KR100958654B1 - Optical module having magnetic align mark for passive alignment and fabrication method thereof - Google Patents

Abstract

In the optical module of the present invention, a substrate alignment mark for manual alignment is formed on one surface, and an element alignment mark for manual alignment is formed on a corresponding surface corresponding to one surface of the substrate, and the substrate alignment mark is aligned with the element alignment mark. It consists of an optical element bonded to the phase. In the optical module of the present invention, the device alignment mark is a metal alignment mark when the substrate alignment mark is a magnet alignment mark, and the substrate alignment mark is a metal alignment mark when the device alignment mark is a magnet alignment mark.

Description

Optical module having magnetic alignment mark for passive alignment and fabrication method

The present invention relates to an optical module and a manufacturing method thereof, and more particularly, to an optical module having a manual alignment mark and a manufacturing method thereof.

In general, precise alignment marks are required to align an optical device, such as a laser diode (LD) or photodiode (PD), to a substrate. When an optical device, such as a laser diode, is bonded to a substrate, a precision of tolerance within 1 μm is required to obtain good optical coupling efficiency. The method of precisely aligning the optical axis by aligning optical elements on a substrate is divided into an active alignment method and a passive alignment method.

The active alignment method is a method of obtaining an optimal alignment by adjusting the position while observing the light intensity with the optical signal turned on. The active alignment method is excellent in optical coupling efficiency because it adjusts the position while observing the light intensity of light emission (LD) or light reception (PD) while aligning at the point of maximum light emission or light reception while the optical device is in operation. However, there is a disadvantage in that the process is complicated and requires a lot of time and cost according to the alignment.

In contrast, the manual alignment method performs alignment without an optical device operating, so precise processing and dimensional control are required for alignment to an accurate position, and the optical coupling efficiency may be low, but the process is relatively simple and fast. The cost is low. Accordingly, a manual alignment method is widely used for reducing the cost of the optical module.

However, as described above, the manual alignment method needs to improve the accuracy of the optical axis alignment because the accuracy of the optical axis alignment is inferior.

The problem to be solved by the present invention is to provide an optical module with excellent precision of optical axis alignment between the optical device and the substrate during manual alignment.

In addition, another object of the present invention is to provide a method for manufacturing the optical module described above.

In order to achieve the above object, in the optical module according to an embodiment of the present invention, a substrate alignment mark for manual alignment is formed on one surface, and an element alignment mark for manual alignment is formed on a corresponding surface corresponding to one surface of the substrate. And an optical element bonded to the substrate by aligning the substrate alignment mark and the element alignment mark.
The element alignment mark is a metal alignment mark when the substrate alignment mark is a magnet alignment mark, and the substrate alignment mark is composed of the metal alignment mark when the element alignment mark is a magnetic alignment mark.

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The shape of the magnet alignment mark may be configured in various ways, such as a cross, a circle, a triangle, or a rectangle. In the optical module according to an embodiment of the present invention, an optical fiber or an optical waveguide is attached or formed to a portion of the substrate, and the optical fiber or the optical waveguide may be manually aligned with the optical element.

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In order to achieve the above-mentioned other object, the present invention provides a method of manufacturing an optical module, the substrate is provided with a substrate alignment mark for manual alignment on one surface. An optical device in which an element alignment mark for manual alignment is formed on a corresponding surface corresponding to one surface of the substrate is prepared. An optical device is bonded to the substrate by aligning the substrate alignment mark and the device alignment mark.
In the manufacture of the optical module of the present invention, when the substrate alignment mark is a magnetic alignment mark, the element alignment mark is formed as a metal alignment mark, and when the element alignment mark is a magnetic alignment mark, the substrate alignment mark is formed as a metal alignment mark. Bonding of the substrate and the optical device may be performed by forming a solder on one surface of the substrate or a corresponding surface of the optical device, and then heating and placing the solder-formed substrate and the optical device on a hot plate. The magnet alignment mark can be formed by sputtering, electron beam deposition, or plating.

