JP2011197186A - Method for manufacturing wafer lens module, and method for manufacturing lens module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for appropriately sticking a wafer lens array having warpage.SOLUTION: The method for manufacturing the wafer lens module obtained by superposing a plurality of wafer lens arrays including a plurality of lenses arrayed one-dimensionally or two-dimensionally, and a substrate part to couple the lenses mutually includes: a step of fixing the wafer lens array on a substrate having higher rigidity than the wafer lens array; a step of remedying the warpage of the wafer lens array in a state the wafer lens array is fixed on the substrate having the higher rigidity; a step of bonding the wafer lens arrays fixed on the substrate having the higher rigidity so that the wafer lens arrays may be opposed to each other; and a step of removing the substrate having the higher rigidity from the wafer lens array after bonding.

Description

  The present invention relates to a method for manufacturing a wafer lens module and a method for manufacturing a lens module using the method for manufacturing a wafer lens module. The present invention also relates to a wafer lens module fixed to a substrate having higher rigidity than a wafer lens array obtained when manufacturing the method for manufacturing the wafer lens module.

  As a general method for manufacturing a wafer lens module, a method of molding resin lens portions on the front and back of a parallel plate as described in Patent Document 1 is known. This method has a problem that the lens performance deteriorates due to reflection at the interface due to the difference in refractive index between the parallel plate and the lens portion. In Patent Document 1, one of the lenses is processed with glass. However, since the glass portion is difficult to process, there is a problem that the lens shape is limited. On the other hand, a method of integrally forming the substrate portion and the lens portion with the same material has also been proposed. For example, it is a method described in Patent Document 2. However, when integrally molding with the same material, the material is substantially limited to resin for convenience of molding. The warpage of the resin wafer lens array becomes a problem. When two or more wafer lens arrays having large warpage are bonded, problems such as optical axis misalignment and adhesion failure are likely to occur when the wafer lens arrays are bonded. As a result, there are problems that the performance of the obtained lens module is deteriorated and the yield of the product is lowered.

  On the other hand, in Patent Document 3, in the case of combining a plurality of lenses, after preparing the lens on a dummy substrate, prepare a set of polished back surfaces of the surfaces on which the lenses are molded, and bond the polished surfaces together. After that, a technique for removing the dummy substrate is disclosed.

WO2008 / 068909 pamphlet WO2008 / 153102 pamphlet JP 2005-43411 A

  As described above, warping may be a problem when wafer lens arrays are bonded together. This is particularly serious in a wafer lens array which is thin and warps. An object of the present invention is to avoid such problems, and it is an object of the present invention to provide a method of manufacturing a wafer lens module capable of appropriately bonding wafer lens arrays that cause warping.

Under such circumstances, as a result of intensive studies by the present inventor, it was studied to correct the warp in a state where the wafer lens array is fixed to a highly rigid substrate. That is, in Patent Document 3, the microlens array is affixed to a dummy substrate and then polished. However, if the microlens array is warped strongly, the dummy substrate may be warped depending on the material of the dummy substrate. There is.
Therefore, in the present invention, the wafer lens array is fixed to a substrate having rigidity higher than that of the wafer lens array, the warp is corrected, and the wafer lens arrays are bonded to each other in this state, so that the wafer is appropriately and accurately obtained. The inventors have found that a lens array can be joined, and have completed the present invention.

