CN111446158A - Metal deposition process after wafer back cutting - Google Patents

Abstract

The invention discloses a metal deposition process after wafer backside cutting. The metal deposition process includes the following steps: primary metal deposition, bonding, thinning, photoresist coating, cutting, adhesive removal, secondary metal deposition, fixing, Debonding, cleaning. The metal deposition process of the present invention forms a first groove on the adhesive by cutting first, and during metal deposition, the metal between the crystal grains falls into the first groove, so that the metal will not affect the adjacent two crystal grains. The die forms adhesion, which replaces the traditional process of depositing metal first and then cutting, avoiding the adhesion of adjacent die by metal during cutting, resulting in wafer cracking, improving the yield of die, and reducing the production cost of die.

Description

A metal deposition process after wafer backside cutting

technical field

The invention relates to a metal deposition process, in particular to a metal deposition process after wafer backside cutting.

Background technique

In the production process of the die, the wafer cleaning, oxide deposition lithography layout, etching patterning, metal deposition and other processes are first completed. Metal deposition process, the current wafer production process is to first complete the wafer cleaning, oxide deposition lithography layout, etching patterning, metal deposition and other processes, and then bond the front side of the wafer to the glass carrier for crystallizing. The backside of the circle is thinned and cleaned by metal deposition and other processes before debonding. However, for wafers thinned to 20 microns to 80 microns, after the metal deposition process is completed, the die cutting process of the wafer is performed. Deposition, when cutting with external force, the shear stress that changes during cutting is easy to crack the wafer, and the die cannot be reworked and is scrapped and damaged.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a metal deposition process after cutting the back of the wafer. By cutting first, a first groove is formed on the adhesive, and during metal deposition, the metal between the crystal grains falls into the first groove. , so that the metal will not form adhesion to the two adjacent dies, which replaces the traditional process of depositing metal first and then cutting, preventing adjacent dies from being adhered by metal during cutting, resulting in wafer cracking and improving the quality of the die. higher yield and lower die production cost.

The object of the present invention can be realized through the following technical solutions:

A metal deposition process after wafer backside cutting, the metal deposition process comprises the following steps:

S1: One Metal Deposition

Metal deposition is performed on the front side of the wafer to form a first deposition layer on the wafer.

S2: Bonding

The front side of the wafer is bonded to a glass carrier, which is provided with adhesive.

S3: Thinning

The backside of the wafer is thinned.

S4: Photoresist Coating

A photoresist coating is performed on the backside of the die, a photoresist coating layer is formed on the die, the die on the front side of the wafer is shielded, and the dicing lines are exposed by exposure and development.

S5: Cutting

The cutting lines between the dies on the wafer are etched and cut to complete the dicing of the dies, and the adjacent dies do not touch after dicing.

S6: Adhesive Removal

An oxygen plasma is used to anisotropically etch the adhesive between the die to form a first groove on the adhesive, and the oxygen plasma simultaneously removes the photoresist coating layer.

S7: Secondary metal deposition

A sputtering machine/evaporator is used to deposit metal on the backside of the crystal grains, and a second deposition layer is formed on the backside of the crystal grains. The directionality/selectivity of the metal deposition is that the metal falls into the first groove so that it falls into the first groove. The metal in the groove is not in contact with the die.

S8: Fixed

Fix the thinned side of the die on the film frame.

S9: Debonding

By laser, the die is detached from the glass carrier.

S10: Clean up

The residue on the front side of the die is cleaned, the die is separated and fixed on the film frame.

Further, the adhesive in S2 adheres the wafer to the glass carrier.

Further, the thickness of the S3 thinning is smaller than the thickness of the wafer.

Further, in the step S5, fluorine-containing plasma is used to etch the wafer.

Further, the cross section of the first groove in S6 is a flat cup-shaped structure.

Further, prior to the anisotropic etching in S6, oxygen plasma is used to isotropically etch the adhesive between the crystal grains to form a second groove on the adhesive.

Further, after the anisotropic etching in S6, oxygen plasma is used to isotropically etch the adhesive between the crystal grains to form a second groove at the bottom of the first groove.

Further, it is characterized in that the depth of the second groove is greater than the depth of the first groove.