The optical module of the present invention can easily align the optical axis to a desired position automatically by simply placing the optical device or the substrate on which the magnet alignment mark is formed at a suitable position with each other by the magnetic force of the N pole and the S pole of the magnet. The optical coupling efficiency can be increased by greatly improving the accuracy of optical axis alignment between the device and the substrate.

In addition, since the optical module of the present invention can be manually aligned with high precision due to the strong magnetic force and the optical elements once aligned, the optical elements are removed from the substrate even during handling (handling) for subsequent processes such as bonding. Departure can be prevented.

In addition, the optical module of the present invention can be placed on a heatable plate (plate) simply by heating the solder above the melting point without using an expensive device such as a flip chip bonding device when bonding the optical element and the substrate manually aligned with high precision Since the time and cost required for the bonding of the optical device and the substrate are greatly reduced, the product price and the productivity can be greatly improved.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments of the present invention illustrated in the following may be modified in many different forms, and the scope of the present invention is not limited to the embodiments described below, but may be implemented in various different forms.

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. In the drawings, the size or thickness of films or regions is exaggerated for clarity. Hereinafter, in the examples, the same reference numerals denote the same members.

The present invention uses a manual alignment method when performing optical axis alignment by aligning optical elements on a substrate, and fabricates an optical module using a manual alignment method. The present invention forms an alignment mark on each of the substrate and the optical device, thereby manufacturing the optical module by aligning the optical device on the substrate. In particular, the present invention forms a magnet alignment mark made of a magnetic material on either or both of the optical device and the substrate to facilitate easy and precise positioning of the substrate and the optical device.

Accordingly, the present invention aligns and precisely bonds the substrate and the optical element by using a magnet alignment mark formed on either or both of the substrate and the optical element without using a flip chip bonding apparatus. The manual alignment method of the present invention does not use an expensive and time-consuming flip chip bonding apparatus. An example of an optical module having such a configuration will be described.

1 and 2 are diagrams illustrating magnet alignment marks formed on a substrate and an optical device constituting an optical module according to the present invention.

Specifically, FIG. 1 illustrates a flip chip bonding substrate 10 having a substrate alignment mark 12 formed on one surface 10a. In Fig. 1, reference numeral 14 denotes a groove on which an optical fiber is to be mounted. FIG. 2 illustrates a flip chip bonding optical device in which an element alignment mark 22 is formed on a corresponding surface 20a corresponding to one surface 10a of the substrate 10. In Fig. 2, reference numeral 24 denotes a laser oscillation unit in which a laser is oscillated when the optical element is a laser diode. In FIG. 1, the substrate 10 uses a silicon substrate. 2 uses a laser diode, that is, a laser diode chip.

1 and 2, the substrate alignment mark 12 and the element alignment mark 22 are composed of magnet alignment marks made of a magnetic material. As an example of a magnetic material, a supermalloy (Ni80 Fe14 Mo5) may be used. The substrate alignment mark 12 and the element alignment mark 22 can be formed in a thin film form on the substrate using a sputtering method. The substrate alignment mark 12 and the element alignment mark 22 can be used as materials as long as they have a magnetic material in addition to the magnetic material. In addition to the sputtering method, a plating method, an electron beam deposition method, and the like can be used.

In the following description, the substrate alignment mark 12 and the element alignment mark 22 may be referred to as substrate magnet alignment mark and element magnet alignment mark, respectively. Then, the substrate magnet alignment mark 12 and the element magnet alignment mark 22 may be referred to as magnet alignment marks.

As will be described in more detail later, since the substrate 10 and the optical element 20 are manually aligned using the magnet alignment marks 12 and 22, a cross, circle, triangle or Various configurations are made in simple forms such as squares. The position where the magnet alignment marks 12 and 22 are placed may also be formed at any position of the substrate 10 or the optical element 20.