Specifically, it was achieved by the following means.
(1) A method of manufacturing a wafer lens module in which a plurality of lens parts arranged in one or two dimensions and a wafer lens array including a substrate part that interconnects the lens parts are overlapped,
Fixing the wafer lens array to a substrate having higher rigidity than the wafer lens array;
A process of correcting warpage with the wafer lens array fixed to a rigid substrate;
Bonding the wafer lens arrays fixed to the rigid substrate so that the wafer lens arrays face each other;
A method of manufacturing a wafer lens module, comprising a step of removing a highly rigid substrate from the wafer lens array after the bonding.
(2) fixing a wafer lens array including a plurality of lens units arranged one-dimensionally or two-dimensionally and a substrate unit interconnecting the lens units to a substrate having higher rigidity than the wafer lens array; ,
Correcting the wafer lens array in a state of being fixed to a rigid substrate;
A process of removing one of the rigid substrates after bonding the wafer lens arrays fixed to the rigid substrate;
Manufacturing of a lens module including a step of cutting each lens unit after removing only one of the rigid substrates from the wafer lens array bonded to the highly rigid substrate, and then removing the other rigid substrate. Method.
(3) The method for manufacturing a lens module according to (2), wherein the highly rigid substrates are different from each other in terms of removing the highly rigid substrates from the bonded wafer lens array.
(4) The manufacturing of the lens module according to (2) or (3), wherein the substrate having high rigidity is heated from the wafer lens array at a temperature in two stages to be removed step by step. Method.
(5) The method for manufacturing a wafer lens module according to (1), wherein the highly rigid substrate and the wafer lens array are joined only by the substrate portion of the wafer lens array.
(6) The method for manufacturing a wafer lens module according to (1), wherein the substrate having high rigidity is fixed by fitting with the irregularities on the surface of the wafer lens array.
(7) The method for producing a wafer lens module according to (1), (5), or (6), wherein a highly rigid substrate is fixed to the wafer lens array using an adhesive sheet.
(8) The method for manufacturing a wafer lens module according to (1), (5), or (6), wherein a highly rigid substrate is fixed to the wafer lens array using an adhesive.
(9) The method for producing a wafer lens module according to (7) or (8), wherein the wafer lens array, the highly rigid substrate, and the adhesive sheet or adhesive have ultraviolet transparency.
(10) The wafer lens array fixed to a highly rigid substrate is corrected by vacuum suction using a jig, and the correction is performed according to any one of (1) and (5) to (9) Manufacturing method of wafer lens module.
(11) Any one of (1) and (5) to (10), wherein when the wafer lens arrays fixed to a highly rigid substrate are bonded together, a process for increasing the parallelism between the wafer lens arrays is performed. A method for producing a wafer lens module according to claim 1.
(12) The method for manufacturing a wafer lens module according to any one of (1) and (5) to (11), wherein the wafer lens array is made of a resin.
(13) A first wafer lens array and a second wafer lens array each including a plurality of lens units arranged one-dimensionally or two-dimensionally and a substrate unit interconnecting the lens units. The first wafer lens array and the second wafer lens array are fixed to a rigid substrate, and the warp is corrected with the first wafer lens array and the second wafer lens array fixed to the rigid substrate. After bonding the one wafer lens array and the second wafer lens array so that the lens sides face each other,
A wafer lens module fixed to a highly rigid substrate, wherein the wafer lens module is obtained by removing one of the highly rigid substrates from the bonded wafer lens array.

  According to the present invention, a wafer lens array having a strong warp can be bonded with high accuracy.

It is the schematic which shows the manufacturing process of the lens module of this invention.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

The method for manufacturing a wafer lens module according to the present invention includes (1) a step of fixing a wafer lens array to a substrate having a higher rigidity than the wafer lens array, and (2) a state in which the wafer lens array is fixed to a substrate having a higher rigidity. A step of correcting warpage, (3) a step of bonding wafer lens arrays fixed to the high-stiffness substrate so that the wafer lens arrays face each other, and (4) a substrate having high rigidity from the wafer lens array after the bonding. The process of removing.
The lens module manufacturing method of the present invention is the above-described method for manufacturing a wafer lens array, in which (5) only one of the rigid substrates is removed from the wafer lens array bonded to the highly rigid substrate. It is preferable to include a step of removing the other rigid substrate after cutting for each lens unit.
Here, the wafer lens array in the present invention is a wafer lens array provided with a plurality of lens portions arranged one-dimensionally or two-dimensionally and a substrate portion that interconnects the lens portions. In the present invention, a wafer lens module is manufactured by overlapping a plurality of such wafer lens arrays. Further, the lens module is manufactured by cutting the wafer lens array for each lens unit.