Further, it is characterized in that the width of the first groove is greater than the width of the second groove.

Beneficial effects of the present invention:

1. The metal deposition of the present invention forms grooves on the adhesive by cutting first. During metal deposition, the metal between the crystal grains falls into the groove, so that the metal will not form adhesion to two adjacent crystal grains. ;

2. The metal deposition of the present invention replaces the traditional process of depositing metal first and then cutting, avoiding the adhesion of adjacent crystal grains by metal during cutting, causing wafer cracking, improving the yield of crystal grains, and reducing the production cost of crystal grains .

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

1 is a schematic diagram of a primary metal deposition structure of the present invention;

Fig. 2 is the bonding structure schematic diagram of the present invention;

Fig. 3 is the thinning structure schematic diagram of the present invention;

Fig. 4 is the photoresist coating structure schematic diagram of the present invention;

Fig. 5 is the cutting structure schematic diagram of the present invention;

6 is a schematic diagram of the adhesive removal structure of the present invention;

Fig. 7 is the enlarged structure schematic diagram of A place in Fig. 6 of the present invention;

8 is a schematic diagram of the adhesive removal structure of the present invention;

Fig. 9 is the enlarged structural schematic diagram at B in Fig. 8 of the present invention;

10 is a schematic diagram of the secondary metal deposition structure of the present invention;

11 is a schematic diagram of the fixed structure of the present invention;

Figure 12 is a schematic diagram of the debonding structure of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

A metal deposition process after wafer backside cutting, the metal deposition process comprises the following steps:

S1: One Metal Deposition

Metal deposition is performed on the front surface of the wafer 1 , as shown in FIG. 1 , a first deposition layer 2 is formed on the wafer 1 .

S2: Bonding

The front side of the wafer 1 is bonded to the glass carrier 4, as shown in FIG. 2, the glass carrier 4 is provided with an adhesive 3, and the adhesive 3 adheres the wafer 1 to the glass carrier by UV bonding 4 on.

S3: Thinning

The backside of the wafer 1 is thinned. As shown in FIG. 3 , the thinned thickness is smaller than the thickness of the wafer 1 .

S4: Photoresist Coating

A photoresist coating is performed on the backside of the die 6. As shown in FIG. 4, a photoresist coating layer 5 is formed on the die 6 to shield the die 6 on the front side of the wafer 1, and is exposed and developed to expose the dicing lines.

S5: Cutting

The cutting lines between the die 6 on the wafer 1 are cut by etching with fluorine-containing plasma. As shown in FIG. 5 , the die cutting is completed, and the adjacent die 6 are not in contact after cutting.

S6: Adhesive Removal

The adhesive 3 between the crystal grains 6 is anisotropically etched by oxygen plasma, and a first groove 7 is formed on the adhesive 3. The cross-section of the first groove 7 is a flat cup-shaped structure, such as As shown in FIG. 6 and FIG. 7 , the photoresist coating layer 5 is simultaneously removed by oxygen plasma.

S7: Secondary metal deposition

A sputtering machine/evaporator is used to deposit metal on the backside of the crystal grains 6, and a second deposition layer 9 is formed on the backside of the crystal grains 6. The directionality/selectivity of the metal deposition, the metal falls into the first groove 7, As shown in FIG. 10 , the metal falling into the first groove 7 is kept out of contact with the crystal grains 6 .

S8: Fixed

The thinned surface of the die 6 is fixed on the film frame 10 , as shown in FIG. 11 .

S9: Debonding

The die 6 is detached from the glass carrier 4 by laser, as shown in FIG. 12 .

S10: Clean up

The residue on the front surface of the die 6 is cleaned, and the die 6 is separated and fixed on the film frame 10 .

Example 2

A metal deposition process after wafer backside cutting, the metal deposition process comprises the following steps:

S1: One Metal Deposition

Metal deposition is performed on the front surface of the wafer 1 , as shown in FIG. 1 , a first deposition layer 2 is formed on the wafer 1 .

S2: Bonding

The front side of the wafer 1 is bonded to the glass carrier 4, as shown in FIG. 2, the glass carrier 4 is provided with an adhesive 3, and the adhesive 3 adheres the wafer 1 to the glass carrier by UV bonding 4 on.