1 and 2, the magnet alignment marks 12, 22 are formed on both the substrate 10 and the optical element 20, but only one of them forms a magnet alignment mark and the other is led by a magnet. It is also possible to form alignment marks. The metal alignment mark may be formed of, for example, gold (Au). For example, when the substrate alignment mark 12 is a magnet alignment mark, the element alignment mark is composed of a metal alignment mark, and when the element alignment mark 22 is a magnet alignment mark, the substrate alignment mark 12 is composed of a metal alignment mark.

1 and 2, the number of magnet alignment marks 12 and 22 is configured as four, but one, two, or plural can be selected as necessary. The size of the magnet alignment marks 12 and 22 may be such that the optical element 20 and the substrate 10 can be automatically aligned by magnetic force.

1 and 2, as an example of the magnet alignment marks 12 and 22, the N pole magnet alignment mark 12a and the S pole magnet alignment mark 12b are formed on the substrate 10 in the horizontal direction, and the optical device 20 is formed. ), The S-pole magnet alignment mark 22a and the N-pole magnet alignment mark 22b are positioned at opposite polarities. In this case, when the optical device 20 is inverted, the substrate 10 and the optical device 20 are located by the magnets by the magnet alignment marks 12 and 22. Alternatively, unlike FIGS. 1 and 2, only one of the N-pole magnet alignment mark 12a and the S-pole magnet alignment mark 12b is formed on the substrate 10, and the optical element 20 also has a polarity opposite to that of the substrate 10. Only one of the S-pole magnet alignment mark 22a and the N-pole magnet alignment mark 22b may be formed.

3 is a view for explaining the manual alignment between the substrate and the optical device of the optical module according to the present invention.

Specifically, FIG. 3 illustrates a substrate 10 on which the magnet alignment marks 12 and 22 of FIGS. 1 and 2 and the optical device 20 align the optical device 20 to a predetermined position by using magnetism. It's a concept. In FIG. 3, the dashed arrows are for showing that the optical elements are attached to the substrate and manually aligned. The substrate alignment mark 12 is formed on one surface 10a of the substrate 10, and the element alignment mark 22 is formed on the corresponding surface 20a corresponding to the one surface 10a of the substrate 10.

The substrate alignment mark 12 and the element alignment mark 22 are aligned to bond the optical elements 20 on the substrate 10 to complete the optical module. That is, the optical module 20 is bonded to the device alignment mark 22 downward (inverted) on the one surface 10a of the substrate 10 having the substrate alignment mark 12, ie, in a flip-chip manner. Complete

In the present invention, the substrate alignment mark 12 and the element alignment mark 22 are substrate magnet alignment marks and element magnet alignment marks. When the substrate magnet alignment mark 12 is composed of the N pole substrate magnet alignment mark 12a and the S pole substrate magnet alignment mark 12b in one direction, the element alignment magnet mark 22 is the N pole substrate magnet alignment mark 12a. And S-pole element magnet alignment marks 22a and N-pole element magnet alignment marks 22b of opposite polarities are respectively located corresponding to the S pole substrate magnet alignment marks 12b.

In the present invention, since the substrate alignment marks (magnet alignment marks 12, 22) have magnetic force, simply placing the optical element 20 at a proper position of the substrate 10 causes the N and S poles to be automatically moved by the magnetic force. The alignment marks 12, 22 can be used to easily align the optical axis with high precision. Of course, the substrate alignment mark and the element alignment mark may be configured in consideration of more complicated shapes, sizes, positions, etc. for high precision alignment.

In the present invention, since the alignment marks (magnetic alignment marks, 12, 22) have a strong magnetic force, once the aligned optical elements 20 are attached by magnetic force, movement of the optical elements after alignment, heating of the substrate and the optical elements, and bonding are performed. The optical device 20 can be prevented from being separated from the substrate 10 even during handling (handling) for a series of subsequent processes such as application of pressure. In the present invention, after the manual alignment by the substrate alignment mark 12 and the element alignment mark 22, the substrate 10 and the optical element 20 are simultaneously heated as described later to convert the optical element 20 into the substrate ( 10) to complete the optical module.

