HK1022744B - Method for manufacturing an optoelectrical and an optoelectrical component manufactured according to the method - Google Patents

Description

Method for manufacturing a photovoltaic element and photovoltaic element manufactured according to this method

Technical content

The invention relates to a method for producing an optoelectronic component, the waveguide of which can be produced from plastic and can be encapsulated with plastic, and to an optoelectronic component produced according to said method.

Background

The introduction of new interactive multimedia services has increased the need for substantial capacity expansion of existing telecommunications network infrastructure, which is not possible if optical fibers are not widely used in the connectivity, transmission, access and system equipment. Low cost waveguide technology should be one of the most important areas that can break through fiber solutions. Epitaxial silicon on silicon has been widely used as a waveguide material in telecommunications applications to date. However, achieving low cost and high volume production requires the introduction of low cost processes in several steps, which can only be achieved through the use of polymeric materials.

Optical components with waveguides made of plastic have not, up to now, reached the high standards required for waveguide memory components made of quartz and glass, for example. If an optical element is not so expensive to manufacture, it should have a greater impact in the development of access and data communication applications, whether it be active or passive. Optoelectronic components which have been commercialized in the field of optical fibers have been based on hermetically encapsulated waveguides of quartz and crystal, which are too costly for mass production.

Disclosure of Invention

According to the present invention there is provided a method of producing an optoelectronic component having a waveguide-connectable junction, wherein a first material is formed as an underlayer on a silicon-based substrate, when the materials are selected in accordance with the requirements for collectively forming the waveguide; forming a second material as a core layer over the first material, using a mask having a suitable waveguide pattern for the element, such that a portion of the second material is removed to form a waveguide pattern in the first material; another layer of the first layer material as a cover layer is added to the waveguide pattern and the voids around the waveguide pattern, resulting in the waveguide pattern being surrounded by the first material; arranging the terminal interfaces of the photoelectric elements according to a required connection form by rubbing and polishing; it is characterized in that benzocyclobutene polymer (BCB) is used as the first layer material, and Cyclotene4024-40 photo-imageable benzocyclobutene polymer (BCB) is used as the second layer material.

According to another aspect of the present invention, there is provided a waveguide-connectable photoelectric element, comprising: a layer of a first material as a bottom layer disposed on a silicon-based substrate; a waveguide pattern of a second material as a core layer disposed on the first material; another layer of a first material as a capping layer placed in the waveguide pattern and the voids around the waveguide pattern, wherein the waveguide pattern is surrounded by the first material; and the first material and the second material are selected to facilitate formation of a waveguide, wherein the first material is benzocyclobutene polymer (BCB) and the second material is Cyclotene4024-40 photo-imageable benzocyclobutene polymer (BCB).

Preferably, the optoelectronic component further comprises at least one active component connected to the waveguide.

Preferably, in the above-described photoelectric element, the waveguide pattern includes at least one splitter pattern.

Preferably, in the optoelectronic device, the waveguide pattern includes at least one directional coupler pattern.

By fabricating a polymeric single crystal mode (SM) waveguide from benzocyclobutane polymer (BCB), it is possible to find a simple, reliable, inexpensive method for fabricating the waveguide. Is commercially availableWith the two grades of BCB applied, they have a difference in refractive index that allows the manufacturer to embed the SM properties in the waveguide. The name of BCB material that is commercially available today is Cyclotene^TMIt is a newer material made by "dow chemical" and the first example of this is the development and application of insulating layers in microelectronic applications. BCB materials have excellent insulation, low water absorption, better planar properties, better thermal stability and lower shrinkage than polyimide. There are two forms of BCB material that are particularly suited for the fabrication of waveguides embedded in SM properties. The thermal protective layer is used to coat the upper and lower layers of the waveguide and the photo-determined texturing agent is called optical BCB, which is used as the waveguide material. In this way, the sealed package of the waveguide chip can be made of plastic, while the sealed package can be formed as a connector interface on the terminal interface of the component.

With this waveguide concept it is possible to obtain a great potential for development with regard to the manufacture of inexpensive optoelectronic components, wherein the waveguide can be connected to active components like PINs and laser diodes in order to, for example, manufacture receiver assemblies. By exploiting the idea of manufacturing optically active and passive components using BCB waveguide technology, the number of difficult steps in development can be reduced to an easily manageable number to facilitate the development of commercially viable products like optical splitters and WDM filter assemblies with MT interfaces at both ends.

