CN101819296B - Method for preparing polysiloxane optical waveguide for optical interconnection - Google Patents

Abstract

The invention discloses a method for preparing a polysiloxane optical waveguide for optical interconnection, and aims to provide a method for preparing an optical waveguide for optical interconnection with a length greater than 20 cm and low cost. The technical solution is to design an optical waveguide pattern and make a template; apply polyvinylidene fluoride solution on the template, and release the mold to obtain a replica; fill the grooves in the replica with a mixture of phenylmethylcyclosiloxane, phenyl After the methylcyclosiloxane mixture is solidified, it becomes the core layer of the ridge waveguide; the tetrakis (trimethylsiloxy) silane mixture is coated on the replica and baked to form a tetrakis (trimethylsiloxy) base) silane film; the replica is peeled off from the tetrakis (trimethylsiloxy) silane film, and the tetrakis (trimethylsiloxy) silane film forms the lower cladding layer; the tetrakis (trimethylsiloxy) ) silane mixture is coated on the ridge waveguide, and the tetrakis (trimethylsiloxy) silane mixture is solidified to form a polymer upper cladding. By adopting the invention, the optical waveguide whose length meets the requirement of optical interconnection between any chips can be prepared, and the process is simple and the cost is low.

Description

A preparation method of polysiloxane optical waveguide for optical interconnection

technical field

The invention belongs to a manufacturing method of an optoelectronic device, in particular to a method for preparing a polysiloxane optical waveguide.

Background technique

Due to the "electronic bottleneck" in the fast calculation and real-time processing of super-parallel, large-capacity data and images, optical interconnection instead of traditional electrical interconnection has become a research hotspot. Especially in the optical interconnection of chips, polymer waveguides have been widely used in optoelectronic printed circuit boards due to their advantages of low cost, simple process, large-scale production and high integration. Seeking low loss and waveguide materials and corresponding manufacturing processes for optical interconnection between chips has always been concerned by people.

Traditional optical integration and optoelectronic integration are done on lithium niobate (LiNbO ₃ ) and silicon-based semiconductor materials. In recent years, people have begun to pay attention to the development and research of organic polymer optical waveguide materials. Compared with traditional inorganic optical waveguide materials, organic polymer optical waveguide materials have the characteristics of higher electro-optical coupling coefficient, lower dielectric constant, shorter response time and smaller heat loss. Moreover, making optical waveguides with polymer materials has these advantages: it is relatively easy to make high-quality polymer waveguide materials, and the refractive index of waveguide materials is easy to adjust; the device manufacturing process is simple and compatible with traditional semiconductor processes, which is conducive to Large-scale production, low cost. The material is fabricated on many types of substrates, facilitating integration with other optoelectronic devices. There are many kinds of materials, so materials with low transmission loss and low price can be selected to make devices.

The sintering temperature of optoelectronic integrated devices is generally 260°C, and the temperature that integrated devices must withstand in the PCB board lamination process is not lower than 180°C. On the other hand, the material is also required to have certain thermal stability during use. At present, some organic polymers (such as polymethyl methacrylate, polystyrene, etc.) used in the preparation of optical waveguides have low glass transition temperature and poor thermal stability, so they are not suitable for optical interconnection between chips. In order to meet the above requirements, the selection of materials must select organic polymers with high glass transition temperature and good thermal stability. Polysiloxane (PDMS) and polyimide (PI) and their derivatives have good properties in this regard.

In terms of preparation process, the traditional polymer waveguide preparation process is based on the traditional semiconductor preparation process. First, the polymer film is prepared on the substrate by spin coating, and the required micropattern is transferred to the metal protective film by traditional photolithography technology, and ICP etching is carried out after the photolithography is completed. In ICP etching, the metal micropattern film protected by photoresist is used as a mask layer, and the unprotected polymer is removed under the bombardment of plasma to form the required polymer microstructure layer, and then The metal micro-pattern film is etched away with an etchant, and the remaining polymer with a micro-pattern structure becomes the core layer of the waveguide material. Finally, the polymer upper cladding layer is spin-coated on the prepared waveguide core layer, and the upper cladding layer is cured by heat treatment to form the optical waveguide layer.

The above-mentioned traditional optical waveguide preparation method has a stable process, and the prepared optical waveguide layer is of high quality, which has great advantages in large-scale production. The disadvantage is that the uniform area of the ultraviolet light of the lithography machine commonly used in the laboratory is limited, and the uniform area of the ion beam in the etching equipment is limited. It is impossible to obtain a large-area uniform film by the spin coating method. Therefore, the traditional optical waveguide preparation method It is difficult to prepare optical waveguides with a length greater than 15 cm, and optical waveguides with a length greater than 15 cm can meet the requirements of optical interconnection between chips. Therefore, new methods must be explored in order to prepare optical waveguides that meet the requirements of optical interconnection between chips.

