DE19653199A1 - Process for the production of a substrate with silicon on an insulator - Google Patents

Abstract

A method of fabricating a SOI substrate includes the steps of: providing a Si device substrate 20 and a handling substrate 25; forming an isolation film 23 in the Si device substrate; forming a first buried oxide film 24A on the Si device substrate including the isolation film; forming a second oxide film 24B on the handling substrate; bonding the device substrate to the handling substrate with surfaces of the buried oxide films in contact; and etching the device substrate 20 to form a Si device layer having a constant thickness. The isolation film 23 may be formed by oxidation of exposed portions of the device substrate uncovered by oxide and nitride layers, or by backfilling etched trenches with oxide.

Description

The present invention relates to a method for producing a substrate Silicon on a semiconductor ("SOI" substrate), and in particular a method for the manufacture thereof Position of an SOI substrate according to claim 1 with a Si device layer of a constant thickness.

In general, a manufacturing process for a complementary metal Oxide Semiconductor ("CMOS") transistor requires a large area separation region that is required to separate facilities and snap or open one To prevent CMOS transistor. However, there are problems by separating a separation area large area to a reduced or enlarged chip size and a reduced level of integration of the facilities.

The SOI technique has been proposed in view of the above problems. With the complete separation between devices prevents an SOI substrate from becoming a has buried insulating layer between an Si-handling substrate and a  Si device substrate is layered or received, the opening or opening of a CMOS transistor and enables high operating speed of the devices.

One of the manufacturing methods for the SOI substrate includes separation by Procedure with implanted oxygen ("SIMOX" procedure), in which oxygen ions are implanted in a Si substrate. However, the SIMOX process has a disadvantage in a surface of a Si layer is slightly moved, smeared or smeared, when oxygen ions are implanted, causing a large amount of leakage current becomes. Therefore, it is difficult to control the thickness of the Si layer when a device is to be trained.

Another available method of fabrication is a silicon bonding and etching back technique on an insulator ("BESOI" technique) in which a Si device substrate is bonded to a Si handling substrate with an insulating layer formed on each substrate , and the Si device substrate is then etched back to form a Si device layer. Referring to Fig. 3A, a Si-A are towards the substrate 1, and a handle substrate 2, in which a buried insulating layer 3 is formed, is provided. The buried insulating layer may be formed on either the device substrate 1 or the handling substrate 2 by oxidation.

Referring to Fig. 3B, the handle substrate 2 and the device substrate 1 with the occurring between the substrates 1 and 2 buried oxide film 3 are connected by fusion or fused. That is most of furnishing the substrate next 1 to a predetermined thickness by grinding and lapping etched or removed and is then chemically and mechanically polished to high precision to a degree, 1 A thereby forming a Si device layer. Referring to Fig. 3C, a release layer 4 in the Si device layer 1 A is formed to define an active region, thereby forming an SOI substrate 100.

The chemical and mechanical polishing method to form the Si layer 1 A unidirectional, it is difficult to control a stopping point for the polishing accurately, so that the thickness of the Si device layer 1 and A is not uniformly constant. Therefore, the yield of semiconductor devices is reduced.

In order to solve the above problem, an alternative BESOI method for producing an SOI substrate has been provided. Referring to FIG. 4A, a Si come device substrate 11 and a Si handle substrate 12 prior. On the Si-Einrichtungssub strat 11 , an etch stop layer 14 with many impurity ions and a Siliconein device layer 15 are each grown by epitaxial deposition. A buried insulating layer 13 is formed on the handling substrate 12 .

Referring to Fig. 4B, the device substrate 11 has been bonded to the handling substrate 12 and is then etched to a thickness of 20 to 50 µm by grinding and lapping. The remaining device substrate 11 and the etching stopper 14 are removed by a selective chemical and mechanical polishing process to form a Si device layer 15 having a constant thickness. Referring to FIG. 4C, a field oxide is formed on the Si device layer 15 16, to define an active region, thereby forming an SOI substrate 200.

As a result, the conventional BESOI technique can form a Si device layer 15 having a constant thickness to improve the yield. However, it has an after part in which a separate additional process is required to form the etch stop device 14 and the Si device layer 15 .

It is the object of the present invention to overcome the disadvantages of To remedy the state of the art at least partially.

It is an object of the present invention to provide a method for producing an SOI To provide substrate that forms a Si device layer that a con constant thickness.

Another object of the present invention is to provide a method to produce an SOI substrate that improves yield by using a silicon Device layer with a constant thickness is produced without an additional process.  

The tasks outlined above are at least partially accomplished by a process with the solved in claim 1 features. In the subclaims are procedural rens variants of a useful and advantageous type defined.

According to one embodiment, a method for producing an SOI substrate is provided, which has the following steps:
an Si device substrate and a handling substrate are provided;
a separation layer is formed in the Si device substrate;
a first buried oxide layer is formed on the Si device substrate that includes the separation layer;
a second oxide layer is formed on the handling or carrier substrate;
the Si device substrate and the handling substrate are bonded to contact or touch surfaces of the buried oxide layers; and
the device substrate is etched to form a Si device layer that has a uniform thickness.