  Hereinafter, a preferred method of manufacturing a lens module according to the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of a surface perpendicular to the lens surface. In FIG. 1, 1 is a wafer lens array, 2 and 2 'are rigid substrates, 3 is an adhesive tape, and 4 and 4' are wafer wafer arrays fixed to a rigid substrate. And 5 'are jigs, and 6 is an adhesive layer. In FIG. 1, the scale up to the steps (2) and (3) are changed. Needless to say, the manufacturing method of the lens module of the present invention is not limited to these methods.

(1) Step of fixing wafer lens array to substrate having higher rigidity than wafer lens array In the present invention, the wafer lens array is fixed to a substrate having higher rigidity than the wafer lens array ((1) in FIG. 1). Normally, the wafer lens array 1 is warped. This is because the wafer lens array is thin. The wafer lens array usually has a maximum width in the direction perpendicular to the lens surface of 500 μm to 1500 μm. In the case of a resin wafer lens array, the warp width is usually several tens of micrometers, for example, 40 to 60 μm. It is extremely difficult to join a plurality of sheets in a warped state with high accuracy. Therefore, in the present invention, it is fixed to the substrate 2 having higher rigidity than the wafer lens array. When the wafer lens array is made of resin, examples of the highly rigid substrate include glass, LCP resin, ceramic, and metal. In the present invention, in particular, when an ultraviolet curable adhesive is used for bonding between lens arrays, an ultraviolet transmissive material is used as the wafer lens array and the highly rigid substrate. Examples of the ultraviolet light transmissive material include high-rigidity plastics such as glass and polycarbonate.
Here, the substrate having higher rigidity than the wafer lens array has a warp width smaller than that of the wafer lens array, and is usually 35 μm or less, and further is about 15 μm to 35 μm. The substrate having higher rigidity than the wafer lens array used in the present invention preferably has a thickness of 500 μm to 1500 μm. By using such a highly rigid substrate, it becomes easy to cut the substrate while it is provided on the wafer lens array.
A method for fixing the wafer lens array to the highly rigid substrate is not particularly defined, but in FIG. In addition, you may bond together using an adhesive agent. The adhesive can be appropriately selected from a photo-curing type, a thermosetting type, a room temperature curing type, a sheet type adhesive, and the like.
Moreover, it is preferable that the highly rigid substrate and the wafer lens array are joined only by the substrate portion of the wafer lens array. By adopting such means, it is possible to prevent the lens portion from being soiled by the bonding member between the substrate and the lens array, and to improve the alignment accuracy between the lens arrays. On the other hand, a highly rigid substrate may be fixed by fitting with the irregularities on the surface of the wafer lens array. Specifically, the concave shape is periodically processed and applied to the wafer lens array, the convex shape is also provided to the rigid substrate at the same period, and the uneven portion is fitted.

  Here, a preferable aspect of the resin wafer lens array will be described. The wafer lens array used in the present invention is preferably made of a resin composition that is cured by heat, or a resin composition that is cured by irradiation with active energy rays (for example, irradiation with ultraviolet rays or electron beams). From the viewpoint of moldability, such as mold shape transfer suitability, it is preferable to have appropriate fluidity before curing. Specifically, a liquid that is liquid at room temperature and has a viscosity of about 1000 to 50000 mPa · s is preferable. On the other hand, it is preferable to have heat resistance that does not cause thermal deformation and coloring even after the reflow process after curing. From this viewpoint, the glass transition temperature of the cured product is preferably 200 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably 300 ° C. or higher. In order to impart such high heat resistance to the resin composition, it is necessary to constrain the mobility at the molecular level, and as effective means, (1) means for increasing the crosslinking density per unit volume, (2) Means utilizing a resin having a rigid ring structure (for example, alicyclic structures such as cyclohexane, norbornane, tetracyclododecane, aromatic ring structures such as benzene and naphthalene, cardo structures such as 9,9-biphenylfluorene, spirobiindane Resins having a spiro structure such as JP-A-9-137043, JP-A-10-67970, JP-A-2003-55316, JP-A-2007-334018, JP-A-2007-238883, etc. (3) means for uniformly dispersing a substance having a high glass transition temperature such as inorganic fine particles (for example, No. 5-209027, JP-described), and the like in the 10-298265 Patent Publication. A plurality of these means may be used in combination, and it is preferable to make adjustments within a range that does not impair other characteristics such as fluidity, shrinkage rate, and refractive index characteristics. From the viewpoint of shape transfer accuracy, a resin composition having a small volume shrinkage due to the curing reaction is preferable. The curing shrinkage rate of the resin composition used in the present invention is preferably 10% or less, more preferably 5% or less, and particularly preferably 3% or less.