4 to 8 are comparative examples for comparison with the present invention, which illustrate manual alignment between a substrate and an optical device of an optical module using a flip chip bonding apparatus.

Specifically, FIG. 4 illustrates a flip chip bonding substrate 30, for example, a silicon substrate, on which a general substrate alignment mark 32a is formed on one surface 30a. FIG. 5 shows a flip chip bonding optical element 40, for example, a laser diode chip or a photo diode chip, in which a general element alignment mark 42 is formed on a corresponding surface 40 a corresponding to one surface 30 a of the substrate 30. One drawing.

FIG. 6 is a conceptual view illustrating the formation of an optical module by manually aligning the substrate 30 and the optical device 40 using the alignment marks 32 and 42. 7 illustrates a state in which the substrate 30 and the optical device 40 are aligned, and FIG. 8 illustrates a state in which the substrate and the optical device are bonded after being aligned.

In Fig. 4, reference numeral 34 denotes a groove in which the optical fiber 35 is to be mounted. In FIG. 5, reference numeral 44 denotes a laser oscillation unit in which a laser is oscillated when the optical element 40 is a laser diode.

As shown in Fig. 4, the general substrate alignment mark 32 is composed of a cross shape 32a and a square shape 32b in different directions. As shown in Fig. 5, the general element alignment marks 42 are arranged in a cross shape 32a and a square shape 32b in different directions so as to coincide well with the general substrate alignment mark 32. The general alignment marks 32 and 42 can be formed by depositing gold (Au) using a sputtering method. As shown in FIG. 6, the substrate alignment mark 32 and the element alignment mark 42 are aligned to bond the optical elements 40 on the substrate 30 to complete the optical module. That is, the general device alignment mark 42 is downwardly (inverted) on one surface 30a of the substrate 30 having the general substrate alignment mark 32, that is, the optical device 40 is bonded by the flip chip method. Complete the module.

When manually aligning using the general substrate alignment mark 32 and the general element alignment mark 42, the comparative example uses a flip chip bonding device for precise alignment. That is, by observing the general substrate alignment mark 32 and the general element alignment mark 42 using the flip chip bonding apparatus, fine adjustment is made to coincide with each other. When an expensive device such as a flip chip bonding device is used when the optical device 40 and the substrate 30 are bonded to each other, the production cost of the optical module becomes very expensive.

In particular, in the comparative example, after the manual alignment by the general substrate alignment mark 12 and the general element alignment mark 22, there is a possibility that the optical element is separated from the substrate during handling for bonding the substrate 30 and the optical element 40. There is a high disadvantage. In this regard, it will be described in more detail with reference to FIGS. 7 and 8.

FIG. 7 illustrates a state in which the substrate 30 and the optical device 40 are aligned in the same manner as in FIG. 6, and determines the accuracy of the alignment by the gap between the square and the cross. As shown in FIG. 7, it can be seen that the substrate 30 and the optical device 40 are correctly aligned. After manual alignment by the general alignment marks 32 and 42, the substrate 30 and the optical device 40 are simultaneously heated using a flip chip bonding apparatus to bond the optical device 40 to the substrate 30. To complete the optical module.

By the way, in the state where the substrate 30 and the optical device 40 shown in FIG. 8 are bonded after being aligned, it is understood that the gap between the square and the cross is widened, resulting in poor alignment accuracy. This is due to the movement of the optical element, the heating of the substrate and the optical element, the application of pressure for bonding, etc., in order to flip chip bond the aligned substrate and the optical element. In particular, there is also a possibility that the optical device 40 is separated from the substrate 30 after actually bonding the substrate 30 and the optical device 40.

9 is a block diagram showing an optical module according to the present invention, Figure 10 is a flow chart showing a manufacturing method of the optical module according to the present invention.