In one embodiment, the step of forming the isolating layer comprises the following steps:
an oxide spot or region or a silicon nitride layer are in particular each formed on the Si device substrate; the oxide spot and the silicon nitride layer are patterned to expose a portion of the Si device substrate where the isolation layer is to be formed; the exposed portion of the Si device substrate is oxidized to form a field oxide as the isolation layer; and
the oxide spot or region and the silicon nitride are removed.

In another embodiment, the step of forming the separation or isolation layer comprises the following steps:
a photoresist pattern is formed on the device substrate to expose the portion of the device substrate in which the isolation layer is formed;
the exposed portion of the device substrate is etched to a predetermined thickness to form trenches;
the photoresist pattern or the photoresist structure is removed;
an oxide layer sufficient to fill the trenches over the device substrate is formed; and
the oxide layer is etched back or etched away in order to form the insulating or separating layer in the trenches.

In one embodiment, the Si device layer is formed by grinding, lapping and subsequent chemical and mechanical polishing of the device substrate is formed, until the separating or insulating layer is exposed.

In another embodiment, the Si device layer is made by grinding, lapping and then etching back or etching away the device substrate until the Isolation or separation layer is exposed.

The objects and features according to the invention are described with reference to the the following detailed description, which with closed claims and the The accompanying diagrams are easier to understand, in which:

FIGS. 1A to 1D are cross-sectional views showing a method for the manufacture of an SOI substrate constitute position according to an embodiment of the present invention;

Figs. 2A to 2C are cross-sectional views showing a method for Her position of an SOI substrate according to another exporting approximate shape representing the present invention;

Figs. 3A to 3C are cross-sectional views showing a method for Her position represent an SOI substrate according to a conventional BESOI technique; and

FIGS. 4A to 4C are cross-sectional views showing a method for Her position represent an SOI substrate according to an alternative ago conventional BESOI technique.

Referring to FIG. 1A, an embodiment of the present OF INVENTION be dung Si device substrate 20 and a handle substrate 25 are provided in accordance with. On the Si device substrate 20 , an oxide spot 21 and a silicon nitride layer 22 are each formed and then patterned to expose a portion of the device substrate 20 where a separation or isolation layer is to be formed .

Referring to FIG. 1B, a field oxide 23 is formed as the isolation or separation area on the exposed portion of the device substrate 20 by a thermal oxidation and oxide patches or region 21 and the silicon nitride layer 22 are then removed. Herein, the thickness "d" of the field oxide 23 , which is the depth of oxidation of the Si device substrate, is the same thickness as that of a Si device layer, and is preferably about 0.1 to about 0.5 µm.

Referring to Fig. 1C buried or covered oxide layers 24 A and 24 B to a predetermined thickness on the device substrate 20 and the handle lo bung substrate 25 is formed. The buried oxide layers 24 A and 24 B can both be formed one on each substrate. At this time, the buried oxide 24 A that is formed on the device layer 20 has a topology or geometry of the layer that results from the field oxide 23 . Therefore, the buried oxide is 24 A chemically and mechanically polished, will have to change the topology to remove, whereby a flat planar surface. Referring to FIG. 1D, the furnishing substrate 20 and the handling substrate 25 are connected to contact the surface of the buried oxide layer 24 A and the surface of the buried oxide layer 24 B. The device substrate 20 is etched to a predetermined thickness by grinding and ragging, and is then chemically and mechanically polished until the surface of the field oxide 23 is exposed, whereby the field oxide 23 is used as an etching stopper. An Si device layer 20 A is thus formed.

According to one embodiment, without a separate process or process step for forming an etching stop device, the Si layer 20 A is formed by an etching process using the field oxide 23 as an etching stop device. An SOI substrate 300 is therefore produced, which has:
a handling substrate 25 ; an insulation layer 24 , which consists of buried or cover th oxide layers 24 A and 24 B, or has these; and
the Si layer 20 A has a constant or uniform thickness without an additional process or process step.

Referring to Fig. 2A of another embodiment of the present invention, a Si device substrate 30 and a handle substrate 35 are provided in accordance with. A photoresist pattern (not shown) is formed on the device substrate 30 , which exposes a portion of the device substrate 30 where a trench T is to be formed.

Next, the exposed portion of the device substrate 30 is etched to a predetermined depth by an anisotropic etching method to form the trench T in which an isolation layer is to be formed. The depth of the trench or groove is preferably approximately 0.1 to approximately 0.5 μm. In addition, the thickness of the trench or groove T later determines the thickness of a Si device layer where a device is to be formed.

After the trench T has been formed, the photoresist or photoresist pattern is removed. The oxide layer 31 is formed over the device substrate 30 with a thickness sufficient to fill the trenches T.

Referring to FIG. 2B, the oxide layer 31 is etched back until the top surface of the device substrate 30 is exposed to form an isolation or separation layer 31 B, which is placed in the trenches T. Thermal oxidation forms above or on the device substrate 30 , which comprises the separating or insulating layer 31 B or the handling substrate 35 .