S3: Thinning

The backside of the wafer 1 is thinned. As shown in FIG. 3 , the thinned thickness is smaller than the thickness of the wafer 1 .

S4: Photoresist Coating

A photoresist coating is performed on the backside of the die 6. As shown in FIG. 4, a photoresist coating layer 5 is formed on the die 6 to shield the die 6 on the front side of the wafer 1, and is exposed and developed to expose the dicing lines.

S5: Cutting

The cutting lines between the die 6 on the wafer 1 are cut by etching with fluorine-containing plasma. As shown in FIG. 5 , the die cutting is completed, and the adjacent die 6 are not in contact after cutting.

S6: Adhesive Removal

First, an oxygen plasma is used to anisotropically etch the adhesive 3 between the crystal grains 6, and a first groove 7 is formed on the adhesive 3. The cross-section of the first groove 7 is a flat cup-shaped structure, As shown in FIG. 6 , FIG. 7 , FIG. 8 , and FIG. 9 , oxygen plasma is used to isotropically etch the adhesive 3 between the crystal grains 6 to form a second groove at the bottom of the first groove 7 8. The depth of the second groove 8 is greater than the depth of the first groove 7 , the width of the first groove 7 is greater than the width of the second groove 8 , and the photoresist coating layer 5 is simultaneously removed by the oxygen plasma.

S7: Secondary metal deposition

A sputtering machine/evaporator is used to deposit metal on the backside of the crystal grains 6, and a second deposition layer 9 is formed on the backside of the crystal grains 6. The directionality/selectivity of the metal deposition, the metal falls into the first groove 7, As shown in FIG. 10 , the metal falling into the first groove 7 is kept out of contact with the crystal grains 6 .

S8: Fixed

The thinned surface of the die 6 is fixed on the film frame 10 , as shown in FIG. 11 .

S9: Debonding

The die 6 is detached from the glass carrier 4 by laser, as shown in FIG. 12 .

S10: Clean up

The residue on the front surface of the die 6 is cleaned, and the die 6 is separated and fixed on the film frame 10 .

Example 3

A metal deposition process after wafer backside cutting, the metal deposition process comprises the following steps:

S1: One Metal Deposition

Metal deposition is performed on the front surface of the wafer 1 , as shown in FIG. 1 , a first deposition layer 2 is formed on the wafer 1 .

S2: Bonding

The front side of the wafer 1 is bonded to the glass carrier plate 4. As shown in FIG. 2, the glass carrier plate 4 is provided with an adhesive 3, and the adhesive 3 adheres the wafer 1 to the glass carrier plate by heating and bonding. 4 on.

S3: Thinning

The backside of the wafer 1 is thinned. As shown in FIG. 3 , the thinned thickness is smaller than the thickness of the wafer 1 .

S4: Photoresist Coating

A photoresist coating is performed on the backside of the die 6. As shown in FIG. 4, a photoresist coating layer 5 is formed on the die 6 to shield the die 6 on the front side of the wafer 1, and is exposed and developed to expose the dicing lines.

S5: Cutting

The cutting lines between the die 6 on the wafer 1 are cut by etching with fluorine-containing plasma. As shown in FIG. 5 , the die cutting is completed, and the adjacent die 6 are not in contact after cutting.

S6: Adhesive Removal

First, the adhesive 3 between the crystal grains 6 is isotropically etched by oxygen plasma, and a second groove 8 is formed on the adhesive 3, as shown in FIG. 6 , FIG. 7 , FIG. 8 , and FIG. 9 . , and then use oxygen plasma to anisotropically etch the adhesive 3 between the crystal grains 6 to form a first groove 7 on the adhesive 3, and the second groove 8 is located at the bottom of the first groove 7 The depth of the second groove 8 is greater than the depth of the first groove 7 , the width of the first groove 7 is greater than the width of the second groove 8 , and the oxygen plasma simultaneously removes the photoresist coating layer 5 .