  Further, the shape of the lens portion is not particularly limited, and can be appropriately adjusted depending on the application. However, the substrate portion and the lens portion are preferably made of a resin composition that has substantially the same optical characteristics when the respective resin compositions are cured. Here, the substantially equivalent optical characteristics are those having a refractive index difference of 0.01 or less and an Abbe number difference of 5 or less. The difference in refractive index is more preferably 0.005 or less, and still more preferably 0.003 or less. The Abbe number difference is more preferably 2 or less, still more preferably 1 or less, and most preferably 0.

(2) Step of correcting warpage in a state where the wafer lens array is fixed to a substrate having high rigidity In the present invention, the wafer lens array 4 fixed to a substrate having high rigidity is corrected in this state (see FIG. 1). (2)). That is, even if the wafer lens array is fixed to a highly rigid substrate, the fixed one 4 is usually warped. This warp width is about the same as the warp width of a highly rigid substrate, and is usually 35 μm or less, and further about 15 μm to 35 μm.
A method for correcting the wafer lens array in a state in which the wafer lens array is fixed to a highly rigid substrate is not particularly defined, but is usually corrected by the correction jig 5. In particular, it is preferable to correct by vacuum suction using a jig. For these methods, the method described in JP-A-8-273208 can be referred to.

(3) The process of joining the wafer lens arrays fixed to the highly rigid substrates so that the wafer lens arrays face each other. Next, the wafer lens arrays fixed to the highly rigid substrates, 4 and 4 ′, are wafer lens arrays. It joins so that it may mutually oppose ((3) of FIG. 1). A lens module with higher accuracy can be obtained by bonding in a state where it is corrected with a jig or the like.
The method of joining is not particularly defined, but is usually bonded with an adhesive tape or an adhesive. As the adhesive, a photo-curing type, a thermosetting type, a room temperature curing type, a sheet type adhesive, or the like can be appropriately selected. It is also possible to use an adhesive in which particles are dispersed for the purpose of controlling the gap between the wafer lens arrays with higher accuracy. The adhesive is more preferably black in which carbon or the like is dispersed and has a light shielding property.
It is also preferable to perform a process of increasing the parallelism between the wafer lens arrays when bonding the wafer lens arrays fixed to a highly rigid substrate. Specifically, an aligner is usually used in bonding wafer lens arrays. Before the wafer lens array is bonded to the rigid substrate, the rigid substrates are prepared so as to face each other in a state where only the rigid substrate is attracted to the vacuum suction holders above and below the aligner. The suction table on one side of the aligner is normally movable and is fixed by vacuum suction. The suction board is pressed against the rigid board on the opposite side while the suction stage is movable, and the suction stage is sucked and fixed in this state. While maintaining this, the wafer lens array is attached to the rigid substrate, and the wafer lens arrays are bonded to each other with the warp corrected. By adopting such means, optical axis misalignment, adhesion failure and the like during bonding of the wafer lens array are improved.
Furthermore, when the wafer lens array is bonded, alignment of the optical axes of these lenses is important. Therefore, the wafer lens array used in the present invention is preferably provided with an alignment mark, and the portion is preferably provided on a portion other than the bonding surface with the highly rigid substrate. By adopting such a configuration, the visual recognition accuracy of the alignment mark is improved, and accordingly, the alignment accuracy of the wafer lens array can be improved.

