JPS6349391B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a color solid-state image sensor plate in which color separation filters are bonded and integrated onto a solid-state image sensor, and more specifically, a method for manufacturing a color solid-state image sensor plate in which a large number of solid-state image sensors and a large number of color separation filters are bonded together at the same time. This invention relates to a method for manufacturing a color solid-state image sensor plate that is highly mass-producible and can be assembled and integrated. Solid-state image sensors include frame transfer CCD, interline transfer CCD, MOS, BBD,
Various types such as CID and PCD are being developed. To create a color solid-state imaging device, color separation is necessary to obtain color signals. To perform color separation, there are two methods: a three-chip method that uses three solid-state image sensors to separate colors using a prism method or a mirror method, a single-chip method that uses a color separation filter to separate colors, and a prism method or a mirror method that separates luminance signals and chroma signals. There are two-panel systems that separate the signals, but color separation filters are required for the single-panel system and the two-panel system. A method of arranging mosaic or stripe-like filter elements corresponding to each element of the solid-state image sensor is to place color separation filters on a transparent support such as glass with a front panel corresponding to each pixel of the solid-state image sensor. A method of forming an image on a solid-state image sensor using a color separation filter formed with a filter element as shown in FIG. (method) and a method (direct method) in which a color separation filter is directly processed and placed on the solid-state image sensor. The present invention relates to the above-mentioned bonding method. To explain an interline transfer type CCD as an example of a method for manufacturing a color solid-state image sensor plate in which color separation filters are laminated and integrated onto a conventional solid-state image sensor, first, the interline transfer type CCD is made into a chip as shown in Figure 1a. The solid-state image sensor 1 corresponds to each pixel 3 of the solid-state image sensor 2 (in this method, it consists of a photosensitive part and a non-photosensitive part such as a shift register part) as shown in FIG. 1 filter element for 2 pixels or 3 filter elements for 2 images
As shown in FIG. 1c, as shown in FIG. The solid-state image sensor and color separation filter are bonded and integrated to produce a color solid-state image sensor plate. Although each pixel is schematically drawn in Figure 1, the number of pixels is generally 60,000 to 350,000. As shown in FIG. 1a, the solid-state image sensor 1 has a light-receiving section 4 where the pixels 3 are assembled and a bonding pad section 5 for taking out the leads, but when bonding the color separation filter 2 shown in FIG. 1b, The bonding pad portion 5 must not be covered by the color separation filter portion. Transparent support 8 of color separation filter
It is necessary to accurately cut the size in advance so that it does not protrude into the bonding pad portion 5. Since it is necessary to expose the bonding pad portion 5 after bonding as described above, it is necessary to cut the color separation filter into pieces for one solid-state image sensor and then bond them together. In addition, in a frame transfer type CCD, the solid-state image sensor is divided into a light receiving section, a storage section, and a shift register section, so it is only necessary to attach a color separation filter so that it corresponds to the light receiving section only. Needless to say. In this case as well, it is necessary to expose the bonding pad portion after bonding the color separation filter. In general, solid-state imaging devices are manufactured using 3-inch or 4-inch Si wafers by arranging a large number of solid-state imaging devices through a normal wafer process to improve mass productivity. Also,
Color separation filters can also be manufactured by arranging a large number of them on a transparent support such as 3-inch or 4-inch glass. However, in the conventional case, if a large number of solid-state image sensors and a large number of color separation filters were bonded together at the same time, the bonding part of the solid-state image sensor would be covered by the color separation filter substrate, so the above method of bonding them at once I can't get it. This problem becomes a very big issue when considering mass production. In the first place, solid-state color cameras are intended to be low-cost cameras, and it is a major problem in the manufacturing process to accurately align and bond each color separation filter. As a method to improve mass production problems in the above bonding method, the present inventors used an adhesive that hardens with ultraviolet rays and also hardens with heat treatment.
