JP2002339079A - Wafer jig for plating - Google Patents

Abstract

(57) [Problem] To provide a wafer jig for plating that prevents electroless plating while preventing a treatment solution relating to plating from flowing around and preventing the influence of a ground effect. SOLUTION: The wafer jig for plating 10 includes a wafer WF.
A protective elastic member 11 which covers the entire periphery of the rear surface of the wafer WF in an electrically insulating relationship with the wafer WF; a wafer mounting plate 12 and an upper lid member 13 which are electrically insulated from the wafer WF;
And these detachable parts 14. A wafer WF on which a protective elastic member 11 is mounted is mounted on a wafer mounting plate 12.
Is arranged. The upper lid member 13 has a close contact portion 131 with the protective elastic member 11 along the peripheral edge of the wafer, and exposes the main surface area of the semiconductor wafer WF while holding the wafer mounting plate 12.
Is pressed from above, screws 141 are inserted into openings provided near the four corners, and tightened with fasteners (screw) 142.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of semiconductor devices, and more particularly, to a plating jig for forming a bump electrode by an electroless plating method.

[0002]

2. Description of the Related Art As the degree of integration of semiconductor integrated circuits increases and the size of semiconductor chips decreases, mounting technology that can support terminal connection at a fine pitch is required. As a mounting technology that can easily respond to this request, there is a TAB (Tape Automate Bonding) mounting used for a TCP (Tape Carrier Package) or the like.

In TAB mounting, lead terminals are connected to bump electrodes. The bump electrode is typically an Au bump, and is generally formed by an electrolytic plating method. A method for forming an Au bump electrode by an electrolytic plating method will be described below.

[0004] For example, an Al pad connected to an internal semiconductor element exposes the surface of an electrical connection region, and the periphery is covered with a passivation film. First, a barrier metal layer and a protective metal layer are stacked, that is, an under bump metal layer is formed by a sputtering method. Thereafter, a resist for bump formation is formed by exposing the electrical connection region of the Al pad and its peripheral portion by photolithography. next,
In accordance with the pattern of this resist, A
u is plated and grown. Thereafter, the under bump metal layer is wet-etched using the Au grown by plating after removing the resist as a mask (for the number of types of layers). Thereafter, an Au bump is formed through annealing or the like. A washing step is appropriately performed in each place.

[0005]

However, the process of forming a bump by the above-described electrolytic plating method is long, and further reduction and rationalization are required. Therefore, recently, formation of a bump electrode by an electroless plating method has been proposed.

The bump electrodes formed by the electroless plating method
Sputter formation and etching of the under bump metal layer can be omitted. Further, the omission of formation of a resist for plating growth can be expected. For these reasons, attention has been paid to the fact that the process can be significantly shortened, and the formation of a bump electrode that is inexpensive and has a short delivery time is realized.

In forming bump electrodes by electroless plating, a ground effect of a semiconductor wafer immersed in a plating solution becomes a problem. For example, when depositing a plating metal for a bump on an aluminum pad, the plating rate varies depending on the potential of the aluminum pad.

That is, the aluminum pad is connected to Si on the substrate with a contact resistance. The Si of the substrate is conducted to the plating solution, and when the electrons of the substrate are released into the plating solution, the electrical position of the aluminum pad moves.

The aluminum pad is subjected to a so-called zincate treatment as a pretreatment for plating, in which the surface of the pad is replaced with Zn. The zincate treatment is to immerse in a treatment liquid containing Zn ions and replace Zn by a reaction of 2Al + 3Zn ²⁺ → 2Al ³⁺ + 3Zn.

The substitution of Zn depends on the potential of the aluminum pad and affects the deposition of the plating metal later. In other words, the number of electrons for the chemical reaction decreases due to the influence of the ground effect. As a result, the ionized bond becomes inactive, and the substitution of Zn on the surface of the aluminum pad is not sufficient.

In order to prevent the influence of such a ground effect, measures have been proposed to apply a considerably large amount of resist to the back surface and peripheral portion of the wafer, or to use a wafer jig for covering the back surface and peripheral portion of the wafer. That is, measures are taken so that the processing solution relating to plating does not flow around the wafer periphery and the back surface.

