CN103178161A

CN103178161A - Method for fabricating micro-lens

Info

Publication number: CN103178161A
Application number: CN2013100918606A
Authority: CN
Inventors: 岳爱文; 胡艳; 李晶; 王权兵
Original assignee: Wuhan Telecommunication Devices Co Ltd
Current assignee: Wuhan Telecommunication Devices Co Ltd
Priority date: 2013-03-21
Filing date: 2013-03-21
Publication date: 2013-06-26
Anticipated expiration: 2033-03-21
Also published as: CN103178161B

Abstract

The invention discloses a method for fabricating a micro-lens. The method comprises the following steps of: A, covering the surface of a wafer (1) with a light-sensitive benzocyclobutene BCB coating (2) and putting the wafer (1) in nitrogen, and heating the wafer (1) at a temperature higher than 100 DEG C, so that the BCB coating (2) is softened and solidified; B, fabricating cylindrical BCB (3) on the surface of the wafer (1) through photoetching; and C, performing thermocuring treatment on the cylindrical BCB (3), and melting the cylindrical BCB (3) into a spherical shape to form a BCB lens (4). With the method provided by the invention, complex processing procedure in the traditional micro-lens fabricating method can be simplified and the fabrication cost can be reduced.

Description

A kind of lenticular manufacture method

Technical field

The present invention relates to chip manufacturing process, relate in particular to a kind of lenticular manufacture method.

Background technology

In the design of high-speed photodetector spare, in order to improve the operating rate of sensitive detection parts, need to reduce the active area of detector, in order to reduce the junction capacitance of device as far as possible.Therefore, in order to obtain up to the bandwidth more than 10GHz, usually need to be with the active area reduced below 30um, but require higher coupling precision less than the active area of 30um, be unfavorable for actual production.

Common way is directly lenticule to be integrated on chip, and integrated lenticule has reduced the coupling difficulty.At present, making lenticular method has following several:

1) reactive ion beam etching (RIBE).The method is to allow ion beam with certain angle etched wafer surface, and wafer is in autorotation simultaneously, because the density of an ion beam that receives on unit are is different, therefore, causes the difference of etching speed, combines and forms lens with the wafer rotation.The shortcoming of the method is complex manufacturing technology, and cost is high, and lens surface is coarse, easily forms the diffuse reflection of light and reduces coupling efficiency.

2) figure transfer method.The method is to produce the column photoresist by photoetching method, then heat under greater than the temperature conditions of 150 ℃, hemisphere of the melt and dissolved rear formation of photoresist, then corrode simultaneously photoresist and wafer in strengthening induction ion etching machine (ICP), photoetching offset plate figure is transferred to and is formed lenticule on wafer the most at last.As seen, the method need to be used expensive ICP equipment, and cost is expensive, and has the coarse problem of lens surface.

3) dotting glue method.The method is to adopt point gum machine periodic epoxy resin glue on wafer surface point, then makes the epoxy resin adhesive curing by heating or ultraviolet lighting.But there is following point in the method, for the device of back side sensitization, is difficult to accomplish that epoxy resin lenses accurately aims at active area.And epoxy resin lenses is difficult to withstand long term exposure higher than the high temperature more than 150 ℃, has integrity problem.

4) employing method 2) described figure transfer method is made the SiOx lens at chip surface.But exist growth thickness to reach the very difficult defective of several micron-sized SiOx film.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of lenticular manufacture method, utilize high temperature resistant (〉 250 ℃) new material benzocyclobutene (BCB) make lenticule, simplifying the complicated processing technique in traditional lenticule manufacture method, and reduce cost of manufacture.

For achieving the above object, technical scheme of the present invention is achieved in that

A kind of lenticular manufacture method comprises:

A, the benzocyclobutene BCB coating 2 of light sensitivity is coated on wafer 1 surface, and be placed in nitrogen, heat under greater than the condition of 100 ℃ Celsius, make described BCB coating 2 softcures;

B, then adopt photoetching process to make column BCB3 on described wafer 1 surface;

C, described column BCB3 is carried out hot curing process, described column BCB3 is melted into spherical formation BCB lens 4.

Wherein: the described BCB coating of heating is more than (2) 5 minutes in steps A.

The diameter of the BCB3 of column described in step B is 30um～50um.

In step C, described column BCB3 being carried out the process that hot curing processes comprises the steps:

C1, under 150 ℃ of conditions Celsius, heated 15 minutes;

C2, be warmed up to 250 ℃ Celsius in 15 minutes;

C3 and then under 250 ℃ of conditions Celsius the heating 60 minutes;

C4, temperature was elevated to 280 ℃ in 10 minutes;

C5, last keeps the temperature of 280 ℃ ~ 350 ℃ to heat 10 minutes, and is naturally cooling.

Further comprise: D, described wafer 1 is placed in chemical vapour deposition (CVD) PECVD machine, makes described BCB lens 4 superficial growth anti-reflection films 5 under greater than 250 ℃ of conditions Celsius.

Described anti-reflection film 5 is SiNx film or SiOx/SiNx composite membrane.