We have developed a method for manufacturing a color solid-state image sensor plate by bonding together a large number of solid-state image sensors and a large number of color separation filters in a single alignment (patent application (1) filed on the same date). Although such a method dramatically improves mass productivity, the following problems still remain. In other words, there is no problem with a large number of solid-state image sensors and color separation filters as long as all of the chips (one solid-state image sensor or one color separation filter) are good. Since each chip is manufactured separately, a certain percentage of the chips that are arranged in large numbers are defective.
When considering the aligned state, defective chips will occur at different positions. There is no problem if the solid-state image sensor and color separation filter located at the same location are defective chips, but this is unlikely to happen. Since solid-state imaging devices and color separation filters are both manufactured through a large number of processes, it is currently almost impossible to manufacture all chips on the same substrate to be of good quality. Moreover, these solid-state image sensors and color separation filters are expensive from the perspective of a solid-state color camera system. The present invention aims to improve the above-mentioned problems, and provides a mass-producible manufacturing method in which a large number of arrayed solid-state image sensors and a large number of arrayed color separation filters are bonded together in a single alignment. In addition, the present invention provides a method for manufacturing a color solid-state image sensor plate in which good chips of the solid-state image sensor or color separation filter are kept separately as good chips, and the yield is further improved. That is, the gist of the present invention is a method for manufacturing a color solid-state image sensor plate, in which the following steps and are performed in order, and then steps and are performed in any order. The solid-state image sensor surface of the solid-state image sensor substrate on which a large number of solid-state image sensors, at least one of which is defective, is arranged, and filter elements arranged in a stripe or mosaic pattern corresponding to each pixel of the solid-state image sensor. A large number of color separation filters, at least one of which is defective, are arranged on a transparent support at the same pitch as the solid-state image sensor, and the filter element surface of the color separation filter substrate is cured with ultraviolet rays and subjected to heat treatment. a step of aligning and adhering to each other through an adhesive that hardens over time; the solid-state image sensor and the above-mentioned solid-state image sensor facing each other through an ultraviolet shielding layer disposed at a position corresponding to at least a bonding pad portion of the solid-state image sensor substrate; Color separation in an ultraviolet irradiation area where at least both the solid-state imaging device and the color separation filter facing each other are non-defective by irradiating ultraviolet rays from the side of the transparent support, excluding at least the area where one of the color separation filters is defective. curing the adhesive in the ultraviolet transmitting region including the peripheral edge of the filter, removing at least a portion of the color separation filter substrate corresponding to the bonding pad portion or the portion and its surrounding area, and then removing the uncured adhesive. removing the color separation filter in the non-ultraviolet irradiation area where one of the solid-state image sensor and the color separation filter facing each other is a defective product, after cleaning with a solvent that dissolves the dye; a step of completely curing the adhesive in all areas between the surface and the remaining filter element surface; and a step of cutting between adjacent bonding pad portions of each solid-state image sensor on the solid-state image sensor substrate. Hereinafter, the above invention will be explained using an interline transfer method.
An example of a CCD will be explained with reference to the drawings. First, as shown in FIG.
As shown in FIG. 2B, there are a large number of color separation filters 26 in which filter elements are formed in a mosaic or stripe pattern so as to correspond to each pixel of the solid-state image sensor 23 in FIG. 2a. An array of color separation filter substrates 22 is prepared. The color separation filter substrate 22 may have a normal wafer shape or a rectangular shape. A layer 27 having an ultraviolet shielding effect (hereinafter referred to as a UV shielding layer) is formed on the color separation filter substrate 22 at least in a portion corresponding to the bonding pad portion 25 of the solid-state image sensor 23. In Fig. 2b, one UV shielding layer is provided on each adjacent bonding patch (in this case, the adhesive between the two parallel UV shielding layers is cured by ultraviolet rays, ensuring secure fixation). However, the two parallel UV shielding layers can also be combined into one. Any embodiment can be used as long as at least the bonding pad portion is covered. In the solid-state image sensor substrate 21 shown in FIG. 2A, for example, it is assumed that among chips Nos. 101, 102, 103, and 104, Nos. 101 and 102 are good chips, and Nos. 103 and 104 are defective chips. Other chips will be omitted to simplify the explanation. Here, whether a chip is a good chip or a defective chip can be easily determined by, for example, probing and checking the electrical characteristics. On the other hand, in the color separation filter board 22 shown in FIG. 2b, for example, among chips No. 201, 202, 203, and 204, No. 201 and No. 203 are good chips, and No. 202 and No. 204 are defective chips. Suppose it was. Other chips will be omitted.