However, in the former case, the resist is applied to the back surface of the wafer by chucking (vacuum suction) the main surface of the wafer, which is the bump forming surface, on a rotary table in a spin coater.
It will be implemented. Since the wafer main surface is brought into contact, the bump formation surface may be considerably damaged.
If even minute scratches are transferred on the bump formation surface, the plating growth during the subsequent bump electrode formation may not be normal.

Regarding the latter wafer jig, it has been considered to use the same configuration as that of a wafer jig that covers and fixes the back surface and peripheral portion of the wafer during electrolytic plating. However, the concern of the plating solution wrapping around the back surface of the wafer is still not solved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has an object to provide a plating wafer jig capable of preventing a treatment solution relating to plating from sneaking in and preventing an effect of a ground effect while enabling electroless plating. It is something to offer.

[0015]

A plating jig according to the present invention is electrically insulated from a semiconductor wafer.
A protective elastic member for covering one peripheral surface of the wafer and covering the entire back surface; a wafer mounting plate on which the wafer to which the protective elastic member is mounted is disposed; and an electrically insulating relationship with the wafer. An upper lid member having a contact portion with a protective elastic member along the wafer peripheral portion and exposing the wafer main surface region, and at least a processing solution relating to plating is prevented from sneaking around other than the exposed portion of the semiconductor wafer. A wafer mounting plate and an upper lid member are pressed down, and a plurality of attachment / detachment portions for holding the semiconductor wafer together with the protective elastic member are provided.

According to the wafer jig for plating according to the present invention, the function equivalent to that of the resist coating step on the back surface of the wafer and the vicinity of the periphery is achieved by the elastic member for protection and the clamping of the wafer mounting plate and the upper lid member. Given. Therefore, it is possible to eliminate the step of applying a resist to the back surface of the semiconductor wafer, which may damage the main surface side (that is, the bump formation surface) of the semiconductor wafer. That is, even if it is immersed in a processing solution for plating,
The vicinity of the wafer edge and the back surface are not exposed. This can prevent the effect of the ground effect.

Another plating wafer jig according to the present invention comprises:
A wafer mounting plate that is electrically insulated from the semiconductor wafer, a protective elastic member that is electrically insulated from the wafer, and that is arranged along the periphery of the wafer and is provided with compressed air therein; Electrically insulated from the wafer,
An upper lid member that is in close contact with the protective elastic member along the wafer peripheral portion to expose the wafer main surface region, and the wafer mounting plate so that at least a processing solution relating to plating does not flow to an exposed portion of the semiconductor wafer other than the exposed portion. And a plurality of attachment / detachment sections for holding down the upper lid member and holding the semiconductor wafer with pressure by the elastic member for protection.

According to the wafer jig for plating according to the present invention, the pressure by the protective elastic member and the holding of the wafer mounting plate and the upper lid member are provided. As a result, the intrusion of the plating solution into the back surface of the wafer is almost certainly prevented at the periphery of the wafer. Therefore, it is possible to eliminate the step of applying a resist to the back surface of the semiconductor wafer, which may damage the main surface side (that is, the bump formation surface) of the semiconductor wafer. That is, even when immersed in a processing solution for plating, the vicinity of the wafer edge and the back surface are not exposed. This can prevent the effect of the ground effect.

It is more preferable that the pressurized air pressure state of the protective elastic member can be confirmed or grasped, and a pressure gauge capable of detecting the pressurized air pressure state of the protective elastic member is further provided.

Further, an elastic member is further provided at a contact portion between the wafer mounting plate and the upper lid member. Further, a structure is provided in which the wafer mounting plate and the upper lid member are fitted to each other in a close contact portion. This allows
The adhesion between the wafer mounting plate and the upper lid member is increased.

[0021]

1 (a) and 1 (b) show the configuration of a plating wafer jig according to a first embodiment of the present invention, wherein (a) is an outline plan view and (b) () Is a sectional view taken along line 1B-1B in FIG.

The plating wafer jig 10 is electrically insulated from the semiconductor wafer WF, and covers the peripheral portion of the wafer WF so as to cover the entire rear surface. Placement plate 12 and upper lid member 1
3 and these detachable parts 14.