Lenticular manufacture method provided by the present invention has the following advantages:

Adopt the inventive method, only need by common photoetching process and heat curing process, benzocyclobutene (BCB) coating is carried out preliminary softcure and follow-up hot setting can form lenticule.Thereby reduced lenticular manufacture difficulty, avoided the complicated technology in traditional lenticule manufacturing process, and had advantages of that cost is low.In addition, because the BCB lens have good light transmission, surface and thermal stability, can be at the direct deposit anti-reflection film of lens surface or other deielectric-coating.The BCB lenticule Heat stability is good of making has improved device reliability.

Description of drawings

Fig. 1 is the schematic diagram of the embodiment of the present invention after wafer surface applies BCB;

Fig. 2 is the schematic diagram that embodiment of the present invention plane of crystal forms column BCB;

Fig. 3 is that column BCB shown in Figure 2 forms the view of BCB lens through hot curing;

Fig. 4 is the schematic diagram of BCB lens surface growth SiNx film in embodiments of the present invention.

[primary clustering symbol description]

1: wafer

The 2:BCB coating

3: column BCB

The 4:BCB lens

5: anti-reflection film.

Embodiment

Below in conjunction with accompanying drawing and embodiments of the invention, method of the present invention is described in further detail.

Fig. 1 is the schematic diagram of the embodiment of the present invention after wafer surface applies BCB.As shown in Figure 1, coat the benzocyclobutene that thickness is the light sensitivity of 10um～15um (BCB) coating 2 on the surface of wafer 1 by glue spreader.Then, described wafer 1 is placed in nitrogen, heats more than 5 minutes under greater than the condition of 100 ℃ Celsius, make BCB coating 2 softcures.

Fig. 2 is the schematic diagram that embodiment of the present invention plane of crystal forms column BCB.As shown in Figure 2, adopt photoetching process to stay on described wafer 1 surface the column BCB3 that diameter is 30um～50um.

Fig. 3 is that column BCB shown in Figure 2 forms the view of BCB lens through hot curing.Under nitrogen environment, described wafer 1 is solidified BCB according to following process:

Step 31: under 150 ℃ of conditions, heated 15 minutes;

Step 32: be warmed up to 250 ℃ in 15 minutes;

Step 33: and then heated 60 minutes under 250 ℃ of conditions;

Step 34: temperature was elevated to 280 ℃ in 10 minutes;

Step 35: keep the temperature of 280 ℃ ~ 350 ℃ to heat 10 minutes, then naturally cooling.

In said process, described column BCB3 is melted into spherical under surface tension effects, forms BCB lens 4, as shown in Figure 3.

Fig. 4 is the schematic diagram of BCB lens surface growth SiNx film in embodiments of the present invention.As shown in Figure 4, directly described wafer 1 is placed in chemical vapour deposition (CVD) (PECVD) machine, makes described BCB lens 4 superficial growth anti-reflection films 5 under greater than 250 ℃ of conditions Celsius.As grow SiNx film or growth SiOx/SiNx composite membrane.

Here, the benzocyclobutene of described light sensitivity (BCB) is the novel reactive resin of gang, both can form thermoplastic polymer, also can form thermosetting polymer, heat decomposition temperature is spent higher than 350, and has good light transmission in 1.3um～1.5um wave-length coverage.And hot curing rear surface planarization is good.Also can be under 250 ℃～300 ℃ conditions Celsius, at anti-reflection film or the growth SiOx/SiNx composite membrane of its surperficial direct growth SiNx.

The above is only preferred embodiment of the present invention, is not for limiting protection scope of the present invention.

Claims

1. a lenticular manufacture method, is characterized in that, comprising:

A, the benzocyclobutene BCB coating (2) of light sensitivity is coated on wafer (1) surface, and be placed in nitrogen, heat under greater than the condition of 100 ℃ Celsius, make described BCB coating (2) softcure;

B, then adopt photoetching process to make column BCB(3 on described wafer (1) surface);

C, to described column BCB(3) carry out hot curing and process, with described column BCB(3) be melted into spherical formation BCB lens (4).

2. lenticular manufacture method according to claim 1, is characterized in that, the described BCB coating of heating is more than (2) 5 minutes in steps A.

3. lenticular manufacture method according to claim 1, is characterized in that, the BCB(3 of column described in step B) diameter be 30um～50um.

4. lenticular manufacture method according to claim 1, is characterized in that, in step C to described column BCB(3) carry out the process that hot curing processes and comprise the steps:

C1, under 150 ℃ of conditions Celsius, heated 15 minutes;

C2, be warmed up to 250 ℃ Celsius in 15 minutes;

C3 and then under 250 ℃ of conditions Celsius the heating 60 minutes;

C4, temperature was elevated to 280 ℃ in 10 minutes;

5. according to claim 1 or 4 described lenticular manufacture methods, is characterized in that, further comprises:

D, described wafer (1) is placed in chemical vapour deposition (CVD) PECVD machine, makes described BCB lens (4) superficial growth anti-reflection films (5) under greater than 250 ℃ of conditions Celsius.

6. lenticular manufacture method according to claim 5, is characterized in that, described anti-reflection film (5) is SiNx film or SiOx/SiNx composite membrane.