Whether a good chip is a defective chip or not can be known in advance through inspection. FIG. 3a is an end view of the solid-state image sensor substrate 21 cut along line A-A' shown in FIG. 2a, and FIG. 3b is an end view of the color separation filter substrate 22 shown in FIG. An end view of the section cut along the ' line is shown. Next, Figure 3c
As shown in FIG. 2, the solid-state image sensor substrate 21 and the color separation filter substrate 22 are accurately aligned and brought into close contact with each other through an adhesive 28 that is cured by ultraviolet rays and also by heat treatment. At this time, care must be taken not to get bubbles or dirt into the adhesive layer 28. Next, as shown in FIG. 3d, the ultraviolet ray 3
is applied to cure the adhesive 28 in the ultraviolet passing region including at least the periphery of each color separation filter in the ultraviolet irradiation region. However, when irradiating ultraviolet rays, only the parts that meet the conditions in the table below are irradiated. The table below is based on the numbers in Figure 3d.

[Table] The method of irradiating ultraviolet rays using the method described above is to use the step-and-repeat method in the area of size
Ultraviolet rays are irradiated based on the inspection data of defective products and the inspection data of good and defective color separation filter chips. It goes without saying that a method of simply masking and irradiating may also be used. In this way, the solid-state image sensor substrate 21 and the color separation filter substrate 22 are accurately aligned and fixed because the adhesive layer in the ultraviolet transmitting region is cured to form a cured adhesive layer 29. At this time, if there is an ultraviolet-transmissive element in the color separation filter element, the adhesive under the filter element in the ultraviolet irradiation area is also cured. In this state, the bonding pad portion 25 of the solid-state image sensing device is covered by the transparent support 22a of the color separation filter substrate 22, so this portion must be removed. Although there are various methods for removing it, it is preferable to use a dicing saw. This removed state is shown in FIG. 3e. At this stage, the uncured adhesive 28 under the UV shielding layer 27 in the UV irradiation areas X ₁ and X ₄ and the UV non-irradiation areas X ₂ ,
Since the adhesive 28 of X ₃ is in an uncured state, it is cleaned with a solvent that dissolves the adhesive. By performing this cleaning, the uncured adhesive 28 can be removed and
The color separation filter chips in the X ₂ and X ₃ sections can also be taken out in their original state (not shown). Color separation filter chip No. 203 is a good chip, so it will be removed and saved. Next, heat treatment is performed to harden the uncured areas of the adhesive layer to complete bonding (not shown). Next, as shown in FIG. 3f, the solid-state image sensor substrate portion is cut by dicing or scriping. In this way, solid-state image sensor chip No. 102 is taken out and saved because it is a good chip. In region X ₁ , both the solid-state image sensor and the color separation filter are of good quality, so a color solid-state image sensor plate A of good quality can be produced. Note that in the area _X4 , both the solid-state image sensor and the color separation filter are defective, so a defective color solid-state image sensor plate B is produced. Here, the good solid-state image sensor chip and the good color separation filter chip, which were stored separately during the manufacturing process, are aligned and bonded together using an adhesive to fabricate a color solid-state image sensor plate. be able to. In this case, a thermosetting adhesive may be used as in the conventional method. In the above manufacturing process, the steps are e-step → heat treatment → f-step, but the steps can also be performed in the order of e-step → f-step → heat treatment. According to the manufacturing method of the present invention, even if a large number of arrayed solid-state image sensor substrates and color separation filter substrates are aligned and bonded together in a process that is highly effective for mass production, each good chip can be made into a single unit without making them defective. Since a color solid-state image sensor plate can be manufactured by laminating them separately, the overall yield can be further increased. Even when bonding individual pieces together, workability is improved by using an adhesive that is cured by ultraviolet light and also cured by heat treatment instead of a thermosetting type adhesive. In addition, in the cutting process shown in FIG. 3f above,
The solid-state image sensor substrate part is SPV-224 manufactured by Nitto Denzai Co., Ltd. or 13673NATURAL CAST manufactured by SEC.
