JP2015088638A - Manufacturing method for composite substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a highly productive composite substrate.SOLUTION: A manufacturing method for a composite substrate comprises: a holding step in which a first substrate 10 formed from an insulation material is held on a first stage 103 and a second substrate 20 is held on a second stage 104; and a step in which the first substrate 10 and the second substrate 20 are joined in contact with each other. The method further comprises a conductive layer formation step in which a conductive layer 30 is formed on the principal surface of the first substrate 10, which is opposite the joined face of the first substrate 10, prior to the holding step. In the holding step, the first substrate 10 is held on the first stage 103 by an electrostatic chuck system.

Description

  The present invention relates to a method of manufacturing a composite substrate having a functional layer and a composite used for manufacturing a functional element such as a semiconductor element.

  In recent years, composite substrates in which two substrates are bonded have been developed. Such a composite substrate assumes that a functional element is formed on at least one substrate.

  As a method for bonding these substrates, for example, there is a technique described in Patent Document 1. In the technique described in Patent Document 1, substrates made of different materials are bonded to each other by applying pressure to each other through a metal intermediate layer between two substrates.

JP 2004-343359 A

  In the technique described in Patent Document 1, two substrates are joined in a vacuum apparatus in which a vacuum chuck cannot be used. However, since a substrate made of an insulating material cannot use an electrostatic chuck, the vacuum apparatus It could not be held inside, and was difficult to join.

  The present invention has been conceived under the above-described circumstances, and an object of the present invention is to provide a method for manufacturing a composite substrate that enables substrates to be bonded regardless of the materials of the substrates to be bonded.

  The method of manufacturing a composite substrate according to the present invention includes a holding step of holding a first substrate made of an insulating material on a first stage and holding a second substrate on a second stage, the first substrate, the second substrate, Including a step of forming a conductive layer on a main surface opposite to the bonding surface of the first substrate prior to the holding step. In the holding step, the first substrate is held on the first stage by an electrostatic chuck method.

  According to the present invention, a highly productive composite substrate can be provided.

1 is a schematic diagram of a room temperature bonding apparatus 100. FIG. (A)-(c) is sectional drawing which shows the manufacturing process of the manufacturing method which concerns on one embodiment of this invention, respectively.

An example of an embodiment of a method for producing a composite substrate of the present invention will be described with reference to the drawings. In the present embodiment, the first substrate 10 and the second substrate 20 are bonded by a bonding apparatus to obtain the composite substrate 1. As an example of the bonding apparatus, a case where a room temperature bonding apparatus 100 that can be brought into contact with each other after being activated and bonded at room temperature will be described. FIG. 1 is a schematic view of the room temperature bonding apparatus 100, and FIGS. 2A to 2C are cross-sectional views illustrating manufacturing steps of the method of manufacturing the composite substrate 1. FIG.

<Jointing device>
As shown in FIG. 1, the room temperature bonding apparatus 100 includes a vacuum chamber (vacuum vessel) 101, a neutron beam (FAB) gun 102, a first stage 103, a second stage 104, and a vacuum pump 105. An exhaust port 101 a connected to the vacuum pump 105 is formed in the vacuum chamber 101. The substrate holding surface 103a of the first stage 103 and the substrate holding surface 104a of the second stage 104 can be arranged to face each other. In this example, the substrate holding surface 103a of the first stage 103 is set downward and the substrate holding surface 104a of the second stage 104 is set upward. The first stage 103 and the second stage 104 are movable in the vacuum chamber 101 and have a position adjusting mechanism (not shown).

  In order to maintain the atmosphere in the vacuum chamber 101 at a high vacuum, generally, the vacuum chamber 101, the first stage 103, the second stage 104, and the position adjustment mechanisms of the first and second stages 103 and 104 are: It is often composed of a metal material such as SUS.

<Conductive layer formation process>
First, the first substrate 10 and the second substrate 20 are prepared. The first substrate 10 is made of a material made of an insulating material, and the second substrate 20 can be appropriately selected as a material capable of expressing the function required for the composite substrate 1 by combining with the first substrate 10. . Examples of the insulating material constituting the first substrate 10 include an aluminum oxide single crystal (sapphire), a silicon carbide substrate, a piezoelectric single crystal substrate, quartz, and a resin substrate. The material constituting the second substrate 20 is appropriately selected from a substrate made of an insulating material similar to the first substrate 10, a semiconductor substrate such as silicon (Si) and germanium (Ge), a substrate made of metal, and the like. Can do.

  Here, as shown in FIG. 2A, the conductive layer 30 is formed on the main surface 10 b opposite to the bonding surface 10 a of the first substrate 10. The conductive layer 30 is not particularly limited as long as it is a conductive material, and a metal such as gold (Au), platinum (Pt) or an alloy, or an oxide conductive material such as ITO (indium tin oxide) is appropriately selected. can do. Moreover, it is good also as a laminated structure of the several layer which consists of these materials.

  However, in order to suppress the entry of impurities into the bonding surface 10a, it is preferable to use a conductive layer made of an element of the material constituting the first substrate 10 and the second substrate 20. For example, when the first substrate 10 is sapphire and the second substrate 20 is a Si substrate, a material such as Al or Si may be selected as the conductive layer 30.