The protective elastic member 11 is a rubber-like seal packing having a bottom covering one peripheral surface of one wafer WF and covering the entire back surface. The wafer mounting plate 12 and the upper lid member 13 are formed of a hard resin plate (for example, a plate made of polytetrafluoroethylene, that is, Teflon (registered trademark)).

The protective elastic member 1 is provided on the wafer mounting plate 12.
The wafer WF on which the wafer 1 is mounted is arranged. Upper lid member 13
Has a contact portion 131 with the protective elastic member 11 along the wafer peripheral portion, and is configured to be pressed from above the wafer mounting plate 12 while exposing the main surface area of the semiconductor wafer WF.

The attachment / detachment section 14 has a configuration in which screws 141 are inserted into openings provided in the vicinity of the four corners of the wafer mounting plate 12 and fastened with fasteners (screw) 142. The wafer WF is held and fixed together with the protective elastic member 11. Each of the screws 141 and 142 uses a member made of polytetrafluoroethylene, that is, Teflon (registered trademark).

By tightening the screws 141 and 142,
The pressure on the protective elastic member 11 at the contact portion 131 increases. This prevents a processing solution relating to plating (a zincate processing solution, a plating solution, or the like) from flowing around the exposed portion of the main surface of the wafer WF.

The plating wafer jig 10 having the above-described structure is used.
Although not shown, a predetermined number is prepared, each of which is stored in a wafer carrier (basket). Then, although not shown, a zincate treatment (replacement of Zn on the pad surface) for immersion in a treatment solution containing Zn ions as a pretreatment of a plating process (not shown) for each wafer carrier, and a predetermined treatment accompanying the electroless plating treatment Immersion in a solution (plating solution) to form electroless plating bumps.

According to the configuration of the first embodiment, the plating wafer jig 10 has a function equivalent to that of the resist coating step on the back surface of the wafer and the vicinity of the peripheral portion, which was conventionally required before the plating step. Therefore, the semiconductor wafer WF
It is possible to eliminate the step of applying a resist to the back surface of the wafer, which may damage the main surface side (that is, the bump formation surface) of the wafer.

That is, since the protective elastic member 11 integrated with the back surface and the wafer mounting plate 12 and the upper lid member 13 are sandwiched from the peripheral portion of the wafer WF, the vicinity of the peripheral portion of the wafer and the rear surface even when immersed in a processing solution relating to plating. Is not exposed. Thus, the effect of the ground effect can be prevented.

FIGS. 2A and 2B show the configuration of a plating wafer jig according to a second embodiment of the present invention, wherein FIG. 2A is an outline plan view and FIG. ) 2B in the figure
It is sectional drawing which follows the -2B line.

The plating wafer jig 20 is provided along the periphery of the wafer WF in an electrically insulated relationship with the semiconductor wafer WF, and is provided with a protective elastic member 21 to which compressed air is applied inside.
It is composed of a wafer mounting plate 22 and an upper lid member 23, which are electrically insulated from the wafer WF, and an attachment / detachment portion 24 thereof.

The protective elastic member 21 is a tube having a compressed air supply section 211 for introducing air (or a specific gas) therein, for example, a donut-shaped polytetrafluoroethylene (Teflon (registered trademark)). It is rubber and has a size arranged near the periphery of the wafer WF. The wafer mounting plate 22 and the upper lid member 23 are made of a hard resin plate (for example, polytetrafluoroethylene (Teflon (registered trademark)).
Manufactured). Alternatively, although not shown, a metal plate made of stainless steel and subjected to insulation coating may be used.

The wafer WF is arranged on the wafer mounting plate 22. The upper lid member 23 has a contact portion 231 that also serves to position the protective elastic member 21 along the peripheral edge of the wafer, and is configured to be pressed from above the wafer mounting plate 22 while exposing the main surface area of the semiconductor wafer WF. .

The attachment / detachment section 24 has a structure in which screws 241 are inserted into openings provided near the four corners of the wafer mounting plate 22 and fastened with fasteners (screws) 242. The wafer WF is held and fixed together with the protective elastic member 11. Each of the screws 241 and 242 uses a member made of polytetrafluoroethylene, that is, Teflon (registered trademark).

By applying compressed air to the inside of the protective elastic member 21 and tightening the screws 241, 242, the pressure on the protective elastic member 21 at the contact portion 231 increases. This prevents a processing solution relating to plating (a zincate processing solution, a plating solution, or the like) from flowing around the exposed portion of the main surface of the wafer WF.