After adhering to adhesive tape such as VINYL FILM and cutting it with a dicing saw until the adhesive tape remains, the distance between each color solid-state image sensor plate A can be expanded by the cutting machine expander device, and the die bonder after cutting Processing with equipment becomes easier. Alternatively, a similar method may be used in which the adhesive tape is adhered, scribed, braked, and then the spacing between each chip is expanded using an expander device. In the above description, an example was used in which the UV shielding layer was provided on the color separation filter substrate, but the UV shielding layer was not provided on the color separation filter substrate but on a separate ultraviolet transparent support, such as a glass plate, It is also possible to carry out the method of the present invention using such a mask. When using such a mask, although not shown, the solid-state image sensor substrate and color separation filter substrate are brought into close contact with each other via an adhesive, and then the UV shielding layer side is placed on the transparent support of the color separation filter substrate. After aligning and adhering, the necessary areas are exposed to ultraviolet light, and then
The mask can be removed and the transparent support corresponding to the bonding pad portions can be removed in the same manner as described above. In addition, in the case of the above method in which a mask in which a UV shielding layer is provided on a separate ultraviolet-transparent support is aligned and exposed on the transparent support of the color separation filter substrate, the color separation filter of the mask is Ultraviolet shielding portions may also be formed in portions of the substrate 22 corresponding to the color separation filters 26 and exposed to ultraviolet light. The hue of the color separation filter element is red,
There are various combinations such as green, blue, yellow, cyan, and transparent. Taking a color separation filter having red, green, and blue filter elements as an example, ultraviolet rays are blocked by the red and green filter elements, but are transmitted through the blue filter element. In other words, when the ultraviolet rays are irradiated in step d of FIG. 3, the adhesive layer in the portions of the color separation filter corresponding to some of the filter elements is cured. Depending on the type of adhesive, there may be a large volume shrinkage due to ultraviolet curing, and there may also be cases where the optical refractive index is not uniform even after subsequent heat curing, so these effects should be prevented. For this purpose, the color separation filter section may be shielded. The second reason is that when an organic dyed filter is used as a color separation filter, it is desirable to shield it from ultraviolet rays because the organic dyed filter has poorer ultraviolet resistance than a dichroic filter. Various filter elements such as dichroic filters, which are multilayer interference thin films, organic dye filters, etc., can be applied to the production of the color separation filter substrate used in the present invention, and conventional manufacturing methods can be used. To form a UV shielding layer or UV shielding portion on the color separation filter substrate or mask support described above
The photomask material used for photoresist plate making during IC manufacturing is used, and the materials include Cr,
After vapor deposition and sputtering of CrOx, Si, SiO ₂ , Ta, etc., plate making and etching are performed to form a UV shielding layer, etc. in a predetermined shape. Alternatively, a UV shielding layer or the like may be formed using a known dichroic filter or organic dyed filter so as to have spectral characteristics that shield ultraviolet rays. Color separation filter on board
When forming a UV shielding layer, use a filter element that blocks ultraviolet rays among the color separation filter elements, and form it in a predetermined position and shape at the same time as the color separation filter manufacturing process, thereby eliminating the need to form a UV shielding layer again. It's convenient. A UV shielding layer may be formed by overlapping color separation filter elements. As the adhesive used in the present invention, any type of adhesive that can be cured by ultraviolet rays and can also be cured by heat treatment can be used. For example, those containing various resins such as acrylic, epoxy, urethane, and styrene resins as main components, and optionally containing ultraviolet curing accelerators, thermosetting accelerators, etc., are preferably used. More specifically, Norland NOA60, NOA61, NOA63, NOA65,
Photobond 100, Photobond 300, Photobond made by Myojo Churchill Co., Ltd.
