of processes can be reduced and the manufacturing cost can be reduced.

  In the present embodiment, a CCD solid-state image sensor is taken as an example. However, the configuration and manufacturing method of the present embodiment can be similarly applied to a MOS solid-state image sensor.

1 is a schematic cross-sectional view of a CCD solid-state image sensor for explaining an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view showing a first manufacturing process example of the CCD solid-state imaging device shown in FIG. Sectional schematic diagram which shows the 2nd example of a manufacturing process of CCD type solid-state image sensor shown in FIG. Cross-sectional schematic diagram showing the manufacturing process of a conventional CCD solid-state imaging device

Explanation of symbols

1 n-type silicon substrate 2 photodiode 3 transfer electrode 4 BPSG film 5 passivation film 6 electrode pad 7 flattening film 8 color filter 10 microlens 11 protective film

Claims (10)

A solid-state imaging device composed of an inorganic material layer including an electrode pad and an organic material layer formed thereon,
A light transmissive protective film that is formed on the organic material layer and protects the organic material layer from damage caused by ashing;
A solid-state imaging device comprising: an opening formed in the organic material layer above the electrode pad. The solid-state imaging device according to claim 1,
A solid-state imaging device, wherein the protective film is a glass film. The solid-state imaging device according to claim 2,
A solid-state imaging device in which the glass film is an organic SOG film. The solid-state imaging device according to claim 2,
A solid-state imaging device in which the glass film is an inorganic SOG film. An inorganic material layer forming step for forming an inorganic material layer including an electrode pad; and an organic material layer forming step for forming an organic material layer on the inorganic material layer.
On the organic material layer, a protective film forming step of forming a light transmissive protective film that protects the organic material layer from damage due to ashing;
A method of manufacturing a solid-state imaging device, comprising: removing the protective film above the electrode pad to expose the electrode pad. It is a manufacturing method of the solid-state image sensing device according to claim 5,
An organic material layer removing step of removing the organic material layer formed above the electrode pad in the process of forming the organic material layer;
A method of manufacturing a solid-state imaging device, comprising: removing the protective film, and then removing the residue generated on the electrode pad by ashing during the formation of the organic material layer. It is a manufacturing method of the solid-state image sensing device according to claim 5,
In the protective film removal step, using a resist mask, the organic material layer formed above the electrode pad is removed together with the protective film,
A method for manufacturing a solid-state imaging device, comprising: an ashing step of removing the resist mask by ashing after removing the organic material layer and the protective film. It is a manufacturing method of the solid-state image sensing device according to any one of claims 5 to 7,
The manufacturing method of the solid-state image sensor whose said protective film is a glass film. It is a manufacturing method of the solid-state image sensing device according to claim 8,
A method for producing a solid-state imaging device, wherein the glass film is an organic SOG film. It is a manufacturing method of the solid-state image sensing device according to claim 8,
A method for producing a solid-state imaging device, wherein the glass film is an inorganic SOG film.

Images