Referring to Fig. 2C, the device substrate 30 and the Handhabungssub be strat 35 is connected by a conventional connection method in which the surfaces of the buried oxide 32 A and 32 B are contacted with each other in contact respectively. Then, the device substrate 30 to a predetermined thickness by grinding and lapping etched or removed, and is then polished chemically and mechanically to the surface of the separation or insulation layer to release 31 B, 30 A thereby forming a Si device layer. Therefore, an SOI substrate 400 will contain:
the handling substrate 35 ;
an insulating layer 32 comprising the buried oxide layers 32 A and 32 B;
the Si layer 30 A, which has a constant or uniform thickness; and
the separation or insulation layer 31 B.

According to the embodiments, although the Si device layer is one, it is possible constant or uniform thickness and a flat surface, by grinding and Lapping and then chemical and mechanical polishing of a furnishing sub strates is formed, by grinding, lapping and subsequent back or Form etching away of the device substrate.

According to the present invention, an insulation layer is formed on the one directional substrate is formed before the joining process and the device substrate is etched using the isolating layer as an etching stopper. As a result, a Si device layer with a uniform thickness without an additional Chen process is formed to form an etching stopper, whereby the yield of Semiconductor devices is improved.

While this invention is described with reference to illustrative embodiments It is not intended to limit this description in a restrictive manner to interpret. Various modifications or changes to the illustrative embodiment shapes as well as other embodiments of the invention will become apparent to those skilled in the art of technology by reference to this description. It will therefore to be considered that the appended claims are any such Modifications or embodiments that cover the actual scope of the Invention fall.

A method for producing an SOI substrate is disclosed. The method comprises the following steps: an Si device substrate 20 and a handling substrate 25 are provided; an insulation film 31b is formed on the substrate Si setup; a first buried oxide layer 32 A is formed on the Si device substrate including the isolation layer; a second oxide layer 32 B is formed on the handling substrate; the device substrate and the handling substrate are bonded to contact or contact the surfaces of the buried or covered oxide layers; and the device substrate is etched to form a Si device layer that has a constant thickness.

Claims (12)

1. A method for producing a substrate with silicon on an insulator, comprising the following steps:
a Si device substrate ( 20 ) and a handling substrate ( 25 ) are provided;
an insulation layer ( 31 B) is formed on the Si device substrate; a first buried oxide layer is formed on the Si device substrate with the isolation layer;
a second buried oxide layer ( 32 B) is formed on the handling substrate;
the Si device substrate and the handling substrate are bonded to contact the surfaces of the first (32A) and the second (32B) buried oxide layers; and
the device substrate is etched to form a Si device layer with a constant thickness. 2. The method of claim 1, wherein the step of forming the isolation layer comprises the following steps:
an oxide spot and a silicon nitride layer are each formed on the device substrate;
the oxide patch and the silicon nitride layer are patterned to expose a portion of the device substrate in which to form the isolation layer;
the exposed portion of the device substrate is oxidized to form a field oxide as the isolation layer; and
the oxide spot or region and the silicon nitride layer are removed. 3. The method according to any one of claims 1 or 2, wherein the thickness of the Si device layers from an oxidation depth of the device substrate in the oxidation step hangs. 4. The method according to any one of claims 1 to 3, wherein the oxidation depth of the Si-Ein directional substrate in about 0.1 to about 0.5 microns. 5. The method according to any one of claims 1 to 4, wherein the step of forming the insulation layer comprises the following steps:
a resist pattern is formed on the device substrate to expose the portion of the device substrate where the isolation layer is to be formed;
the exposed portion of the device substrate is etched to a predetermined depth to form trenches;
the photoresist pattern or the photoresist layer is removed; an oxide layer sufficient to fill the trenches over the device substrate is formed; and
the oxide layer is etched back or etched away to form the isolation or separation layer in the trenches. 6. The method of claim 5, wherein the step of etching back the oxide layer is performed until the device substrate is exposed. 7. The method according to any one of claims 5 or 6, wherein the thickness of the Si device layer depends on the depth of the trench or groove. 8. The method of claim 7, wherein the depth of the trench or groove in about 0.1 to is about 0.5 µm.   9. The method according to any one of claims 1 to 8, wherein the step of forming the buried or covered oxide layers by thermal oxidation becomes. 10. The method according to any one of claims 1 to 9, wherein the step of etching the Device substrates by using the insulation layer as one Etching stop device is carried out. 11. The method according to any one of claims 1 to 10, wherein the Si device layer by Grinding and lapping the Si device substrate to a predetermined thickness and then chemically and mechanically polishing the Si device substrate is performed until the insulation or separation layer is exposed. 12. The method according to any one of claims 1 to 11, wherein the Si device layer by grinding and lapping the Si device substrate to a predetermined thickness and subsequent etching back or away of the Si device substrate is carried out, until the insulation or separation layer is exposed.