500, Sonnebond manufactured by Atsushi Gijutsu Co., Ltd., manufactured by Konishi Co., Ltd.
Examples include UVAC, UV03162, Adeka Ultraset manufactured by Asahi Denka Kogyo Co., Ltd., and adhesives based on these adhesive resins and appropriately containing a thermosetting accelerator. In the present invention, the preferred thickness of the adhesive layer is 4
It is about ~100μ. Further, in the present invention, the cleaning agent used to remove the adhesive in a partially cured state includes, for example,
Solvents such as toluene, trichlene, xylene, and benzene can be used, and as a cleaning method, the above-mentioned solvent is preferably sprayed after the step of removing the transparent support substrate portion located at the bonding pad portion shown in FIG. In some cases, ultrasonic cleaning may be performed after spray cleaning. The above is mainly an interline transfer type CCD.
Although we have explained the case using other methods, such as frame transfer method CCD, MOS,
Of course, the present invention can also be applied to solid-state imaging devices such as BBD, CID, and PCD. According to the present invention, it is possible to mass-produce color solid-state image sensor plates, and the overall yield can be further improved, which is a great advantage, and it is extremely effective industrially. The present invention will be further explained below with reference to Examples. Example 1 As shown in FIG. 3, a solid-state imaging device substrate in which a large number of solid-state imaging devices are arranged on a 3-inch wafer is prepared (FIGS. 2a and 3a). In addition, a 1000 Å film of Cr was sputtered on a 3-inch glass substrate with a thickness of 0.4 mm as a UV shielding layer, and then plate etching was performed to form a UV shielding layer on the bonding pad portion of the solid-state image sensor. Then, a color separation filter substrate on which a large number of color separation filters made of organic dyed filters are arranged is prepared by a conventional method (FIGS. 2b and 3b). Next, using a urethane adhesive NOA60 manufactured by Norland Co., Ltd., the solid-state image sensor substrate and color separation filter are accurately aligned without any bubbles or dust (Figure 3c). Next, ultraviolet rays having a slap-and-repeat mechanism are sequentially applied to each chip in the size of area X. However, the area where one of the corresponding solid-state image sensors and color separation filters is a good chip and the other is a defective chip is not irradiated with ultraviolet rays. In this way, each chip area is sequentially irradiated with ultraviolet rays for 1 minute using a 1KW mercury lamp. In FIG. 3d, areas X ₁ and X ₄ are irradiated. _X2 , _X3
The area is No. 102 chip, No. 203 chip, and No.
Since the chip 202 was defective, it was not irradiated with ultraviolet light (Figure 3d). After the above steps are performed, the aligned state will be maintained even if the parts are moved. Next, the transparent support (glass) located at the bonding pad portion of the solid-state image sensor is cut out using a resin blade with a blade width of 100 μm using a dicing saw (FIG. 3e). In this case, it is necessary to accurately control the cutting depth of the blade so as not to damage the surface of the bonding pad. Next, it is cleaned with Triclean to clean the adhesive in the dissolvable area. In this case, color separation filter chips No. 202 and No. 203 can be removed, but No. 203 is saved as it is a good chip. Next, heat treatment is performed at 160°C for 3 hours. Next, the solid-state imaging device is cut using a dicing saw in the usual manner. Here, solid-state image sensor No. 102 is saved because it is a good chip.