The use of a "retainer" type MT coupling interface in accordance with the present invention enables low manufacturing costs and more compact structural components than, for example, so-called stranded configurations.

Meanwhile, new technologies for mass production at low cost must be taken into consideration. Therefore, for these purposes, in high volume production, the ability to inject and transfer pressure to small plastic parts with very tight tolerances must be enhanced. In the first case, the potential reliability problems of the active components, as the plastic material handling and compatibility problems of the device become more apparent, can be solved in the manner described above in a later step.

Fig. 1 shows a power splitter assembly according to the present invention.

Fig. 2 shows a part of an electron beam mask for waveguide production.

FIG. 3 illustrates a sealed optical splitter assembly in accordance with the present invention connected to a ribbon fiber connectivity connector.

Figure 4 shows the damping curve for a 3.6 cm long, 6Tm BCB waveguide.

Fig. 5A and 5B show the optical effect curves of the directional coupler.

The method of producing an optoelectronic component according to the invention, i.e. the production technique forming the method, is based on the manufacture of BCB single crystal mode waveguides, and the packaging of these components with simultaneous passive tuning. The workflow for manufacturing SM-BCB waveguides will first be explained as follows:

according to fig. 1, the waveguide configuration in the power splitter assembly can be composed of: first an under-coating 1 of BCB (no anti-oxidant) on a substrate 2, such as a 1.3 cm thick silicon wafer, followed by a core of photo-formable BCB (Cyclotene 4024-40)3 and an over-coating of BCB (no anti-oxidant) 4. The bottom or lower coating layer 1 was spin-deposited on the silicon wafer 2 by BCB without antioxidant XU13005.19 at 1200 revolutions at 10Tm, followed by a special procedure of "low temperature bake" in a pan furnace under nitrogen atmosphere. The core 3 was spin-deposited by Cyclotene4024-40 at 3000 rpm, 5Tm, then prebaked in a convection oven at 90 ℃ for 10 minutes, bonded by means of a lithographic mask 5, and cured by electron beam exposure to form a waveguide pattern, see fig. 2. Development was carried out at DS3000, 30 ℃ for 15 minutes, followed by rinsing with soap and aqueous solution, followed by drying with a spinner or a washer and dryer. And then carrying out low baking according to a special IMC baking program in a nitrogen environment in the tray furnace. Topcoat 4 was formed by BCB spin deposition without antioxidant XU13005.01 at 1200 revolutions, 10Tm, followed by a special procedure of "low bake" in a pan oven under nitrogen atmosphere. Like the V-shaped grooves on a 0.75Tm silicon wafer, the arrangement 6 can be formed using BCB as a mask, where the best three masks must be used last. When the silicon wafer is subsequently placed in a tool to be compression cast, the waveguide chip is sawn from the silicon wafer by suitable standard methods in the later component manufacturing stage.

In this example, the V-shaped grooves on the silicon are adapted to match the shape of the holes 7 for the guide pins 8 of the MT connector to the pins of the assembly, which can be pressed in. In this manner, a high-quality process of photolithography can be used for the arrangement of the guide pins of the waveguide connector. BCB plastic is used for waveguides, encapsulation and optical interfaces of waveguides, and shaping of silicon, respectively. The final step in the manufacture of the component is the polishing of the interface 9, silicon and plastic (BCB), which can be finished using common polishing techniques as are used when polishing an MT connector. As shown in fig. 2, a line 10, a dispenser 11 and a directional coupler pattern 12 may be created using an electron beam of a lithographic mask 5 assembly. Fig. 2 shows an electron beam mask 5 with several different patterns. The distance between the waveguides at the termination interface may be 250Tm, where the chip size is required to fit, for example, the distance space to withstand the pressure. The bending radius for the Y-splitter and the directional coupler can be chosen to be around 30 mm. The directional couplers may have a width of 6 to 10Tm and different lengths and spacings. A typical core thickness may be chosen to be 7 Tm.

The diverter/distributor may be coupled to an associated connector. Research has been conducted on the optical properties of both encapsulated and non-encapsulated waveguides. On a die, the SM properties of different batches of BCB waveguides have been studied, where some reproducibility has been shown. Preliminary burn-in tests have also been performed and have demonstrated that the SM properties are retained for at least one year for non-encapsulated waveguides. With respect to multimode waveguides, the attenuation that has been determined by the "cutback measurement" method is about 0.6 dB/cm.