Here, as shown in FIG. 1, it is preferable that the wafer lens arrays included in the wafer lens arrays 4 and 4 ′ fixed to a highly rigid substrate have different optical characteristics and lens shapes. It is particularly preferable to join two or more wafer lens arrays having different Abbe numbers. The wafer lens array on the high Abbe number side preferably has an Abbe number of 50 or more, more preferably 55 or more, and particularly preferably 60 or more. The refractive index is preferably 1.52 or more, more preferably 1.55 or more, and particularly preferably 1.57 or more. The wafer lens array on the low Abbe number side preferably has an Abbe number of 30 or less, more preferably 25 or less, and particularly preferably 20 or less. The refractive index is preferably 1.60 or more, more preferably 1.63 or more, and particularly preferably 1.65 or more.
The lens shape is appropriately modified according to these optical characteristics. The lens shape is not limited to a convex spherical surface, and may be a concave spherical surface or an aspherical surface, and various combinations of convex or concave spherical surfaces or aspherical surfaces can be used.

(4) Step of removing a highly rigid substrate from the wafer lens array after bonding In the present invention, the highly rigid substrate is removed from the wafer lens array after bonding of the wafer lens arrays fixed to the highly rigid substrate (FIG. 1). (4)). Here, the highly rigid substrate may be removed at the same time, but it is preferable to remove one by one step by step. In the present invention, it is more preferable to remove the other rigid substrate after cutting for each lens unit in a state where only one of the rigid substrates is removed from the wafer lens array bonded to the rigid substrate. . This point will be described later.
The method for removing the substrate having high rigidity is not particularly defined, and for example, the adhesive can be melted and peeled off by heating.

(5) The process of removing the other highly rigid substrate after cutting for each lens unit in a state where only one of the highly rigid substrates is removed from the wafer lens array bonded to the highly rigid substrate. As described above, after cutting each lens unit with only one of the rigid substrates removed from the wafer lens array bonded to the highly rigid substrate ((5-1) in FIG. 1), the other stiffness is obtained. It is preferable to remove the high substrate ((5-2) in FIG. 1). Multiple benefits can be obtained by gradual removal. First, the wafer lens module can be easily cut. That is, when the wafer lens module is cut, the lens may be damaged. However, in the present invention, it is possible to suppress the damage at the time of cutting. Second, since the warp of the lens array along with the rigid substrate is corrected by the adsorption table of the dicer, the perpendicularity of the cut surface to the substrate surface is improved. Third, handling of the cut lens module is improved. For example (usually a temporary fixing sheet such as a dicing tape is used for cutting the wafer shape, but the process of using the dicing tape is simplified by cutting the wafer while it is attached to a rigid substrate on one side as in the present invention. In addition, since the lens portion is covered with a rigid substrate, contamination of the lens portion can be prevented, that is, in the present invention, the rigid substrate is In addition to correcting warpage, it is possible to improve handling and protect the lens surface by using a dummy substrate not only in cutting (dicing) and the subsequent stage (pickup or the like).

  Moreover, in the present invention, it is preferable that the conditions for removing the highly rigid substrate when the highly rigid substrate is removed from the bonded wafer lens array are different between the highly rigid substrates 2 and 2 ′. For example, it is conceivable to use adhesives having different melting temperatures. By adopting such means, it is possible to easily remove the rigid substrate one by one only by heating at two stages of temperature.

  The lens module obtained by the method of the present invention can be preferably used for an imaging unit or the like. For example, an imaging unit including the lens module of the present invention, comprising an imaging device and a semiconductor substrate provided with the imaging device, wherein the substrate portion and the semiconductor substrate are integrally bonded via a spacer. Can be mentioned.

