CN104409582A - LED (light-emitting diode) wafer pasting method - Google Patents

Abstract

The present invention is applicable to the field of LED production, and provides a method for bonding LED wafers, comprising: placing wax on a ceramic plate, and keeping the wax in a liquid state by heating; placing the wafer regularly on a surface covered with liquid wax On a ceramic plate; cover the wafer with wax-absorbing paper; carry out the pressing operation, and remove the wax-absorbing paper after the wax solidifies. By setting the wax-absorbing paper before the chip pressing operation, the extra operation of manual wax scraping in the prior art is avoided, the labor cost is reduced, and the efficiency of the wafer bonding process during the wafer grinding process is improved.

Description

A method for bonding LED wafers

technical field

The invention belongs to the field of LED production, in particular to a method for bonding LED wafers.

Background technique

The semiconductor LED manufacturing process in the prior art usually includes: after the wafer front-end process is completed, the wafer needs to be thinned. According to the different requirements of different LED products for the wafer, it is thinned to different thicknesses to ensure that the thickness of the wafer is Meet the requirements to carry out the subsequent splitting process. Among them, the thinning process includes wafer bonding, rough grinding, polishing, cleaning and wafer loading operations.

In the traditional LED manufacturing process, wax paper is used for wafer bonding. However, on the one hand, due to the cleanliness and uniformity of the wax paper, it is easy to cause dark cracks and large wafer errors after wafer bonding; on the other hand, manual labor is required. Wax scraping increases production costs and reduces production efficiency.

Contents of the invention

The purpose of the embodiments of the present invention is to provide a method for bonding LED wafers to solve the problems in the prior art that manual wax scraping is required, which increases production costs and reduces production efficiency.

On the one hand, an embodiment of the present invention provides a method for bonding LED wafers, the method comprising the following steps:

Place the wax on a ceramic plate, and keep the wax in a liquid state by heating; place the wafer regularly on the ceramic plate covered with liquid wax; cover the wafer with wax-absorbing paper; carry out the pressing operation, and wait for the wax to solidify Remove the wax paper.

On the other hand, the beneficial effects of a method for bonding LED wafers provided by the embodiments of the present invention include: placing the wax on a ceramic plate, and keeping the wax in a liquid state by heating; wax on the ceramic plate; cover the surface of the sheeting plate with wax-absorbing paper; carry out the tableting operation, and remove the wax-absorbing paper after the wax solidifies.

In the embodiment of the present invention, wax-absorbing paper is provided before the chip pressing operation, thereby avoiding the additional operation of manually scraping wax in the prior art, reducing labor costs, and improving the efficiency of the wafer bonding process during the wafer grinding process.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings that need to be used in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only the drawings of the present invention. For some embodiments, those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is a flow chart of a method for bonding LED wafers provided by an embodiment of the present invention;

2 is a flow chart of a method for bonding LED wafers according to an embodiment of the present invention;

3 is a flow chart of a method for bonding LED wafers according to an embodiment of the present invention;

FIG. 4 is a top view of a ceramic disc with discrete wafers laid out according to an embodiment of the present invention;

Fig. 5 is a side view of a tabletting operation provided by an embodiment of the present invention;

Fig. 6 is a side view of a tabletting operation provided by an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Embodiment one

As shown in Figure 1, it is a flow chart of a method for bonding LED wafers provided by the present invention, said method comprising the following steps:

In step 202, wax is placed on a ceramic dish and heated to keep the wax in a liquid state.

Wherein, when using the method of setting wax paper in the prior art, a layer of wax paper can be placed between the wax and the ceramic plate, as shown in FIG. 5 .

Wherein, when the wax paper in the prior art is not used, the wax will be inspected for quality when purchased to confirm that it does not contain impurities that may cause the surface of the wafer to wear.

In a specific implementation, the wax can be placed on the ceramic disc by pouring or spraying.

In step 204, the wafers are regularly placed on a ceramic plate covered with liquid wax.