In this way, the solid-state image sensor and color separation filter are integrated in the X ₁ and X ₄ sections. X _4th part is defective, but
X ₁ part can produce good quality color solid-state image sensor plates.

[Brief explanation of the drawing]

FIG. 1 is for explaining an example of a method for manufacturing a color solid-state image sensor plate by a conventional method. FIG. 1a is a plan view of a solid-state image sensor plate made into a chip, and FIG. FIG. 1c, which is a plan view of the separation filter, is a schematic cross-sectional view showing a solid-state image sensor and a color separation filter bonded together. Figure 2a
2 is a plan view showing an example of a solid-state image sensor substrate used in the manufacturing method of the present invention, and FIG. 2b is a plan view showing an example of a color separation filter substrate used in the manufacturing method of the present invention. FIGS. 3a to 3f are schematic cross-sectional views illustrating each step of the manufacturing method of the present invention. 21 ... Solid-state image sensor substrate, 22 ... Color separation filter substrate, 22a... Transparent support, 23...
Solid-state image sensor, 24... Light receiving section, 25... Bonding pad section, 26... Color separation filter, 2
7...UV shielding layer, 28...Adhesive, 29...Curing adhesive, 30...Ultraviolet light, _X1 , _X4 ...Ultraviolet irradiation area, _X2 , _X3 ...Ultraviolet non-irradiation area, A ...
...Color solid-state image sensor board.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a color solid-state image sensor plate, characterized in that the steps of and below are performed in order, and then the steps of and are performed in any order. At least one of the plates is defective. A solid-state image sensor substrate on which a large number of solid-state image sensors are arranged has a solid-state image sensor surface and a filter element arranged in a stripe or mosaic pattern corresponding to each pixel of the solid-state image sensor, and at least one is defective. An adhesive that can be cured by ultraviolet rays and can also be cured by heat treatment is used to bond a filter element surface of a color separation filter substrate in which a large number of color separation filters are arranged on a transparent support with the same pitch as the solid-state image pickup device. a step of aligning and bringing them into close contact through the solid-state imaging device substrate, one of the solid-state imaging device and the color separation filter facing each other through an ultraviolet shielding layer disposed at a position corresponding to at least a bonding pad portion of the solid-state imaging device substrate; Ultraviolet rays are irradiated from the side of the transparent support, excluding at least the area that is a non-defective product, and ultraviolet rays are transmitted including the periphery of each color separation filter in the ultraviolet irradiation area where both the solid-state imaging device and the color separation filter facing each other are non-defective products. curing the adhesive in the area, removing at least a portion of the color separation filter substrate corresponding to the bonding pad portion or the portion and its surrounding area, and then cleaning with a solvent that dissolves the uncured adhesive; and a step of removing the color separation filter in the ultraviolet non-irradiation area where one of the solid-state image sensor and the color separation filter facing each other is a defective product, and heat treatment is performed to separate the solid-state image sensor surface and the remaining filter element surface. a step of completely curing the adhesive in all areas between the two; and a step of cutting between adjacent bonding pad portions of each solid-state image sensor on the solid-state image sensor substrate. 2. The method of manufacturing a color solid-state image sensor plate according to claim 1, wherein the ultraviolet shielding layer in the step is previously provided on the color separation filter substrate. 3. The color according to claim 1, wherein the ultraviolet shielding layer in the step is provided by placing a mask having an ultraviolet shielding layer on an ultraviolet transparent support and closely contacting the transparent support. A method for manufacturing a solid-state image sensor plate. 4. The method of manufacturing a color solid-state image sensing device plate according to claim 3, wherein the mask further has an ultraviolet shielding portion at a position corresponding to each color separation filter within the ultraviolet irradiation area. 5. The color solid-state image sensor plate according to claim 1, 2, 3, or 4, wherein the step is performed with the solid-state image sensor substrate adhered to an adhesive tape. Manufacturing method.