FIGS. 3 (a), 3 (b) and 3 (c) are schematic diagrams each showing an example of a compressed air supply mode for the protective elastic member 21 having the configuration of FIG. In FIG. 3A, the compressed air supply unit 211 tightens the wafer mounting plate 22 and the upper lid member 23 to some extent with screws 241, 242. Next, after air is introduced from the compressed air supply unit 211 and appropriate pressurization is performed on the peripheral portion of the wafer WF, the compressed air supply unit 211 is closed with a closing member 31 such as a valve or a cap. If necessary, screw 24
Further tightening may be performed at 1,242. In such a form, the pressure on the peripheral portion of the wafer WF by the protective elastic member 21 is increased, so that the processing solution relating to plating does not flow to the exposed portion of the main surface of the wafer WF.

In FIG. 3B, the compressed air supply unit 211
Are the screws 241 and 241 on the wafer mounting plate 22 and the upper lid member 23.
At 42, it is tightened to some extent. Next, the connection pipe 32 is attached to the compressed air supply unit 211, air is supplied from a compressed air supply source (not shown), and appropriate pressure is continuously applied to the peripheral portion of the wafer WF.

That is, appropriate pressurized air pressurization is maintained without closing the pressurized air supply unit 211 as shown in FIG. In such a form, the pressure applied to the peripheral portion of the wafer WF by the protective elastic member 21 is increased so that the processing solution relating to plating does not spill to portions other than the exposed portion of the main surface of the wafer WF.

In FIG. 3C, a pressure gauge 33 capable of detecting a pressurized air pressurized state is provided near the pressurized air supply unit 211. 3 (a) and 3 (b).
It can be added to any form. This allows
This makes it possible to always recognize and grasp whether an appropriate pressurization is applied to the peripheral portion of the wafer WF.

In addition, when adding to the form of FIG.
Instead of the configuration in which the pressure gauge 33 is provided in the vicinity of the compressed air supply unit 211, a configuration in which the pressure gauge 33 is provided in a shared portion of a compressed air supply source (not shown) may be employed.

The wafer jig 20 for plating shown in FIG. 2 employing one of the forms shown in FIGS. 3A to 3C.
Although not shown, a predetermined number is prepared, each of which is stored in a wafer carrier (basket). Then, although not shown, a zincate treatment (replacement of Zn on the pad surface) for immersion in a treatment solution containing Zn ions as a pretreatment of a plating process (not shown) for each wafer carrier, and a predetermined treatment accompanying the electroless plating treatment Immersion in a solution (plating solution) to form electroless plating bumps.

According to the configuration of the second embodiment, the same effect as the configuration of the first embodiment can be obtained. That is, the plating wafer jig 20 can omit the step of applying the resist to the back surface of the wafer and the vicinity of the peripheral portion, which has been required before the plating step.

The protective elastic member 21 for sealing the peripheral edge of the wafer WF using the compressed air and the holding of the wafer mounting plate 12 and the upper lid member 13 prevent the processing liquid relating to plating from entering the rear surface of the wafer. Is almost certainly blocked. Thus, the effect of the ground effect can be prevented.

FIG. 4 is a first modification showing the configuration of FIG. 2B as an example. Wafer mounting plate 22 and upper lid member 2
A resin-based elastic member 41 may be further provided at the close contact portion 3. Thereby, the adhesion between the wafer mounting plate 22 and the upper lid member 23 is further increased, and the intrusion of the processing solution relating to plating from between the wafer mounting plate 22 and the upper lid member 23 is further prevented.

FIG. 5 is a second modification showing the configuration of FIG. 2B as an example. Wafer mounting plate 22 and upper lid member 2
3, a resin-based elastic member 51 is further provided at the contact portion.
Further, a structure (fitting portion 52) that fits each other may be added. Thereby, the wafer mounting plate 22 and the upper lid member 23
The adhesion of the plating solution is further increased, and the intrusion of the processing solution relating to plating from between the wafer mounting plate 22 and the upper lid member 23 is further prevented. The addition of the configuration of the fitting portion 52 also contributes to the positioning of the wafer mounting plate 22 and the upper lid member 23. It should be noted that various other forms of the fitting portion 52 can be considered.