Since 1990, people have developed various direct writing technologies (Direct Writing), such as micro pen direct writing, diamond tool direct writing, laser direct writing, laser micro cladding direct writing, etc. A representative method is the micro-pen direct writing method of electronic components. It mainly uses a specially designed micro-pen, and uses the CAD/CAM function of the workbench to directly place the electronic paste on the designated position on the surface of the substrate to form a circuit board or functional components. For the specific design method of Micropen direct-write wiring, see the US patent: "Carl E, Drumheller.Inking System for Producing Circuit Patterns.US Patent4485387, 1984." method and its special direct writing device, application number 200610019923.7". The device prepares the waveguide by controlling the on-off of the airflow in the pressurized air pipe, adjusting the size of the air pressure, and providing the required pressure to the slurry in the material storage chamber of the micro-pen.

Direct writing technology generally has CAD/CAM functions, and can realize flexible manufacturing without masks, with high processing accuracy and no pollution. The disadvantage is that the direct writing device is expensive, the production cost is high and the production cycle is long.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing a polysiloxane optical waveguide used for optical interconnection. The method can be used to prepare a polysiloxane optical waveguide with a length greater than 20 cm, and has low cost, simple process and easy operation.

Technical scheme of the present invention is:

The first step is to use computer-aided design tools to design an optical waveguide pattern whose cross-section matches the core diameter of the multimode fiber and whose length meets the requirements for optical interconnection between chips, and submit the optical waveguide pattern to a professional plate-making company to make a template.

In the second step, polyvinylidene fluoride is dissolved in dimethylacetamide solvent, and the mass ratio of polyvinylidene fluoride powder to dimethylacetamide solvent is 1:8. Mix and stir at room temperature, then raise the temperature to 50°C and reflux for half an hour to obtain a translucent polyvinylidene fluoride solution.

In the third step, the polyvinylidene fluoride solution is coated on the prepared template, and the thickness of the polyvinylidene fluoride solution is controlled to be 1-1.5 mm. Let the dimethylacetamide solvent in the polyvinylidene fluoride solution fully volatilize at room temperature, and release the cured polyvinylidene fluoride film from the template to obtain a replica of the template. The replica has grooves in it which will be used in the next step to make the core of the waveguide.

The fourth step is to mix the phenylmethylcyclosiloxane solution with its supporting curing agent solution in a mass ratio of 1:1 to obtain a phenylmethylcyclosiloxane with a viscosity of 4,000mPa s and a refractive index of 1.543. Mixture. Fill the grooves in the replica with phenylmethylcyclosiloxane mixture, bake at 100°C to 105°C for one hour, and the phenylmethylcyclosiloxane mixture will become the core layer of the ridge waveguide after solidification .

The fifth step is to mix the tetrakis (trimethylsiloxy) silane solution with its supporting curing agent solution in a mass ratio of 10:1 to obtain a tetrakis (trimethylsiloxy) silane with a viscosity of 4,000 mPa s and a refractive index of 1.41. Silyloxy) silane mixture. The tetrakis(trimethylsiloxy)silane mixed solution is placed in a closed container to evacuate, and then ultrasonic vibration is used to remove the air bubbles in the tetrakis(trimethylsiloxy)silane mixed solution. Coat tetrakis (trimethylsiloxy) silane mixed solution on the replica filled with phenylmethylcyclosiloxane mixed solution by salivation method, tetrakis (trimethylsiloxy) silane and replica Baking together at a temperature of 80° C. to 90° C. for one hour allows the tetrakis(trimethylsiloxy)silane mixture to undergo a cross-linking reaction and solidify to form a tetrakis(trimethylsiloxy)silane film.

In the sixth step, the replica is peeled off from the tetrakis (trimethylsiloxy) silane film, and the tetrakis (trimethylsiloxy) silane film forms the lower cladding layer, leaving the tetrakis (trimethylsiloxy) ) phenylmethylcyclosiloxane on a silane film to form the core layer. The polyvinylidene fluoride that may remain on the lower cladding and core layer can be dissolved with acetone, and a ridge waveguide with air as the upper cladding is initially formed.