Usually, a vacuum chuck is used to suck the wafer onto the ceramic plate. Of course, it can also be realized by using the mechanical arm based on drag and drop. It is also possible to use a mould, first place the wafer on the corresponding mould, and then move them to the ceramic disc together. The above-mentioned several ways are just examples, and other ways of placing wafers also belong to the protection scope of the present invention.

In step 206, wax-blotting paper is covered on the wafer.

The wax-absorbing paper can be the filter paper used in daily experiments, or the dust-free paper imported from abroad, or other materials with better wax-absorbing effect.

In step 208, the sheet pressing operation is performed, and the wax-absorbing paper is removed after the wax solidifies.

The tablet pressing operation makes the wafer stick to the ceramic plate smoothly and stably, and the solidified wax can fix the wafer so that it does not move left and right. The layered effect diagram is shown in Figure 6.

In a specific implementation, the wafer on the ceramic disc is usually pressed by a pressing disc, and after tens of seconds, the heating of the wax on the ceramic disc is gradually stopped, so that the wax on the ceramic disc is solidified.

In the embodiment of the present invention, wax-absorbing paper is provided before the chip pressing operation, thereby avoiding the additional operation of manually scraping wax in the prior art, reducing labor costs, and improving the efficiency of the wafer bonding process during the wafer grinding process.

What needs to be added is that if the existing technology involves placing wax paper before placing the wafer, due to the elasticity of the wax paper itself, the staff may cause the existence of air between the wax paper and the ceramic disc when placing it, thus affecting the subsequent pressing operation. cause potential risks. For example, if the existing technology involves placing wax paper before placing the wafer, since the air generated between the wax paper and the ceramic plate cannot escape during the placement process, it is difficult to spread the wax paper and eventually affect the thickness of the wafer. negative effect.

Embodiment two

As shown in Figure 2, it is a flow chart of a method for bonding LED wafers provided by the embodiment of the present invention. Compared with Embodiment 1, it adds a wax filtration process. As can be seen from Figure 2, the method provided by the present invention An embodiment of a method for LED wafer bonding includes:

In step 201, the wax is filtered and purified, so that there are no impurities in the treated wax that may cause abrasion on the surface of the wafer.

In step 202, wax is placed on a ceramic dish and heated to keep the wax in a liquid state.

In step 204, the wafers are regularly placed on a ceramic plate covered with liquid wax.

In step 206, wax-blotting paper is covered on the wafer.

In step 208, the sheet pressing operation is performed, and the wax-absorbing paper is removed after the wax solidifies.

The tablet pressing operation makes the wafer stick to the ceramic plate smoothly and stably, and the solidified wax can fix the wafer so that it does not move left and right. The layered effect diagram is shown in Figure 6.

In the embodiment of the present invention, due to the addition of wax filtration and purification treatment, it compensates for the scratches and wear on the surface of the wafer during the tableting operation due to impurities between the wafer and the ceramic disk after removing the wax paper protective layer in the prior art . Further, it is also possible to avoid the existence of wax paper, because of the problem of the density and quality of the wax paper, it is impossible to realize the smooth and stable fixing of the wafer on the ceramic plate in the wafer pressing operation.

In addition to the content already disclosed in Embodiment 1 and Embodiment 2, there is an improved solution based on the above embodiment, which specifically includes: when the wafer is discretely placed on a ceramic plate, the wax-blotting paper is covered on the wafer Before the circle above also includes:

According to the cross-sectional area of the wafer to be polished, the wax-absorbing properties of the wax-absorbing paper, the area of the ceramic plate, and the amount of wax placed on the ceramic plate, calculate the size of the wax paper covering a single wafer, and cut out the wax paper according to this size. One or more wax-blotting papers covered on the wafer, and the cut-out wax-blotting papers are covered on each wafer.

This improvement scheme takes into account the size of the surface of the ceramic disk itself in the cross section of the wafer to be ground, so that the amount of liquid wax remaining on the surface of the ceramic disk after the wafer is placed in step 204 can be calculated, and further based on the wax-absorbing characteristics of the wax-absorbing paper. A wafer is used to absorb the blotting paper area required for the liquid wax around it, so that a custom-sized blotting paper is cut out for the wafer. The improved method reduces waste of wax-absorbing paper and saves production cost.