The configurations shown in FIGS. 4 and 5 may be added to the configuration shown in FIG. 1 of the first embodiment (not shown). Thereby, the adhesion between the wafer mounting plate 12 and the upper lid member 13 is further increased, which also contributes to protection from excessive tightening.

Note that the attachment / detachment portion between the wafer mounting plate and the upper lid member in each of the above embodiments is not limited to the configuration of the tightening screw like the attachment / detachment portions 13 and 23. It is sufficient that the wafer mounting plate and the upper lid member can be held so that the processing solution relating to plating does not sneak around other than the exposed portion of the wafer WF, and other fastening configurations are also conceivable.

[0048]

As described above, according to the present invention, it is possible to eliminate the step of applying a resist to the back surface of a semiconductor wafer, which has a risk of damaging the main surface side (ie, the bump forming surface) of the semiconductor wafer. By holding the semiconductor wafer and insulation-related wafer mounting plate and the upper lid member with the elastic member for protection,
The vicinity and the back surface of the wafer edge are not exposed to the processing solution relating to plating, and the adverse effect of the ground effect is not exerted. As a result, it is possible to provide a highly reliable plating wafer jig that prevents the treatment solution relating to the plating such as the plating solution from flowing around and prevents the effect of the ground effect while enabling the electroless plating.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) show a configuration of a plating wafer jig according to a first embodiment of the present invention, respectively.
(A) is an outline plan view, (b) is 1B-1B in (a) figure.
It is sectional drawing which follows a line.

FIGS. 2A and 2B show the configuration of a plating wafer jig according to a second embodiment of the present invention, respectively.
(A) is an outline plan view, (b) is 2B-2B in (a) figure.
It is sectional drawing which follows a line.

3 (a), 3 (b) and 3 (c) are schematic diagrams each showing an example of a compressed air supply mode for the protective elastic member having the configuration of FIG.

FIG. 4 is a cross-sectional view according to a first modification showing the configuration of FIG. 2B as an example.

FIG. 5 is a cross-sectional view according to a second modification showing the configuration of FIG. 2B as an example.

[Explanation of symbols]

 10, 20 ... Plating wafer jig 11,21 ... Protective elastic member 12,22 ... Wafer mounting plate 13,23 ... Top lid member 131,231 ... Adhesive part 14,24 ... Removable part 141,142,241,242 ... Screw 211 ... Compressed air supply unit 31 ... Closing member 32 ... Connection pipe 33 ... Pressure gauge 41,51 ... Elastic member 52 ... Mating part WF ... Semiconductor wafer

Claims (5)

[Claims] 1. A protective elastic member which is electrically insulated from a semiconductor wafer, covers a peripheral portion of one wafer and covers the entire back surface, and the wafer having the protective elastic member mounted thereon is disposed. A wafer mounting plate, an upper lid member electrically insulated from the wafer, having a contact portion with the protective elastic member along the wafer peripheral portion, and exposing the wafer main surface region; A plurality of attachment / detachment sections for pressing the wafer mounting plate and the upper lid member so that the processing liquid does not sneak around other than the exposed portion of the semiconductor wafer, and holding the semiconductor wafer together with the protective elastic member. A plating jig for plating. 2. A wafer mounting plate electrically insulated from a semiconductor wafer, and a protection plate electrically insulated from the wafer and arranged along a peripheral portion of the wafer and provided with compressed air therein. An elastic member, an upper insulating member that is electrically insulated from the wafer, is in close contact with the protective elastic member along the periphery of the wafer, and exposes the wafer main surface area, A plurality of attachment / detachment parts for holding down the wafer mounting plate and the upper lid member so as not to go around other than the exposed part of the wafer, and holding the semiconductor wafer with pressure by the protective elastic member,
A wafer jig for plating, comprising: 3. The wafer jig for plating according to claim 2, further comprising a pressure gauge capable of detecting a pressurized and pressurized state of said protective elastic member. 4. The plating jig according to claim 1, wherein an elastic member is further provided at a contact portion between the wafer mounting plate and the upper lid member. 5. The plating wafer jig according to claim 1, further comprising a structure that fits into a close contact portion between the wafer mounting plate and the upper lid member.