Specifically, FIG. 9 illustrates the final optical module 70 after flip chip bonding and bonding the substrate 10 and the optical device 20 using the magnet alignment marks 12 and 22. In the optical module 70, an optical fiber 52 that is aligned with an optical axis corresponding to the laser oscillator 24 is attached to a portion (one side) of the substrate 10. The optical fiber 52 includes a core portion 54. As described above, the laser oscillator 24 and the core 54 align the optical axis with high accuracy by aligning the substrate and the optical device 20 using the magnet alignment marks 12 and 22 in a manual alignment method. Although the optical module 70 of FIG. 9 is shown as an optical fiber attached to a portion of the substrate 10, an optical waveguide may be attached or formed in the substrate.

Here, the manufacturing method of the optical module 70 will be described with reference to FIGS. 1 to 3, 9, and 10. As described above, a substrate on which a substrate alignment mark for manual alignment is formed on one surface is prepared (step 60). An optical device in which an element alignment mark for manual alignment is formed on a corresponding surface corresponding to one surface of the substrate is prepared (step 62). As described above, at least one of the substrate alignment mark and the element alignment mark is formed of a magnet alignment mark. The magnet alignment mark can be formed by sputtering, electron beam deposition, or plating.

Next, the substrate alignment mark and the element alignment mark are aligned to bond the optical elements on the substrate (step 64). Bonding of the substrate and the optical device is performed by forming solder on one surface of the substrate or a corresponding surface of the optical device, and heating the substrate on which the solder is formed by placing the substrate and the optical device on a hot plate. In other words, the substrate and the optical element automatically aligned using the substrate alignment mark and the element alignment mark are placed on a heatable hot plate, and then the solder formed on either side of the substrate and the optical element is heated above the melting point and the substrate and the optical element are separated. Bond.

1 and 2 are diagrams illustrating magnet alignment marks formed on a substrate and an optical device constituting an optical module according to the present invention.

3 is a view for explaining the manual alignment between the substrate and the optical device of the optical module according to the present invention.

4 to 8 are comparative examples for comparison with the present invention, which illustrate manual alignment between a substrate and an optical device of an optical module using a flip chip bonding apparatus.

9 is a block diagram showing an optical module according to the present invention.

10 is a flowchart illustrating a method of manufacturing an optical module according to the present invention.

Claims (10)

A substrate on which a substrate alignment mark for manual alignment is formed on one surface; And An element alignment mark for manual alignment is formed on a corresponding surface corresponding to one surface of the substrate, and the substrate alignment mark and the element alignment mark are aligned with each other to form an optical element bonded to the substrate. The element alignment mark is a metal alignment mark when the substrate alignment mark is a magnet alignment mark, and the substrate alignment mark is a metal alignment mark when the element alignment mark is a magnetic alignment mark. delete delete The optical module of claim 1, wherein the magnet alignment mark has a cross shape, a circle, a triangle, or a rectangle. The optical module according to claim 1, wherein an optical fiber or an optical waveguide is attached to or formed on a portion of the substrate, and the optical fiber or optical waveguide is manually aligned with the optical element. delete delete Preparing a substrate having a substrate alignment mark for manual alignment formed on one surface thereof; Preparing an optical device in which an element alignment mark for manual alignment is formed on a corresponding surface corresponding to one surface of the substrate; And Bonding the optical device on the substrate by aligning the substrate alignment mark and the device alignment mark; The device alignment mark is formed of a metal alignment mark when the substrate alignment mark is a magnet alignment mark, and the substrate alignment mark is formed of a metal alignment mark when the device alignment mark is a magnet alignment mark. . The method of claim 8, wherein the bonding step of the substrate and the optical device, Forming solder on one surface of the substrate or a corresponding surface of the optical device; And the substrate and the optical element on which the solder is formed are placed on a hot plate and heated. The method of claim 9, wherein the magnet alignment mark is formed by sputtering, electron beam deposition, or plating.

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