In the seventh step, the tetrakis (trimethylsiloxy) silane mixture is coated on the ridge waveguide with air as the upper cladding prepared in the sixth step, and the tetrakis (trimethylsiloxy) silane is mixed The liquid solidifies to form a polymer overcladding. A ridge-shaped waveguide with phenylmethylcyclosiloxane as the core layer and tetrakis(trimethylsiloxy)silane as the upper and lower cladding layers is obtained.

Adopt the present invention can reach following technical effect:

1. Since the length of the optical waveguide pattern designed in the first step of the present invention meets the requirements for optical interconnection between chips, the preparation of the template is a mature technology, and the length is obtained according to the length of the optical waveguide pattern, so the present invention can be used to prepare the length to meet the requirements of any inter-chip The optical waveguide required for optical interconnection makes it easy to prepare an optical waveguide with a length greater than 20 cm.

2. Because the phenylmethylcyclosiloxane used as the core layer and the tetrakis (trimethylsiloxy) silane of the cladding have a high glass transition temperature and good thermal stability, the optical waveguide prepared by the present invention can be used for Optical interconnection on PCB board based on lamination process.

3. Since the materials of the core layer and the upper and lower cladding layers are polysiloxane when the optical waveguide is prepared by the present invention, the transmission loss of the prepared optical waveguide is low, lower than 0.14dB/cm.

4. The process of the present invention is simple and easy to operate.

Description of drawings

Fig. 1 is the general flowchart of the present invention;

Fig. 2 is a schematic view showing the changes of components of the optical waveguide prepared by the present invention.

Detailed ways

Fig. 1 is an overall flow chart of the present invention, and Fig. 2 is a schematic view showing changes of components of the optical waveguide prepared by the present invention.

As shown in Figure 2 (a)-(e), the steps of the present invention are:

(1) Use computer-aided design tools to design an optical waveguide pattern whose cross-section matches the core diameter of the multimode fiber and whose length meets the requirements for optical interconnection between chips, and submit the optical waveguide pattern to a professional plate-making company to make template 1, as shown in Figure 2 (a) shown.

(2) Dissolving polyvinylidene fluoride, that is, polyvinylidene fluoride powder, in dimethylacetamide dimethylacetamide solvent, the mass ratio of the two is 1:8. Mix and stir at room temperature, then raise the temperature to 50° C. and reflux for half an hour to obtain a translucent polyvinylidene fluoride solution.

(3) Coating the template 1 with a polyvinylidene fluoride solution, controlling the thickness of the polyvinylidene fluoride solution to be 1-1.5 mm. The dimethylacetamide solvent in the polyvinylidene fluoride solution was allowed to fully evaporate at room temperature, and after curing, the polyvinylidene fluoride film was released from the mold to obtain the replica 2 of the template 1, as shown in Figure 2(b).

(4) Mix the phenylmethylcyclosiloxane solution with its supporting curing agent solution in a mass ratio of 1:1 to obtain a phenylmethylcyclosiloxane mixture, which is mixed with phenylmethylcyclosiloxane Fill the grooves in replica 2 with liquid, bake at 100° C. to 105° C. for one hour, and obtain the core layer 3 after curing the phenylmethylcyclosiloxane mixture, as shown in FIG. 2( c ).

(5) Mix the tetrakis(trimethylsiloxy)silane solution with its supporting curing agent solution at a mass ratio of 10:1 to obtain a tetrakis(trimethylsiloxy)silane mixed solution. The tetrakis(trimethylsiloxy)silane mixed solution is placed in a closed container to evacuate, and then ultrasonic vibration is used to remove the air bubbles in the tetrakis(trimethylsiloxy)silane mixed solution. Coat tetrakis (trimethylsiloxy) silane mixed solution on replica 2 filled with core layer 3 by salivation method, put tetrakis (trimethylsiloxy) silane and replica 2 together at 80℃～ Bake at 90°C for one hour to allow the tetrakis(trimethylsiloxy)silane mixture to undergo a crosslinking reaction and solidify to form a tetrakis(trimethylsiloxy)silane film 4, as shown in Figure 2(d) .

(6) The replica 2 is peeled off from the tetrakis (trimethylsiloxy) silane film 4, and the tetrakis (trimethylsiloxy) silane film 4 forms the lower cladding layer 5, leaving the tetrakis (trimethylsiloxy) silane film The phenylmethylcyclosiloxane on the siloxy)silane film 4 forms the core layer 3, as shown in FIG. 2(e). The polyvinylidene fluoride that may remain on the lower cladding layer 5 and the core layer 3 can be dissolved with acetone to initially form a ridge waveguide with air as the upper cladding layer.