Embodiment Three

As shown in Figure 3, it is a flow chart of a LED wafer bonding method provided by the embodiment of the present invention. This method can be considered as an improvement of Embodiment 1 or Embodiment 2. For the description of the same execution steps, refer to the embodiment Embodiment 1 and Embodiment 2 will not be repeated here. As can be seen from FIG. 3, an embodiment of a method for bonding LED wafers provided by the present invention includes:

In step 302, wax is placed on a ceramic dish and heated to keep the wax in a liquid state.

In step 304, the wafers are regularly placed on a ceramic plate covered with liquid wax.

In step 306, wax-absorbing paper is covered on the surface of the tablet disc.

In step 308, the sheet pressing operation is performed, and the wax-absorbing paper is removed after the wax solidifies.

In the third embodiment of the present invention, it is further considered that when the wax-absorbing paper is covered on the wafer, impurities may fall into the liquid wax, and the impurities move between the wafer and the ceramic disc during the tableting operation, and finally May cause abrasion of the wafer surface. Therefore, this embodiment changes the conventional idea that wax-absorbing paper is placed on the wafer in the prior art, and directly covers the wax-absorbing paper on the wafer plate, thereby avoiding that the impurities that may exist in the wax-absorbing paper have time to settle on the wafer. At the interface between the circle and the ceramic disc.

Embodiment Four

In order to understand the present invention more clearly, the fourth embodiment further illustrates the features of the present invention by giving specific examples of the effect diagrams during the bonding process. As shown in FIG. 4 , the wafers 12 are discretely arranged on the ceramic disc 14 (top view), and may also be arranged horizontally and/or vertically in specific implementations.

As shown in FIG. 5 , the wax paper 10 is used as the backing of the wafer 12 , and the wax-absorbing paper 16 is used, which is a side view of the wafer pressing operation.

As shown in Fig. 6, the wax paper 10 is not used, but the wax absorbing paper 16 is used, which is a side view of the sheet pressing operation.

Preferably, the wafer bonding process involved in the above embodiments is completed in a clean environment, such as an industrial clean room.

Those of ordinary skill in the art can also understand that all or part of the steps in the methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. Storage media, including ROM/RAM, magnetic disk, optical disk, etc.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (6)

1. A method for sticking LED wafers, characterized in that the method comprises: Place the wax on a ceramic plate and keep the wax in a liquid state by heating; Place the wafer regularly on a ceramic plate covered with liquid wax; Cover the wafer with wax-blotting paper; Carry out the tableting operation, and remove the wax blotting paper after the wax solidifies. 2. The method according to claim 1, wherein the wax is purified before being placed on the ceramic disc to remove impurities that may cause wear on the surface of the wafer. 3. The method according to claim 1 or 2, characterized in that, the process of sticking sheets is completed in a dust-free environment. 4. The method according to any one of claims 1-3, wherein when the wafer is discretely placed on the ceramic plate, before covering the wax-blotting paper on the wafer, it also includes: According to the cross-sectional area of the wafer to be polished, the wax-absorbing properties of the wax-absorbing paper, the area of the ceramic plate, and the amount of wax placed on the ceramic plate, calculate the size of the wax paper covering a single wafer, and cut out the wax paper according to this size. One or more wax-blotting papers covered on the wafer, and the cut-out wax-blotting papers are covered on each wafer. 5. A method for sticking LED wafers, characterized in that the method comprises: Place the wax on a ceramic plate and keep the wax in a liquid state by heating; Place the wafer regularly on a ceramic plate covered with liquid wax; Cover the surface of the plate with wax-blotting paper; Carry out the tableting operation, and remove the wax blotting paper after the wax solidifies. 6. The method according to claim 5, wherein the wax is purified before being placed on the ceramic disc to remove impurities that may cause wear on the wafer surface.