S7: Secondary metal deposition

A sputtering machine/evaporator is used to deposit metal on the backside of the crystal grains 6, and a second deposition layer 9 is formed on the backside of the crystal grains 6. The directionality/selectivity of the metal deposition, the metal falls into the first groove 7, As shown in FIG. 10 , the metal falling into the first groove 7 is kept out of contact with the crystal grains 6 .

S8: Fixed

The thinned surface of the die 6 is fixed on the film frame 10 , as shown in FIG. 11 .

S9: Debonding

The crystal grains 6 are detached from the glass carrier plate 4 by heating, as shown in FIG. 12 .

S10: Clean up

The residue on the front surface of the die 6 is cleaned, and the die 6 is separated and fixed on the film frame 10 .

In the description of this specification, description with reference to the terms "one embodiment," "example," "specific example," etc. means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one aspect of the present invention. in one embodiment or example. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention.

Claims (10)

1. a metal deposition process after cutting the back of the wafer, is characterized in that, the metal deposition process comprises the following steps: S1: One Metal Deposition Metal deposition is performed on the front surface of the wafer (1), and a first deposition layer (2) is formed on the wafer (1); S2: Bonding bonding the front side of the wafer (1) on a glass carrier plate (4), and the glass carrier plate (4) is provided with an adhesive (3); S3: Thinning thinning the backside of the wafer (1); S4: Photoresist Coating A photoresist coating is performed on the backside of the die (6), a photoresist coating layer (5) is formed on the die (6), the die (6) on the front side of the wafer (1) is shielded, exposed and developed to expose the Cutting line; S5: Cutting The cutting lines between the die (6) on the wafer (1) are etched and cut to complete the die cutting, and the adjacent die (6) are not in contact after cutting; S6: Adhesive Removal The adhesive (3) between the crystal grains (6) is anisotropically etched by oxygen plasma, a first groove (7) is formed on the adhesive (3), and the photoresist coating layer is simultaneously removed by the oxygen plasma (5); S7: Secondary metal deposition Metal deposition is carried out on the backside of the crystal grains (6) using a sputtering machine/evaporator, and a second deposition layer (9) is formed on the backside of the crystal grains (6). In a groove (7), the metal falling into the first groove (7) is not in contact with the crystal grain (6); S8: Fixed fixing the thinned surface of the die (6) on the film frame (10); S9: Debonding Debonding the crystal grains (6) from the glass carrier plate (4) by debonding; S10: Clean up The residue on the front surface of the die (6) is cleaned, the die (6) is separated and fixed on the film frame (10). 2. metal deposition process after a kind of wafer back cutting according to claim 1, is characterized in that, in described S2, adhesive (3) adheres wafer 1 on glass carrier by heating bonding/UV bonding The wafer ( 1 ) is adhered to the glass carrier plate ( 4 ) on the plate 4 . 3. The metal deposition process after cutting the back of the wafer according to claim 1, wherein the thickness of the thinned S3 is smaller than the thickness of the wafer (1). 4. The metal deposition process after cutting the back side of the wafer according to claim 1, wherein the wafer (1) is etched by using a fluorine-containing plasma in the S5. 5 . The metal deposition process after wafer backside cutting according to claim 1 , wherein the cross section of the first groove ( 7 ) in the S6 is a flat cup-shaped structure. 6 . 6. metal deposition process after a kind of wafer back cutting according to claim 1, is characterized in that, before the anisotropic etching in described S6, adopts oxygen plasma isotropic etching between the stickiness between crystal grains (6) The mixture (3) is formed, and a second groove (8) is formed on the adhesive (3). 7. metal deposition process after a kind of wafer back cutting according to claim 1, is characterized in that, adopts oxygen plasma isotropic etching between crystal grains (6) after the anisotropic etching in described S6 The mixture (3) is formed, and a second groove (8) is formed at the bottom of the first groove (7). 8. The metal deposition process after wafer back cutting according to any one of claims 6-7, wherein the depth of the second groove (8) is greater than the depth of the first groove (7) depth. 9. The metal deposition process after wafer back cutting according to any one of claims 6-7, wherein the width of the first groove (7) is greater than the width of the second groove (8) width. 10 . The metal deposition process after wafer backside cutting according to claim 1 , wherein debonding is performed by means of laser/heating in the S9 . 11 .

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