  The formation method of the conductive layer 30 is not particularly limited, and may be formed by a thin film formation method such as a vapor deposition method, or may be formed by applying a conductive material.

  Such a conductive layer 30 may be formed not only on the main surface 10b but also on at least a part of a surface (side surface) excluding the bonding surface 10a. In this case, it serves as a protective layer for the first substrate 10.

  The conductive layer 30 may not cover the entire main surface 10b. The conductive layer 30 may be partially exposed from the conductive layer 30 as long as the substrate can be fixed by the electrostatic chuck method described later. Further, it may be divided into a plurality of conductive layers 30.

<Holding process>
Next, as shown in FIG. 2B, the first substrate 10 is arranged such that the conductive layer 30 side is in contact with the substrate holding surface 103 a of the first stage 103 of the room temperature bonding apparatus 100, and the first stage 103. Similarly, the second substrate 20 is held on the substrate holding surface 104a of the second stage 104 of the room temperature bonding apparatus 100 with the bonding surface 20a facing upward.

  Here, the first substrate 10 is held on the first stage 103 by an electrostatic chuck method. Similarly to the first substrate 10, the second substrate 20 may be fixed by an electrostatic chuck method, or may be held by being placed on the second stage 104.

  In this example, the first stage 103 holds the first substrate 10 downward, but even if held in this way, the first substrate 10 can be held without dropping.

<Joint process>
Next, as shown in FIG. 2C, the first substrate 10 held on the first stage 103 and the second substrate 20 held on the second stage 104 are bonded.

  For joining the two, the joint surfaces 10a and 20a may be activated by irradiating with plasma, ion gun, FAB gun or the like and then brought into contact with each other. A layer that mediates the bonding may be interposed, and the bonding may be performed by applying stress or heating.

  In this example, the above-described room temperature bonding apparatus 100 is used to hold the first substrate 10 on the first stage 103 so that the bonding surface 10a is on the lower side and the bonding surface 20a on the second stage 104 to be on the upper side. Then, the second substrate 20 is held, and the bonding surfaces 10 a and 20 a are activated by the FAB gun 102.

  Then, the activated bonding surfaces 10a and 20a are brought into contact to bond the first substrate 10 and the second substrate 20 together. Here, in order to increase the contact area with the activated bonding surfaces 10a and 20a, it is preferable to make contact and pressurize. In addition, since this pressurization is intended only to increase the contact area, joining is possible with a smaller load than a joining method in which joining is performed only by pressurization without normal activation.

  In this way, the composite substrate 1 in which the first substrate 10 and the second substrate 20 are joined is obtained.

  By passing through such a process, even if the first substrate 10 is made of an insulating material, the provision of the conductive layer 30 enables reliable chucking by electrostatic attraction. In this example, both can be bonded in the room temperature bonding apparatus 100).

  Also, when the composite substrate 1 is obtained and then processed by another vacuum apparatus, the handling becomes easy, and the composite substrate 1 having high versatility can be provided. Examples of such processing include a process of forming a thin film, physically etching, or implanting a dopant into a semiconductor material with a CVD apparatus, a sputtering apparatus, or the like.

  In the above example, the case where the first stage 103 is positioned above the second stage 104 and the first substrate 10 is held downward has been described as an example. However, the first stage 103 and the second stage 104 are described. The positional relationship may be reversed. That is, the first stage 103 may be positioned on the lower side, and the substrate made of an insulating material may be held on the lower stage.

In that case, the substrate holding surface 103a of the first stage 103 is upward, but the first substrate 10 can be brought into contact with the second substrate 20 in a flat state with improved warping by an electrostatic chuck method. Since it can do, contact between joining surfaces becomes easy and it becomes possible to raise joint strength with few load.

  Further, since the stress can be applied to the first substrate 10 at the time of bonding, it is effective when it is desired to apply compressive stress to the first substrate 10 in the composite substrate 1 after bonding.

  Furthermore, in this example, the example in which the conductive layer 30 is formed only on the first substrate 10 has been described. However, when the second substrate 20 is made of an insulating material, the conductive layer is also formed on the second substrate 20. Also good.

  In this example, the first stage 103 and the second stage 104 are separated from each other in the vertical direction in the vacuum apparatus (the room temperature bonding apparatus 100 in the above example). The first stage 103 and the second stage 104 may be arranged apart from each other. In that case, the necessity for the conductive layer 30 increases more.

  In the above-described example, the conductive layer 30 has been described using a conductive material as an example. However, any material can be used as long as it is a material that enables electrostatic chucking.

1 .. Composite substrate 10 .. First substrate 20 .. Second substrate 30 .. Conductive layer

Claims (1)

A holding step of holding the first substrate made of an insulating material on the first stage and holding the second substrate on the second stage; and a step of bringing the first substrate and the second substrate into contact with each other. In a method for manufacturing a composite substrate including:
Prior to the holding step, including a conductive layer forming step of forming a conductive layer on the main surface opposite to the bonding surface of the first substrate,
A method of manufacturing a composite substrate, wherein in the holding step, the first substrate is held on the first stage by an electrostatic chuck method.

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