CN103193192A

CN103193192A - Method for isolating functional structure Si and sacrificial layer Si in bulk silicon machining

Info

Publication number: CN103193192A
Application number: CN2012100026784A
Authority: CN
Inventors: 刘瑞文; 焦斌斌; 孔延梅; 李志刚; 卢狄克; 陈大鹏
Original assignee: KUNSHAN MICROOPTICS ELECTRONIC CO Ltd
Current assignee: KUNSHAN MICROOPTICS ELECTRONIC CO Ltd
Priority date: 2012-01-06
Filing date: 2012-01-06
Publication date: 2013-07-10

Abstract

The invention discloses a method for isolating functional structure Si and sacrificial layer Si in bulk silicon machining. The method comprises the following steps: 1, taking an SOI silicon chip which sequentially comprises, from top to bottom, an upper silicon layer, a silicon oxide layer and a lower silicon layer, and manufacturing a device part on the upper silicon layer as needed for the utilization of a deep etching technology and an oxidizing technology of the functional structure Si to realize the isolation of the functional structure Si from the sacrificial layer Si; 2, depositing a masking layer on the surface of the lower silicon layer, etching away the needless masking layer to expose the lower silicon layer, and carrying out deep silicon etching of the exposed lower silicon layer until the silicon oxide layer is exposed; 3, etching away superfluous silicon on the upper silicon layer; and 4, etching away the silicon oxide layer exposed in step 2. The method allows the functional structure silicon to be completely surrounded, and the complete corrosion of the sacrificial layer Si and the complete reservation of the structure layer Si to be realized through utilizing the high selection ratio of the above two materials in corrosion release, and the technological difficulty of the method is substantially reduced, so the method is especially suitable for the large-scale production.

Description

The partition method that in the processing of body silicon, is used for the Si of functional structure Si and sacrifice layer

Technical field

The present invention relates to a kind of partition method that in the processing of body silicon, is used for the Si of functional structure Si and sacrifice layer.

Background technology

In the MEMS device, there is quite a few device need make cavity structure or directly with the substrate hollow out, implementation structure separates with substrate.For example, apply to core texture---the cantilever beam structures of new-type memory or measuring surface form instrument, the free standing structure film structure of acceleration transducer, shear force sensor, temperature sensor, the core devices of non-refrigerated infrared detector---infrared focal plane array etc.Such device is finished by silicon substrate surface micro-processing technology and the combination of body micro-processing technology usually, is conducive to large-scale production.But as the making of hanging structures such as cantilever beam, generally need to adopt the sacrifice layer release tech, and the sacrificial layer release process complexity can cause the adhesion of structure sheaf and substrate usually after the release, be head it off, a kind of method is for to make little tip in functional layer or substrate.Little tip is made through excessive erosion usually, and corrosion can cause the corrosion non-uniform phenomenon usually for a long time, causes the actual effect of partial function structure, is unfavorable for the making of big array; Utilize the high heat capacity thermal conductance characteristic of Si to improve the performance of device as heat sink structure as infrared focal plane array, but by increasing this structure, release to structure causes great difficulty, the corrosion release process is difficult to hold, the inhomogeneities of the long-time corrosion zone of causing just discharges and finishes on the other hand, corrosion is owed in the regional excessive erosion that has, the zone that has, and causes some regional performance off-design.Technology realizes very difficult, needs strict assurance, is unfavorable for the production of large scale array.

Summary of the invention

In order to overcome above-mentioned defective, the invention provides a kind of partition method that in the processing of body silicon, is used for the Si of functional structure Si and sacrifice layer, this method can make functional structure silicon be surrounded fully, corrosion utilizes the high selectivity of two kinds of materials when discharging, realized that Si as sacrifice layer is corroded fully and kept fully as the Si of structure sheaf, technology difficulty reduces greatly, especially is fit to manufacturing of big displayization.

The present invention for the technical scheme that solves its technical problem and adopt is: a kind of partition method that is used for the Si of functional structure Si and sacrifice layer in the processing of body silicon may further comprise the steps:

1. get soi wafer, this soi wafer is followed successively by upper silicon layer, silicon oxide layer and lower silicon layer from top to bottom, makes device portions on described upper silicon layer as required, and the Si that is used for functional structure utilizes deep etching technology to add the oxidation technology, realizes the isolation with sacrifice layer silicon;

2. deposit one deck masking layer on the surface of lower silicon layer, and unwanted masking layer etched away, expose lower silicon layer, begin to carry out the deep erosion of silicon on this lower silicon layer surface of exposing then, till etching into silicon oxide layer;

3. silicon etching unnecessary on the above-mentioned upper silicon layer is fallen;

4. the silicon oxide layer that above-mentioned steps is exposed in 2. etches away.

As a further improvement on the present invention, the material of described masking layer is one of photoresist, silica and aluminium.

The invention has the beneficial effects as follows: by SOI oxygen buried layer and deep trouth oxide layer, function Si and the Si that is used for sacrifice layer are isolated fully, when bulk silicon etching, play a very good protection; Solve long-time corrosion inhomogeneous problem when discharging, simplified the corrosion release process; The processing step of element manufacturing is simplified; Being highly suitable for large scale array makes.

Description of drawings

Fig. 1 is one of the method for the invention step structural representation;

Fig. 2 is two structural representations of the method for the invention step;

Fig. 3 is three structural representations of the method for the invention step;

Fig. 4 is four structural representations of the method for the invention step.

The specific embodiment

A kind of partition method that is used for the Si of functional structure Si and sacrifice layer in the processing of body silicon is characterized in that may further comprise the steps:

1. get soi wafer, this soi wafer is followed successively by upper silicon layer 1, silicon oxide layer 2 and lower silicon layer 3 from top to bottom, make device portions (as shown in Figure 1) on described upper silicon layer as required, the Si that is used for functional structure utilizes deep etching technology to add the oxidation technology, realizes the isolation with sacrifice layer silicon;

2. deposit one deck masking layer 4 on the surface of lower silicon layer, and unwanted masking layer etched away, expose lower silicon layer, begin to carry out the deep erosion of silicon on this lower silicon layer surface of exposing then, till etching into silicon oxide layer (as shown in Figure 2);

3. silicon etching unnecessary on the above-mentioned upper silicon layer is fallen (as shown in Figure 3);

4. the silicon oxide layer that above-mentioned steps is exposed in 2. etches away (as shown in Figure 4).

Preferably, the material of above-mentioned masking layer is one of photoresist, silica and aluminium.

Claims

1. partition method that is used for the S i of functional structure S i and sacrifice layer in body silicon processing is characterized in that may further comprise the steps:

1. get soi wafer, this soi wafer is followed successively by upper silicon layer (1), silicon oxide layer (2) and lower silicon layer (3) from top to bottom, makes device portions on described upper silicon layer as required;

2. deposit one deck masking layer (4) on the surface of lower silicon layer, and unwanted masking layer etched away, expose lower silicon layer, begin to carry out the deep erosion of silicon on this lower silicon layer surface of exposing then, till etching into silicon oxide layer;

2. the partition method that is used for the Si of functional structure Si and sacrifice layer in body silicon processing according to claim 1, it is characterized in that: the material of described masking layer is one of photoresist, silica and aluminium.