(7) Coat the mixed solution of tetrakis(trimethylsiloxy)silane on the ridge waveguide with air as the upper cladding prepared in step (6), and solidify to form the polymer upper cladding 6, as shown in the figure 2(f). A ridge waveguide in which phenylmethylcyclosiloxane is used as the core layer 3 , tetrakis(trimethylsiloxy)silane is used as the upper cladding layer 6 and the lower cladding layer 5 is obtained.

Claims (5)

1. A preparation method for a polysiloxane optical waveguide for optical interconnection, characterized in that it may further comprise the steps: The first step is to use computer-aided design tools to design an optical waveguide pattern whose cross-section matches the core diameter of the multimode fiber and whose length meets the requirements for optical interconnection between chips, and submit the optical waveguide pattern to a professional plate-making company to make a template; In the second step, polyvinylidene fluoride powder is dissolved in dimethylacetamide solvent, the mass ratio of polyvinylidene fluoride powder and dimethylacetamide solvent is 1:8, mixing and stirring at room temperature, and then the temperature is raised to Reflux at 50°C for half an hour to obtain a translucent polyvinylidene fluoride solution; In the third step, the polyvinylidene fluoride solution is coated on the prepared template (1), and the dimethylacetamide solvent in the polyvinylidene fluoride solution is fully volatilized at room temperature, and the cured polyvinylidene difluoride The vinyl fluoride film is released from the template (1) to obtain a replica of the template (2); The fourth step is to mix the phenylmethylcyclosiloxane solution with its supporting curing agent solution in a mass ratio of 1:1 to obtain a phenylmethylcyclosiloxane mixture; use the phenylmethylcyclosiloxane The mixed liquid fills the grooves in the replica (2), and is baked at a temperature of 100° C. to 105° C. for one hour, and the phenylmethylcyclosiloxane mixed liquid becomes the core layer (3) of the ridge waveguide after curing; The fifth step is to mix the tetrakis (trimethylsiloxy) silane solution with its supporting curing agent solution in a mass ratio of 10:1 to obtain a tetrakis (trimethylsiloxy) silane mixed solution; Methylsiloxy) silane mixture is placed in a closed container to evacuate, and then ultrasonic vibration is used to remove the bubbles in the tetrakis (trimethylsiloxy) silane mixture; The silyloxy) silane mixed solution is coated on the replica (2) filled with the phenylmethylcyclosiloxane mixed solution, and the tetrakis (trimethylsiloxy) silane and the replica (2) are heated together at 80 Bake for one hour at a temperature of °C to 90°C to cause the tetrakis(trimethylsiloxy)silane mixture to undergo a crosslinking reaction and solidify to form a tetrakis(trimethylsiloxy)silane film (4); In the sixth step, the replica (2) is peeled off from the tetrakis (trimethylsiloxy) silane film (4), and the tetrakis (trimethylsiloxy) silane film (4) forms the lower cladding layer (5) , the phenylmethyl cyclosiloxane left on the tetrakis (trimethylsiloxy) silane film (4) forms a core layer (3), and initially forms a ridge waveguide with air as the upper cladding; In the seventh step, the tetrakis (trimethylsiloxy) silane mixture is coated on the ridge waveguide with air as the upper cladding prepared in the sixth step, and the tetrakis (trimethylsiloxy) silane is mixed The liquid is solidified to form an upper cladding layer (6) of the polymer, and obtain a core layer (3) with phenylmethylcyclosiloxane, tetrakis (trimethylsiloxy) silane as an upper cladding layer (6) and a lower cladding layer (6). Ridge waveguide with cladding (5). 2. a kind of preparation method for the polysiloxane optical waveguide that is used for optical interconnection as claimed in claim 1, it is characterized in that when polyvinylidene fluoride solution is coated on the template (1) that has prepared Control the thickness of the polyvinylidene fluoride solution to be 1-1.5mm. 3. a kind of preparation method for the polysiloxane optical waveguide that is used for optical interconnection as claimed in claim 1, it is characterized in that the viscosity of described phenylmethylcyclosiloxane mixed liquid is 4,000mPa·s, refraction The rate is 1.543. 4. a kind of preparation method for the polysiloxane optical waveguide that is used for optical interconnection as claimed in claim 1, is characterized in that described tetrakis (trimethylsiloxy) silane mixed solution viscosity is 4,000mPa. s, the refractive index is 1.41. 5. a kind of preparation method for the polysiloxane optical waveguide that is used for optical interconnection as claimed in claim 1, it is characterized in that possibly residual The polyvinylidene fluoride was dissolved in acetone.

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