Shown in fig. 3 is a packaged directional coupler 13 which is connected to a fibre optic connector and a so-called MT connector 14. The transfer casting process is used to encapsulate the waveguide structure and to form an optical MT interface. The material used should be a thermosetting plastic containing silicon. To align the waveguides according to the interface, V-grooves are etched in the silicon substrate using a standard process, such as KOH. These V-grooves are inserted by metal pins in the mold tool and then form precise holes for MT-port guide pins. In this case, the accuracy of the orientation depends on the lithographic method used for patterning the waveguide, and the KOH etching the V-grooves, which makes the mechanical stability of the plastic material unimportant. This technique has the potential to achieve single mode performance, i.e., a directional accuracy of about ± 0.5 Tm. The MT interface of the BCB waveguide on the silicon carrier is polished for optical connectivity by a modified standard method.

To evaluate the so-called BCB waveguides, optical losses on the packaged and non-packaged linear waveguides were measured, while the directional coupler structures were also optically evaluated. Optical losses for different waveguide widths were measured by spectroscopic analysis in the wavelength range 0.6-1.6 Tm. The light from the white light source is coupled at its butt end to a waveguide using a single mode fiber, which may be, for example, a flexible gel. At the output, the BCB waveguide is coupled to a multimode fiber (NA ═ 0.25) using a flexible colloidal body.

Fig. 4 shows a spectral diagram for a waveguide after input and output losses have been added. For straight waveguides with a width of up to 12Tm, single mode performance was determined. A typical curve of the amount of light loss as a function of wavelength is shown on the graph for a 6Tm waveguide. The results show that with polished termination interfaces, the optical loss of the packaged straight waveguides is nearly the same as the optical loss of the waveguides with polished termination interfaces, but not packaged straight waveguides.

Fig. 5A and 5B show measurement curves for a directional coupler structure, where the measurements shown with other measurements demonstrate that the waveguide method developed is able to better separate the cases of wavelengths 1330 and 1550. The figures are given only as examples of development of the properties of the directional coupler. In the joining region, the directional couplers have the same interaction length, but different interaction lengths in the waveguide. For each directional coupler, light is input into one of two input waveguides. Fig. 5A shows the effect of light as measured from the same channel of waveguide and fig. 5B shows the effect of light as measured from different channels of waveguide. The results here are shown as a function of waveguide spacing. In the figures a and B show that the directional coupler with a waveguide pitch of 5.9Tm acts like a VDM filter that can separate 1.31Tm and 1.53Tm wavelengths with two output ports. It can therefore be said that by using a BCB waveguide for the optical passive branching arrangement, single mode performance can be achieved using standard methods that are not complex, the waveguide can be used as a straight waveguide, power splitter and VDM filter with or without active components, and the waveguide interface polishing also allows the use of plastic encapsulation and standard methods.

Claims (5)

1. Method for producing an optoelectronic component with a waveguide connection, wherein,

forming a first material as an underlayer on a silicon-based substrate when the materials are selected to collectively form the waveguide;

forming a second material as a core layer over the first material, using a mask having a suitable waveguide pattern for the element, such that a portion of the second material is removed to form a waveguide pattern in the first material;

another layer of the first layer material as a cover layer is added to the waveguide pattern and the voids around the waveguide pattern, resulting in the waveguide pattern being surrounded by the first material;

arranging the terminal interfaces of the photoelectric elements according to a required connection form by rubbing and polishing;

it is characterized in that the preparation method is characterized in that,

benzocyclobutene polymer (BCB) was used as the first layer material and Cyclotene4024-40 photo-imageable benzocyclobutene polymer (BCB) was used as the second layer material.

2. A waveguide-connectable optoelectronic component, comprising:

a layer of a first material (1) as a bottom layer on a silicon-based substrate (2);

a waveguide pattern of a second material (3) as a core layer placed on the first material;

a further layer of a first material (4) as a cover layer placed in the waveguide pattern and the interstices around the waveguide pattern, in which the waveguide pattern (3) is surrounded by the first material (1, 4);

and the first material and the second material are selected to facilitate formation of a waveguide,

characterized in that said first material (1, 4) is benzocyclobutane polymer (BCB) and said second material is Cyclotene4024-40 photo-imageable benzocyclobutane polymer (BCB).

3. The photovoltaic element of claim 2, further comprising an active element coupled to the waveguide.

4. Optoelectronic component according to claim 2 or 3, characterized in that the waveguide pattern comprises a splitter pattern (11).

5. An optoelectronic component according to claim 2 or 3, wherein the waveguide pattern comprises a directional coupler pattern.