  The wafer lens module manufacturing method of the present invention can efficiently manufacture a wafer lens module even if a wafer lens array with strong warpage is used. Furthermore, in the method for manufacturing a lens module according to the present invention, there are various merits such as improvement of handling property and prevention of dirt in addition to correction of warping by removing a substrate having high rigidity in stages. Therefore, it can be preferably used for a precision element.

DESCRIPTION OF SYMBOLS 1 Wafer lens array 2 Rigid substrate 3 Adhesive tape 4 Wafer lens array fixed to a rigid substrate 5 Jig 6 Adhesive layer

Claims (13)

A method of manufacturing a wafer lens module in which a plurality of lens parts arranged in a one-dimensional or two-dimensional manner and a plurality of wafer lens arrays each including a substrate part that interconnects the lens parts are overlapped,
Fixing the wafer lens array to a substrate having higher rigidity than the wafer lens array;
A process of correcting warpage with the wafer lens array fixed to a rigid substrate;
Bonding the wafer lens arrays fixed to the rigid substrate so that the wafer lens arrays face each other;
A method of manufacturing a wafer lens module, comprising a step of removing a highly rigid substrate from the wafer lens array after the bonding. Fixing a wafer lens array including a plurality of lens portions arranged in one dimension or two dimensions and a substrate portion interconnecting the lens portions to a substrate having higher rigidity than the wafer lens array;
Correcting the wafer lens array in a state of being fixed to a rigid substrate;
A process of removing one of the rigid substrates after bonding the wafer lens arrays fixed to the rigid substrate;
Manufacturing of a lens module including a step of cutting each lens unit after removing only one of the rigid substrates from the wafer lens array bonded to the highly rigid substrate, and then removing the other rigid substrate. Method. The method for manufacturing a lens module according to claim 2, wherein conditions for removing a substrate having high rigidity when the substrate having high rigidity is removed from the bonded wafer lens array are different between the substrates having high rigidity. 4. The method of manufacturing a lens module according to claim 2, wherein the substrate having high rigidity is removed from the wafer lens array step by step by heating at a temperature of two steps. The method for manufacturing a wafer lens module according to claim 1, wherein the rigid substrate and the wafer lens array are joined only by the substrate portion of the wafer lens array. 2. The method of manufacturing a wafer lens module according to claim 1, wherein the substrate having high rigidity is fixed by fitting with the irregularities on the surface of the wafer lens array. 7. The method of manufacturing a wafer lens module according to claim 1, wherein a highly rigid substrate is fixed to the wafer lens array using an adhesive sheet. 7. The method of manufacturing a wafer lens module according to claim 1, wherein a highly rigid substrate is fixed to the wafer lens array using an adhesive. 9. The method for manufacturing a wafer lens module according to claim 7, wherein the wafer lens array, the rigid substrate, and the adhesive sheet or adhesive have ultraviolet transparency. 10. The method of manufacturing a wafer lens module according to claim 1, wherein a wafer lens array fixed to a highly rigid substrate is corrected by vacuum suction using a jig. 11. The wafer according to claim 1, wherein when the wafer lens arrays fixed to a highly rigid substrate are bonded to each other, a process for increasing the parallelism between the wafer lens arrays is performed. A method for manufacturing a lens module. The method for manufacturing a wafer lens module according to claim 1, wherein the wafer lens array is made of a resin. A first wafer lens array and a second wafer lens array each having a plurality of lens portions arranged in a one-dimensional or two-dimensional manner, and a substrate portion for interconnecting the lens portions. First wafer fixed to a rigid substrate with the first wafer lens array and the second wafer lens array fixed to a rigid substrate while the warp is corrected. After joining the lens array and the second wafer lens array so that the lens sides face each other,
A wafer lens module fixed to a highly rigid substrate, wherein the wafer lens module is obtained by removing one of the highly rigid substrates from the bonded wafer lens array.

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